Key Aspects of Project Design for Polymer Flooding at the Daqing Oilfield
- Dongmei Wang (Daqing Research Institute) | Randall S. Seright (New Mexico Tech) | Zhenbo Shao (PetroChina Co. Ltd.) | Jinmei Wang (Daqing Oilfield Company Ltd.)
- Document ID
- Society of Petroleum Engineers
- SPE Reservoir Evaluation & Engineering
- Publication Date
- December 2008
- Document Type
- Journal Paper
- 1,117 - 1,124
- 2008. Society of Petroleum Engineers
- 4.1.2 Separation and Treating, 4.1.5 Processing Equipment, 5.4.1 Waterflooding, 5.1 Reservoir Characterisation, 3.3 Well & Reservoir Surveillance and Monitoring, 4.3.4 Scale, 5.4.7 Chemical Flooding Methods (e.g., Polymer, Solvent, Nitrogen, Immiscible CO2, Surfactant, Vapex), 5.7.2 Recovery Factors, 5.7.5 Economic Evaluations, 1.6.9 Coring, Fishing, 5.3.2 Multiphase Flow, 5.2 Reservoir Fluid Dynamics
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This paper describes the design procedures that led to favorable incremental oil production and reduced water production during 12 years of successful polymer flooding in the Daqing oil field. Special emphasis is placed on some new design factors that were found to be important on the basis of extensive experience with polymer flooding. These factors include (1) recognizing when profile modification is needed before polymer injection and when zone isolation is of value during polymer injection, (2) establishing the optimum polymer formulations and injection rates, and (3) time-dependent variation of the molecular weight of the polymer used in the injected slugs.
For some Daqing wells, oil recovery can be enhanced by 2 to 4% of original oil in place (OOIP) with profile modification before polymer injection. For some Daqing wells with significant permeability differential between layers and no crossflow, injecting polymer solutions separately into different layers improved flow profiles, reservoir sweep efficiency, and injection rates, and it reduced the water cut in production wells. Experience over time revealed that larger polymer-bank sizes are preferred. Bank sizes grew from 240-380 mg/L·PV during the initial pilots to 640 to 700 mg/L·PV in the most recent large-scale industrial sites [pore volume (PV)]. Economics and injectivity behavior can favor changing the polymer molecular weight and polymer concentration during the course of injecting the polymer slug. Polymers with molecular weights from 12 to 35 million Daltons were designed and supplied to meet the requirements for different reservoir geological conditions. The optimum polymer-injection volume varied around 0.7 PV, depending on the water cut in the different flooding units. The average polymer concentration was designed approximately 1000 mg/L, but for an individual injection station, it could be 2000 mg/L or more. At Daqing, the injection rates should be less than 0.14-0.20 PV/year, depending on well spacing.
Many elements have long been recognized as important during the design of a polymer flood (Li and Niu 2002; Jewett and Schurz 1970; Sorbie 1991; Vela et al. 1976; Taber et al. 1997; Maitin 1992; Koning et al. 1988; Wang et al. 1995; Wang and Qian 2002; Wang et al. 2008). This paper spells out some of those elements, using examples from the Daqing oil field. The Daqing oil field is located in northeast China and is a large river-delta/lacustrine-facies, multilayer, heterogeneous sandstone in an inland basin. The reservoir is buried at a depth of approximately 1000 m, with a temperature of 45°C. The main formation under polymer flood (i.e., the Saertu formation) has a net thickness ranging from from 2.3 to 11.6 m with an average of 6.1 m. The average air permeability is 1.1 µm2, and the Dykstra-Parsons permeability coefficient averages 0.7. Oil viscosity at reservoir temperature averages approximately 9 mPa·s, and the total salinity of the formation water varies from 3000 to 7000 mg/L. The field was discovered in 1959, and a waterflood was initiated in 1960. The world's largest polymer flood was implemented at Daqing, beginning in December 1995. By 2007, 22.3% of total production from the Daqing oil field was attributed to polymer flooding. Polymer flooding should boost the ultimate recovery for the field to more than 50% OOIP--10 to 12% OOIP more than from waterflooding. At the end of 2007, oil production from polymer flooding at the Daqing oil field was more than 11.6 million m3 (73 million bbl) per year (sustained for 6 years). The polymers used at Daqing are high-molecular-weight partially hydrolyzed polyacrylamides (HPAMs).
During design of a polymer flood, critical reservoir factors that traditionally receive consideration are the reservoir lithology, stratigraphy, important heterogeneities (such as fractures), distribution of remaining oil, well pattern, and well distance. Critical polymer properties include cost-effectiveness (e.g., cost per unit of viscosity), resistance to degradation (mechanical or shear, oxidative, thermal, microbial), tolerance of reservoir salinity and hardness, retention by rock, inaccessible pore volume, permeability dependence of performance, rheology, and compatibility with other chemicals that might be used. Issues long recognized as important for polymer-bank design include bank size (volume), polymer concentration and salinity (affecting bank viscosity and mobility), and whether (and how) to grade polymer concentrations in the chase water.
This paper describes the design procedures that led to favorable incremental oil production and reduced water production during 12 years of successful polymer flooding in the Daqing oil field.
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Chen, F., Li, Y., and Niu, J. 2004. Summarization on the technology ofmodification profile in-depth in Daqing. Petroleum Geology & OilfieldDevelopment in Daqing 23 (5): 97-99.
Craig, F.F. 1991. The Reservoir Engineering Aspects of Waterflooding.Monograph Series, Richardson, Texas 3: 29-77.
Demin, W., Jiecheng, C., Junzheng, W., and Gang, W. 2002. Experiences Learned After Productionof More Than 300 Million Barrels of Oil by Polymer Flooding in Daqing OilField. Paper SPE 77693 presented at the SPE Annual Technical Conference andExhibition, San Antonio, Texas, 29 September-2 October. DOI:10.2118/77693-MS.
Demin, W., Jingcun, Z., Fanru, M., Heng, L., Lin, L., and Bohui, H. 1995. Commercial Test of Polymer Floodingin Daqing Oil Field, Daquing Petroleum Administrative Bureau. Paper SPE29902 presented at the International Meeting on Petroleum Engineering, Beijing,14-17 November. DOI: 10.2118/29902-MS.
Fulin, Y., Demin, W., Xizhi, Y., Xinguang, S., Qinghai, C., and Iei, Z.2004. High Concentration PolymerFlooding is Successful. Paper SPE 88454 presented at the SPE Asia PacificOil and Gas Conference and Exhibition, Perth, Australia, 18-20 October. DOI:10.2118/88454-MS.
Gao, S., and Su, Y. 2004. The development project design of polymer floodingfor the Central of Xing4-5 in Daqing. Yearly Report 12:16-17.
Guo, W., Cheng, J., and Liao, G. 2002. The current situation on EORtechnique in Daqing. Petroleum Geology & Oilfield Development inDaqing 21 (3): 1-6.
Jang, Y. 1994. Optimization Conditions for Polymer Flooding, Chap.12, 3-5. Beijing: Petroleum Industry Publishing Company of China.
Jewett, R.L. and Schurz, G.F. 1970. Polymer Flooding--A CurrentAppraisal. JPT 22 (6): 675-684. SPE-2545-PA. DOI:10.2118/2545-PA.
Koning, E.J.L., Mentzer, E., and Heemskerk, J. 1988. Evaluation of a Pilot Polymer Floodin the Marmul Field, Oman. Paper SPE 18092 presented at the SPE AnnualTechnical Conference and Exhibition, Houston, 2-5 October. DOI:10.2118/18092-MS.
Li, Y. and Niu, J. 2002. The study of adjustment measures during polymerflooding. Yearly Report 12.
Liao, G., Niu, J., Shao, Z., and Chen, P. 2004. The effectiveness andevaluation for industrialized sites by polymer flooding in Daqing. PetroleumGeology & Oilfield Development in Daqing 23 (1): 48-51.
Maitin, B.K. 1992. PerformanceAnalysis of Several Polyacrylamide Floods in North German Oil Fields. PaperSPE 24118 presented at the SPE/DOE Enhanced Oil Recovery Symposium, Tulsa,22-24 April. DOI: 10.2118/24118-MS.
Qiao, E., Li, Y., and Liu, P. 2000. Application of PI decision technique inPuCheng oilfield. Drilling & Production 23 (5): 28-25.
Seright, R.S. 1983. The Effectsof Mechanical Degradation and Viscoelastic Behavior on Injectivity ofPolyacrylamide Solutions. SPEJ 23 (3): 475-485. SPE-9297-PA.DOI: 10.2118/9297-PA.
Seright, R.S., Lane, R.H., and Sydansk, R.D. 2003. A Strategy for Attacking Excess WaterProduction. SPEPF 18 (3): 158-169. SPE-84966-PA. DOI:10.2118/84966-PA.
Shao, Z., Chen, P., Wang, D., and Wu, L. 2005. Study of the Dynamic Rulesfor Polymer Flooding in Industrial Sites in Daqing. The Thesis Collectionfor EOR Technology 12: 1-8.
Shao, Z., Fu, T., and Wang, D. 2001. The determinate method of reasonablepolymer volume. Petroleum Geology & Oilfield Development in Daqing20 (2): 60-62.
Sorbie, K.S. 1991. Polymer-Improved Oil Recovery. Glasgow, Scotland:CRC Press.
Sun, C., Wang, D., Zhou, Z., and Shao, Z. 1989. The Development of PolymerFlooding Simulator. Yearly Report 12: 2-6.
Taber, J.J., Martin, F.D., and Seright, R.S. 1997. EOR Screening CriteriaRevisited--Part 1: Introduction to Screening Criteria and Enhanced RecoveryField Projects. SPERE 12 (3): 189-198. SPE-35385-PA. DOI:10.2118/35385-PA.
Trantham, J.C., Threlkeld, C.B., and Patternson, H.L. 1980. Reservoir Description for aSurfactant/Polymer Pilot in a Fractured, Oil-Wet Reservoir--North Burbank UnitTract 97. JPT 32 (9): 1647-1656. SPE-8432-PA. DOI:10.2118/8432-PA.
Vela, S., Peaceman, D.W., and Sandvik, E.I. 1976. Evaluation of Polymer Flooding in aLayered Reservoir with Crossflow, Retention, and Degradation. SPEJ16 (2): 82-96. SPE-5102-PA. DOI: 10.2118/5102-PA.
Wang, D. and Qian, J. 2002. The development project design of polymerflooding for Eastern in Sazhong in Daqing. Yearly Report 12:34-35.
Wang, D., Han, P., Shao, Z., Hou, W., and Seright, R.S. 2008. Sweep-Improvement Options for theDaqing Oil Field. SPEREE 11 (1): 18-26. SPE-99441-PA. DOI:10.2118/99441-PA.
Wang, Z., Han, C., Hou, J., and Wu, W. 2001. The polymer molecular weightand the factors affecting flow properties. Journal of Daqing PetroleumTransactions 25 (1): 18-20.
Wu, L., Chen, P., and Lu, J. 2005. Study of injection parameters forseparate layers during the period of polymer flooding. Petroleum Geology& Oilfield Development in Daqing 24 (4): 75-77.
Wu, W. et al. 2001. The polymer molecular weight and the factors affectingflow properties. Journal of Daqing Petroleum Transactions 25 (1):18-20.
Yuan, Q. 2005. Terms of Oil/Gas Reservoir Engineering. China Patent NumberSY/T, 6174.
Zhang, G. and Seright, R.S. 2007. Conformance and Mobility Control:Foams vs. Polymers. Paper SPE 105907 presented at the InternationalSymposium on Oilfield Chemistry, Houston, 28 February-2 March. DOI:10.2118/105907-MS.
Zhang, Y., Li, C., and Wang, X. 2004. Discussions on the technical of stringwith backflush for separate layers during the period of polymer flooding.Oil & Gas Ground Engineering 23 (9): 26-27.