Predictive Evaluation Of “Sweet Spot” For Tight Sandstone Gas In The Aheluo Formation In The Northern Kuqa Depression

With the in-depth development of tight oil and gas exploration in China,the Tarim Basin has also entered the tight oil and gas exploration stage.The northern structural belt of Kuqa Depression has excellent petroleum geological conditions and rich oil and gas resources.With the continuous deepening of exploration work,it is necessary to further predict the development location and distribution characteristics of tight sandstone gas "sweet spots" in the area,providing a basis for subsequent exploration and development research.This study comprehensively analyzes the geological characteristics of gas reservoir in combination with drilling data,logging data,thin section data,productivity data and seismic data,and summarizes the control factors of "sweet spot" from four aspects: structure,Source rock,reservoir and cap rock.Fine calibration of the main target layers in the research area,clarifying the structural,stratigraphic,and fault distribution characteristics through the interpretation of important layers and faults;On this basis,fracture fracture prediction,post stack wave impedance inversion,and hydrocarbon detection were carried out to obtain quantitative data for three important parameters involved in this "sweet spot" prediction.The multi-parameter weighting method was used in this area,from qualitative to quantitative,to delineate the scope of the "sweet spot" area based on the weighted results.Research has shown that the distribution of "sweet spots" in this area is controlled by three aspects: fractures,reservoirs,and hydrocarbon sources.A set of fault-fracture prediction methods suitable for the complex tectonic zone in the front of the foreland basin is proposed.After multi window dip scanning and structural guided filtering of the data volume,ant body attributes and maximum likelihood attributes are extracted,and the distribution of fault-fractures in the area is comprehensively characterized by multiple attributes.Combining key physical parameters for rock physics analysis,a post stack porosity co simulation inversion was carried out with an average porosity of more than 4% as the lower limit of reservoir physical properties.The inversion results predicted the distribution pattern of the reservoir.Using the high-frequency gas attenuation principle in the frequency domain to detect hydrocarbons and predict favorable gas bearing areas in the area.Driven by data,the range of5 "sweet spots" areas is delineated through the weighted results of the multi-parameter weighting method.The research results are highly consistent with the distribution of production capacity of each well,which is of great significance for guiding the deployment of well locations and exploration and development in this area.