基于井震融合的碳酸盐岩古岩溶残丘储层刻画方法

Reservoir Characterization Method of Carbonate PaleokarstResidual Hill Based on Well-seismic Fusion

北大港构造带千米桥奥陶系潜山顶部发育的碳酸盐岩古岩溶残丘作为一种重要的古地貌和油气储集单元,具备良好的成藏条件,有效地刻画古岩溶残丘储层对于残丘储层的油气运移聚集分析及勘探开发有着非常重要的意义。本文首先应用地震印模法对千米桥奥陶系潜山风化壳岩溶古地貌进行精细刻画,揭示该区发育5个岩溶残丘,4个岩溶沟谷,表现为山上有山的特征;同时井震融合分析认为潜山风化壳储层大多分布在风化壳面以下0~200 m范围内,主潜山各区块风化壳残余厚度差别较大,岩溶残丘之上构造高点残余厚度大。通过成像测井和常规测井曲线上异常显示识别残丘风化壳内幕发育的岩溶洞穴,主要有大溶洞和中小溶蚀孔洞两种。应用提频地震体开展正演模拟,明确优势缝洞体储层的地震反射特征,结合张量方向场裂缝定量预测技术,能精细地预测碳酸盐岩缝洞复合体储层,以指导残丘风化壳储层油气潜力目标区的评价开发。

The carbonate paleokarst residual hills developed at the top of the Qianmiqiao Ordovician buried hill of the Beidagang structural belt,as an important ancient landform and oil and gas reservoir unit,have good conditions for reservoir formation.Effective characterization of paleokarst residual hill reservoirs is of great significance for the analysis of oil and gas migration,accumulation,and exploration and development of residual hill reservoirs.In this paper,the application of seismic impression method can effectively depict the ancient landforms of weathering crust karst of Qianmiqiao Ordovician buried hill,with 5 karst residual hills and 4 karst valleys developed throughout the area,characterized by mountains on the mountain.Well seismic fusion analysis suggests that most of the buried hill weathering crust reservoirs are distributed within the range of 0~200 m below the surface of the weathering crust.The residual thickness of the weathering crust in each block of the main buried hill varies greatly,and the residual thickness of the structural high points above the karst residual hills is large.Karst caves developed within the weathering crust of residual hills are identified through abnormal display on imaging logging and conventional logging curves,mainly consisting of two types:large karst caves and small and medium-sized karst caves.Applying frequency enhanced seismic bodies for forward modeling,clarifying the seismic reflection characteristics of advantageous fractured and vuggy reservoirs,and combining tensor directional field fracture quantitative prediction technology can accurately predict carbonate fractured and vuggy complex reservoirs,and guide the evaluation and development of oil and gas potential target of residual weathering crust reservoirs.