Research On Enhancing Residual Oil Recovery Of Channel Sandstone Reservoir In Daqing LSX Oilfield By Using Horizontal Wells

Horizontal well has such advantages as large producing area, slower water invasion, high-degree employment of pay zones. America and Canada are representative in the overseas oilfields. Shengli and Xinjiang oilfields are pioneers in the domestic oilfields where horizontal wells have been widely applied. Since 2003, CNPC has lunched a project named as"Feasibility Research and Field Test of Producing Residual Oil by Using Horizontal Well Technology in Daqing Oilfield", which aimed to use horizontal well to tap the residual oil at the top of thick pay zones that can not be developed by vertical wells .By using residual oil analysis, this project demonstrates the limitation of applying horizontal well technology due to reservoir and residual oil development degree. In combination with residual oil identification under the dense well pattern of high water cut oilfield, by means of modern large deviation drilling, LWD and cuttings logging detection and logging interpretation, horizontal well reservoir engineering geographic development program was optimized, and the first filed test of tapping residual oil on the top of thick pay zones by using horizontal well in Daqing oilfield was performed. Without similar geography and development conditions at home and abroad, through field tests of two opposite horizontal wells, the project evaluated the feasibility of using horizontal wells to tap the residual oil at the top of thick pay zones, and preliminarily reached the conclusion that both success and risk exist during the application of horizontal wells in Daqing LSX oilfield.According to the comprehensive evaluation of horizontal well field test, the application and promotion of horizontal well is decided by reservoir type evaluation, horizontal segment position design, directional drilling, reservoir protection, completion and perforation, logging and testing and numerical simulation etc. The application of horizontal well in Daqing oilfield is limited largely by the current reservoir and residual oil and well pattern that cause small distance of horizontal segment to the aquifer and quick watered out speed. Combining with the scale of polymer flooding in Daqing oilfield, the project creatively put forward the new idea of binging horizontal well technology and tertiary recovery together.The method and conclusion of this project have profound signification for the application of horizontal well to enhance the recovery of reservoir in Daqing oilfield.