Study On Sequence Stratigraphy And Sedimentary Facies Of Cretaceous In Southwest Tarim Basin

The study area is located in the southwest of Tarim Basin,including four tectonic units of Kashi depression,Shache uplift,Yecheng-Hetian depression and Maigaiti slope.Objective to study the layer of Cretaceous,including the Kezilesu group and Yengisar group.According to the research contents,the theories,combined with the status quo of research formation carbonate rocks and sequence home,based on analysis of thin sections,cores,drilling,logging,geochemical and geophysical data carefully,research objective layer of rock type,heavy product environment,sequence stratigraphic relationship,analysis of the tower the southwest area of Cretaceous favorable reservoir facies.The tectonic movement of the Cretaceous strata in the southwest of the Tarim Basin is mainly in the middle of Yanshan,the late Yanshan and the early Himalayan orogeny.On the eastern margin of the southern margin of the Western Tethys,Tasinan,the lower Cretaceous succession and Jurassic like continental deposits.Over the same period by a global sea-level rise during the period of whole transgression,Taxinan Upper Cretaceous-Paleogene Eocene Wulagen formation in marine sediments.Taxinan Cretaceous lagune and controlled by the salinity open platform and evaporate platform depositional system of marine sediment,alluvial fan fan delta lacustrine depositional system in continental sedimentary development.Based on the sequence stratigraphy theory,combined with the sedimentary background,rock stratigraphy,seismic stratigraphy analysis,southwestern Tarim Cretaceous were identified two sequence 2: SSQ1,SSQ2,three grade sequence 3: KSQ1-KSQ3.Based on the study of the cross section and seismic facies,the sedimentary facies distribution and its main controlling factors are studied.Finally,the sedimentary facies and the distribution of sedimentary facies are revealed.Taxinan Cretaceous sequence formation and controlling factors of tectonic subsidence,sea-level change and climate.The control of tectonic movement sequence mainly in the sequence boundary and the influence on the palaeogeomorphology;formation and evolution of sequence system tracts by sea-level control interface three order sequence;ancient climate change affects the change types of carbonate platform and platform edge position..The synthetic sequence,sedimentary characteristics and reservoir characteristics analysis,Taxinan Cretaceous main favorable reservoir zones for the lower Cretaceous SSQ1(Kezilesu group)favorable reservoir facies is mainly fan delta plain facies(alluvial fan margin)and fan delta front sandstone,siltstone;Upper Cretaceous KSQ3(from Yigeziyaformation)favorable reservoir facies are mainly open platform limestone,dolomite and Tan particle cloud matter collapse breccia.The reservoir space is mainly composed of intergranular(dissolved)pores,intragranular(dissolved)pores,Bone pores,cast pores and dissolved pores.