Study And Evaluation On The Features Of Reservior Of He 8 And Shanl Section Of The Permian In The Certain District Sulige

Located in northern Ordos basin,with carboniferous and permian gas-bearing horizon,Sulige gas field has He 8 and Shan 1 member as one of the main production layers in this area and the detailed study of its reservoir characteristic is to provide a reference for further exploration and development.With He 8 and Shan 1 member in the middle of Sulige gas field as study subjects,this paper is a comprehensive and in-depth study of the diagenesis,reservoir characteristic,etc.with sedimentological and theoretical geologies and analysis of data from information like normal properties,casting lamella test,cathodoluminescence and scanning electric microscope combined with previous research results and analytical data from logging well and core permeability.Study showed that the rock types of the He-8 member reservoirs are predominantly of lithic quartz sandstone and quartz sandstone and Shan 1 member reservoirs of quartz sandstone and the reservoirs in study area was subjeted to strong diagenesis;compaction,cementation and quartz overgrowth were found main reasons of a reduction of porosity and permeability in sedimentary layers.Constructive diagenesis mainly includes metasomatism and alteration,dissolution and rupturing,etc.Pores of reservoirs in study area were predominantly developed into intergrain porespace,intergranular and intragranular dissolution pore,inter-granular dissolution pore,matrix dissolution pore and breaking crack.Analysis of sedimentary environment shows that He 8 member and Shan 1 member in study area were shallow water delta system during the deposition,with distributary channel sand body from which delta plain subfacies were developed most widely distributed as the most important reservoir sandbody.In conclusion of the results above,study area was divided into 3 types of reservoirs.Type I:K>1×10-3?m2,?>12%,with higher porosity and permeability and thick sand bodies,high quality reservoir in study area.Type ? a:0.6×10-3?m2<K?1×10-3m2,10%<??12%,with higher porosity and permeability and thick sand bodies,fair quality reservoir in study area.Type ?b:0.3×10-3p.m2<K?0.6×10-3?m2,9%<??10%,with lower porosity and permeability and thin sand bodies,general quality reservoir in study area.Type?:0.1×10-3?m2<K?0.3×10-3?m2,5%<??9%,with very low porosity and permeability and thin sand bodies,poor quality reservoir in study area.