Reservoir Evaluation Of The Upper Triassic Xu-2 Member In The Lianhuashan-Zhangjiaping Area In Southwestern Sichuan

Lianhuashan-Zhangjiaping areasare the production capacity replacing areas of SouthwestemSichuan.Thegas flow is abundant on ZJXwell,LHX-lwelland other wells,which give us confidence to believe in that the gas are very rich in all of the"Lianhuashan-Zhangjiaping structural zone".To expedite the exploration and development of the Upper Triassic Xujiahe Formation in southwest ofSichuan,and provide the geological suggestionsto the next location deployment.In this paper,we take the second member of Xujiahe Formationin Lianhuashan and Zhangjiaping Area of SouthwesternSichuanas the research objects.Based on the previous research results and basic geological data of the research area,combine with the information of regional geology,well drilling of multi-port explorationdevelopment well,testing and analysis of testing and logging data,use a multidisciplinary approach and a systematic study on the stratigraphic characteristics,sedimentary facies,reservoir characteristics and reservoir logging interpretation of the second member,finally,the distribution of reservoir is determined.According to the information of the outcrop profile,core and logging data,we consider that the study area,second Member of Xujiahe Formation is divided into ?,?,?,IVlayer from down to up.There are dark grey lithic sandstones on bottom ?and top IV,which are about 50 m and 20 m thick respectively.The central part ?,? are mainly composed of feldspar quartz sandstone and lithic argillaceous sandstone.The stratum of the study area from Zhangjiaping to Lianhuashan is a tendency of thinning.The type of reservoir rock in the study area is quartz sandstone,which mainly distributed in I and IV layer.The porosity is mainly distributed between 1%and 4%.The permeability is around 0.0001 mD?0.001 mD.The pore types are mainly intergranular pores and intergranular micropores.And thetectonic fractureare mainly composed of horizontal facture and low-angle oblique facture.The reservoir space combination type is intergranular micropore+dissolution hole+structural crack.The reservoir type is fracture-pore type reservoir.The second Member of Xujiahe Formation of the study area belongs to the fluvial-dominated detla sedimentary system.The main is in the delta plain subfacies and delta front subfacies,five microfacies were developed,such as river swamp,distributary channel,underwater distributary channel,estuary sandbair and distal bar.The secondarv reservoirstratum in the study area is mainly distributed in distributary channel,underwater distributary channel and estuarine sand dam.The reservoir is mainly formed after dissolution and rupture.With the comprehensive evaluation of drilling display and reservoir logging,it is believed that the vertical reservoir developea lot and thin,uneven distribution in the plane in the study area.Reservoir mainly distribute in ?,? cycleof thesecond member of Xujiahe Formation.The thickness is about 4?25m.Then it is distributed in ? cycle of the second member of Xujiahe Formation.The thickness is about 3?12m,it is mainly distributed in ZJX well area of Zhangjiaping area.The next is in LHX-1 well area of Lianhuashanarea.