The Control Effect Of Present Gas And Water Distribution In Combination And Evolution Of Fault And Sand Body

Various types of gas reservoir formed by fault and sand body have become one of the major objectives of natural gas development in our country currently.Fault and sand body themselves are main channels in the accumulation process of the natural gas vertical and lateral migration and accumulation.There is a large amount of previous research in the two of fault and sand body alone.However,there are few studies on the fault and sand body distribution combination evolution on the controlling factors of gas and water transportation and clustering.Almost all the accumulation of oil and gas fields are not the results of single conducting channel migration and the natural gas from fault to sand body is inevitably subject to the impacts of a combination and evolutionary relationships of the fault and sand body.In this paper,the study on the fault and sand body distribution gas and water control is based on the study of influential factors of faults on gas and water and river way sand body characteristics on the influential factors of the gas and water and uses a case analysis method of the fault and sand body space distribution and combination.The study takes the gas reservoir in western Sichuan sag Jurassic Shaximiao formation as an example.Firstly,modern gas and water distribution was analyzed by a typical well profile gas and water recognition analysis;secondly,through ancient structure restoration study,the tectonic evolution and tectonic features in the key tectonic period were discussed;then by a systematic study of fault style,fault tectonic differences,fault formation period and evolution,the influential factors of the fault evolution on the gas and water were investigated;and finally,by combing river way sand body characteristics and distribution principles and through typical river way gas and water profile anatomy,studies on fault and body sand distribution combination were conducted.The fault and sand body static distribution types were divided into two categories of V type combination of faults and sand bodies,and inverted V type combination of faults and sand bodies.The study suggested that the fault and sand body V type combination was favorable to natural gas migration and accumulation,while the fault and sand body inverted V type combination was unfavorable to natural gas migration and accumulation.On the basis of the study of tectonic dynamic evolution,the fault and sand body dynamic distribution types were divided into three categories of fault and sand body evolution from a V type into an inverted V type,fault and sand body continuous V type distribution,and fault and sand body continuous inverted V type distribution combination.The study suggested that fault and sand body continuous V type distribution was the most favorable to natural gas migration and accumulation;fault and sand body evolution from the V type into the inverted V type was relative favorable to natural gas migration and accumulation;and the fault and sand body continuous inverted V type distribution combination was unfavourable to natural gas migration.By combining fault and sand body distribution dynamic evolution types and river way sand body connectivity degree of difference,fault and sand body distribution combination on the controlling of the current gas and water were systematically analyzed.Fault and interval river way sand body showing a continuous V type combination or an evolution from a V type combination to an invert V type combination during the fault and sand body distribution and combination evolution was conducive to natural gas migration and accumulation;fault and continuous river way sand body showing a continuous V type combination or an evolution from a V type combination to an inverted V type combination during the fault and sand distribution combination evolution was more favorable to natural gas migration and accumulation;and fault interval or continuous river way sand body distribution combination evolution showing a continuous inverted V type combination was not conducive to natural gas migration and accumulation.