辫状河三角洲前缘评价剩余油分布的水淹模式——以温西三块水淹层评价为例

Evaluation on remaining oil with hydrologic model in braidriver deltas front subfacies: A case of swept layer in Wenxisan Block

针对温西三块辫状河三角洲前缘水下分流河道、河口坝、席状砂、远砂微相砂体受河道水流和湖浪双重作用,砂体结构特征及赋存状态复杂,在注水开发中水淹程度及其测井响应具有不同的变化特征,提出了辫状河三角洲前缘评价剩余油分布的7种水淹模式。不同水淹模式分布发育于不同的微相单渗砂或叠置单渗砂层中,它们在注水开发中,由于油层层内或层间差异引发注入水线推进不均匀,造成油层内部或油层间纵向和横向层间干扰,形成中弱水淹或未水淹层。其中主体微相河道正向单渗、河道叠置渗水淹模式,注水开发水线推进时有不均,常在油层上部或叠置层间差异层形成中弱水淹层位;非主体微相席状砂渗、远砂渗注水开发水线推进差,常形成全层段弱水淹或未水淹层位。它们分别造成目的层段已动用油层和基本未动用油层的剩余油分布及挖潜部位。该研究以实例,具体分析了不同沉积微相控制水淹模式的测井响应特点及其解释方法,阐明了该区水淹层剩余油挖潜的主要方向和目标。

Both of stream and lake wave have influence on braid-river deltas front subfacies, including under- water distributary channel mouth bar sand sheet and distal sands in Wenxisan Block. The structure and store of sand are complicated. Proposed is the thought that establishes seven kinds of watered-out mode to evaluate dis- tribution of remaining oil in braid-fiver deltas front subfaeies basedr on the variation characteristics of the wa- tered out degree and logging response. Different kinds of watered-out mode develope in single permeability sand bed or superimposed permeability, and difference in the single sand or between the layers usually lead to uneven distribution of water line. It＇s the reason of mid-weak or non watered flooded zones beacause of inter- oil formation. Waterflooding usually performs poorly in the secondary microfacies including sand sheet and dis- tal sands, and forms weak or non wateredflooded area in the layers. They show the distribution of remaining oil and improvement layer in the developed and undeveloped reservoir. The paper analyzes logging response and interpretation of watered-out mode according to different sedimentary microfacies with an instance and illumi-nate the direction and target to further develop the remaining oil in the flooded layer of the area.