Optimization Of CBM Well Pattern In Large Dip Seam

Xinjiang is rich of coalbed methane resource,but its coal seam is of large thickness,multilayers and large angle.The seepage characteristics,pressure drop characteristics and gas-water saturation is quite different from nearly horizontal coal seam.Related research is rare,which makes the well type,selection and optimization of well pattern lack of sufficient theoretical supports.Taking the Baiyanghe mining area of Fukang,Xinjiang province,as the research area,a numerical model fits the actual situation of the research area is established after production geological data is collected and collated.In view of the seepage characteristics of vertical and horizontal wells with large dip angle;The influence of coal seam thickness,layers and dip Angle on pressure drop and the pressure drop characteristics of vertical and horizontal Wells;The distribution of residual gas content in vertical and horizontal Wells is studied by means of theoretical analysis,statistical analysis and numerical simulation.Based on the above research results,the development well type in the research area is optimized,and it is considered that the coal seam well is more suitable for production in the development zone.By fitting the existing production data,the existing well pattern is optimized: combining the economic model and the economic limit well pattern,the optimal well spacing of the rectangular well pattern is 250m×312.5m.By numerical simulation,it is considered that 300m+200m well spacing of triangular well pattern is the optimal well spacing when reservoir inclination Angle is 50°.This paper makes up for the gaps of seepage law and pressure drop propagation characteristics of the large-dip and multiple-thickness coal seam,and has certain guiding significance for the selection of well type and the optimization of well pattern deployment in the large-dip and multiple-thickness coal seam,which lays a foundation for the future on-site production of coal-bed methane in the large-dip and multiple-thickness coal seam.