特低渗油藏氮气泡沫驱适应性评价及效果分析

Adaptability Evaluation and Effect Analysis of Nitrogen Foam Flooding in Ultra-Low Permeability Reservoirs

为了提高延长油田沙家沟区块氮气泡沫驱开发效果,对其进行了适应性评价和效果分析。沙家沟区块位于陕北斜坡东部宝塔油田南部,主力油层为长6储层,各小层平均渗透率均介于0.69×10^-3~1.38×10^-3μm^2,属于低孔-特低渗储层。该区块天然能量开发时间长,且注水开发前全区综合含水率高达40%,水驱开发半年后普遍出现水窜、水淹现象。分析表明,氮气泡沫驱在沙家沟区块具有较大潜力,其适应性较好,可以有效降低自然递减率,起到明显的降水增油效果。

In order to improve the development of nitrogen foam flooding in Shajiagou block of Yanchang Oilfield,this paper carried out the evaluation and effect analysis of nitrogen foam flooding in Shajiagou block.Shajiagou block is located in the southern part of Baota Oilfield in the eastern Shaanxi Slope.The main oil layer is Chang 6 reservoir.The average permeability of each small layer is between 0.69×10^-3-1.38×10^-3μm^2,which belongs to the low porosity-extra low permeability reservoir.The natural energy development time of this block is long,and the comprehensive water content of the whole area before flooding development is as high as 40%.After half a year of water flooding development,water logging and flooding are common.Nitrogen foam flooding has great potential in Shajiagou block.The on-site experiment results show that the nitrogen foam flooding has good adaptability in Shajiagou block,which can effectively slow down the natural decline rate of Shajiagou block and play an obvious role in precipitation and oil increase.