深层致密碳酸盐岩走滑断裂带核带结构与断控储集体簇状发育模式:以塔里木盆地顺北4号断裂带为例

Fault zone architecture of strike-slip faults in deep,tight carbonates and development of reservoir clusters under fault control:A case study in Shunbei,Tarim Basin

综合利用地震属性、常规/成像测井、取心标定以及生产动态资料,通过对顺北4号断裂带内部核带结构综合厘定与统计分析,开展走滑断裂断控型储层发育特征研究。研究结果表明,走滑断裂带核带结构决定了主要储层类型,分段构造样式控制了核带结构及其对应优势缝洞的发育部位。断裂带内部并非“连片”发育均质储集体,在单个断面的控制范围内,角砾带与裂缝带通常呈组系展布,规模储层之间夹持致密的基岩,整体构成簇状发育特征。不同类型分段内部,断面控制的核带结构也有各自的特点。压隆段活动强度大,内部钻井揭示的角砾带和裂缝带从数量和宽度上均具有明显优势,呈现出“多破碎带+多裂缝带”的特征。拉分段核带结构多发育在边界断面附近,内部核带结构欠发育,活动强度仅次于压隆段。平移段活动强度为3类分段中最弱,核带结构规模相对最小,单断面控制的裂缝带个数最少且间距最大。为了最大限度地动用有效储层以获得更高的单井产能,应根据不同分段类型各自核带结构的发育特点,有针对性地设计井轨迹,确保尽可能多地钻揭断裂带内部核带结构。结合单井单位压降产能分析表明,储集体规模并非控制单井产能的唯一因素,不同性质分段的储集体连通性可能是控制单井产能的另一个关键因素。

Combining seismic attribute analysis,well/imaging logging,coring calibration,and production performance data analysis,the fault zone architecture of the Shunbei No.4 fault zone is determined and statistically analyzed to obtain insights into the characteristics of reservoir development under strike-slip fault control.The results show that the type of reservoir rock space is determined by the fault zone architecture which,in turn,is controlled by the segmentation structural style of the fault zone,as are the locations of favorite fractures and caves.In fact,the development of reservoir rocks in the interior of the fault zone is highly inhomogeneous,as fault braccias and damage zones usually develop into clusters within a single seismic-scale fault plane,with wall rocks in between the fracture zones.The fault zone architecture differs under different segmentation structural styles(e.g.,push-ups,pull-aparts,strike-slip,etc.).The push-up structure is characterized by high fracture intensity,with densely distributed fault breccias and fracture zones;whereas in the pull-apart structure fault braccias/fracture zones are mostly localized in fault plane boundaries where the fault zone architecture is less developed.In comparison,the strike-slip structure is characterized by lower fracture intensity and the least number of fault zones and greater spacing between them.To maximize the production of effective reservoirs and obtain higher single-well productivity,the well trajectory should be designed based on the fault zone architectural characteristics under different structural styles.As the productivity of a single well per unit pressure drop is taking into account,it is clear that the size of the reservoir is not the only factor controlling the single-well productivity but also the reservoir connectivity across different segments.