考虑启动压力的整体压裂优化设计及应用

Optimal Design and Application of the Integral Fracturing Taking into Account the Impact of Threshold Pressure

通过建立整体压裂数学模型和物理模型,结合鄂尔多斯盆地伊陕斜坡中段长6层位的启动压力梯度和渗透率的关系图版,形成适用于陕北鄂尔多斯盆地低渗透油藏菱形反九点井网、考虑启动压力梯度的整体压裂优化设计模型。通过数值模拟,分析启动压力梯度对具体某区块菱形反九点井网中压裂油井采出程度、采油速度、含水率、见水时间、油水井最佳缝长比和最佳导流能力等参数的影响。应用正交设计法和熵信息法等方法,模拟优化筛选出适用于该区块的最佳整体压裂参数组合。现场压裂试验表明,数值模拟计算结果与实际生产数据相符程度高,且通过对比试验井与邻井生产数据,验证了优化后的设计对开发效果具有明显的提升作用,验证了整体压裂模型及优化设计方法的有效性,对低渗透油藏压裂开发具有借鉴作用。

Abstract Based on establishing a integral simulation model and physical model, combined with master curve between threshold pressure gradient and permeability of Chang 6-layer in Yi-Shan slope in Ordos Ba- sin, a integral fracturing optimization model considering threshold pressure applicable to diamond inverted nine-spot well pattern in low permeability reservoir in Ordos Basin, northern Shaanxi province is formed. By simulating pro- duction performance, the impact of threshold pressure gradient on recovery percent, production rate, water cut-re- covery, water breakthrough time, optimal ratio of fracture half length to well spacing and optimal fracture conductiv- ity of diamond inverted nine-spot well pattern fracturing in this block are analyzed. Adopting orthogonal design and entropy information method, the optimal scheme is selected. Through the comparison between the production data of field fracturing experimental well and the adjacent well and the simulated result, the effect of optimization design has been validated. The result offers reference for fracturing application of low-permeability reservoirs.