Research and Practice of Development Model during the Continental Heavy Oil Field’s Extra-high Water Cut Stage in the Bohai Sea

Abstract The formation mechanism, production limits and injection-production pattern of residual oil were studied by laboratory experiment, micropore simulation and reservoir engineering. The findings indicate that when injection times increase, the displacement efficiency rises as well. The residual oil mostly remains in the pore throat, which has a radius of 10 to 50 μ m, with a mean pore throat radius of 35 μ m.. As the displacement pressure gradient increases from 0.004MPa/m to 0.012MPa/m, When the displacement ratio of piston type increases and the displacement ratio of water film flow drops, the displacement efficiency grows. The horizontal well pattern’s gradient of displacement pressure is increased by 1.5 ~ 1.7 times compared with the oriented well pattern, and the displacement efficiency is increased by 12% ~ 15%. The development of the Bohai oilfield during the ultra-high water cut stage has been informed by the aforementioned findings, forming a horizontal well joint directional well three-dimensional pattern development model, oil production rate increased from 1.3% to 2.3%, and water drive recovery rate increased from 24.5% to 38.6%, realizing efficient development in the ultra-high water cut stage, and providing reference for the development of similar oil fields.