压裂液滤失性对增油效果的影响和作用机理

Effect of Fracturing Fluid Loss Property on Oil Increase and Mechanism of Action

潘 赫 卢祥国 谢 坤 王珂昕

PAN He LU Xiangguo XIE Kun WANG Kexin

非均质油藏水驱或聚合物驱后， 油井附近区域中低渗透储层难以波及， 剩余油饱和度较高。为深入了解压裂液滤失性对压裂增油效果的影响， 比较了 5种压裂液的滤失性能， 通过改变压裂液滤失时间和裂缝长度， 研究了压裂液滤失性对增油效果的影响和作用机理。结果表明， 与改性胍胶相比， 合成聚合物压裂液滤性能良好， 滤失液可以将水平裂缝入口附近区域岩心中剩余油驱替到岩心深部区域， 在后续水驱作用下剩余油再沿裂缝返回采出端， 达到提高采收率的目的。通过选择压裂液类型以及增加压裂施工时间和裂缝长度， 可使压裂液滤失量增加， 滤失液波及体积增大， 发生运移剩余油量增加， 导致采收率增幅提高。从技术经济效益角度考虑， 推荐 “聚合物溶液+聚合物凝胶” 段塞组合进行施工， 合理的压裂裂缝长度为 1/5～ 1/3注采井距。图9表 4参 16

After water or polymer flooding in heterogeneous reservoir， middle and low permeability lays in the vicinity of oil well were difficult to reach and the saturation of remaining oil was high. In order to further understand the effect of fracturing fluid filtration on fracturing and oiling， the filtration performance of five fracturing fluids was compared. By changing the filtration time of fracturing fluid and crack length， the effect and the mechanism of fracturing fluid filtration on oil increment were studied. The results showed that the filtration performance of polymer fracturing fluid was better than that of modified guar gum. Filtrate loss fluid could displace the remaining oil near the entrance of horizontal fracture to the deep area of core. The residual oil returned to production points along cracks under the action of subsequent water flooding， which improved oil recovery. By selecting the type of fracturing fluid and increasing fracturing construction time and crack length， the loss of fracturing fluid increased， the swept volume of filtrate fluctuated and the volume of surplus oil increased， as a result， the ultimate enhanced oil recovery rate increased. Under the consideration of economic benefits， the construction with a combination slug of polymer fluid and polymer gel was recommended. Rational fracture length ranged from 1/5 to 1/3 of injection-production well spacing.

10.19346/j.cnki.1000-4092.2017.02.011