The Pore Structure Characteristics Of The Mud Shale In The Fourth Member Of The Fu 4th Member In The Gaoyou Sag, Subei Basin And The Logging Identification Of The Reservoi

The continental shale reservoirs in China has play an importance and difficulty role inthe unconventional oil and gas exploration and development.And the complex pore structure of shale reservoirs making logging response regularity is unlcear.That reslut in the difficulty of pore structure sdtudy and shale reservoirs identification.Choose shale in E1F4 of Gaoyou Sag as an example.Then,launched a study of pore sturcture characteristics and shale reservoir recongnition with well logging data and gas logging data.The pore types of shale include intergranular pores,intercrystalline pores,dissolution pores,organic matter pores and microfractures.Based on these pore types,classified the pore structure into 3 major categories and 6 small classes with electron microscopy,nuclear magnetic resonance experiments and core physical properties.And the next step is to complete the analysis of the lithology characteristics,hydrocarbon potential,mineral content,fracturing resistance,geochemical characteristics and electrical characteristics.And pointed out which kind of pore structure type belongs to high-quality shale reservoirs.Meanwhile,the shale of Gaoyou Sag developed some fractures.Like low angle joints,oblique cracks and high angle fracture.Most of them are filled with calcite.Then,analyzed the log response characteristics of fractured shale.And using imaging logging and stone filter data,to comprehensively identifed the shale fractures.Taking into account the complex characteristics of shale lithology,it can be divided into three major categories:lime mudstone,organic-rich shale and other rokcs.In addition,on the basis of well logging and gas logging data combination,selected six kinds of curves to establish the radar chart,such as natural gamma curve,acoustic curve,density curve,resistivity curve,drilling curve,total hydrocarbon content curve.And the chart is help to identify shale reservoirs.Besides,considering the shale pore structure,divided reservoirs into three categories.The characteristics of class Ⅰ reservoir is Ⅰ1 pore stucture type,lime mudstone generally,highest brittleness index value and higher productivity.Class Ⅱ reservoir is Ⅰ 2 and Ⅱ1 pore stucture type with micro-fracture,lime mudstone mostly and higher brittleness coefficient values.Class Ⅲ reservoir is Ⅱ2 and Ⅲ1 pore stucture type,organic-rich shale generally.All these studies provide a reference for the shale reservoir identification and reservoir division of Subei Basin.The completion of this paper supply a practical method for the pore structure characteristics research,lithology and reservoir identification,and reservoir type division.And which also provides a more reliable basis for further exploration.