Integrated Research Of Gas Exploration Technology In The Upper Triassic Formation In Southwestern Part Of Sichuan Basin

Taking gas reservoir in the2nd member of Xujiahe Formation in the Mesozoic Triassic in southwest of Sichuan basin as the study objective, guided by clastic rock sedimentology, reservoir geology, structure geology and reservoir description theory, using multidisciplinary and integrated means combining seismic, drilling, logging data and practical exploration effect as the basis, this paper carries out reservoir earthquake prediction geophysical technology, reservoir evaluation geology, logging technology, hydrocarbon reservoir protection, drilling and completion technology system analysis, and establishes a set of supporting technology of low permeability and low porosity, crack-pore type tight sandstone exploration and development in western Sichuan.In the research of structural trap evaluation and geophysical technology of reservoir earthquake prediction, focused on collection and imaging processing, a set of technology series are formed suitable for mountain full3D data processing. Through structural analysis of different area, supporting structure style and structure modeling technology are formed, and based on analysis and interpretation of tectonic deformation times in western Sichuan, mountain seismic integrated interpretation technology and complicated structure trap identification technique are formed. For reservoir fine forecast, on the basis of speed characteristics analysis of the2nd member of Xujiahe Formation, proving the typical well geology, logging response model, finally establish sandstone reservoir geophysical model, through theoretical derivation and forward modeling study to clear about seismic response characteristics of different types of reservoirs. Through logging curve normalized processing, seismic high resolution processing and horizon fine calibration, conventional seismic profile response characteristics analysis of typical wells, and carrying out waveform classification and joint inversion method and combining with seismic attribute analysis, crack detection and fluid detection methods, etc. to perform comprehensive prediction on reservoir lithology, physical property and gas-bearing content.The2nd member of Xujiahe Formation in southwestern Sichuan are massive sandstones belonging to channel, debouch bar facies of delta depositional system, mainly feldspar quartz sandstones and lithic feldspar quartz sandstones. Reservoir matrix property is poor, commonly with characteristics of low porosity, low permeability, high water cut, small throat, strong heterogeneity, reservoir validity depending on the development of fractures, furthermore the quality of reservoir and gas well productivity are closely related with the development degree of fractures. To settle the difficulty of the low porosity and low permeability tight sandstone reservoir logging evaluation, geological research and well logging interpretation technology of low porosity and low permeability tight sandstone reservoir are formed.The paper summarizes the initial version of natural gas integrated exploration techniques systematically for the first time, which are suitable for Upper Triassic in Southwestern Sichuan, such as trap description, reservoir evaluation. The summary lays a foundation for integrated exploration of sandstone reservoir of Xujiahe Formation in southwestern Sichuan.