The Research and Application of Segregated Completion Technology in Horizontal Wells in the Heavy Oil Reservoirs

Abstract

Liaohe oilfield is the biggest production base of the heavy oil in China. There are more than 800 horizontal wells with thermal recovery in the heavy oil reservoirs. Most of them adopt screen to complete the wells without packer outside of the casing, which results in packing off annulus space between screen and layer and only commingled steam or step steam can be injected inside the screen. Because of the areal and vertical anisotropy of the reservoirs, the horizontal sections are exploited unequally. According to the statistics, the horizontal wells with nonuniform exploitation accounts for 80 percent of all the horizontal wells with thermal recovery, and only 1/3 to 1/2 of the horizontal sections are comparatively well produced. The oil well productivity is seriously affected. So based on step steam injection inside the screen, we have developed the segregated completion and segregated steam injection technology applied to the horizontal wells with thermal recovery in heavy oil reservoirs. By means of the research on the segregated completion technology and development of high temperature ECP and casing thermal centralizer, which formed the corresponding technology applied in the horizontal wells with thermal recovery. Till now this technology has been applied in 8 wells, and average cyclic steam/oil ratio increased 0.1 plus, and the uniform development level of the horizontal section has been improved and the oilfield’s development effect has been advanced obviously.