The Effect of Well Completion Fluid Loss on Productivity Evaluation in Tight Sand Gas Reservoir: A Case Study from East China Sea Gas Well
Keywords:Tight gas reservoir, Fluid loss, Well completion, Water blocking, Deliverability test.
Fluid loss is inevitable in the well drilling and completion, which may cause series of formation damage such as clay swelling, solid plugging and water blocking. In tight sand gas reservoir, water blocking has become the major damage factor for economical developing. In deliverability test, water blocking will bring an inaccurate productivity test result to affect the following development strategy. With the development of East China Sea gas field, well drilling is focusing on the deeper tight sand formation. The tiny pore throat and high capillary pressure can bring out serious water blocking damage during well drilling and completion. The damaged zone can mislead the resource assessment and productivity evaluation. In this paper, an exploration well X in East China Sea gas field is selected as the research target to investigate the water blocking mechanism and physical process during well drilling and completion process. This study compares the productivity performance of X well with fluid loss and no fluid loss models through numerical modeling approach based on the actual data. Sensitive studies are also performed in the simulation. Results show that the excessive fluid invasion pressure and lower matrix permeability will result in serious water blocking damage to mislead the resource assessment and productivity evaluation even in underbalanced well drilling. Interestingly, extending shut-in time can make the gas production rate quickly reach the peak value in the early production stage, while it can decrease the cumulative gas production in whole production process. This study can provide an avenue to initiate quantitative analysis on resource assessment, and gas productivity evaluation strategy after water invasion during the well drilling and completion in tight sand gas reservoir of East China Sea.
Bahrami H, Reza Rezaee M, Nazhat D, et al. Effect of Water Blocking Damage on Flow Efficiency and Productivity in Tight Gas Reservoirs. SPE Production and Operations Symposium, Oklahoma City, Oklahoma, 2011; 27–29 March. https://doi.org/10.2118/142283-MS
Keelan DK, Koepf EH. The role of cores and core analysis in evaluation of formation damage. J Petrol Technol. 1977; 29(05): 482-490. https://doi.org/10.2118/5696-PA
Holditch SA., Factors affecting water blocking and gas flow from hydraulically fractured gas wells. J Petrol Technol. 1979; 31(12): 1,515-1,524. https://doi.org/10.2118/7561-PA
Bennion DB, Thomas FB, Bietz RF. Low permeability gas reservoirs: problems, opportunities and solutions for drilling, completion, stimulation and production. SPE Gas Technology Symposium. 1996. https://doi.org/10.2118/35577-MS Zhou XP, Sun L, Cheng CG. Study on water blocking of low permeability gas reservoir. Special Oil & Gas Reservoirs, 2005; 12(5): 52-54. (In Chinese).
Wills HA, Miskimins JL, Kazemi H. Coupled 3D Numerical Investigation of Hydraulic Fracture Cleanup for Both Slickwater and Gelled Fluids. SPE Annual Technical Conference and Exhibition. 2009. https://doi.org/10.2118/124327-MS
Tsar M, Bahrami H, Rezaee R., et al. Effect of drilling fluid (water-based vs oil-based) on phase trap damage in tight sand gas reservoirs.SPE Europec/EAGE Annual Conference. 2012. https://doi.org/10.2118/154652-MS
Bahrami H, Rezaee R, Clennell B. Water blocking damage in hydraulically fractured tight sand gas reservoirs: An example from Perth Basin, Western Australia. J of Petrol Sci Eng. 2012; 88: 100-106. https://doi.org/10.1016/j.petrol.2012.04.002
Ghanbari E, Dehghanpour H. The fate of fracturing water: A field and simulation study. Fuel 2015; 163: 282-294. https://doi.org/10.1016/j.fuel.2015.09.040
Ward JS, Morrow NR. Capillary pressures and gas relative permeabilities of low-permeability sandstone. SPE Format Evaluat. 1987; 2(03): 345-356. https://doi.org/10.2118/13882-PA
Fairhurst DL, Indriati S, Reynolds BW, et al. Advanced technology completion strategies for marginal tight gas sand reservoirs: a production optimization case study in South Texas. SPE Annual Technical Conference and Exhibition. 2007. https://doi.org/10.2118/109863-MS
Wells JD, Amaefule JO., Capillary pressure and permeability relationships in tight gas sands. SPE/DOE Low Permeability Gas Reservoirs Symposium. 1985. https://doi.org/10.2118/13879-MS
Bahrami N. Evaluating factors controlling damage and productivity in tight gas reservoirs. Springer Science & Business Media. 2013; 24-26. https://doi.org/10.1007/978-3-319-02481-3
Law BE, Curtis JB. Introduction to unconventional petroleum systems. AAPG Bullet. 2002; 86(11): 1851-1852. https://doi.org/10.1306/61EEDDA0-173E-11D7- 8645000102C1865D