顺北地区断控缝洞体测井响应特征和类型识别方法

顺北地区断控缝洞体蕴藏有丰富的油气资源, 断裂带控制了油气运移和聚集。断裂带结构复杂, 发育断层、裂缝等多种储集空间, 断层中充填不同物质。多种类型的储集空间和充填物导致常规测井响应复杂, 加之研究区测井资料不尽相同, 断控缝洞体类型识别困难。依据录井和电成像测井等信息, 确定了未充填断裂洞穴型、角砾充填断裂洞穴型、泥质充填断裂洞穴型和裂缝型4种断控缝洞体类型。分析了单井测井资料, 包括各种测线曲线、无密度测井曲线、无密度和无能谱测井曲线、无密度和无中子测井曲线、无密度和无中子以及无能谱测井曲线和无中子和无能谱测井曲线共6种情况。对比不同类型断控缝洞体的自然伽马、无铀伽马、声波时差、中子、密度、深侧向和浅侧向电阻率等测井响应差异, 将测井响应两两组合进行交会分析, 优选出5个对断控缝洞体类型敏感的测井响应交会图版, 结合不同的测井资料情况, 形成4套逐级识别断控缝洞体类型的流程, 建立了一种利用常规测井资料识别断控缝洞体类型的方法。应用该方法对顺北地区实际井资料进行处理解释, 识别结果与岩心、电成像测井解释结论一致。该识别方法能满足研究区各种测井曲线资料情况的断控缝洞体类型识别需求, 识别结果为断裂带内部结构解释提供有效支撑。

Fractures dominated hydrocarbon migration and accumulation in fault-karst reservoirs with abundant resources in Shunbei area.Multi-type reservoir spaces in faults and cracks and various interstitial materials lead to complicated log responses, and different logging suites employed in this area further intensify the complexities of fault-karst reservoir identification.In terms of well logs and electric imaging logs, we establish 4 fault-karst reservoir types: unfilled fault-cave reservoir, breccia-filled fault-cave reservoir, mud-filled fault-cave reservoir, and fractured reservoir.Six cases are involved: complete suite of logs, suite with no density log, suite with no density and spectral logs, suite with no density and neutron logs, suite with no density, neutron, and spectral logs, and suite with no neutron and spectral logs.In accordance with GR, KTH, acoustic time, neutron, density, deep resistivity, and shallow resistivity responses of different reservoir types and 2D crossplots of log data, 5 templates are formulated for fault-karst reservoir identification.In view of different logging suites, 4 workflows are established for step-by-step fault-karst reservoir identification using routine log data.We use this methodology for log data processing and interpretation in Shunbei area, and the results of identification which are reconciled with core and electric imaging log interpretations offer support to internal structure interpretation in fault zones.This methodology is feasible for all logging suites in the area of interest.