【摘要】 下奥陶统马家沟组风化壳储层是鄂尔多斯盆地苏里格气田重要的接替产层,具有"储层厚度薄、非均质性强、孔隙结构复杂"三大特点,多种储层发育控制因素共同作用,致使有利勘探区的预测难度极大。为此,从苏5区块马五41储层的地球物理响应特征出发,对古岩溶高地上的风化壳储层解释技术进行了新的探索:应用构造导向滤波技术提高原始地震资料信噪比,在此基础上利用地震振幅及几何属性分别对孔洞和微断裂进行预测;利用印模法进行古地貌恢复,精细刻画局部岩溶构造单元;进行精细构造解释落实局部微幅圈闭。结合上述成果对马五41储层有利勘探目标进行综合预测,经实钻井验证应用效果良好,实现了苏里格气田马家沟组风化壳储层勘探上的突破,并取得了以下认识:1沉积、古岩溶和微幅构造共同影响苏里格气田岩溶高地风化壳气藏的发育;2通过古地貌分析寻找岩溶发育区及刻画沟槽展布规律是研究马五41储层的关键;3地震分频振幅属性和几何属性相结合是研究岩溶储层储集空间的有效技术手段;4微幅构造影响马五41层复合气藏的气水分布。更多还原

【Abstract】 The weathered crust reservoirs in the Majiagou Fm are important potential pay zones for the successive production in the Sulige Gas Field of the Ordos Basin.However,they are characterized by "small thickness,strong heterogeneity and complex watergas contact" and their development is controlled jointly by multiple factors,thus their accurate mapping is quite challenging.In view of the geophysical responses of O1m541(the first interval of 4th sub-member in the 5th member of the Lower Ordovician Majiagou Fm)in Block Su 5,we studied the seismic prediction techniques of the weathered crust reservoirs on fossil karst highlands.The structural-oriented filtering technique was used to improve the SNR of the raw seismic data.The seismic amplitude and geometric attributes were used to predict pores,vugs and microfractures respectively.The moulding method was applied to restore palaeotopography and describe in detail the local karst structural units.Local traps with small amplitudes were mapped through detailed structural interpretation.The comprehensive prediction results of the favorable exploration targets in the O1m541 were well verified by drilling data,leading to a breakthrough of exploration of weathered crust reservoirs in the Majiagou Fm in the Sulige Gas Field.The following understandings were obtained.(1)Sedimentation,palaeo-karst and small-amplitude structures jointly control the development of the weathered crust reservoirs on karst highlands in the Sulige Gas Field.(2)Identification of areas with well-developed karst through palaeogeomorphic analysis is the key to the study of reservoirs in O1m541.(3)Integration of seismic frequency-division amplitude attributes with geometric attributes is an effective way to study the space of karst reservoirs.(4)Small-amplitude structures influence the gas-water contact of the composite gas reservoirs in O1m541.更多还原