The Study Of Sedimentary And Reservoir Characteristic Of Permian In Sichuan Western

The paper take Permian in southern of sichuan basin as the study object,Guided by Sequence stratigraphy theory,By reserch methods of well drilling,outcrops,Seismic sequence interpretation and Lithofacies paleogeographic plotting, take Sequence stratigraphy and Sedimentary system research as study line,focused on reservoir and cap in the sequence framework,and combining with the results of early oil and gas exploration,Systematic research on the Permian sedimentary and Reservoir characteristics.This thesis mainly carried out the drilling and outcrop sequence stratigraphic classification, identification, seismic sequence analysis, sequence comparison, outcrop sedimentary facies analysis, single well sedimentary facies analysis, sedimentary 、facies horizontal contrast, unconformable surface characteristics, reservoir characteristics and reservoir prediction, etc., and develop the related datum.For single well, outcrop and seismic sequence analysis, identify the 6 kinds of sequence interface(unconformable surface, super surface on the transgression, flooded unconformity surface, volcanic events, surface and lithology conversion palaeokarstification surface), the combination of geological and geophysical exploration, through the analysis of the characteristics of seismic facies in the sequence framework, western sichuan Permian is divided into two secondary sequence, 10 sequence, finally established the sequence stratigraphic framework in the study area.Conducted between drilling and well- seismic comparative study on the seismic sequence stratigraphy, SQ1- SQ6 period, the overall performance for the south to north of shallow depth, low north reflects rising datum, the meteorological pattern in geomorphology, sequence structure style of TST equal HST or less; SQ7- SQ10 period, the overall performance of the northwest shennan east shallow, reflecting rising datum, north west northwest low southeast high palaeogeomorphology pattern, the sequence of structural styles for the same TST equal HST or less.Through the single well, outcrop and seismic facies sedimentary characteristics research, this thesis mainly divided into the two major categories of carbonate platform and carbonate ramp depositional model, were divided into rivers, coastal, carbonate ramp, edge platform and shelf- basin and so on five big sedimentary system, 10 types of facies and more than 30 types of microfacies.Combined with the Permian sequence characteristics in western sichuan region within the sequence framework, to prepare Permian lithofacies paleogeographic map on the tertiary sequence in the western sichuan region, and analyzes the palaeogeographic evolution: SQ1- SQ6(middle Permian) sedimentary period in large-scale transgression, and to carbonate with large spatial distribution; SQ7- SQ8 period(wu guping period) has experienced the dongwu movement, the earth’s crust uplift and denudation, the basalt eruption large area, mainly developed binhai-carbonate platform sedimentary system; SQ9- SQ10 period(changxing period), the main development of coastal sedimentary system and edge platform sedimentary system, and formed concave and within the reef in the open platform central.According to the distribution of depositional systems in space, combination and the ancient landscape development situation, analyzes the different platform structure type of phase control store: gentle slope type carbonate platform controlled the gentle slope, and gentle slope shoal development controlled reservoir development; Edge carbonate platform control platform, platform margin reef and the development of the platform edge slope facies, platform edge reef facies control of reservoir development; Epicontinental sea carbonate platform control evaporation, limitations, and open platform facies, then control the platform shoal, restricted platform facies dolomite reservoir development. Permian in sichuan basin formation of Qixia formation group of high-energy beach facies fracture- pore type reservoir, Maokou formation set of beach facies and karst pore-cave reservoirs, changxing group within the reef facies dolomite(limestone) pore type reservoir, etc.Through analysis of the Permian reservoir basic characteristics, diagenesis, ancient landform characteristic, pore evolution and reservoir distribution,point that marginal high-energy facies belt and high-energy beach facies belt in the table is the basis of high quality beach reservoir development, exposed corrosion and dolomization(or) is the key to carbonate reservoir with high quality development, rupture and deep dissolution to further improved the reservoir performance; the karst reservoir development is mainly controlled by two factors, high-energy shoal microfacies and karst slope composite is the favorable conditions of karst reservoir development, structural cracks further improved reservoir performance.Combined with reservoir control factors, through means such as geology, sesmic prediction, indicated that the qixia reservoir development mainly in Qixia group2, predict dolostone distributed mainly in chengdu- xinfan – huilong and xinchang tectonic belt; Maokou formation reservoir main development group in the upper, on the basis of the analysis of micro geomorphology, for thatch-roofed shoal karst gully and faults has carried on forecast, western sichuan dongpo seam structural belt karst cave reservoir development, especially in thezhixin-huilong area is development; Changxing group in western sichuan depression edge reef reservoir developedt, luodai-xinfan area developed the similar seismic reflection characteristics of the reef. Through comprehensive analysis, western sichuan area Permian qixia group, MAO group, the changxing group reservoir developed,and has great exploration potential.