提高非均质砂岩油田水驱采收率的新思路

在非均质、低渗透砂岩油田水驱开发的中后期,剩余油分布具有如下特点:①注采井网不合理在单砂体中造成有采无注,有注无采及注采失调,从而形成剩余油。②砂体单向受效,在翼侧形成剩余油。③砂体非均质严重,在高渗透地带造成水窜,在低渗透地区形成剩余油。基于剩余油分布的上述特点,分析目前开发剩余油所普遍采取的两种方法具有的不足,即井网加密受到储量丰度的局限及油田综合调整具有复杂、工作量大、难于管理、成本高,使上述剩余油在注水与采油分井进行的开发模式下很难得到充分开发,因此提出了开发剩余油、提高非均质低渗透砂岩油田水驱采收率的新思路——同井分层注、采开发模式,并以大庆葡萄花油田南部(葡南)为例进行了效果预测,结果表明:利用该模式可使葡南油田水驱采收率比标定值提高3.7%。

A NEW IDEA FOR IMPROVING WATER FLOOD EOR IN HETEROGENEOUS MEDIUM SANDSTONE OIL FIELD

During the metaphase and later stage of water flooding in heterogeneous medium and low permeability oil field,the remaining oil have characteristics of distribution describing as follow:(1) The irrationality of injection production pattern led to production without injection or injection without production or imbalance of injection production in single sand body,so it results in produced remaining oil; (2) Sand body was affected on one side,and remaining oil was produced in both flanks of sand body; (3) The heterogeneity of sand body caused water's breakthrough in high permeability area and produces remaining oil in low permeability part.On the basis of distributing characteristics of remaining oil mentioned above,analysing the shortcomings that two methods have,which was adopted at large in remaining oil development at present,namely,pattem in fill was restricted on reserve abundance and comprehensive adjustment was characterized with complex,a mass of work,difficult to manage and high cost.It was difficult to develop remaining oil fully by the mode of division of injection production wells,so the author put forward a new idea about developing remaining oil and improve water flood EOR in heterogeneous medium and low permeability oil field_separate layer injection production development mode in the same well,and water flood EOR can improve 3.7 percent over standard value by use of this mode through effect prediction in the south of Putaohua oil field in Daqing.