论文部分内容阅读
页岩气井的压后排采过程呈现明显的阶段性特征,根据生产气液比与累积产气量的关系曲线可将整个排采阶段划分为早期阶段和晚期阶段。在排采生产早期,气井表现为气液同产,并以产液为主,此时页岩基质向裂缝系统的供气能力不足,整个水力裂缝系统(主压裂缝、次级压裂缝及沟通天然裂缝)可视为封闭体系。从物质平衡原理出发,建立了基于排采早期阶段生产数据的压裂裂缝初始体积和面积的计算模型,并以龙马溪组典型页岩气井进行了实例分析。结果显示,分析井的裂缝体积为注入压裂液量的70%左右,裂缝面积可达10~7 m~2量级,较大的改造裂缝面积也说明压裂形成了较复杂的缝网,提高了气井有效泄流面积。该模型解释结果与页岩气井排采参数和产气能力吻合良好,是评价压裂裂缝参数和改造效果的有效途径,对矿场水力压裂效果评估具有指导意义。
According to the curve of gas-liquid ratio and cumulative gas production, the whole discharge stage can be divided into the early stage and the late stage according to the obvious stage characteristics. In the early stage of discharge production, the gas wells showed gas and liquid co-production and dominated by liquid production. At this time, the supply capacity of shale matrix to the fracture system was insufficient. The entire hydraulic fracture system (main fracture, secondary fracture and communication Natural cracks) can be regarded as a closed system. Based on the principle of material balance, a calculation model of initial volume and area of fracturing fractures based on production data in the early stage of production recovery was established. The typical shale gas wells in Longmaxi Formation were analyzed. The results show that the fractured volume of the analytical well is about 70% of the injected fracturing fluid and the fracture area can reach the magnitude of 10 ~ 7 m ~ 2. The larger fractured area also indicates that fracturing results in a more complicated fracture network, Improve the gas well effective drainage area. The interpretation of the model is in good agreement with the production parameters of shale gas well and the gas production capability, which is an effective way to evaluate the fracture parameters and the effect of fracturing. It is instructive to evaluate the effect of hydraulic fracturing in the mine.