Research on optimal production distribution of tight sandstone gas reservoir

Abstract

The determination of dynamic reserves is an important basis for rational production allocation. Based on the Yan’an Gas Field, the modified flowing material balance equation is established considering the changes of gas viscosity and compressibility. At the same time, a reasonable production allocation method for gas wells is developed. The result shows: ① μgCg decreases with pressure and increases with temperature. ② The error of the modified flowing material balance method is smaller compared with the flow material balance method, and the error is 1.25 %. ③ The great change of the production will affect the accuracy of the modified flow material balance method, especially the shut-in for a long time before the pressure drop production is calculated at a certain time, so the points with relatively constant should be selected as far as possible. ④ When the dynamic reserves are used for allocation, the initial decline rate decreases by 74.65 % on average, and the stable production period increases by 21.28 % and the stable production period increases by 1.79 % compared with the allocation method of open flow rate. ⑤ When there is a large error of dynamic reserves, it will lead to production deviation from the reasonable value. The findings of this study can help for the accurate evaluation of dynamic reserves and reasonable production allocation of tight gas wells in the Yan’an gas field, and is an important guide for the formulation of a rational plan for the gas reservoir and its economic and efficient development.