页岩气平台式井组井间干扰影响因素分析及井距优化

Analysis of influencing factors of interwell interference in shale gas well groups and well spacing optimization

以页岩气平台井组井间干扰影响因素为研究对象,利用数值试井分析技术,研究了不同储层基质渗透率、压裂改造参数、井间距、激动强度等参数对井间干扰的影响程度.在此基础上,掌握了页岩气水平井不同生产时间的压力分布特征,明确了井间干扰对气井最终可采储量(EUR)的影响程度,形成了综合考虑气井EUR和井控地质储量采收率的井距优化分析方法.结果表明:在天然裂缝不发育、井间人工缝网未沟通的情况下,压力波在改造区外传播范围有限,页岩气平台井组井间干扰强度一般较弱,在改造区及其附近压降程度最大,优化井距时不仅要考虑井间是否有压力干扰响应,更要考虑压力干扰的强度;天然裂缝越发育、压裂改造范围越大,则井间干扰越明显,优化井距要综合考虑天然裂缝发育程度及压裂改造范围的影响;受井间干扰影响,气井EUR随井距增加而增加、但增加幅度逐渐变小,采收率则随井距增加而下降、下降幅度逐渐增大;需要根据平台井组地质工程特征,综合考虑气井EUR和井控地质储量采收率优化井距.

Taking shale gas platform well groups inter-well interference factors as the research object,using numerical well test analysis technology,the degree of impact of different reservoir matrix permeability,fracturing parameters,well spacing,activation intensity and other parameters on inter-well interference are studied. On this basis,the pressure distribution characteristics of shale gas horizontal wells at different production times were grasped,and the degree of impact of inter-well interference on gas wells’ EUR was clarified,and well spacing optimization was formed that comprehensively considered gas wells’ EUR and well-controlled geological reserve recovery factor analytical method. The results show that when the natural fractures are not developed and the artificial fracture network between wells is not communicated,the propagation range of pressure waves outside the reconstruction area is limited,and the interference intensity between well groups of shale gas platform well groups is generally weak. The pressure drop degree is the largest in the fractured zone and around.When optimizing well spacing,it is necessary to consider not only whether there is pressure interference response between wells,but also the intensity of pressure interference;the more natural fractures develop and the greater the range of fracturing reformation,the more obvious the interference between wells,and optimization well spacing should take into account the development of natural fractures and the impact of fracturing reconstruction range;affected by inter-well interference,the EUR of gas wells increases with the increase in well spacing,but the increase gradually decreases,and the recovery rate decreases with the increasing well spacing.It is necessary to optimize the well spacing based on the geological engineering characteristics of the platform well group,comprehensively considering the gas wells’ EUR and the well-controlled geological reserves recovery factor.