Abstract: Taking Gangdong development area of Dagang Oilfield with mid-later developing phase as an example, some geology and drilling-exploitation engineering factors controlling residual oil formation and distribution including the seepage discrepancy of inner layers, plane and inter layers, positive micro-structure of oil formation, updip pinching of sand bodies, default shielding, non-perforated oil layers and well condition deterioration were investigated. The results show that the key geology factor affecting residual oil formation and distribution includes the reservoir seepage discrepancy. The vertical inner seepage discrepancy led the residual oil to be mainly distributed in the mid-upper sections of positive rhythm sands. The important residual oil abundance zones are in the sand amalgamation belts on plane, and the relative low-permeability areas are in the major sand boundaries. The non-coupling property of geology factors such as size and shape of sand and inter seepage discrepancy to the engineering factors such as well deployment led to the combination of multi-operating mechanism such as injection-production well pattern imperfect, non-controlled well pattern, injection-production relation inefficiency. The different kinds of residual oil distribution, such as plane residual oil stagnant area, non-producing oil sand body, suppressing high pressure residual oil layers, are easy to be formed.

Key words: reservoir, residual oil distribution, control factor, non-coupling property, Dagang Oilfield

摘要： 以进入开发中、后期的大港油田港东开发区为例,研究了储层层内、平面、层间渗流差异,油层正向微构造、砂体上倾尖灭、断层屏蔽等地质因素以及油层未射孔、井况恶化等钻采工程因素对剩余油形成与分布的控制作用.研究结果表明,储层的渗流差异是影响剩余油形成与分布的关键地质因素,垂向上层内渗流差异导致剩余油主要分布在正韵律型砂体的中上部;平面上的砂体拼接带及主砂体边缘相对低渗透区域是剩余油富集的重要场所.砂体规模与形态、层间渗流差异等地质因素与井网部署等工程因素的非耦合性导致注采井网不完善、井网控制不住、注采关系失效等多种作用机制,结果形成平面剩余油滞留区、未动用的油砂体、憋高压的剩余油层等多种形式的剩余油分布.

关键词: 储层, 剩余油分布, 控制因素, 非耦合性, 大港油田