Seepage Characteristics And Well Pattern Optimization Of Tight Sandstone Gas Reservoirs With Narrow Channels In Western Sichuan

Dense sandstone gas has become a key development area of unconventional natural gas resources in the world.The dense sandstone gas resources in West Sichuan Sag are huge,but the reservoir rocks in this area are dense and heterogeneous,water saturation is high,water production is severe,and the river channel is narrow and complex,which ultimately makes the well pattern construction and development difficult and inefficient.Therefore,it is an urgent to study the seepage characteristics and the design and optimization of well pattern of dense sandstone gas reservoirs in Western Sichuan depression.Based on the full investigation of dense sandstone reservoir evaluation and well pattern construction and development engineering,combined with the sedimentary and physical characteristics of gas reservoir,through the analysis of seepage experimental results and numerical simulation,the mechanism model is established to study the seepage characteristics of JS gas reservoir.Through the study of the mechanism models and the channel models intercepted from reservoir model,the well pattern of different river channels is classified and designed.The main study are as follows:(1)Based on geological analysis and channel sand body width and physical properties,the channel is divided into three categories and six sub-categories,the main production channels are ?-A,?-B and ?-A.Through numerical simulation,the stress sensitive data are analyzed,and it is clear that the effect of stress sensitivity on high permeability wells is higher than that of low permeability wells;through numerical simulation,the experimental results of overburden pressure phase permeability are evaluated.To make the production difference clear between the changing phase relative permeability curve and the single phase.The mechanism model is used to evaluate the channel seepage.The thicker the reservoir is,the wider the channel is,the longer the stable production period is,and the higher the cumulative gas production is.(2)Through numerical simulation,the economic effects and production characteristics of different schemes are analyzed and compared,and the optimum well pattern on different sand body characteristics are optimized,and the optimum horizontal well parameters under different sand body are optimized.Horizontal well length:?-A:600-800m,?-B:800-1000m,?-A:1000-1200m;horizontal well control scope:?-A:650m,?-B:500m,?-A:450m;suitable channel width of row wells:?-A:>1200m,?-B:>800m,?-A:>600m;reasonable row spacing:?-A:400m;reasonable linear well spacing of horizontal well:?-A:600-800m,?-B:500-600m,?-A:400-500m;Reasonable spacing of vertical well pattern:I-A:600-700 m,?-A:300-400 m.(3)Through classified discussion of the defferent types of well pattern parameters,compare their economic effects,and optimize the best well pattern parameters and the best well pattern form of different river channels.Class ?-A channel:staggered row horizontal well pattern or mixed well pattern;Class I-B channel:linear horizontal well pattern;Class II-A channel:vertical-horizontal well mixed well pattern.Through the above research,the seepage characteristics and well pattern design principles and process of tight sandstone narrow channel gas reservoirs in Western Sichuan are determined,which provides theoretical support for the development of gas reservoirs in this area.