Evaluation On Feature Of T₃x～2 Compact Sandstone Reservoir Of Yazihe Structure In West Sichuan Downwarp

The compact clastic rock gas reservoir has taken a very important position in the world's natural gas resource. According to estimate the world's unconventional gas (include compact clastic rock gas) is almost at the unexploitive stage. With the drying up of the of the conventional gas resource, the exploitaion and utilizing of the unconventional gas resource are gradually becoming exigent. The large-middle compact clastic rock gas fields of our country are mainly in large thick sedimentary rock with over 3000m of Upper Triassic in west Sichuan downwarp,having abundant of material source that generates oil. This is a type of gas reservoir where the reservoir rock is near the source rock and the gathering of oil and gas can be found in anticipation.Yazihe structure which lies in the middle-south section of west Sichuan downwarp, has better prospect of oil and gas exploitation.It is an important structure for the further exploitation. Triassic is the most abundant and the total intension of gas it generates approaches to 320×10~8,being regarded as the champion of the whole Sichuan basin.Because of the ample of gas source ,it's necessary to get further acquaintance of Yazihe area and try to establish middle-large oil-gas reservoir.According to gathering plentiful relative datum of of Xuer section of Yazihe structure and seismic, well logging, surveys, core ect during the exploitation and exploration,the research starts with analise of slice data, core observation and core specimens,then combines with coordination, analyse, concluding and the former research result.The article recognizes the tectonic feature of Xuer section of Yazihe structure and it's tectonic evolution,analyzes the distributing feature of oik, gas, water, their dominated factor, the pressure feature of gas reservoir and especially the conservative condition of Xuer gas reservoir.At the same time,the article acquaintances the depositional feature and sedimentary environment and discusses the main genesis typeof reservoir sandstone.By analyzing the physical feature and physical relation of reservoir rock, the article first classifies and evaluates the reservoir rock simply ,then concludes it's feature of reservoir and permeability. According to detailed core observation and fracture explanation in well logging ,the article uses single well fracture indentifying and evaluation to confirm the section where the fracture growths,putting emphases on the method to get parameter of fracture,such as fracture width and fracture porosity.Finally,combining with the principal curvature for tectonics deformation the article predicts the plane fracture of reservoir and weave the general evaluation map of crack fracture growth.