页岩气井产量的工程影响因素

Engineering factors Influencing on production rate in shale gas wells

为了充分认识页岩气井在衰竭开采过程中,气井产量受工程因素的影响,解决目前压裂改造后页岩气井产量影响因素研究不够全面,特别是影响因素主次不明确的问题,以典型TY页岩气藏为研究对象,基于页岩多维多尺度的渗流数学模型,编制了求解软件,分析了页岩气井产量影响因素的主次关系,主要包括裂缝高度、水平井长度、裂缝长度、压裂簇数和段间距等。研究结果表明:在不同因素影响下,页岩气井累计产气量的增加幅度不同,裂缝高度对累计产气量的增加幅度为138%、水平井长度为109%、裂缝长度为103%,压裂簇数为17%、段间距为-8%。结论认为:①压裂造成的裂缝高度是影响页岩气井产量的主要因素,次要因素分别为水平井长度、裂缝长度、压裂簇数和段间距;②裂缝高度越高、水平井长度越长、裂缝长度越长、压裂簇数越多、段间距越小,页岩气井稳产时间越长,累计产气量越大;③典型TY页岩气藏TY1H井合理开发的最优化参数为压裂簇数3簇,段间距为80 m,裂缝高度为35 m,裂缝长度为120 m,水平井长度为1 750 m。

In order to make clear the engineering factors influencing on the production rate in shale gas wells during depletion production and solve such problems that these influencing factors after fracturing are not understood completely,especially considerable ambiguity about primary and secondary influencing factors,typical TY shale gas reservoirs were tak⁃en as objectives.A kind of solution software was developed on the basis of one multi-dimensional,multi-scale mathematic percolation model.Furthermore,both primary and secondary relationships among these factors,including fracture height,horizontal-well length,fracture length,number of fracturing clusters,and stage spacing were analyzed.It is indicated that an increasing amplitude of cumulative production rate in shale gas wells is quite different under these distinct influencing factors,for example,138%for fracture height,109%for horizontal-well length,103%for fracture length,17%for number of fracturing clusters,-8%for stage spacing,individually.It is concluded that(1)the primary influencing factor should be fracture height induced by fracturing,and the secondary ones include horizontal-well length,fracture length,number of fracturing cluster,and stage spacing;(2)both stable production time and cumulative production rate increase with the increase of fracture height,horizontal-well length,fracture length,and number of fracturing cluster,along with the de⁃crease of stage spacing;and(3)for typical TY shale gas reservoirs in TY1H well,the optimized parameters for a rational development should be fracturing clusters of 3,stage spacing of 80 m,fracture height of 35 m,fracture length of 120 m,and horizontal-well length of 1750 m.