Lithofacies Modeling Of Coalbed Methane And Analysis Of Influencing Factors Of Gas Production In TB Block In Australia

Located in the main gas producing area of the M coalbed gas field in the Bowen Basin,Australia,the TB block has great development potential.The target stratum is the middle coal rank stratum of the Permian,and three sets of coal seam groups R,F and M are developed in turn,each set of coal seam group has many single coal seams.At present,the main production layer of coalbed methane is located in the M coal seam group,which has many characteristics,such as many types of coal seams,thin coal seams,rapid lateral changes and many influencing factors of coalbed methane,which greatly restrict the efficient development of coalbed methane.It is very important for the efficient and low-cost development of coalbed methane to analyze the influencing factors of coalbed methane based on the understanding of the distribution characteristics of coal reservoirs in the study area.Therefore,based on the establishment of the lithofacies model of the study area and the definition of the characteristics of coalbed methane reservoir,this paper intends to carry out the analysis of the influencing factors of gas production,so as to achieve the research significance of guiding the development of coalbed methane.The basic research data of this paper mainly includes seismic data,logging data,core data and previous research results.Through the research of fine interpretation of coal seam structure and coal seam logging data,on the basis of three-dimensional seismic data density and natural gamma attribute body inversion to build a basic model,combined with the results of single well lithofacies interpretation,according to the lithofacies relationship between natural gamma curve and density curve to build Lithofacies interpretation model.then take the lithofacies model as the constraint,combined with the analysis results of reservoir physical parameters,establish the attribute model of gas content,ash content,permeability and so on.Based on the geological model,this paper analyzes the influencing factors of the main gas production from four aspects of single well attribute,plane attribute,seismic attribute and reservoir physical property parameter attribute.It is clear that the gas production of layer M is negatively related to the depth of coal seam,the density of coal seam,the thickness of overlying sandstone,the thickness of coal seam and the minimum curvature of seismic attribute,positively related to the top stratum dip angle,stratum azimuth angle,permeability and the maximum curvature of seismic attribute.The research results of this paper can notonly provide theoretical guidance for the next development of TB block,but also provide reference for the development of medium-coal rank coalbed methane in China.