Study On The Production Laws Of Horizontal Wells And Numerical Simulation In Tight Sandstone Gas Reservoir With Narrow Channel

ZJ gas field is a typical narrow channel tight sandstone gas reservoir with low permeability(<0.1md under reservoir),narrow channel(300~1000m)and thin thickness(5~30m).At present,the gas reservoir is mainly developed by horizontal wells.It is very important to optimize the deployment of horizontal wells,increase the well-control reserves and keep the stable production of the gas field.In this paper,we focus on the law of fluid flow in reservoirs and horizontal well by the production dynamic analysis,streamline simulation and numerical simulation.Some important conclusions are listed as follows:(1)The production performance of gas wells has been evaluated by gas-reservoir method.The results showed that huge difference of gas-well production rate(average daily gas production of a single well was 0.02~9.3×10~4m~3/d),high production rate of a single well in the early period(3.45×10~4m~3/d),short stable production period(11 months),and small dynamic reserve of a single well(average 0.417×10~8m~3)can be observed.At present,the average oil pressure of a single well was 4.01MPa,and it has entered the low-pressure production stage.(2)The production performance of multi-stage fractured horizontal wells were evaluated with the method of streamline simulation.The research shows that with the decrease of river channel width,the controlled reserves of a single well decrease,the decline rate of production and pressure is accelerated,the production contribution of side fractures increases,the eccentricity of horizontal well position reduces the influence on production,and the interference of multi-well production increases.With the increase of reservoir thickness,the controlled reserves of a single well increase,and the gas well cumulative production increased linearly with the reservoir thickness under different river widths.With the increase of reservoir matrix permeability,the flow capacity of fluid in the reservoir becomes better,and the production effect of gas well in the wide channel is better than that in the narrow channel under the same permeability.Under heterogeneous reservoirs,gas well production is better in the following two cases:the physical properties in the area with poor physical properties are completely fractured in the direction of the river,the physical properties in the middle are better in the direction of the vertical river.(3)The historical fitting and production prediction were completed by using the numerical simulation of gas reservoir,and the historical fitting study of 85 wells in 7 layers in the main river channel was completed,the fitting rate of a single well was 93%.By the beginning of the prediction,the cumulative gas production is 24.3×10~8m~3,the proportion of utilized reserves is48.9%,and the recovery percent of utilized reserves is 23.54%.(4)It is predicted that in 20 years of production,the cumulative gas production of the gas reservoir is 51.47×10~8m~3,and the cumulative gas production can be increased by 3.51×10~8m~3through drilling new wells and surface pressurization.Multi-stage fracturing horizontal wells can be used for narrow channel gas reservoir development in ZJ gas field.