H. Yang, K. Wei, X. Qiu, C.C. Zhou
University of Wyoming,
Keywords: water channeling, horizontal well, tight fractured oil reservoir, gel dam, plugging agent
Summary:To address severe problems concerning water channeling in water flooding development of Chang 8 reservoir in Honghe oilfield, characterized by ultra-low permeability of matrix and extensive network of natural and artificial fractures, experimental research on polymeric gel and field trial of constructing a gel-dam of polymeric gel on horizontal injector have been conducted. With the viscosity of polymeric gel as an evaluation index, the formula of polymer gel plugging agent was optimized under the simulated condition of Honghe oilfield. The abilities including aging resistance, salt tolerance, shearing resistance, plugging and erosion resistance were evaluated with sand filling tube model. The laboratory results showed that the new plugging agent indicated superior performances, including ability to adjust gelling time within 4~10 days, salinity resistance up to 10×104 mg/L, resistance to Ca2+concentration up to 8,000 mg/L, high resistance to shearing and erosion, as well as plugging rate up to 95%. The field tests regarding two wells indicated that with the application of gel-dam technology, the oil production rate of producers increased, while water cut decreased. The accumulated increased oil was up to 102t, and water cut dropped from 99.0% to 92.3% , with effective duration of over 217days. Basing on the results of laboratory and field trial, Gel Dam Technology on horizontal injector wells could meet the requirement of deeply plugging dominant channels, thus resolving the problem of water channeling associated with horizontal injectors during water flooding in Honghe oilfield.