致密气藏水平井压裂缝不均匀产气试井分析  

Well testing analysis of multi-fractured horizontal well with unequal gas production of fractures in tight gas reservoir

作　　者：严谨[1] 何佑伟 史云清[1] 郑荣臣[1] 程时清[2,3] 于海洋[2,3] 李鼎一[2,3] 

机构地区：[1]中国石化海相油气田开发重点实验室,北京100083 [2]中国石油大学(北京)油气资源与工程国家重点实验室,北京102249 [3]中国石油大学(北京)石油工程教育部重点实验室,北京102249

出　　处：《天然气地球科学》2017年第6期839-845,共7页Natural Gas Geoscience

基　　金：中国石化海相油气田开发重点实验室基金项目"致密气藏压裂井不均匀产气试井解释模型及方法研究"(编号:G5800-15-ZSWX057)资助

摘　　要：现场测试资料表明,压裂水平井部分裂缝产气量很小,甚至不产气,但现有试井模型几乎都未考虑其对试井解释的影响。因此,采用源函数、纽曼乘积方法建立了水平井压裂裂缝不均匀产气试井模型,通过数值反演得到了考虑井筒存储和表皮效应的井底压力解,绘制了水平井压裂裂缝不均匀产气试井典型图版,并研究了各裂缝产气量、裂缝半长、裂缝数量、裂缝间距和裂缝导流能力对压力动态特征的影响。水平井压裂裂缝均匀产气和不均匀产气在试井典型图版上呈现出不同特征。缝间干扰越小,早期径向流越明显,且在压力导数曲线上表现为约等于0.5/N的水平段。致密储层渗透率小,测压资料难以反映出系统径向流特征,如果把早期径向流当作系统径向流解释会导致解释出的渗透率与真实值存在约N倍的差异,因此在致密气藏试井解释中应该考虑不均匀产气对压力响应特征的影响,准确识别早期径向流阶段。最后给出了压裂裂缝不均匀产气的参数解释方法,为更细致地评价水平井压裂裂缝产气能力提供了借鉴。Field-test data indicate that some fractures have little or no contribution to the total gas produc- tion. However, most well-testing models did not consider the effects of unequal gas production of fractures （UGPF） on well testing interpretation.Therefore, this paper establishes a well-testing model with consider- ation of UGPF based on the source function and Newman＇s product. Then,type curves of multi-fractured horizontal well（MFHW） with UGPF are developed through numerical algorithm to involve the effects of wellbore storage and skin factor. Sensitivity analysis （i. e. UGPF, fracture half-length, number of fractures, fracture spacing） are further discussed.There have big differences among well-testing type curves between equal gas production of fractures（EGPF） and UGPF.The early-radial flow behaves as a horizontal line with the value of nearly 0.5/N in the pseudo-pressure derivative curves when the interferences among fractures are tiny.Permeability of tight gas reservoir is very low so that the field-test data is hard to reflect the char- acteristics of pseudo-radial flow regime.If the early-radial flow regime is mistaken as the pseudo-radial flow regime, the interpreted permeability will be incorrect. Therefore, the effect of UGPF on well testing inter- pretation in tight gas reservoir should be investigated.Finally,this paper provides a method to estimate the parameters,which can be regarded as a reference for fracture performance evaluation.

关 键 词：致密气藏 压裂水平井 不均匀产气 试井分析 格林函数 纽曼乘积方法 

分 类 号：TE132.2[石油与天然气工程—油气勘探]