DLLT SERVMANUAL(770.00353).pdf

8/14/2019 DLLT SERVMANUAL(770.00353).pdf

1/295

DUAL LATEROLOG - MSFL TOOL

(DLLT-B)

SERVICE MANUAL

CONFIDENTIAL

December 1992

Manual Number 770.00353


2/295

NOTICE

All information contained in this manual is confidential and proprietary property of Halliburton

Energy Services, a division of Halliburton Company. Any reproduction or use of these instructions,

drawings, or photographs without the express written permission of an officer of Halliburton EnergyServices is forbidden.


3/295

REVISION RECORD

DUAL LATEROLOG - MSFL TOOL

(DLLT-B)Service Manual No. 770.00353

DATE DESCRIPTION

12/92 Initial manual release (NW)

01/95 Removed shop calibration and field check procedures from

the manual. Also made minor corrections and additions

throughout the manual. Manual is now Revision A.


4/295

DISCLAIMER

The drawings in this manual were the most recent revisions and the best quality available at the time

this manual was printed. We recommend that you check your manual for individual drawing clarity

and revision level. Should you have equipment with revisions later than the drawings in this manual,

or should you require higher quality drawings than the drawings in this manual, order replacements

from the Engineering Print Room in Houston.


5/295

i (Rev. 01/95)

CONTENTS

SECTION 1, GENERAL INFORMATION

No. Title Page

1.1 INTRODUCTION .................................................................................................... 1-1

1.2 EQUIPMENT DESCRIPTION ................................................................................ 1-2

1.3 DLLT-B TOOLSTRING, 3.01134 ........................................................................... 1-5

1.3.1 Cable Electrode Assembly, 3.60000 (3.10142 Optional) ........................................... 1-6

1.3.2 Power and Telemetry Section Assembly, 3.01132..................................................... 1-6

1.3.3 Isolation Sub Assembly, 3.39020............................................................................... 1-81.3.4 Measurement Section Assembly, 3.01133 ................................................................. 1-8

1.3.5 Electrode Sonde Assembly, 3.10510 ......................................................................... 1-8

1.3.6 MSFL Mandrel Assembly, 3.33175........................................................................... 1-9

1.3.7 Centralizer Equipment ............................................................................................... 1-9

1.3.8 MSFL Calibrator Box, 3.01209............................................................................... 1-10

1.3.9 Dual Laterolog Formation Simulator Set, 3.34254.................................................. 1-10

1.4 SPECIFICATIONS................................................................................................. 1-10


6/295

(Rev. 01/95) ii

CONTENTS (Continued)

SECTION 2, THEORY OF OPERATION

No. Title Page

2.1 PRINCIPLES OF OPERATION .............................................................................. 2-1

2.1.1 Nature of the Measurements...................................................................................... 2-1

2.1.2 Dynamic Focusing ..................................................................................................... 2-3

2.1.3 DLLT-B Depths of Investigation............................................................................... 2-5

2.1.4 MSFL Investigation................................................................................................... 2-7

2.2 POWER AND TELEMETRY SECTION OVERVIEW (3.01132)......................... 2-9

2.3 POWER SUPPLY BOARDS BLOCK DESCRIPTION........................................ 2-11

2.4 POWER SUPPLY BOARDS CIRCUIT DESCRIPTIONS................................... 2-13

2.4.1 +5-Vdc Rectifier/Filter Board (3.29710) ................................................................. 2-13

2.4.2 Dual!15-Vdc Rectifier/Filter Boards (3.29712)........................................................ 2-14

2.4.3 !15-Vdc Regulator Boards (3.29733) ....................................................................... 2-15

2.4.4 +40-Vdc Unregulated Board (3.29714)................................................................... 2-16

2.5 RTU/RTU I/F OVERVIEW.................................................................................... 2-17

2.6 REMOTE TELEMETRY UNIT (RTU)................................................................. 2-18

2.6.1 Block Description.................................................................................................... 2-18

2.6.2 Circuit Description................................................................................................... 2-23


7/295

iii (Rev. 01/95)


No. Title Page

2.7 RTU INTERFACE (RTU I/F) ................................................................................ 2-23


2.7.2 RTU I/F Analog Board Circuit Description............................................................. 2-25

2.7.3 RTU I/F Logic Board Circuit Description............................................................... 2-29

2.7.4 General Comments RTU I/F.................................................................................... 2-51

2.8 RELAY DRIVER BOARD (3.42022).................................................................... 2-53

2.9 REFERENCE COUPLING BOARD (3.42065)..................................................... 2-55

2.10 MEASUREMENT SECTION OVERVIEW (3.01133)......................................... 2-56

2.11 TOOL SWITCH POSITION BOARD (3.32045)................................................... 2-61


2.11.2 Switch Position........................................................................................................ 2-62


2.12 LATEROLOG OSCILLATOR BOARD (3.33947) ............................................... 2-65



2.13 POWER AMPLIFIERS .......................................................................................... 2-68

2.14 DUAL SONDE PREAMPLIFIER BOARD (3.33949).......................................... 2-70


8/295


9/295

v (Rev. 01/95)


No. Title Page

2.23 ELECTRODE SONDE........................................................................................... 2-96

2.24 MSFL AND CALIPER OVERVIEW..................................................................... 2-97

2.24.1 General Description ................................................................................................. 2-97

2.24.2 Detailed Description ................................................................................................ 2-97

2.25 CALIPER MEASUREMENT BOARD (3.02060)................................................. 2-99

2.26 OSCILLATOR BOARD (3.10467) ...................................................................... 2-101

2.27 POWER AMPLIFIER BOARD (3.10500) ........................................................... 2-103

2.28 PREAMPLIFIER BOARD (3.10506)................................................................... 2-105

2.29 FOCUS CONTROLLER BOARD (3.10502)....................................................... 2-107

2.30 MEASUREMENT BOARD (3.10504) ................................................................ 2-110


10/295

(Rev. 01/95) vi


SECTION 3, DISASSEMBLY AND ASSEMBLY

No. Title Page

3.1 INTRODUCTION .................................................................................................... 3-1

3.2 SPECIAL TOOLS AND SUPPLIES REQUIRED.................................................. 3-1

3.3 DISASSEMBLY....................................................................................................... 3-2

3.3.1 Power and Telemetry and Measurement Sections ..................................................... 3-2

3.3.2 Isolation Sub.............................................................................................................. 3-5

3.3.3 Electrode Sonde......................................................................................................... 3-63.3.4 Powered Mandrel..................................................................................................... 3-11

3.4 BRIDLE DISASSEMBLY/ASSEMBLY............................................................... 3-20

3.4.1 Cable Electrode Assembly (3.60000)....................................................................... 3-20

3.4.2 Rigid Bridle (3.10142) ............................................................................................. 3-20

3.5 ASSEMBLY ........................................................................................................... 3-24

3.5.1 Power and Telemetry and Measurement Sections ................................................... 3-243.5.2 Isolation Sub............................................................................................................ 3-26

3.5.3 Electrode Sonde....................................................................................................... 3-28

3.5.4 Powered Mandrel..................................................................................................... 3-32


11/295

vii (Rev. 01/95)


SECTION 4, CALIBRATION

No. Title Page

4.1 DLLT-B THEORY OF CALIBRATION................................................................. 4-1

4.1.1 DLLT-B..................................................................................................................... 4-2

4.1.2 MSFL Mandrel .......................................................................................................... 4-6

4.2 CALIPER THEORY OF CALIBRATION............................................................... 4-9

4.3 PREPARATION FOR CALIBRATION ................................................................ 4-10

4.3.1 Equipment Required ................................................................................................ 4-10

4.3.2 Formation Simulator Set (3.34254) ......................................................................... 4-10

4.3.3 Bridle (3.60000 or 3.10142) and Wireline Inspection.............................................. 4-10

4.3.4 Service Unit (Truck or Skid) ................................................................................... 4-12

4.4 CALIBRATION SET-UP....................................................................................... 4-13

4.4.1 Toolstring Assembly................................................................................................ 4-13

4.4.2 MSFL Calibrator/Formation Simulator Set.............................................................. 4-13

4.5 PERFORMING AND INTERPRETING THE SHOP

CALIBRATION...................................................................................................... 4-15


12/295

(Rev. 01/95) viii


SECTION 5, TROUBLESHOOTING AND REPAIR

No. Title Page

5.1 INTRODUCTION .................................................................................................... 5-1

5.2 REQUIRED TEST EQUIPMENT ........................................................................... 5-2

5.3 FOCUSING PROBLEMS......................................................................................... 5-3

5.3.1 Focusing Noise .......................................................................................................... 5-4

5.3.2 Focusing Offsets ........................................................................................................ 5-6

5.3.3 Open Control Loops.................................................................................................. 5-85.3.4 V0Measure Noise.................................................................................................... 5-10

5.3.5 Current Return Resistance....................................................................................... 5-11

5.4 V0MEASURE BOARD CHECKS......................................................................... 5-12

5.5 PREAMPLIFIER CHECKOUT ............................................................................. 5-14

5.5.1 Upper Preamplifier Checks ...................................................................................... 5-14

5.5.2 Lower Preamplifier Checks...................................................................................... 5-15

5.6 MONITOR AMPLIFIER BOARD CHECKS (Dual or Auxiliary)......................... 5-16

5.7 CONTROLLER BOARD CHECKS ...................................................................... 5-18

5.7.1 A* Controller Board Checks ................................................................................... 5-18

5.7.2 A3Controller Board Checks .................................................................................... 5-19

5.8 POWER AMPLIFIER AND OUTPUT

TRANSFORMER CHECKS .................................................................................. 5-21


13/295

ix (Rev. 01/95)


No. Title Page

5.9 I0MEASUREMENT BOARD CHECKS............................................................... 5-23

5.10 SWITCH POSITION BOARD CHECKS .............................................................. 5-26

5.11 DLLT-B OSCILLATOR BOARD CHECKS......................................................... 5-28

5.12 A0CONTROLLER BOARD CHECKS ................................................................. 5-29

5.13 MSFL MANDREL TROUBLESHOOTING......................................................... 5-31

5.14 PHASE DETERMINATION USING THELISSAJOUS FIGURES .......................................................................................... 5-33

5.15 TROUBLESHOOTING USING THE 1553 BUS TESTER.................................. 5-36

SECTION 6, REFERENCE MATERIAL

6.1 INTRODUCTION .................................................................................................... 6-1

6.2 PUBLICATIONS AND PROCEDURES LIST ....................................................... 6-1

6.3 TOOL PICK-UP AND ASSEMBLY INSTRUCTIONS ......................................... 6-2

6.4 OFFSET ADJUSTMENTS....................................................................................... 6-3

6.5 CORRECTION CHARTS ........................................................................................ 6-4

6.6 DLLT-B PROMS/EPLDS LISTS............................................................................. 6-5

6.7 DLLT-B O-RING LISTS........................................................................................ 6-12


14/295

(Rev. 01/95) x

CONTENTS (Concluded)

No. Title Page

6.8 ISOLATION SUB (3.39020) O-RING LIST ......................................................... 6-13

6.9 MSFL MANDREL ASSEMBLY O-RING LISTS ................................................ 6-14

6.10 RECOMMENDED SPARE PARTS LIST............................................................. 6-15

6.11 DLLT-B SPECIAL EQUIPMENT LIST ............................................................... 6-19

6.12 DLLT-B TEST FIXTURES LIST.......................................................................... 6-21

6.13 DLLT FORMATION SIMULATOR CHECKOUT .............................................. 6-22

6.14 MSFL CALIBRATOR CHECKS........................................................................... 6-54

6.15 THINGS TO KNOW.............................................................................................. 6-55

6.16 READER'S COMMENT SHEET........................................................................... 6-56


15/295

xi (Rev. 01/95)

EXHIBITS

No. Title Page

1-1 Tool Configuration, DLLT-B.................................................................................... 1-4

2-1 Principle of Dynamic Focusing .................................................................................. 2-3

2-2 Shallow Laterolog Current Flow ............................................................................... 2-6

2-3 Focusing, MSFL Investigation................................................................................... 2-8

2-4 Block Diagram, Power and Telemetry..................................................................... 2-10

2-5 Block Diagram, DLLT-B Power Supplies............................................................... 2-12

2-6 Schematic, +5-Vdc Rectifier/Filter Board................................................................ 2-13

2-7 Schematic, +15-Vdc Rectifier/Filter Board.............................................................. 2-14

2-8 Schematic, +15-Vdc Regulator Board..................................................................... 2-15

2-9 Schematic, +40-Vdc Unregulated Board................................................................. 2-162-10 Block Diagram, Remote Telemet Unit..................................................................... 2-19

2-11 Manchester Encoding Method................................................................................. 2-20

2-12 Word Formats.......................................................................................................... 2-21

2-13 PROM Header Jumpers........................................................................................... 2-22

2-14 Schematic, Sample and Hold Amplifier.................................................................... 2-28

2-15 Schematic, Clock Generator .................................................................................... 2-30

2-16 Timing Diagram, RTU I/F Logic Board .................................................................. 2-31

2-17 Schematic, Preset and Receive Control.................................................................... 2-32

2-18 Schematic, Transmit Control ................................................................................... 2-33

2-19 Schematic, Control/Status Register ......................................................................... 2-352-20 Schematic, Preset/ID Register ................................................................................. 2-37

2-21 Schematic, Data Acquisition Control....................................................................... 2-40

2-22 Schematic, Data RAM............................................................................................. 2-46

2-23 Timing Diagram, Power-Up Reset........................................................................... 2-47

2-24 Timing Diagram, Receive Control Word................................................................. 2-48

2-25 Timing Diagram, Transmit ID.................................................................................. 2-49

2-26 Timing Diagram, Transmit Data .............................................................................. 2-51

2-27 Block Diagram, Relay Driver Board........................................................................ 2-53

2-28 Schematic, Relay Driver Board................................................................................ 2-54

2-29 Schematic, Reference Coupling Board .................................................................... 2-55


16/295

(Rev. 01/95) xii

EXHIBITS (Continued)

No. Title Page

2-30 Block Diagram, Measurement Section .................................................................... 2-572-31 DLLT-B Electrode Current Supplies....................................................................... 2-58

2-32 Block Diagram, Tool Switch Position Board........................................................... 2-61

2-33 Schematic, Tool Switch Position Board .................................................................. 2-64

2-34 Block Diagram, Laterolog Oscillator Board ............................................................ 2-65

2-35 Schematic, Laterolog Oscillator Board.................................................................... 2-67

2-36 Simplified Schematic, A4+Power Amplifier ............................................................. 2-68

2-37 Interconnect Diagram, Laterolog Drive Transformes .............................................. 2-69

2-38 Block Diagram, Dual Sonde Preamplifiers............................................................... 2-70

2-39 Schematic, Dual Sonde Preamplifiers ...................................................................... 2-71

2-40 Block Diagram, Dual Monitor Amplifier ................................................................. 2-732-41 Schematic, Dual Monitor Amplifier Board .............................................................. 2-75

2-42 Block Diagram, A3Controller.................................................................................. 2-77

2-43 Schematic, A3Controller Board............................................................................... 2-79

2-44 Block Diagram, A* Controller Board...................................................................... 2-80

2-45 Schematic, A* Controller Board.............................................................................. 2-82

2-46 Schematic, A4Capacitor Board ............................................................................... 2-83

2-47 Block Diagram, Auxiliary Monitor Board ............................................................... 2-84

2-48 Schematic, Auxiliary Monitor Board ....................................................................... 2-86

2-49 Block Diagram, A0Controller Board....................................................................... 2-87

2-50 Schematic, A0Controller Board............................................................................... 2-882-51 Block Diagram, I0Measurement Board................................................................... 2-89

2-52 Schematic, I0Measurement Board........................................................................... 2-92

2-53 Block Diagram, V0Measurement Board ................................................................. 2-93

2-54 Schematic, V0Measurement Board......................................................................... 2-95

2-55 Block Diagram, MSFL and Caliper Section............................................................. 2-98

2-56 Block Diagram, Caliper Survey............................................................................... 2-99

2-57 Schematic, Caliper Measurement Board................................................................ 2-100

2-58 Block Diagram, Oscillator Board........................................................................... 2-101

2-59 Schematic, Oscillator Board................................................................................... 2-102

2-60 Block Diagram, Power Amplifier Board................................................................ 2-1032-61 Schematic, Power Amplifier Board........................................................................ 2-104

2-62 Block Diagram, Preamplifier Board....................................................................... 2-105


17/295

xiii (Rev. 01/95)

EXHIBITS (Concluded)

No. Title Page

2-63 Schematic, Preamplifier Board............................................................................... 2-1062-64 Block Diagram, Focus Controller Board ............................................................... 2-107

2-65 Schematic, Focus Controller Board....................................................................... 2-109

2-66 Block Diagram, Measurement Board .................................................................... 2-110

2-67 Schematic, Measurement Board ............................................................................ 2-111

3-1 Removing the DITS Connector from the Pressure Housing...................................... 3-4

3-2 Sonde A0Electrode Disassembly............................................................................... 3-7

3-3 Lower Hermetic Connector Area .............................................................................. 3-8

3-4 Sonde Hermetic Puller............................................................................................... 3-9

3-5 Upper Hermetic Connector Area............................................................................. 3-103-6 Installing the DITS Connector Into the Pressure Housing....................................... 3-25

4-1 DLLT-B/MSFL Mandrel Calibration Set-up........................................................... 4-14

5-1 A0Drive Equivalent Circuit ....................................................................................... 5-3

5-2 Example of Noise at TP1 and TP2 of DMA Board................................................... 5-6

5-3 V0Noise Sources..................................................................................................... 5-10

5-4 LLD Current Return Equivalent Circuit................................................................... 5-11

5-5 Monitor Board Test Setup....................................................................................... 5-17

5-6 Power Amplifier Circuitry........................................................................................ 5-225-7 Phase Measurement Using Lissajous Figures........................................................... 5-34

5-8 Measuring Peak-to-Peak Amplitudes of Composite Signals.................................... 5-35

6-1 PROM U19 (3.34552), RTU Data Board ................................................................. 6-6

6-2 PROM U13 (3.42264), RTU Data Board ................................................................. 6-7

6-3 PROM U1 (3.42165), Relay Driver Board................................................................ 6-8

6-4 PROM U2 (3.42126), RTU I/F Logic Board ............................................................ 6-9

6-5 PROM U5 (3.42128), RTU I/F Logic Board .......................................................... 6-10

6-6 EPLD U1 Driver-Enabled States............................................................................. 6-11


18/295

(Rev. 01/95) xiv

TABLES

No. Title Page

1-1 Laterolog Electrode Array......................................................................................... 1-91-2 MSFL Pad Array..................................................................................................... 1-10

2-1 Channel Assignments, DLLT-B............................................................................... 2-26

2-2 State of Switches and Resultant Gain of U3 ............................................................ 2-27

2-3 Signal Ranges and Resolutions, RTU I/F Analog Board ......................................... 2-28

2-4 Control PROM Byte Format ................................................................................... 2-39

2-5 Map PROM and Multiplexer Address 01 ................................................................ 2-41

2-6 Map PROM Byte Format ........................................................................................ 2-42

2-7 Acquisition Control Circuit Control States .............................................................. 2-43

2-8 Read Cycle Circuit Control States ........................................................................... 2-442-9 Stored Data Locations............................................................................................. 2-45

2-10 MAP PROM Maps and Channels Acquired ............................................................ 2-52

2-11 EPLD U1 Driver Assignments................................................................................. 2-62

2-12 Integrator Responses ............................................................................................. 2-107

4-1 Apparent Resistance and Telemetry Gain Ranges...................................................... 4-3

4-2 Nominal Values of Simulated Formation Resistivities................................................ 4-4

4-3 Bridle Continuity Checks ......................................................................................... 4-11

4-4 Bridle Bell Housing Leakage Check ........................................................................ 4-12

5-1 Power Amplifier Check Points................................................................................... 5-8

5-2 Outputs For Relay Drivers and Analog Switch Drivers........................................... 5-27

5-3 Sample calibration Box Values ................................................................................ 5-31


19/295

xv (Rev. 01/95)

TABLES (Concluded)

No. Title Page

6-1 DLLT-B PROMs/EPLDs.......................................................................................... 6-56-2 3.01132 Power and Telemetry Section O-rings....................................................... 6-12

6-3 3.01133 Measurement Section O-rings.................................................................... 6-12

6-4 3.10510 Electrode Sonde O-rings............................................................................ 6-12

6-5 3.39020 Isolation Sub O-rings................................................................................. 6-13

6-6 3.33175 MSFL Mandrel Assembly O-rings............................................................. 6-14

6-7 DLLT-B Recommended Spare Parts List................................................................ 6-15

6-8 DLLT-B Special Equipment List ............................................................................. 6-19

6-9 Pair-wise Terminal Resistance, 1-Ohmmeter Box.................................................... 6-22

6-10 Pair-wise Terminal Resistance, 100-Ohmmeter Box................................................ 6-30

6-11 Pair-wise Terminal Resistance, 1,000-Ohmmeter Box............................................. 6-386-12 Pair-wise Terminal Resistance, 10,000-Ohmmeter Box........................................... 6-46

6-13 MSFL Calibrator Tolerances ................................................................................... 6-54


20/295

1-1 (Rev. 01/95)

SECTION 1

GENERAL INFORMATION

1.1 INTRODUCTION

This technical manual provides theory of operation and maintenance for the Dual Laterolog - MSFL

Tool (DLLT-B). Study the manual closely to develop a thorough understanding of the equipment

before operating or servicing for the first time. Observe all precautionary notes to minimize the risk

of either personal injury or equipment damage.

Tabbed contents sheets physically divide the manual into six sections.

Section 1, General Information, discusses the scope and arrangement of the manual, describes

the tool and explains its purpose, and lists equipment specifications.

Section 2, Theory of Operation, presents the principles of operation of the DLLT-B. It also

includes a functional description of the hardware accompanied by block diagrams and detailed

circuit descriptions.

Section 3, Disassembly/Assembly, contains step-by-step disassembly and assembly procedures

for the DLLT-B. A list of special tools and equipment required to disassemble and assemble

the DLLT-B is also provided.

Section 4, Calibration, contains theory of calibration and a list of calibration equipment with

applicable set-up and verification.

Section 5, Troubleshooting, contains a series of circuit checks complete with corresponding

values (voltage, resistance, etc.). These checks are provided to help isolateelectrical/electronic faults to a repairable level. A list of test equipment along with

appropriate set-up also is provided.


21/295

(Rev. 01/95) 1-2

Section 6, Reference Material, contains material which may be helpful during operation,

maintenance, and troubleshooting of the Dual Laterolog - MSFL Tool. A Reader's Comment

sheet on which you can comment about errors or omissions in the manual is also included.

1.2 EQUIPMENT DESCRIPTION

The DLLT-B (Exhibit 1-1) is a subsurface electric logging tool that provides signals which are

processed to produce four logs: three resistivity logs and a caliper log. The resistivity measurements

are a deep investigation laterolog curve, a shallow investigation laterolog curve, and a micro-

spherically focused log (Rxo) curve.

The signals which the DLLT-B inputs to the telemetry system are voltages representing seven analog

parameters:

Deep survey current (I0d)

Deep survey voltage (V0d)

Shallow survey current (I0s)

Shallow survey voltage (V0s)

MSFL survey current (IA)

MSFL survey voltage (VE)

Caliper potentiometer voltage (CALP)

The deep and shallow laterolog logs together with the MSFL log provide an indication of true

formation resistivity (Rt). The three logs can be used to determine resistivity profiles around the

borehole, resulting in more accurate determination of Rtwhen appreciable invasion of drilling-mud

filtrate in the formation is encountered.

The MSFL curve is a measurement of the resistivity of the flushed zone (Rxo), the zone adjacent to the

wellbore, in which drilling-mud filtrate has displaced formation fluids. The deep and shallow apparent

resistivities (LLS and LLD), together with the MSFL measurement of Rxo, are sufficient to determine

the true formation resistivity (Rt) and the depth of invasion. Depth of invasion is obtained using the

invasion correction chart (see Subsection 6.5). Together with the mud-filtrate resistivity, the Rxo

measurement provides an indication of the formation factor and an indication of porosity, through use

of the Archie equation.


22/295

1-3 (Rev. 01/95)

Used in conjunction, the three resistivity curves (deep, shallow and Rxo) can indicate the presence of

movable hydrocarbons in the formation. In a water zone, where the resistivity of the mud filtrate is

nearly equal to the resistivity of the formation water, the curves of the deep laterolog, shallow

laterolog, and MSFL are nearly the same. In an oil zone under similar conditions, the MSFL log still

measures resistivity of the zone containing mud filtrate, while the deep and shallow laterologinvestigations are affected by the higher resistivity of the undisturbed oil bearing zone. Delineation

between oil and water zones remains readily apparent so long as the resistivity of the mud filtrate is

no more than three or four times the resistivity of the formation water.

The borehole diameter measurement provided by the caliper survey is used to make borehole effect

corrections for the deep and shallow laterolog curves. The caliper curve is also useful for calculating

cement volume requirements, determining the presence and thickness of mud cake, selecting packer

seats, etc.


23/295

(Rev. 01/95) 1-4

Exhibit 1-1: Tool Configuration, DLLT-B


24/295

1-5 (Rev. 01/95)

1.3 DLLT-B TOOLSTRING, 3.01134

A typical DLLT-B toolstring consists of the following functional components, listed in descending

order from the top of the string (See Exhibit 1-1):

Cable Electrode Assembly, 3.6000 (Optional rigid cable electrode 3.10142)

DSTU-B, 3.34839 (The subsurface telemetry unit is not a part of the DLLT-B, but it is

necessary for tool operation.)

Optional tools. Any optional survey tools (usually the NGRT-A) that are run with the

DLLT-B are inserted into the toolstring here.

Power and Telemetry Section Assembly, 3.01132

Centralizer Equipment, 3.35130 and 3.07055

Isolation Sub Assembly, 3.39020

Measurement Section Assembly, 3.01133

Electrode Sonde Assembly (Laterolog Sonde), 3.10510

MSFL Mandrel Assembly, 3.33175

The DLLT-B also requires the use of the HLS standard surface reference electrode. This electrode is

commonly referred to as the "N" electrode or "the fish" and should be separate from the SP reference

electrode.

Although not part of the toolstring, the MSFL Calibrator (3.01209) and DLLT-A Dual Formation

Simulator Set (3.34254) are required for DLLT-B - MSFL calibration.


25/295

(Rev. 01/95) 1-6

1.3.1 Cable Electrode Assembly, 3.60000 (3.10142 Optional)

The Cable Electrode Assembly is a 90-foot long (the optional rigid cable electrode is 63.5-feet long)

disconnectable, sleeve-insulated assembly. It consists of a connector (called the "torpedo") whichcouples the DLLT-B to the seven-conductor (7C) wireline cable running to the surface

instrumentation in the truck, an insulated length of 7C cable containing two electrodes, and a bell

housing that connects it to the DSTU. One of the electrodes serves as the remote current return

electrode for the deep laterolog. The other electrode serves as the SP-survey electrode, if that option

is run.

The Cable Electrode Assembly connects the logging cable mechanically and electrically to the

downhole toolstring consisting of the DSTU, any optional tools, and the DLLT-B at the bottom of

the string. More important, the Cable Electrode Assembly provides sufficient insulation between the

current return electrode and the Laterolog Sonde to minimize distortion of the required current flow

patterns (out in the formation) for the deep laterolog investigation.

The cable electrode bell housing contains a passive notch filter to suppress the shallow frequency

(1050 Hz) component of the DITS telemetry.

The Rigid Cable Electrode (3.10142) is available as an option.

1.3.2 Power and Telemetry Section Assembly, 3.01132

The Power and Telemetry Section Assembly consists of the dc-power supply package, the Remote

Telemetry Unit, the RTU interface (RTU I/F), and the mandrel arms open/close controller. The top

of the Power and Telemetry Section Assembly connects to the bottom of the DSTU. The bottom of

the Power and Telemetry Section Assembly connects to the Isolation Sub.


26/295

1-7 (Rev. 01/95)

Power Supply

The power supply package, located in the upper two thirds of the Power and Telemetry Section

Assembly, provides the following voltage supplies:

Dual!15-Vdc regulated supplies

+5-Vdc regulated supply

+40-Vdc unregulated relay supply

Remote Telemetry Unit (RTU)

The Remote Telemetry Unit (RTU) is a standard two-board set: the RTU Control board (3.30920)

and RTU Data board (3.30921). These boards, together with the RTU Interface (RTU I/F), serve as

the digital data communication link between the DSTU and the DLLT-B. The RTU receives

operational commands from the DSTU which place the DLLT-B in its various modes of operation,

and it sends digitized telemetry data up to the DSTU.

RTU Interface

The RTU I/F consists of two circuit board assemblies: the RTU Analog I/F board (3.29786) and RTU

Logic I/F board (3.30477). These boards digitize the measured signal data and pass them to the

RTU. The RTU I/F also passes commands from the logging system to the tool switch position

circuits.

Mandrel Arms Controller

The mandrel arms controller extends (opens) and retracts (closes) the arms on the MSFL Mandrel. If

instrument power is lost, the mandrel arms will retract upon application of 400-Hz power at the

surface.


27/295

(Rev. 01/95) 1-8

1.3.3 Isolation Sub Assembly, 3.39020

The Isolation Sub Assembly is installed between the Power and Telemetry Section Assembly and the

Measurement Section Assembly to break electrical continuity between the electronics housings. The

sub has 37-pin connectors at the top and bottom and is wired one-to-one.

1.3.4 Measurement Section Assembly, 3.01133

The Measurement Section Assembly contains the majority of the circuitry to perform the LLD, LLS

and MSFL surveys. The top of this section connects to the bottom of the Isolation Subassembly.

The bottom connects to the top of the Electrode Sonde Assembly (laterolog sonde).

1.3.5 Electrode Sonde Assembly, 3.10510

The Electrode Sonde Assembly (laterolog sonde) consists of a Crossover Sub Assembly (3.39113),

the deep and shallow electrode array, the deep and shallow preamplifiers, and the bellows assemblies.

The laterolog sonde consists of 13 electrodes (Survey, Guard, and Monitor) separated by rubber

insulating material. Table 1-1 lists the 13 electrodes and their functions.


28/295

1-9 (Rev. 01/95)

Table 1-1: Laterolog Electrode Array

Electrode Function

A0 Survey-current emitting electrode for both deep and shallow investigations

A3+, A3- Guard electrodes for both deep and shallow investigations

A4+, A4- Guard electrodes for deep investigation and current return electrodes for the shallow

investigation

M1+, M1- Monitor electrodes for both the deep and shallow investigations

M2+, M2- Monitor electrodes for shallow investigation and formation voltage

M3+, M3- Monitor electrodes for deep investigation

A*+, A*- Monitor electrodes for deep investigation

1.3.6 MSFL Mandrel Assembly, 3.33175

The MSFL Mandrel Assembly consists of an upper pressure-equalized section and a lower section

with two retractable arms. The upper section contains the piston-type pressure equalization

mechanism, the arm actuating motor, the caliper potentiometer, and the ball-screw actuator. Pads are

mounted on the arms of the lower section. One of the pads is the MSFL electrode array (5 concentric

rings). Table 1-2 lists the MSFL electrodes. The other pad is a wear shoe. The top of the mandrelconnects to the laterolog sonde. The bottom of the mandrel is the bottom of the tool string.

1.3.7 Centralizer Equipment

Centralization equipment for the DLLT-B toolstring consists of a slip-over centralizer (3.35130) and

a 8-fin rubber standoff (3.07055). The slip-over centralizer is normally installed on the Power and

Telemetry Section above the isolation joint. The 8-fin rubber standoffs are usually installed between

the A4!and A*! electrodes on the sonde. A rubber standoff may also be installed in place of the

slip-over centralizer when restrictive borehole conditions are present. The standoffs can be trimmed

to fit various borehole sizes.


29/295

(Rev. 01/95) 1-10

Table 1-2: MSFL Pad Array

Electrode Function

A0 Survey-current emitting electrode for the MSFL

M0 Voltage monitor electrode

A1 Focusing electrode

M1 Monitor electrode

M2 Monitor electrode

1.3.8 MSFL Calibrator Box, 3.01209

The MSFL Calibrator Box is used to perform shop calibrations on the MSFL circuitry. The calibrator

connections are made to the pad rings and the mandrel housing with a special contact fixture that is

included with the calibrator box. A switch is used to select from a network of resistors, which

simulate electrical loading of the MSFL pad, corresponding to various resistivities.

1.3.9 Dual Laterolog Formation Simulator Set, 3.34254

The DLLT-A Formation Simulator set is also used for DLLT-B. It consists of five networks that are

used to implement shop calibration of the Dual Laterolog measurements. Each resistor network

simulates a 0.1 ohmmeter (ohm-m), 8-inch diameter borehole resistivity, and a particular formation

resistivity (1, 10, 100, 1,000, or 10,000 ohmmeters). Each resistor network electrically simulates the

corresponding borehole-formation impedance between all electrode pairs.

1.4 SPECIFICATIONS

See next two pages for the current Tool Technical Specifications data:

.


30/295

H A L L I B U R T O N

Revised 02/2000

Dual Laterolog Logging Tool (DLLT-B)Tool Part Number: 100129973 DIMENSIONS AND RATINGS

Max Temp: 350F (177C) Max Press: 20,000 psi (137,895 Kpa)

Max OD: 3.63 in (9.27 cm). Min Hole: 4.5 in (11.4 cm).

Length*: 33.25 ft (10.13 m) Max Hole: 24 in (61 cm)

Weight: 400 lb (182 Kg)

* Without MSFL assembly. If the MSFL assembly is not used, a 3.63-in. (9.22 cm) -

OD assembly of the same length as the MSFL assembly must be attached to the

lower end of the DLLT-B sonde.

BOREHOLE CONDITIONSBorehole Fluids: Salt Fresh Oil Air

Recommended Maximum Logging Speed: 100 ft/min (60 ft/min with MSFL)

30.48 m/min (18.28 m/min with MSFL)

Tool Positioning: Centralized Eccentralized

HARDWARE CHARACTERISTICSSource Type: 131.25-Hz (LLd) and 1,050-Hz (LLs) coil arrays

Sensor Type: Four sets of monitor electrodes

Sensor Spacings: Proprietary

Sampling Rate: 4 or 10 samples/ft

No. Windows: na Full Spectrum: na

Combinability: DITS-combinable (requires a maximum of 30 words per frame)

MEASUREMENTDeep Medium

Principle Laterolog Laterolog

Range 0.2 to 40,000 ohmm 0.2 to 2,000 ohmm

Vertical Resolution (90%) 24 in. (61 cm) 24 in. (61 cm)

Depth of Investigation (50%) 60 to 84 in.

(152 to 213 cm)

24 to 36 in.

(61 to 91 cm)

Sensitivity 1% of reading 1% of reading

Accuracy, the greater of 2% or 0.2 ohmm 2% or 0.2 ohmm

Primary Curves LLd, LLs

Secondary Curves SP

CALIBRATION

Primary: Resistor networkSecondary: Resistor networkWellsite Verifier: Internal calibration

PHYSICAL STRENGTHS*

Hardware Tension Compression Torque

Tool 130,000 lb

(59,000 Kg)

130,000 lb

(59,000 Kg)

600 lb-ft.

(815 N-m)

Otherna na na* Stregnths apply to new tools at 70F (21C) and 0 psi.

** As low as 11,000 lb (4,990 Kg) in washouts

Measurement

Assembly

Sonde

Assembly

Power andTelemetry

Section

Isolation

Subassembly

3.63 in.

39

9.0 in.

108.0 in.

177.0 in.

96.0 in.

18.0 in.

MEASURE POINTSMeasurement Measure Point

(Referenced from bottom of tool)

LLd* 19 ft. (5.79 m)

LLm* 19 ft. (5.79 m)

SP** (Rigid bridle) 2.96 ft.(0.9 m)

* This distance includes a 122-in. assembly (not shown) that must be attached to

the bottom of the DLLT-B if the MSFL is not run.

** The SP measure point is referenced from the bottom of the cable electrode. This

distance does not include the length of the DLLT-B or other tools in the string..


31/295

H A L L I B U R T O N

Revised 12/99

Micro Spherically Focused Log Tool (MSFL)Tool Part Number: 3.33175

DIMENSIONS AND RATINGSMax Temp: 350F Max Press: 20,000 psi

Max OD: 5 in. Min Hole: 6 in.Length: 10.18 ft Max Hole: 20 in.

Weight: 214 lb

BOREHOLE CONDITIONS

Borehole Fluids: Salt Fresh Oil Air

Recommended Maximum Logging Speed: 60 ft/min

Tool Positioning: Centralized Eccentralized

HARDWARE CHARACTERISTICS

Source Type: 960-Hz electrode array

Sensor Type: Electrode array

Sensor Spacings: na

Firing Rate: naSampling Rate: 4 or 10 samples/ft

No. Windows: na Full Spectrum: na

Combinability: DLLT-B

MEASUREMENT

Principle: Focused microresistivity

Range: 0.2 to 2,000 ohmm

Vertical Resolution: 3 in.

Depth of Investigation (50%): 1 to 4 in.

Sensitivity 1% of reading

Accuracy: 7% or 0.1 ohmm, whichever is greater

Primary Curves: MSFL

Secondary Curves: Caliper

CALIBRATION

Primary: Resistor network, gauge ringSecondary: Resistor network, gauge ringWellsite Verifier: Internal calibration

PHYSICAL STRENGTHS*

Hardware Tension Compression Torque

Tool Joints na na na

Other na na na

* Strengths apply to new tools at 70F and 0 psi.

MSFL

Mandrel

4.0 in.

122.3 in.

73.7 in.

48.6 in.

3.63 in.

4.0 in.

3.63 in.

MEASURE POINTSMeasurement Measure Point

(Referenced from bottom of tool)

MSFL 32 in.

Caliper 32 in.


32/295


33/295


34/295

2-3 (Rev. 01/95)

Exhibit 2-1: Principle of Dynamic Focusing

2.1.2 Dynamic Focusing

Exhibit 2-1 illustrates how the laterolog electrode array prevents the deep (LLD) survey current from following the

path of least resistance up and/or down the borehole fluid, by focusing this current into the formation.

An ac voltage (VA0) applied across the central electrode (A0) and a remote current return electrode (B) causes

survey current I0to flow through the formation toward the return electrode.

Similarly, an ac voltage VA4+ is applied between the upper focusing electrode (A4+) and the remote current

return electrode (B).

Finally, an ac voltage (VA4-) is applied between the lower focusing electrode (A4-) and the remote current

return electrode (B).


35/295

(Rev. 01/95) 2-4

The three voltages at A0, A4+, and A4- are applied in phase and have approximately the same magnitude. Since the

voltages are in phase, the focusing currents repel the survey current from the A0 electrode, forcing it to flow in a

relatively thin horizontal layer (approximately 2-feet thick) at right angles to the borehole before it begins to flow

toward the remote current-return electrode (B).

Electrodes A3+and A3- are also used to focus current into the formation. A vernier voltage is applied to A3+with

respect to A4+, keeping these two electrodes at approximately the same potential (the vernier voltage is small with

respect to the voltage on A4+ and A3+ with respect to B). Similarly, a small vernier voltage is applied to A3-withrespect to A4-, keeping these two electrodes at the same potential.

To keep electrodes A3+, A3-, A4+, and A4-at the correct potentials (those potentials which keep I0focused as a relatively

thin horizontal layer) as the tool moves upward through the successive formation beds during logging, sets of monitor

electrodes are used, positioned as shown in Exhibit 2-1. If a potential difference is sensed across a set of monitor

electrodes (M1/M3or A4/A*), it indicates that current is straying up or down the borehole. The potential of the guard

electrodes is increased or decreased to maintain the focused path of survey current I0into the formation, maintaining

essentially a zero voltage drop (or gradient) across each of the four pairs of monitor electrodes. If I0starts to flow up

toward A3+, the voltage at electrode M1+ becomes larger than the voltage at electrode M3+. In this case, the A*

controller increases the voltage applied to A3+and A4+. These increased potentials tend to push the survey currentdown, restoring to zero the potential difference at the M1+/M3+pair.

If I0starts to flow down toward A3-, the voltage at electrode M3-becomes smaller than the voltage at electrode M1-. In

this case, the A* Controller increases the potential at A4-and A3-until zero gradient is restored at the M1-/M3-pairs.

If a potential difference is sensed at the A*/A4+electrode pair, the A3Controller adjusts the relative potential difference

between A4+ and A3+. Any necessary adjustment of the A4+ and A3+ potential, to keep M1+/M3+ at zero, is

simultaneously performed by the A* Controller.


36/295

2-5 (Rev. 01/95)

Similarly, if a potential difference is sensed at the A*- and A4- electrode pair, the A3Controller adjusts the relative

potential difference between the A4-/A3- electrodes. Simultaneous adjustment, if necessary, is made by the A*

Controller to regulate the M1-/M3-potential difference to zero.

The survey voltage, V0, between a downhole electrode (M2-) and a remote surface electrode (N) is measured to

calculate the resistivity. The voltage is not measured with respect to B because the potential at B, relative to N, is

influenced by the resistivity of the bed opposite B (e.g. Delaware Gradient effect), the proximity of casing, and the mud

resistivity.

The survey current (I0) from the current transformer is emitted from the A0 electrode and is measured by the I0

Amplifier.

2.1.3 DLLT-B Depths of Investigation

The DLLT-B performs resistivity measurements with three different depths of investigation into the formation. These

three resistivities are used to obtain true formation resistivity (Rt) and the invasion diameter (di). The three depths o

investigation are:

Approximately 5 - 7 feet into the formation (deep laterolog investigation)

Approximately 2 - 3 feet into the formation (shallow laterolog investigation)

Flushed zone (Rxo), a few inches into the formation (MSFL investigation)

The deep (LLD) and shallow (LLS) investigations, are performed simultaneously, using common electrodes. The LLD

and LLS share some of their electrodes on a common sonde, but are electrically operated to minimize the effects of one

upon the other. The circuits of the deep investigation operate at a frequency of 131.25 Hz, while the circuits of theshallow investigation operate at a frequency of 1050 Hz. Operating the electrodes at different frequencies allows

non-interacting measurements of the relatively deep and shallow resistivities. Harmonically related measurement

frequencies provide voltage or current measurement extraction at each separate frequency from a composite two-tone

waveform.


37/295

(Rev. 01/95) 2-6

The previous discussion (2.1.2) relates the operation of the LLD, and how dynamic focusing is accomplished to

regulate four focusing-electrode potentials at A3+, A3-, A4+, and A4-.

The shallow investigation functions similar to the deep, but uses two guard electrodes instead of four (see Exhibit 2-2)

The outermost deep guard electrodes (A4+/A4-) are utilized as close-spaced return electrodes for the shallow

investigation.

Exhibit 2-2: Shallow Laterolog Current Flow


38/295

2-7 (Rev. 01/95)

The potential at the two LLS guard electrodes A3+ and A3-are controlled by the A3Controller so that the M1/M2

potential differences at 1050 Hz are regulated to zero. The LLS currents from A0and the A3electrodes return to the

A4 electrodes. Since the return electrodes are relatively close to the A0 electrode, less focusing distance into the

formation is achieved. The reduction in the guard electrode length for the LLS, as compared to LLD, produces a

shallower investigation.

The use of voltage monitoring electrodes (which do not emit current and separate current-emitting electrodes), in

combination with the precision feedback control, minimizes the adverse effects due to electro-chemical reaction at theelectrode surfaces. This electro-chemical reaction can deteriorate simpler guarding arrangements (e.g. M904 Dua

Guard). The shallow investigation is performed by moving the current return close to the guarded electrodes. Thi

arrangement retains borehole guarding to a greater degree than can be obtained with a shallow guard measurement

system where the degree of focusing alone is decreased to provide a shallow investigation means.

2.1.4 MSFL Investigation

The Micro-Spherically Focused Log (MSFL) investigation is made by pad-mounted current electrodes to achieve a

spherically focused survey current that is dynamically maintained (see Exhibit 2-3). The MSFL measurement involvesonly the first few inches of the formation adjacent to the borehole (the flushed zone), in which drilling fluid has

displaced all formation fluids. The MSFL provides a measurement of the flushed zone resistivity (Rxo), with low

mudcake correction. The electrodes for the MSFL device are located on a pad-mounted array, which is in turn is

located on a powered caliper arm at the bottom of the tool.

The MSFL measurement electrode array consists of a survey current electrode (A0), a voltage monitor electrode (M0)

a current electrode A1), and two focus monitor electrodes M1 and M2). These electrodes are configured as five

concentric rectangular rings on the pad. When the flexible pad is pressed against the borehole wall (to minimize the

borehole affects on the resistivity measurement), the A0electrode emits current directly into the formation, returning to

the mandrel body (current return) and to the A1) electrode. Only the survey current Is) is measured, although thefocusing current (If) is also emitted from the A0) electrode (returning to A1). Any potential difference between monitor

electrodes M1and M2 is detected and adjusts the drive amplitude to the A1 electrode to correct for the error, thus

dynamically focusing the survey current around the monitor pair. The focusing monitors (M1and M2) are located

outside the focusing ring (A1), between the A1electrode and the current return (mandrel body). The measured voltage

between the M0electrode and the M1/M2transformer center tap are on surfaces of equal potential which approximated

hemispherical shape. This voltage measurement excludes the region immediately adjacent to the A0electrode, thus

minimizing borehole fluid and mudcake influences on this resistivity measurement.


39/295

(Rev. 01/95) 2-8

Exhibit 2-3: Focusing, MSFL Investigation


40/295

2-9 (Rev. 01/95)

2.2 POWER AND TELEMETRY SECTION OVERVIEW(3.01132)

The Power and Telemetry (P&T) Section (Exhibit 2-4) of the DLLT-B provides low-voltage power to the

measurement section of the tool string. The P&T section also contains signal digitizing circuitry, an RTU, and a

400-Hz control circuit (for the MSFL Mandrel).

60-Hz instrument power from the service unit is applied to the toolstring on conductors 1, 2, 4, and 5 of the

7-conductor cable. The 60-Hz power is applied to conductor 1 with respect to 2 and conductor 4 with respect toconductor 5. 400-Hz auxiliary power to run the MSFL Mandrel is applied to the tool by driving conductors 1 and 2

against conductors 4 and 5. Transformers T1, T2, and T3 provide low voltage 60-Hz power to the 5-Vdc and 15-Vdc

supplies in the P&T section. Transformer T3 has a center-tapped primary to couple the 400-Hz power from the cable

to the mandrel motor control circuitry (K1, K2, etc.). The 400 Hz over-voltage protection circuit consists of a

saturable reactor (L7), which limits the 400-Hz voltage amplitude present on the logging cable and tool conductors,

when the MSFL mandrel motor switches out of the circuit at the end of travel. The P&T section provides two

independent"15-Vdc supplies and a +5-Vdc supply for operation of the Measurement Section. An unregulated 40-Vdc

supply is used to energize all relays in the Power and Telemetry sections. Unregulated +15-Vdc energizes

Measurement section relays.

Communications between the BCU and the DLLT-B is accomplished with a standard RTU over a serial-data 1553

Bus. The tool order function of the RTU boards is disabled in the DLLT-B.

Analog data from the measurement section is digitized by the RTU Analog Interface. Digitized data is stored by the

RTU Logic Interface, which transmits data to the RTU upon request.

The RTU Logic Interface contains a control register, which stores the last word received by the DLLT-B from the

BCU. This data word is utilized by the DLLT-B to determine the desired mode of operation for the tool (LOG

OPEN MANDREL, etc.)

Cable conductors 3 and 6 are coupled together in the P&T section through capacitors to form a V 0 reference

conductor for the measurement section.


41/295

(Rev. 01/95) 2-10

Exhibit 2-4: Block Diagram, Power and Telemetry


42/295

2-11 (Rev. 01/95)

2.3 POWER SUPPLY BOARDS BLOCK DESCRIPTION

Power for the DLLT-B is provided by the 60-Hz instrument power. The power supply package,

located in the Power and Telemetry Section, provides the tool with four voltage supplies, as follows:

Dual"15-Vdc regulated supplies (650 milliamperes)

+5-Vdc regulated supply (250 milliamperes)

+40-Vdc unregulated supply (110 milliamperes)

Exhibit 2-5 is the block diagram of the power supply. Except for the unregulated +40 Vdc supply, the

voltage supplies follow the standard design of transformer, rectifier/filter, regulator/filter. One of the

15-Vdc dual supplies is connected in common to the +5-Vdc and the +40-Vdc supplies. The other"15-

Vdc dual supply is independently grounded in the measurement section.

The two"15-Vdc supplies, used to power the laterolog and MSFL measurement circuitry, receive input

power from the secondary winding of transformer T1. Both the positive and negative supplies use the

same regulator structure, with the output of the negative regulator grounded to provide the -15-Vdc.

The +5-Vdc supply, used primarily for logic, receives its input from the secondary winding of

transformer T3. The +40-Vdc supply, used to energizing the K1 and K2 relays (located in the Power

and Telemetry Section 3.42081), receives its input power from a secondary of transformer T3.


43/295

(Rev. 01/95) 2-12

Exhibit 2-5: Block Diagram, DLLT-B Power Supplies


44/295

2-13 (Rev. 01/95)

2.4 POWER SUPPLY BOARDS CIRCUIT DESCRIPTIONS

The INSTRUMENT configuration supplies instrument power and the AUXILIARY configuration

supplies 400-Hz motor auxiliary power to operate the MSFL Mandrel motor. Instrument power to

transformers T1 and T2 (two R-1163's and an R-1184) appears on pins J1-13, 14, 16, 19 of the 19-pin

connector. J1-16 and J1-19 have 120 VRMS applied between them. An independent 120 VRMS

appears between J1-13 and J1-14. Auxiliary power appears between the pairs J1-13, 14 and J1-16, 19.

The power supply package in the Power and Telemetry Section (3.01132) provides six dc-voltage

supplies: two"15-Vdc regulated, 650-Ma supplies, a +5-Vdc regulated, 250-mA supply, and a +40-Vdc

unregulated, 110-mA supply.

2.4.1 +5-Vdc Rectifier/Filter Board (3.29710)The +5-Vdc Rectifier/Filter board (3.29710) is used primarily for logic. Exhibit 2-6 is the schematic

for the +5-Vdc Rectifier/Filter board. It receives input power from a secondary winding of transformer

T3 (R-1164). A full-wave bridge, consisting of diodes CR1, CR2, CR3, and CR4, rectifies the ac

voltage. Inductor L3 (C-1137), capacitors C1, C2, C5, and resistor R2 form a choke-input filter to

smooth the rectified ac voltage from CR1-CR4. Voltage regulator Q5 uses the input dc voltage to

maintain a constant 5-Vdc output. Diode CR5 protects Q5 against reverse voltage. Resistor R1

discharges output filter capacitors C3 and C4 and establishes critical load current in the filter inductor.

Exhibit 2-6: Schematic, +5-Vdc Rectifier/Filter Board


45/295

(Rev. 01/95) 2-14

2.4.2 Dual 15-Vdc Rectifier/Filter Boards (3.29712)

The two"15-Vdc Rectifier/Filter boards power the laterolog instrument sections. Both the positive and

negative supplies utilize the same regulator structure. The output of the negative regulator is grounded

to obtain the -15 volts.

Exhibit 2-7 is the schematic for the"15-Vdc Rectifier/Filter board. The unregulated +15-Vdc circuitry

receives input power from a secondary winding of transformer T1. A full-wave bridge consisting of

diodes CR1, CR2, CR3, and CR4 rectifies the ac voltage. Choke L1 (C-1136) smoothes the rectified

voltage, and capacitors C1, C2, C3, and C4 provide filtering. Resistor R1 establishes critical load

current through the choke L1. The unregulated dc output is used as an input voltage source by the"15-

Vdc Regulator board. The circuitry for the unregulated -15-Vdc supply is identical except that the

output is grounded to obtain the -15-Vdc.

Exhibit 2-7: Schematic, +15-Vdc Rectifier/Filter Board


46/295

2-15 (Rev. 01/95)

2.4.3 15-Vdc Regulator Boards (3.29733)

Operation of the two 15-Vdc Regulator boards are identical. Exhibit 2-8 is the schematic of the+15-Vdc Regulator boards. Rectified and filtered dc is supplied to the source (terminal 6) of the

series-pass regulator Q1 (IFR 9130). Conduction of Q1 is controlled by increasing or decreasing the

gate voltage (terminal 1) with respect to the source (terminal 6). This gate/source voltage controlling

Q1 is determined by the current through R6, which is the collector current of transistor Q2

(2N2895A). A resistor/divider network (R10, R16, R12) divides the regulated output voltage.

Op-amp AR2 compares the divided voltage from the resistor/divider string to a precision reference

voltage established by zener diode VR4, diode CR2, and resistor R9. The output of the op-amp

adjusts the base current of transistor Q2 through resistor R7 to control the conduction of Q1 and

regulate its output voltage. Diodes CR4, CR6, and zener diode VR8 act as a voltage reference at

circuit startup. This reference voltage is zero. Capacitors C4 and C5 provide local filtering of both the

input and output of the regulator. Capacitors C8, C10, and resistor R18 provide closed loop

stabilization of the regulator while allowing fast response of the regulator to line or load changes.

Exhibit 2-8: Schematic, +15-Vdc Regulator Board


47/295

(Rev. 01/95) 2-16

2.4.4 +40-Vdc Unregulated Board (3.29714)

The Unregulated +40-Vdc board, shown schematically in Exhibit 2-9, receives input power from a

secondary of transformer T3. A full-wave bridge consisting of diodes CR1 through CR4 (1N 5811)

rectifies the input ac voltage. Resistors R1, R2, and capacitor C1 serve as a smoothing filter for the

+40-Vdc output.

Exhibit 2-9: Schematic, +40-Vdc Unregulated Board


48/295

2-17 (Rev. 01/95)

2.5 RTU/RTU I/F OVERVIEW

The Remote Telemetry Unit (RTU) and RTU Interface (RTU I/F) combination consists of four PC

boards located in the Power and Telemetry Section of the tool. These boards are:

RTU Control Board (3.30920)

RTU Data Board (3.30921)

RTU Interface Analog Board (3.29786)

RTU Interface Logic Board (3.30477)

These boards together serve as the digital communication link between the DSTU and the tool.


49/295

(Rev. 01/95) 2-18

2.6 REMOTE TELEMETRY UNIT (RTU)

2.6.1 Block Description

Exhibit 2-10 is a functional block diagram of the RTU. The RTU main functional blocks are:

1553 bus transformer and transceiver

Manchester Encoder/Decoder integrated circuit

Downlink logic

Uplink logic

Tool interface conversion and decoding logic:

- Tool address/command decode logic

- Tool bus control logic

- Serial-to-parallel conversion logic for receiving data from the DSTU via the 1553 bus

- Tool status port logic

- Parallel-to-serial conversion logic for transmitting data from the tool to the DSTU via

the 1553 bus


50/295

2-19 (Rev. 01/95)

Exhibit 2-10: Block Diagram, Remote Telemetry Unit

Information goes to and from the DLLT-B via the 1553 bus. Data is encoded as Manchester II

bi-phase, where a "logic one" is transmitted as a positive pulse followed by a negative pulse, and a

"logic zero" is transmitted as a negative pulse followed by a positive pulse. This method of encoding

provides either a positive or negative transition for each bit and facilitates the use of isolation

transformers for connection to the 1553 bus. Each encoded word consists of 20 bits (3 for sync, 16 for

data, and 1 for parity) transmitted at a rate of 217.6 kilobits-per-second. Exhibit 2-11 shows the

Manchester II encoding method.


51/295

(Rev. 01/95) 2-20

Exhibit 2-11: Manchester Encoding Method

Word Formats

The 1553 data bus uses three types of word formats: Command, Status, and Data (see Exhibit 2-12).

A command word from the DSTU consists of a positive-to-negative sync pulse (three bit times wide),

a T/R bit to indicate whether the RTU is to transmit or receive data, seven bits of remote terminal

address, three subaddress/mode bits, five bits to specify either the word count or the mode code, and a

parity bit. A status word sent back by the addressed RTU consists of a positive-to-negative sync pulse,

an error bit, the RTU address, a busy bit, two unused bits, an RTU order bit, four status bits, and a

parity bit. A data word either to or from an RTU consists of a negative-to-positive sync data pulse, 16

bits of data, and a parity bit.


52/295

2-21 (Rev. 01/95)

Exhibit 2-12: Word Formats

Tool Address and Command Functions

Each DITS tool has a unique remote terminal address. The remote terminal address of the DLLT-B is

04 HEX. Through communication with the RTU, the tool can be placed in any of four modes, report

its tool ID, or transmit tool data.

The tool ID function transmits the 16-bit tool ID word to the DSTU. The tool ID word is set by a

series of jumper wires on the RTU I/F logic board. The jumpers are selected so that each tool has a

unique tool ID. The 16-bit ID allows for 65,526 DLLT-B tools, each having a unique tool ID.


53/295

(Rev. 01/95) 2-22

The data field for the tool ID function is structured as follows:

15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 0

CONFIGURATION REVISION SERIAL NUMBER

LEVEL

Bits 15 and 14 are used for tool configuration, bits 13, 12, and 11 for tool revision level, and bits 10

through 0 for the tool serial number.

Configuration of RTU Control and Data Boards

Although the RTU control and data boards are standard for all DITS compatible tools, the boards must

be configured for each tool with plug-in jumpers, a word-count PROM, and an address decoder

PROM. Specific configuration items for the boards in the DLLT-B are:

U19 - PROM 3.34552, RTU Data board 3.30921

U13 - PROM 3.42264, RTU Data board 3.30921

R4 - 402 ohm resistor, RTU Control board 3.30920

PROM Header jumpers (see Exhibit 2-13)

Exhibit 2-13: PROM Header Jumpers


54/295

2-23 (Rev. 01/95)

2.6.2 Circuit Description

For a description of the Remote Telemetry Unit (RTU) circuits, refer to the DSTU/RTU Maintenance

and Repair Manual (770.00259). Section 8, Reference Material lists the RTU PROMS used for

application in the DLLT-B.

2.7 RTU INTERFACE (RTU I/F)

2.7.1 Block Description

The 15-channel RTU I/F used in the DLLT-B consists of an analog board and a logic board. The RTU

I/F Analog board (3.29786) receives differential analog inputs and processes them through a pair of

input multiplexers, a differential amplifier, two programmable gain stages, sample and hold, and a

12-bit Analog-to-Digital Converter (ADC). The RTU I/F Logic board (3.30477) controls the analog

input channel selected, the setting of the programmable gain stages, and the timing of sample/hold and

ADC. The logic board provides memory space for the collected data and communicates with the RTU

boards, receiving control words and transmitting ID information data when requested.

Data Organization

For each input channel selected the logic board sequences the analog board through the acquisition

cycle for a gain of 1, gain of 8, and gain of 64. The four bits selecting the gain comprise the address of

the RAM memory, so any given address in RAM will always hold data for the same input channel on

the same gain setting. Each input channel will always be sequenced through all three gain settings.

The number of input channels sampled and the sequence of these channels are controlled by two

factors. A map PROM on the logic board contains several possible input channel sample-sequence

configurations (maps). The particular map active at any given time is determined by the last control

word received from the RTU. The same map is followed when data is transmitted to the RTU.


55/295

(Rev. 01/95) 2-24

Operating Mode Peculiarity

The RTU I/F for the DLLT-B is designed to use only one of the two DITS system formats for

downloading operating mode commands. This interface uses the format in which the mode command

has a bit set to indicate that a 16-bit control word will follow. The operating mode is always set by a

16-bit control word. The other format, a 4-bit mode command, CANNOT be used with this tool. The

RTU handles control word buffering and initiates handshaking with the RTU I/F to load the control

word.

Power-Up Reset Sequence

The power-up reset sequence provides the tool with a preset operating mode. The acquisition

sequence also is initiated at the beginning as determined by the map selection present. The DLLT-B

preset is 00E1H (Shallow Cal) and is set by J3 on the RTU I/F Logic board (3.30477).

Receive Control Word Sequence

The RTU initiates handshaking to indicate that it has placed a data word on the bus. This word is used

as a control word by the DLLT-B.

Transmit ID Sequence

The ID is a 16-bit word requested through the RTU that is used to identify the tool attached. The ID

is set by J2 on the RTU I/F Logic board (3.30477).

Transmit Data Sequence

Data is normally requested in a block. The RTU I/F will send data in a sequence as determined by the

MAP in use in the MAP PROM, as selected by bits of the control word. After each data word is sent,

the RAM address is changed to the next data location for access according to the MAP.


56/295

2-25 (Rev. 01/95)

Data Control

Whether transmitting data or collecting data, the sequence of channels is controlled by the map PROM

U5, and the sequence of gain setting within each channel is controlled by the control PROM U2. The

control PROM also controls the timing of the functions on the RTU Analog board.

2.7.2 RTU I/F Analog Board Circuit Description

The RTU I/F Analog board performs all of the analog processing for the RTU I/F. The board consists

of an input multiplexer, a differential amplifier, two programmable gain amplifier stages, a sample and

hold amplifier, and an Analog-to-Digital Converter (ADC). (See drawing 3.29786, sheet 4 of 4.)

Input Multiplexer

The input multiplexer consists of 16-channel multiplexers U1 and U2. Analog data appearing at the

multiplexer input (IN1 through IN16) is passed to its output (OutA and OutB) upon application of a

specific channel's address at the address inputs (A0 through A3). For example, the signal tied to IN2

will be passed to OutA and OutB when the binary address 0 0 0 1 is applied to A3, A2, A1, and A0,

respectively. Channel IN1 is permanently tied to ground, providing a ground reference used to obtain

RTU I/F offset readings. During logging, these readings are subtracted from each of the other channel

readings by the surface computer to compensate for any zero drift in the RTU I/F. Two input

multiplexers are used so that differential signals can be processed, single-ended signals can be

accounted for, and small variations in the ground potential of the measurement sections can be

compensated. Table 2-1 shows the channel assignments for the DLLT-B.


57/295

(Rev. 01/95) 2-26

Table 2-1: Channel Assignments, DLLT-B

MULTIPLEXER ADDRESSSIGNAL

MULTIPLEXER

CHANNELA 3 A 2 A 1 A 0

CALIPER IN2 0 0 0 1

MSFL VE IN3 0 0 1 0

MSFL IA IN4 0 0 1 1

V0SHALLOW IN5 0 1 0 0

I0SHALLOW IN6 0 1 0 1

V0DEEP IN7 0 1 1 0

V0DEEP IN8 0 1 1 1

GROUNDED IN1 0 0 0 0

Differential Amplifiers

Amplifiers AR1, AR2, and AR3 combined, comprise the differential amplifier used to convert the

incoming differential signal to a single-ended signal required by the ADC.

Programmable Gain Stages

Following the differential amplifier are two programmable gain stages, each stage having a selectable

gain of X1 or X8. With the two stages in series, selectable gains of X1, X8, and X64 are available.

The programmable amplifiers are identical, each having a gateable 8:1 attenuator followed by an X8

amplifier. The first stage is comprised of AR4, U3, R7, R8, and R9. With switch 6-7 of U3 closed and

switch 2-3 of U3 open, the stage has a gain of 8 since the input attenuator (R7, R8) is out of the circuit.

With switch 2-3 of U3 closed and switch 6-7 of U3 open, the input attenuator is connected to the

input of AR4, resulting in a gain of one for the stage. The second stage, consisting of AR5, U3, R12,

R13, and R14, functions in the same way as the first. The gain of each stage is controlled by logicsignals GAIN B0, GAIN B0/, GAIN B1, and GAIN B1/. GAIN B0 and GAIN B0/ control the first

stage, and GAIN B1 and GAIN B1/ the second stage. Since the two control signals to each stage

complement each other, only one switch in the stage is closed.

Table 2-2 shows the state of each switch in U3 and the resultant gain of the two stages as a function of

the four control signals.


58/295

2-27 (Rev. 01/95)

Table 2-2: State of Switches and Resultant Gain of U3

SIGNAL U3 SWITCHES

B1/ B1 B0/ B0 14-15 10-11 6-7 2-3 GAIN

1 0 1 0 Open Close Open Close 1

0 1 1 0 Close Open Open Close 8

0 1 0 1 Close Open Close Open 64

Sample and Hold Amplifier

Exhibit 2-14 is a simplified circuit diagram of the sample and hold (S/H) amplifier. The S/H amplifier

circuit is unique in that the signal to be digitized (VIN) is amplified by a factor of -0.763 (R18#R17),

and an offset of -3.75 volts [10 x (R18#R19)] is added to it. An input level of -1.000 volt to the S/H

amplifier results in an output of -2.297 volts. This configuration of the S/H amplifier allows the RTU

I/F to process positive signals with some positive offset and also signals that are slightly negative.

Mode selection of the S/H amplifier is controlled by the logic signal SAMPLE/. A logic LOW on this

line closes switch U4, which allows the S/H amplifier output to follow the input signal shown in the

following equation:

VOUT = -3.75 - (0.763 VIN)

With a logic level HIGH on the SAMPLE/ line, the output of the S/H amplifier maintains the level

appearing at its output just prior to SAMPLE/ going HIGH, and no longer follows the input signal.

The S/H amplifier is placed in the HOLD mode (SAMPLE/ = HIGH) just prior to an A/D conversion

and remains in the HOLD state until the conversion is completed.


59/295

(Rev. 01/95) 2-28

The ADC (U5) is a 12-bit converter configured for a"5-Vdc signal range. Conversion is initiated with

the signal CONVERT/ by pulsing it LOW. The conversion is completed 12 clock cycles after the time

CONVERT/ is pulsed LOW. An external clock is provided for the ADC so it can run synchronously

with the RTU I/F. The external clock, derived from the RTU I/F master clock, runs at a 200-kHz rate.

This clock rate allows for a conversion to be completed in 60 microseconds.

The RTU I/F Analog board has the capability of digitizing a maximum of 16 differential signals (one

permanently tied to ground) at three different sensitivities. For the DLLT-B, only eight of the input

channels are assigned. Table 3-3 lists the resulting signal ranges for the three gain ranges of the RTU

I/F Analog board.

Table 2-3: Signal Ranges and Resolutions, RTU I/F Analog Board

SIGNAL LIMITS (VOLTS)

GAIN Minimum Maximum RESOLUTION (VOLTS)

X1 -1.628 11.47 3.2 millivolts

X8 -0.205 1.433 400 microvolts

X64 -0.0256 0.179 50 microvolts

Exhibit 2-14: Schematic, Sample and Hold Amplifier


60/295

2-29 (Rev. 01/95)

2.7.3 RTU I/F Logic Board Circuit Description

The RTU I/F Logic board consists of seven major circuits:

Clock generator

Preset and receive

Transmit Control

Control/status registers

Preset/ID registers

Acquisition control

Random access Memory (RAM)

Detailed descriptions of the above listed circuits are discussed first, followed immediately by their

respective timing diagrams. Refer to drawing 3.30477 during the circuit descriptions.

Clock Generator Circuit

Timing for all circuits on the two RTU I/F boards is generated by the clock generator circuit (Exhibit

2-15). The master clock for the clock generator is the 1-MHz clock oscillator U6. The output of U6

is tied to the clock input of binary counter U8, which is configured as a five state counter. Following

the fifth state, the counter returns to its zero state, controlled by the output of U9-6. Clock signals

CLK1 through CLK4 are generated by inverting the outputs of U8. The clock for the ADC

(ADCLOCK) is active only when SAMPLE/ is HIGH, indicating that the S/H amplifier is in the

HOLD mode and that a conversion will be initiated. Clock signal SHCLOCK is not used. Exhibit

2-16 shows the timing of the clock generator and summarizes the sequence of operation of the RTUI/F Logic board.


61/295

(Rev. 01/95) 2-30

Exhibit 2-15: Schematic, Clock Generator


62/295

2-31 (Rev. 01/95)

Time

1 CONTROL PROM is enabled (MAP PROM Address Complete).

2 MAP PROM is enabled, completing the RAM address.

3 RAM address is latched; internal coding is enabled.

4 RAM enabled for Read or Write, depending on the write state.

5 RTU Buffers are clocked, if data is being read from RAM. New control states are latched; counters are

incremented if enabled. CONTROL PROM, MAP PROM and RAM are disabled.

Exhibit 2-16: Timing Diagram, RTU I/F Logic Board


63/295

(Rev. 01/95) 2-32

Preset and Receive Control Circuit

The preset and receive control circuit (Exhibit 2-17) controls the sequencing of power-up reset, and

the reception of a control word from the RTU. The power-up reset provides the tool with a preset

operating mode and thus prevent the tool from coming up in an undesirable mode. For the DLLT-B,

the preset control word is 00E1. This control word instructs the RTU I/F to use map 01, and places

the tool in the SHALLOW CAL mode.

Exhibit 2-17: Schematic, Preset and Receive Control


64/295

2-33 (Rev. 01/95)

Transmit Control Circuit

The transmit control circuit (Exhibit 2-18) initiates transmit data requests from the RTU. The data

requested is either the collected data from the RAM on the RTU I/F Analog board and the RTU I/F

status word, or the ID word of the RTU I/F.

Documents

DLLT SERVMANUAL(770.00353).pdf