Example 1 Data Preparation 2011

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© 2010 Weatherford. All rights reserved.

Data Preparation – Part 1

Example 1

Luis G. Prada

Rev. Feb 2012

1


Data Preparation: First Example

• Import gauge data file

– This file contains data from a single gauge

• Delete pre-test and post-test data

• Remove noise

• Define flow periods

• Reduce number of data points

• Smooth data

• Define Well, Layer and Fluid Parameters

• Check log-log plot

2




Data Preparation – Initial Configuration

• Look at the gauge data file Example01_1.tpr in a text editor

(Notepad, etc)

– Check units used, layout of file, etc

• Start PanSystem, or File / New if already running

• Configuration>>General

– Change data directory name to course data folder

• Configuration >> Units

– Select OILFABS Units System (Default)

• Data Preparation >> Well and Reservoir Description

– Select Oil as Reservoir Fluid Type (Default)

• Import/Export Data >> ASCII

– Select Example01_1.tpr 3


Data Preparation – Import Data

• The actual column headers which appear initially depend on whatyou did last time.

• We will reset these correctly.4





• Most non-numerical data is not displayed in Space/Tab mode

• If you have not already inspected the file with a text editor, view the entireheader (for units, etc) by switching to Fixed column widths mode:

5



• Note data column format /units:

– Column 1: Time in decimal hours

– Column 2: Pressure in psia

– Column 3: Temperature in oF

– The import dialog allows for a temporary change of units if needed for the importof gauge data

• This file can be loaded easily with the Space/Tab option

– Switch back from Fixed column widths to Space/Tab delimited

• Enter Number of lines in header

• Click in each column in turn and:

– Select data type from Date, Time, Gauge, Skip (to omit a column)

– Select time format from drop-down menu

– Select gauge data type from drop-down menu

– Change Column Name from default if desired6





• Click Import or Import & Plot

Gauge on surface

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• A format template can be used for quick set-up next time

a similar file is to be imported

• Click on “No” for this particular example

• Data import should take a matter of seconds

• Number of Data Points Imported are shown

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• To plot the imported data (if not plotted already), double-

click the dataset(s) of interest from the Data Files/Column

List on Navigation Pane

Data Preparation - Plot

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• Different dataset(s) can be added or removed from the

active plot


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Data Preparation – Edit

• Dataset(s) can be edited by clicking on Data Preparation

>> Gauge Data >> Edit Data

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Data Preparation - Edit

• There is a selection of

time formats• Any data can be

functioned (shift and

multiplier)

• Copy to/Paste from

Clipboard

• Insert new rows / delete

rows

• View imported file header

• When you OK from here,

PanSystem will check forinvalid data, time

continuity errors, etc

13


Data Edit Plot

• Zoom in on a section of pressure data around 17.5 hrs.

• Note stair-steps. Read the step size. Explain….

• What are the large pressure spikes?

Zoom a box

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• Delete data at start and end during running in (RIH) and pulling out

(POH)

– Draw boxes with Select Points in a box icon around theRIH data at the start of the test and click Delete Selected Pointsicon or {Del} key

– Repeat for the POH data

– Recover last deletion with Undo

– Recover all deletions with Initialise

– Repeat the two deletions

– Confirm deletions to clear memory

– Check with the Show no. of points icon

• There should be about 25,000 data points remaining

• Save file as Example01_1.panx

Data Edit Plot

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Data Edit Plot

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• Outliers can be removed by:

– Selecting individual points and deleting with or {Del}

– Drawing a box around a group of points and deleting

– Using the statistical Outlier Removal facility in Data Reduction

• The best choice for large datasets!

Data Edit Plot – outlier removal

Outliers

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• With successive passes of the Outlier Remover in

– Outliers lying closer and closer to the main data are removed

as the region of tolerance is narrowed

– A new data group with a prefix RD1 is created, containing thereduced dataset

Data Edit Plot – Outlier Removal

After two passes of the Outlier Remover

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• Define the flow periods:

– Zoom-in on the beginning of the initial flow period

– Select the ‘ Pick nearest data point’ option and pick the

beginning of the first drawdown

– Leave the flowrate as 0

• The flowrate is thevalue just before the

event – ie: zero because

there was no flowbefore the test started

– Click OK

– Unzoom (Resume Original View)

Data Edit Plot – Flow Periods

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• Zoom in on the initial flowing period

– There appears to have been a

(partial) valve closure

– We will ignore this, as we don‟t

have any info about what

happened….

• Zoom in on the start of the

initial buildup


Initial flow period

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• There was a small pressure drop (rate

increase) prior to shut-in• To pick the shut-in point either:

– Pick by eye using the „Mark exact position‟ option or

– Use the „Mark point fromintersection of two lines‟ option

– Enter a Rate of 400 STB/day

• The flowrate is the value justbefore the event – ie: during the

flowing period

• Positive for production, negative

for injection


Rate change point

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• Unzoom

• Remove T from the plot:

– Right click the

Pressure data set on

the Navigation Pane

– Select Remove from

active plot

– Select Temperaturedata set

• Right-hand axis is nowscaled for flow rate only

Data Edit Plot – flow periods

Flowrate

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• Zoom-in on the end of the

buildup period and use the‘Pick nearest data point’

option to define the end of

the buildup

• Leave the flowrate at zero

• Zoom out (Resume Original

View)

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• Proceed in this manner – zoom in, pick, zoom out -

through the test, picking the ends of the flow periods and

the shut-ins

– The „intersecting lines‟ option is the best one to use

for the flowing periods in this particular test

• Enter 400 STB/day for each Rate

– The „Nearest point‟ option works

well for the shut-ins

• For a shut-in, the Rate is zero

– The final shut-in appears to have

required three attempts to close

the valve 24




• The plot builds a step profile based on the time and rate

values entered at the rate changes


Rate schedule

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• Click on Data Preparation >> Rate changes >> Rate Changes

• The times, pressures and rates that you have just picked are stored

in the Rate Changes table. Cumulative production is calculated.

– If you change an entry here, it will change on the plot, and vice

versa


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• To enter events that occurred before the test started (if any), insert new rows

and type in the times and rates.

– Times can be negative (unless in 24-hr clock format)

– Remember that the rate goes at the end of the test period

– The very first rate entry should be zero – Pressures can be left at zero (no gauge data!)

• For the current DST, there were no previous events

– Cancel from the dialog to clear any modifications


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Data Reduction

• Select interval to reduce:

– Test period (in ruler bar)

– Whole test (no selection in ruler bar)

– Box (draw with mouse)

– Zoom portion

• Click Data Reduction facility

Methods of reduction(described in Help {F1})

Some options use a selecteddata column

Name of new reduced data file.PanSystem keeps the original file, just in case…

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• Undo the last reduction action

• Restore all unconfirmed data changes

– The deleted points are in fact retained in memory and simplyflagged as “do not display”

– The options above simply remove some or all of the flags to allow

re-display

• Confirm reduction(s) and compress data

– The “Confirm” button clears the flagged data from memory

– and can not recover points that have been cleared by

Data Reduction

PanSystem keeps the original dataand creates a new file for the reduced data with

the prefix RD1

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Data Smoothing

• Select interval to smooth:

– Test period (in ruler bar)

– Whole test (no selection in ruler bar)

– Box (draw with mouse)

– Zoom portion

• Click Data Smoothing button

Determines the number of pointsto be used in smoothing window

Sampling time-base for the data

Weighting to be applied

Might improve appearance at startand end of data.

Described inHelp {F1}

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Data Smoothing

Select the data column

that you would like tosmooth

Define the name ofsmoothed output data

column (or accept default

prefix SM1….)

PanSys creates a new data column for thesmoothed data, with the prefix SM1

Here, we have smoothed the pressure

data Pressure #1 contained in thereduced dataset RD1 EXAMPLE01_1

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Data Preparation – rock and fluid properties

• Go to Data Preparation >> Well ,reservoir & fluid description >> Analytical Model

• Enter the following data in the Fluid Control, Well Control, and Layer

Control Tabs:

• Rw = 0.35 f t.

• h = 87 ft.

• Ø = 0.17

• Bo = 1.12 res bbl/STB Note that mandatory parameters appear in red:

• oil = 0.7 cp

• Ct = 5.2E-5 psi-1

• Click OK

• Save File

See Help for detailed

definitions (Index or

{F1} from each dialog)

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Analysis – the log-log plot

• Select Analysis

–If your input data are not OK, you will not be able to proceed!

• Select the final build-up in the ruler bar

• Select Plot Types and Click Log-Log Plot

icon

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Log-Log Plot – quality check

• Note that in the early time region the pressure and derivative datashould follow a unit slope trend and overlay each other. If not, the

BU start time T0 and/or pressure P0 have not been defined properly.

• Return to the DataEdit Plot and take a

close look at the pointyou picked,

or:• Adjust T0 and P0 to

find a „good‟ valuevia the button.

• Save the file

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• Look at the gauge data file example01_2.tpr in a text editor (Notepad,

etc)

– File contains 2 gauges

– Date is included

– Note gaps in temperature

• The gauges were prog-

rammed not to acquire

T data unless a certain

minimum change

occurred (0.01°F)

– Note data columns areof constant width

• Compare example01_1,

where they get wider as

the numbers get bigger

Data Preparation: Second Example

35


Data Preparation - Import

• Start PanSystem, or File / New if already running

• Configuration >> Units

– Select OILFABS Units System (Default)

• Data Preparation >> Well and Reservoir Description

– Select Oil as Reservoir Fluid Type (Default)

• Import/Export Data >> ASCII

– Select Example01_2.tpr

36





• In Space/Tab delimited mode, the gaps cause the pressure andtemperature values to get mixed up

– This import mode cannot handle missing data

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– The data are now being confined to their correct columns

• Next we need to define the column configuration for import….

• Switch to Fixed column widths mode

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• Position the column markers as explained in the panel on the right

– Create new column markers as necessary

- One more is needed here, for the date

• Identify the data in each column

– For time, use (Date)HH:MM:SS if importing the date too

• Header has 15 lines

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• Save the file as Example01_2.panx

• Import the data. (Save the template.)

• If it doesn‟t look like this, delete the imported data and try again

– use the template and find the error(s)

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• Right click the x-axis

– Select Date option

– The time format should change to 24-hr clock (Date)HH:MM:SS

– Adjust the time scale to look similar to the plot shown below

Data Preparation – date display

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Example 1

END OF EXAMPLE 1

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Documents

Example 1 Data Preparation 2011