Studies On Sedimentary Facies Of Shan1 And He8 Section,Southern East ? Block Of Sulige Gas Field In Ordos Basin

Sulige gas field is one of the large lithologic gas reservoirs found in the Upper Paleozoic of the Ordos Basin.Shan1 and He8 located in the south of Dong block ?of the gas field is one of the main gas storages of natural gas.However,the main developed section of the study area is the Lower Paleozoic Ma 5,and the detailed study of the sedimentary facies of the Upper Paleozoic Shan1 and He8 has not been started,which is of great significance to guide the further exploration and development of the area.In order to solve the production requirement of the production unit,this paper makes a detailed study of the Shan1 and He8 in the southern part of the Dong ?area of Sulige gas field in Ordos Basin based on the previous research results and the production methods,and uses the disciplines such as sedimentology,petroleum geology and logging.The paper makes a detailed analysis of the sedimentary micro-facies of the Shan1 and He8 of the study area.The main results and awareness are as below:1.According to the Isochrones in stratigraphy,the sedimentary rhythmic character,the ES curves character and the lithological variation character,Shan 1 member and He 8 member are fine divided into 7 layers,which are Shan1-1,Shan1-2,Shan1-3,He81-1,He81-2,He82-1,He82-2.The fine division of small layers is beneficial to the description of single sand body in interest interval and sedimentary micro-facies.And it also helps to study and develop the favorable layers more amyl and precisely.2.In the study area,the thickness of Shan1 strata is 30-40 m.And the middle strata is uplifted and thin.Shan1 is fine divided into Shan1-1,Shan1-2,and Shan1-3.In Shan1 stage,the1 study area is in the reducing sedimentary environment background,and the coal streak is often found in core observation and outcrop.The main rock type of Shan1 is lithic quartz sandstone,lithic sandstone and quartz sandstones.The texture maturity is high,the shape is round and the color is often grey.3.In the study area,the thickness of He8 strata is 56-68 m.The thickness changes a little,and the strata is plain.The sand-strata ratio is higher than that of Shan1 strata.He8 member is fine divided into He81-1,He81-2,He82-1,He82-2,of which the sand body development of He82-2 is best and is the main layer of research and development.The main rock type of He8 member is lithic quartz sandstone and quartz sandstones,and the content of lithic sandstones relatively low.The plant fossils can be found occasionally and the sorting is middle,and the shape is often sub angular,and the color is often grey.4.The paper fine divide the single-well facies of 7 layers,and describe the sedimentary facies distribution of 7 layers combined with the sand-strata ratio.Through analysis,it is known that Shan 1 member is meandering delta sedimentation,and the width of river is 3-5km,and the sand body is superimposed in the channel intersection and the thickness is more than 20 m.The width of point bar sand is often 1-2km,and the orientation length is often 3-5km,7-8km at most,the thickness of single sand body is often 1.3-19.7m.He8 is braided delta sedimentation,and the width of river channel is 10-15 km,and the width in the intersection is 30-40 km,and the thickness is 20-30 m.The width of channel bar is of no obvious regularity,often 3-7km,and the orientation is more than 11 km,and the thickness of single sand is more than 10 m.5.This paper focuses on the study of the structure and sedimentary evolution of the Ordos Basin,and focuses on the study of the rock types,the rock structure and the sedimentary structure of the Shan 1 and He 8 in the third member of the East Triassic of the Sulige region.The 8th period belongs to the semi-arid-semi-humid,sedimentary water micro-salty environment,the development of alluvial plain sedimentary system,the study area Shan 1 section for the meandering river delta plain,He 8 braided river delta plain.6.During the sedimentary period of the Shan 1,the tectonic activity is relatively calm and the meandering river is mainly developed with the secondary erosion action.The tectonic action is uplifted during the 8th section of the reservoir.During this period,the main lateral erosion the braided river sediments are mainly developed,but in the late stage of the reservoir 8,the supply of the source area in the northern part of the study area is reduced,and the mudstone section is flooded.