Prediction For Tight-Fracture Sandstone Reservoirs Of The Second Part Of Xujiahe Formation, Upper Triassic In He Xing Chang-Luo Jiang Area In West Sichuan Depression

Based on 3- D seismic well and logging data, mainly by means of advanced seismic theories of reservoirs prediction and other corelational multidisciplinary, an extensive and indepth studying on the tight sandstone reservoir with fracture of the second part of the Xujiahe formation in West Sichuan Depression has been carried out. A series of theoretical viewpoints and research fruition are concluded as follows:.1 On the basis of analysis of the regional and local structure characteristics and evolution, A conclusion comes in to being: inchoate and nowadays structure traps and the match model between structure and fracturation system are the main factors in controlling the formation of effective traps.2 By means of seismic stratigraphy and sequence stratigraphy, the text analysized the charateristics of the second part of Xejiahe Formation, the framework of sequence stratigraphy constainted by seismic reflection in equal time has been established. Analyzed the sedimental mechanics charateristics of different cycle types,the paper predicts regulation of sandston' s distribution inside the framework of sequence stratigraphy and remarked source-reservoir-cap rock assemblages.3 After analysed the deformation of the structures and fractures, predicted 2-D fractural degree through the study of natural fracture net, indentified and evaluated fracture though logging data, analysed 3-D seismic coherence data> counted the dip angle' s of strata etc, the distribution of fracture is pointed out, the prediction methods which combined with geological and geophysical technologies of the fractural zones in the tight sandstone is also presented.4 On the basis of identifying favorable logging faces to recognize effective reservoirs and studying the reservoirs' charateristics in logging and seismic data; the model of the reservoirs' seismic response is established. According to the research, the pointed geophysics methods to detect gas in tight reservoir with fracture are made out.5 Centered about the principal factors which control the forming of the gas pools, analysed of trap' s effectivity, combined with the distribution of advantaged reservoirs and fractures, the author predicted effective reservoirs and the rich zones of gas, well site and the area of the future exploration are pointed out.This paper has been put a series of theories in front edge into practice, the real drilling data shows a high consistency with the prediction, this paper also provides correlative research with systemic and compositive methods of gas' prediction for references.