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Successful control of high water production with thixotropic conformance technology in a horizontal well: Diagnosing the water production mechanism

Abstract:

Conformance technology is the application of processes to reservoirs and boreholes to reduce water production, enhance recovery efficiency, or satisfy a broad range of reservoir management and environmental objectives. An operator desired to isolate aquifer zones and reduce water production in a horizontal section. First discussed is problem identification in the oil producing well; following, the application of reservoir simulation to determine the amount of and the most appropriate treatment application is discussed. Depending on fluid density differences and wellbore deviation, conventional conformance treatments can tend to slump/rise along horizontal or highly deviated sections, compromising the placement accuracy and overall treatment success. The stress-dependent (thixotropic) rheological properties of the conformance technology service used in this project provides rapid viscosity increase during placement, allowing the treatment to remain in place until in-situ crosslinking occurs at a pbkp_redicted time, helping to provide a competent seal across the targeted area. A reservoir simulator was used to optimize the design of a conformance treatment and to evaluate the efficiency of the conformance solution. During pumping of the conformance system for the isolation of the lower zone because of water problems, it was observed that the entrance of the two sealing systems to the formation increased the pumping pressure, showing the sealing effect. Additionally, the thixotropic characteristic of the conformance sealant could help keep the systems in place until they acquired the consistency to complete the isolation of the water zone. Water production after conformance treatment was reduced by almost 65%, aligned to the expected results from diagnostics. A successful conformance operation was completed in a horizontal section, overcoming the natural tendency of standard fluids to slump/rise along horizontal or highly deviated sections. The proper conformance diagnostics with a reservoir simulator was vital to the success of this project