Commercial Test of Polymer Flooding in Daqing Oil Field Daqing petroleum Administrative Bureau

Wang Demin, SPE Member, Zhang Jingcun, Meng Fanru, Liu Heng, Li Lin, Han Bohui, Qi Lianqing Abstract Commercial pilot test of polymer flooding in Daqing oil field has been conducted for nearly two years, this paper summarizes the operating procedures and its initial results. Although this test is far from completion, it is successful according to the analysis of the obtained data which is marked by dramatic decrease of watercut of oil wells, increase of oil production by times, and accordance of the production behaviour with the predicted value on the whole. This test provides excellent prospects for large scale polymer flooding in Daqing oil field. Introduction Daqing oil field is a heterogeneous sandstone reservoir formed by "fluvial delta system", and is characterized by low reservoir temperature, low salinity of formation water and medium viscosity of crude oil, which are favourable geological characteristics for polymer flooding. Four small scale polymer flooding pilot tests have been conducted in Daqing oil field from 1972 to 1993, and have obtained relatively good results, recovery rate was increased by more than 10%, and incremental oil for each ton of polymer was more than 150 tons. For many years, polymer screening, polymer degradation and core flooding by polymer have been studied in the laboratory, which have provided theoretical basis for pilot tests. To prove the polymer flooding result under condition of current well pattern and well spacing of the oil field, which is "large well spacing and many well groups", and to provide practical basis for commercial polymer flooding, preparation for this commercial test began to be made from 1990. Polymer flooding was started in January 1993, and the test is presently under way. RESERVOIR DESCRIPTION AND RESIDUAL OIL DISTRIBUTION The test area is located in the northern part of Saertu oil field and the test layers are Pu l (Fig. 1). This areal was put into development by line well pattern water injection in 1963. From the end of 1990 to the beginning of 1991, 50 new wells were drilled to conduct this commercial test, consisting 25 five-spot area well patterns with an injection production well spacing of about 250 m. There are 61 production and injection wells together in the test area, among them 25 are injection wells (including one original injection well and three converted injection wells), 36 are production wells (including eight original production wells). P. 127