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p o t . ~ / ~ e / i # 9 r l - - P DESIGN AND IMPLEiMENTATION OF A CO2 FLOOD UTILIZING 0 S

ADVANCED RESERVOIR CHARACTERIZATION AND HORIZONTAL INJECTION WELLS IN A SHALLOW SHELF CARBONATE APPROACHING

WATERFLOOD DEPLETION

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Cooperative Agreement Number:

Contractor Name and Address:

Date of Report:

Award Date:

Anticipated Completion Date:

Government Award for 1996 Fiscal Year:

Project Director:

DOE Project Officer:

Reporting Period:

DE-FC22-94BC14991

Phillips Petroleum Company 4001 Penbrook Street Odessa, Texas 79762

August 9,1996

June 3,1994

January 2,2001

$2,659,515

John S. Chimahusky

Jerry F. Casteel

April 1,1996 - June 30,1996

DISCLAIMER

Portions of this document may be illegible in electronic image products. Images are produced from the best available original document.

DISCLAIMER

This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liabiiity or responsibility for the accuracy, completeness, or use- fulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any spe- cific commercial product, process, or service by trade name, trademark, manufac- turer, or otherwise does not necessarily constitute or imply its endorsement, m m - mendotion, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.

OBJECTIVE

The fKst objective is to utilize reservoir characterization and advanced technologies to optimize the design of a carbon dioxide (CO,) project for the South Cowden Unit (SCU) located in Ector County, Texas. The SCU is a mature, relatively small, shallow shelf carbonate unit nearing waterflood depletion. The second objective is to demonstrate the performance and economic viability of the project in the field. This report includes work on the reservoir characterization and project design objective and the demonstration project objective.

SUMMARY OF TECHNICAL PROGRESS

PHASE I

Identification of Potential Foamin? Surfactants for CO, Mobilitv Control

Surfactant Adsorption Studies

Earlier adsorption tests performed with various surfactants in the South Cowden Unit field cores indicated a strong dependency of adsorption value on core porosity rather than the surfactant type. Due to the severe inhomogeneity of the South Cowden cores, Baker Dolomite cores were chosen for surfactant adsorption tests to rank the best two surfactants identified through foam tests. Thirteen adsorption tests were performed with solutions of Chaser CD-1045 and Rhodapex CD-128 in synthetic South Cowden Unit brine. In each test about 30 mg (0.5 - 1.7 pore volume slugs) of a given surfactant was injected into the core at 1000,2000, or 3000 ppm. Table 1 summarizes the results for these tests. The average surfactant adsorption for Rhodapex CD-128 and Chaser CD-1045 calculated for all concentrations and the three techniques were 99.8 and 420.9 lbdacre-ft, respectively. The average surfactant adsorption for Chaser CD-1045 in cores at residual oil saturation for three surfactant concentrations measured with the techniques listed above was calculated to be 557.3 lbs/acre-ft, which represents an increase of about 32% over the tests performed in the absence of oil.

Hydroxyethyl cellulose (250 ppm) was evaluated as a potential sacrificial agent to reduce the adsorption of Chaser CD-1045. After circulating a solution of 250 ppm HEC-25 in synthetic South Cowden Brine for several days to reach equilibrium, adsorption averaged 446.6 lbs/acre-ft vs. an average of 420.9 lbs/acre-fi calculated for this surfactant in the absence of sacrificial agent. Based on these results, this product does not appear to reduce the adsorption of Chaser CD-1045 in a dolomite core. Also listed in Table 1 are the adsorption results for the injection of Rhodapex CD-128 in a Baker Dolomite core with an average adsorption of 149.9 lbs/acre-ft. This test was followed

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with the injection of Chaser CD-1045 in the same core, resulting in an average adsorption of 489.9 Ibdacre-ft. These results indicate that the use of Rhodapex CD- 128 ahead of Chaser CD-104 5 also does not decrease the adsorption of Chaser CD-1045.

- CO, Miscible WAG Trawed Gas Exneriments

Carbon dioxide (CO,) relative permeability, trapped gas saturation, and hysteresis effects are key parameters in determining injectivity and displacement in a miscible CO, water alternating gas (WAG) injection project. In an effort to better understand CO, miscible WAG behavior in the South Cowden reservoir, several coreflood experiments were conducted to measure these key parameters. The results of coreflood experiments and associated simulation runs are documented in paper SPE 35429 “Determination of Relative Permeability and Trapped Gas Saturation for Predictions of WAG Performance in the South Cowden CO, Flood”, presented at the SPEDOE Tenth Symposium on Improved Oil Recovery held in Tulsa, OK, 21-24 April 1996.

PHASE I1

Drill, Re-Activate. and Convert Wells

Drill and Complete Horizontal In-iection Wells 6C25H W-1) and 7C-11H Ef-2)

The drilling and completion operations for the horizontal CO, injection well 6C-25H (€3-1) commenced March 17, 1996, and was completed in 28 days. The experience gained during the drilling of this well resulted in time and money savings on the drilling of the second well. Drilling and completion operations for the second horizontal CO, injection well 7C-11H (H-2) commenced April 14, 1996, and was completed in 20 days.

The design parameters and the actual drilling results, depicted in Table 2, are in excellent agreement. A visual representation of the drilling curves for Wells 6C-25H and 7C-11H are included as Figures 1 and2.

Conventional drilling operations had to be modified in several ways to accomodate the drilling of the horizontal wells. The drilling contractor had to provide an adequate mud system to effectively condition the polymer mud system. In addition to the rig specifications, a centrifuge had to be utilized to further condition and maintain the mud, thus optimizing the polymer mud properties. A polymer-based mud system was utilized in order to enhance penetration rates, hole conditioning, and limit the possibility of stuck pipe. In addition, triplex pumps with sufficient horse power were

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required to reduce MWD pulse reading interference, and maximize mud motor performance.

The wells were designed mechanically to optimize well injection performance and usefid life. Both wells were designed to accomodate 9-5/8", 36 ppf, J-55 surface casing; 7", 20 ppf, J-55 production casing through the curve; and a 6-1/8" openhole injection interval. The production casing was designed with 7" tubulars to accomodate 3-1/2" production tubing. The 20 ppf casing weight was used more for additional conosional wear allowables than for design dictated by the predicted injection bottomhole pressure. The cased curve trajectory was designed to accomodate 125' of production casing within the target injection interval. Wellbore schematics of horizontal injection Wells 6C-25H and 7C-11H are included as Figures 3 and 4.

Convert Five Wells for Water In-iection

Operations commenced to convert SCU Wells Nos. 2-21,5-02 and 8-18 to water injection.

Construct. Modifv, and UDYrade Facilities for fniection and Production

Purchase Land. Install Perimeter Fence and H2S Monitors

Five of six private lots in Section 17 of the South Cowden Unit have been purchased, with negotiations continuing on the sixth lot, for the construction of production facilities, The main 250- acre tract of land where CO, flood facilities are located is currently being leased. Purchase of the land is anticipated to reduce costs associated with right of way and damages for installation of injection lines and production flowlines.

Nineteen of twenty-one hydrogen sulfide (H,S) monitors have been installed and are operational. All H2S monitors along the perimeter fence have been installed and are operating. If H_S is detected by any of the monitors, an alarm is sent via radio to the Phillips Petroleum Odessa office South Cowden Unit (SCU) Supervisory Control and Data Acquisition (SCADA) computer, which in-turn sends a message to an operator on call who will have an alpha-numeric pager. If the operator on call cannot be reached, a list of people will be called until someone acknowledges the alarm.

The perimeter fence is approximately 95% complete. This fence is to prevent public entrance into the project area, provide protection fiom exposure to H2S and protect against vandalism. The fence will be completed upon purchase of the sixth private lot.

Modi@ or Upgrade Production Facilities

Construction of the new Tract 6 Satellite facility continues. A new production header is complete,

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and a new production separatm and test separator have been built and installed, tieing the facility into the Tract 6 main battery. As C02 content of the produced gas increases in the SCU producing wells, individual wells will be rerouted and tied into the new Tract 6 satellite facility.

Construct Compression Facilities

Production Operators, Inc. (POI) completed construction of their re-injection facility on June 2 1 , 1996. The facility is currently equipped with a 330 H.P. Caterpillar Natural gas engine / Ariel compressor package rated up to 1.0 Mmscfd, and includes a Glycol gas dehydration skid for removing water from the produced gas prior to re-injection.

Installation of Injection Runs at Headers and Wellheads

Installation of injection runs to all four of the CO, WAG injection wells is completed. Installation continues at the water injection wells.

Installation of Fiberclass WAG Svstem

Installation is completed on new fiberglass WAG system to the four CO, WAG injection wells. Installation consisted of approximately 5600' of 2", and 2400' of 3" 2500-psig fiberglass pipe.

Installation of H,O and C 0 2 Manifold

Construction and installation of the H20 and C Q (WAG) manifold is completed. The injection manifold consists of eight (8) 2" stainless steel injection runs, and will accomodate the four SCU WAG wells, three future leaseline wells, and one spare. The injection chokes on each injection run are fully-automated and control the volume of water or C02 going to each WAG well.

Iniection Svstem Replacement

Replacement of the old water injection system is essentially completed. Replacement consisted of the installation of 2000 psig fiberglass pipe in the following lengths and sizes: 5 100' of 4", 3200' of 3", 1600' of 2-1/2" and 11000' of 2".

Cathodic Protection

Logging runs using a Cathodic Protection Evaluation Tool (CPET) were made in the SCU #6-20 and

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#7-05 wells. A cathodic protection deep anode bed was installed near the SCU if6-20 well and both wells logged first without cathodic protection and then logged with the cathodic protection system turned on. Log evaluation is to continue before a decision is made whether or not to install fieldwide cathodic protection on all the wells.

Installation of Supervisorv Control and Data Acauisition (SCADA) Equipment

The SCADA system has been installed and is operating. WAG injection manifold pressures and flow rates are being sent to the SCADA computer located in the Phillips Petroleum Odessa office, along with various alarms. Installation of producing well pump-off controllers continues. Well performance and status will also be sent via radio to the SCADA computer.

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Table 1 Summary of Adsorption Tests in Baker Dolomite Cores

Surfactant Injected lRun I ICorelResiduall Sacrificial I Cone. I Solution I Net Wt.

No. No. Oil(y/n) Agent Name (PPm) Wt- (€9 (ms) 1 B-07 n none CD-128 1000.2 30.00 30.01 2 8-06 n none CD-128 1991.5 15.00 29.87

I 31 IB-05 In Inone ICD-128 I 3011.31 lO.0OI 30.11

- Amount Adsorbed Avg.

Lbs/Acre-F t Each Overall

99.8 1

Commcnt 7 4 B-09 n none CD-1045 1000.0 30.00 30.00 529.9 331.1 79.4 313.5 5 B-08 n none CD-1045 1998.1 15.00 29.97 525.7 494.3 175.0 398.3 6 B-03 n none CD-1045 2998.5 10.00 29.99 424.5 645.3 502.2 524.0 7 B-12 n none CD-1045 2999.0 10.35 31.04 473.8 455.2 273.0 400.6 8 8-04 n none CD-1045 3000.2 10.00 30.00 535.0 395.2 474.0 468.1 420.9 2

9 B-15 y none CD-1045 999.7 30.00 29.99 753.1 581.5 457.9 597.5

1 1 B-13 y none CD-1045 2998.2 10.35 31.03 652.4 617.8 352.4 540.9 557.3 3 10 B-14 y none CD-1045 2000.0 15.00 30.00 698.0 560.1 342.2 533.4

1 121 IB-16 In 1250 ppm HEC -25 ICD-1045 I 2970.81 lO.OOl 29.711.. 457.91 NMI 435.31 446.61 446.61 4 I

13A B-11 n none CD-128 2996.6 10.00 29.97 194.0 84.3 171.4 149.9 149.9 5 13B B-11 n none CD-1045 2991.8 10.00 29.92 793.2 443.2 233.3 489.9 489.9 6

Commem 1. Average for Rhodapex CD-128 (no oil, no sacrificial agent) 2. Average for Chaser CD-1045 (no oil, no sacrificial agent) 3. Average for Chaser CD-1045 (residual oil, no sacrificial agent) 4. Average for Chaser CD-I 045 (no oil, sacrificial agent is 250 ppm HEC-25) 5. Duplicate test for Run Number 2 6. Chaser CD-1045 following Rhodapex CD-128

TABLE 2

South Cowden Unit Horizontal Injection Well Results

6C-25H

DLS I 12"1100'

Azimuth 76" East of True North

42 12' ~

Casing Placement 4684' TVD 14859' TMD (8 1.2")

Csg Pt Deflection 440' Length from Vertical

Curve Length 75 1'

9W Lateral Depth

Lateral Length 2000' (measured from csg shoe)

4706' TVD 14963' TrvlD

6C-25H 7C-llH Actual Design

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' 10.96V100' (AVG) I 12"/100'

75.33" East of True North (AVG)

42 12' 4195'

6Y West of True North

4681' TVD 14955' TMD 467 1' TVD I 491 5' (83") TblD (86")

462' 447'

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1935' 1303'

7C-llH Actual

11.39"IlOO' (AVG)

65.27O West of True North (AVG)

4195'

4672' TVD 14907' TklD (87")

476' ~

775'

4675' TVD 14970' TMD

1337'

NOTE: All depths are measured from the RKB height. 6C-25H surface elevation: 2934' 7C-11H surface elevation: 2935' Surface locations were 70' apart

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FIGURE 1

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FIGURE 2 . .----.. .. . . . . . . . . . . . .. . . , . . ::_ , : .. . , _ . . . _ , . ;.:.

, . .... . . .::_ _:.. . . ' . .

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PHILLIPS' Well Name: South Cowden Unit %-25H

Location: Ector County, 7X Casing: 9 4 8 " 36# J-55; 640 Sx Lead, 150 Sx Tail

Cement Circulated to Surface 7" 26# J-55; 480 Sx Lead, 150 Sx Tail Cement Circulated to Surface - -

Description: 1. D. O.D. Length Bottom of Assembly 4,943.30

3.250" 4.500" 0.50' 4,942.81

8 P.C. 3-1R" EVE Pup Joint 2.992" 3.500" 8.00 4,934.58

Wireline Re-Entry Guide

"X" Nipple (Nickel Plated) 2.313" 3.750" 1 .OO' 4,933.21

6 Duoiine 2-1R" EUE Pup Joint 2.770" 3.500" 6.00' 4,926.99

7" PLS Packer (18,OOW Compression) 3.000" 5.900" 4.00' 4.923.14

with 3" Bore Plastic Coated and Nickel Plated Inclination 80.8'

x' Nipple (Nickel Plated) 2.313" 3.750"

Tubing (23 Joints)

"x" Nipple (Nickel Plated) Inclination 0.76

Tubing to Surface (133 Joints)

2.313" 3.750"

Depth

1.00' 4,921.77

4,198.63

1 .OO' 4.1 97.26

4.iai.26

NOTE: Tubing ID 2.770"

Through the Tube Connection ID 2.670"

Drift10 2.375"

FIGURE 3

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PHILLlPS Too O F Well Name: South Cowden Unit # 7 C I l H Lead Cenent

Location: Ector County, TX Casing: 9-5/8" 36# J-55; 640 Sx Lead, 150 Sx Tail

Cement Circulated to Surface 7" 263 J-55; 440 Sx Lead, 150 Sx Tail Cement Circulated to 6OO'per Temp. Survey

Hole Deviation: 88" @ 4907' I. D. O.D. Lengtft Depth I

Bottom of Assembly 4,ac1a.m

2. 8'P.C. 3-1/2" EUEPup Joint 2992" 3.500" 8 . i ~ 4,889.54

4. 6' Duoline 3-IR" EUE Pup Joint 2770" 3.500" 6.17- 4,aaa.oo

3.250" 4.500"

X Nipple (Nickel Plated) .. 2313" 3.750"

5. 7" PLS Packer (18.000# Compression) 3.000" 5.900"

hth 3" Bore Plastic Coated and Nickel Plated lnclination 83.0'

6. X Nipple (Nickel Plated) 2.313" 3.750" 1 . 3 ~ 4,876.78

7. Tubing (22 Joints) 4 2 7 . M

. X Nipple (Nickel Plated) inchaffon 2.0' 2.313" 3.750" 1.37 4,225.67

Surface (133 Joints) 17.00

NOTE: Tubing ID 2.770"

Through the Tube Connection ID 2.670" --.7

. . . Drift ID 2.375"

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