聚合物驱后油层优势渗流通道识别与治理

聚驱后油层剩余油分布高度零散,空间上中低水洗部位与优势渗流通道交互分布,开采难度大,经济效益差。如何识别和治理优势渗流通道是目前聚驱后油层开发中急需解决的问题。以大庆油田萨南开发区一类油层某区块为例,通过定义有效渗透率、含油饱和度界限,结合动态资料识别并验证优势渗流通道,描述其动态特征,与大庆长垣油田其他开发区聚驱后油层优势渗流通道发育特征基本一致。根据优势渗流通道的发育及动态特征的差异性,明确调整方向,采取黏度优化、分层、堵水、调剖等治理方法,取得了较好现场应用效果,为聚驱后油层优势渗流通道的识别与治理提供了依据。

IDENTIFICATION AND CONTROL OF THE PREFERENTIAL SEEPAGE CHANNELS FOR THE OIL RESERVOIRS AFTER THE POLYMER FLOODING

After the polymer flooding,the remained oil in the reservoirs is extremely dispersed,the water flooded parts in the medium and lower waterflooded positions are alternately distributed with the preferential seepage channels,so the production difficulty is rather bigger and the economic benefit is so poorer.How to identify and control the preferential seepage channels is the issue to be solved urgently in the present polymer flooded reservoirs.Taking a certain block of the first-type reservoir in Sanan Developing Area of Daqing Oilfield as an example,by means of defining the boundary values of the effective permeability and oil saturation,integrated with the dynamic data,the preferential seepage channels were identified and verified.And moreover the dynamic characteristics were described,compared with the other developing area of Daqing Placanticline Oilfields;the developed characteristics of the preferential seepage channels after the polymer flooding were generally coincident.According to the differences of the channel development and dynamic characteristics,the adjusting directions were made clear,with the help of the controlling and stimulating method such as the optimized viscosity,layer separation,water plugging,profile control and so on,much better field application effects were achieved.All the results have provided the evidences for the identification and management of the preferential seepage channels after the polymer flooding of the oil reservoirs.