Study On Genetic Mechanism And Logging Characterization Method Of Natural Fracture Of Tight Sandstone Reservoir

Tight sandstone reservoir is the key research target oil and gas exploration field in the present and future.Natural fractures are a common type of reservoir space in tight sandstone reservoirs.It is often associated with multiple tectonic movements.The development of natural fractures improves the physical properties of tight sandstone reservoirs with low porosity and low permeability,thus raising the reservoir space and seepage capacity.The Xujiahe Formation gas reservoir in Xinchang gas field is a deep tight sandstone gas reservoir in this article.After years of exploration and development practice,it has been proved that fracture development is the key factor of natural gas enrichment and high yield,and is also the key factor for characterizing the good and bad of the tight sandstone reservoir.But how to characterize the fracture and the genetic mechanism of fracture is a blank and urgent scientific problem.The tight gas reservoir of Xujiahe Formation in Western Sichuan is taken as the research object in this paper.First,through a large number of core observation,thin slice analysis,core calibration imaging logging,imaging logging calibration routine logging,and rock mechanics test data analysis,based on the previous research achievements,the researcher summarized the characteristics,causes and development of different types of fractures in tight sandstone reservoirs,and made clearly the genesis mechanism,development characteristics and the influencing factors in the diagenesis evolution process.Secondly,the logging and petrophysical response characteristics of tight sandstone reservoir fractures,non fractures and different genetic fractures are analyzed.By using conventional logging data and petrophysical data,a quantitative identification model of fractures is established,and the quantitative identification of fractures in tight sandstone reservoirs is realized.Then by using the response characteristics of the conventional logging and the rock mechanics parameters,establish the discriminant model and criterion for different genetic fractures and realize the identification and division.Finally,a comprehensive identification model and criteria for different genetic fractures in tight sandstone reservoirs are established.It provides a strong geological basis for the selection of "desserts" and the improvement of reservoirs in oil and gas exploration and development.It is of great significance to the study of gas reservoirs with similar geological background both at home and abroad.