复杂断块油藏二氧化碳驱挖潜高部位剩余油方案研究

Research on recovery of oil by CO_2 flooding in high layers of complex fault reservoirs

C区块戴一段油藏是中孔中高渗砂岩层状复杂断块油藏。属于高含水、高液量、高采出程度的低效开发老油田,利用常规手段挖潜断块高部位剩余油成本高、效益差。此油藏为边底水驱动的大倾角层状油藏,油水界面已经推至构造高部位油井,构造顶部无井网控制造成部分储量失控,同时地层埋深较浅,地层压力低二氧化碳无法实现混相驱。利用油气重力分异作用,实施二氧化碳气顶驱,促使油气界面均匀推进,避免"低注高采"造成的气窜问题,提升二氧化碳有效利用率。

Dai 1 member in block C is a multi-layer complex fault block reservoir with middle porosity and high permeability sandstone. This reservoir is a large dip stratified reservoir with multi-layer driven by edge-bottom water. The lack of the well pattern control at the top of the structure makes some reserves out of control. Meanwhile,the pressure of it is low,that makes the misciblephase displacement of CO2 impossible. According to these situations,we realized the gas cap drive of CO2 by the gravitational differentiation to promote the evenly advance of oil and gas interface.