川西侏罗系低渗透致密砂岩气藏增压开采效果及其影响因素OA

To clarify the effects and influencing factors of supercharging production for the Jurassic low-permeability tight sandstone gas reservoirs in the western Sichuan Basin,the single-well recoverable reserves under supercharging production were predicted by the pressure drop and production decline methods.Based on the physical property analysis,gas-water two-phase flow experiments,logging interpretation,and production performance data,the exploitation of major gas reservoirs was investigated under the conditions with or without supercharging,so that the effects and influencing factors of supercharging production were analyzed.The following results are obtained.(i)Supercharging production can eliminate the constraint of pipeline pressure on low-pressure and low-yield wells,extend the production life,and improve recovery factor,while enhancing gas production by virtue of higher production pressure difference.(ii)After implementing supercharging production,wells in major gas reservoirs exhibit the average wellhead abandonment pressure decreased by 0.5-1.3 MPa,the average newly added recoverable reserves of 101×104-200×104 m3 individually,and the recovery efficiency improved by 2.55%-7.63%.(iii)The supercharging production effect is jointly influenced by reservoir physical properties,water saturation,and supercharging timing.The newly added recoverable reserves per well are positively correlated with porosity and permeability,and negatively correlated with water saturation.Gas wells in reservoirs with permeability greater than 0.15 mD and water saturation less than 45%reflect good supercharging effects;whereas gas wells in reservoirs with permeability less than 0.15 mD and water saturation greater than 60%show relatively poor effects.For reservoirs with water saturation between 45%and 60%,the better the reservoir physical properties,the better the supercharging effects.(iv)When the difference between the tubing and the pipeline pressures is less than 0.35 MPa,the effects are satisfactory,and the single-well incremental recoverable reserves are greater than 200×104 m3.This research provides guidance and reference for the gas well selection for supercharging production in the study area and also for the similar gas reservoirs in other regions.