气井产量递减类型及气藏地质工程因素分析——以柿庄南矿区煤层气井为例

The CBM Production Decline Type and Gas Reservoir Geological and Engineering Influencing Factors

为提高煤层气井单井产能,有必要弄清气井产量下降阶段时间的长短,递减速率的快慢,遵循何种递减类型等.在研究柿庄南煤层物性的基础上,结合区块内43口进入递减期的典型气井,利用Aprs递减分析方法,拟合出各井的递减模型,计算出各井的递减速率,从气藏地质和气藏工程两个角度研究煤层气井产量递减的控制因素.结果表明,煤层气井产量以指数递减和调和递减为主,初始递减率较小.影响煤层气单井产能的气藏地质因素主要包括煤层厚度、孔隙度、渗透率、相对渗透率、含气量、吸附常数、煤层压力和临界解析压力;气藏工程因素主要包括井底流压、表皮因子、边界半径和裂缝参数.

In order to improve CBM wells＇ productivity, it is necessary to clarify the duration of gas production decline, the rate of decreasing speed and the descending types. On the basic study of physical properties in Shi Zhuang-Nan, combining with the 43 wells whose productivity have showed typically decreasing phase, the decreasing model of each well is fitted and their decreasing rate is calculated by using the method of Aprs declining analysis. From gas reservoir geological and reservoir engineering aspects, the declining and controlling factors of CBM well ＇ s production are analyzed. Generally, descending types of CBM wells＇ productivity is mainly exponentially decreasing and reconcile decreasing, and the initial decline is small. Geological factors mainly include coal thickness, gas content, adsorption constants, seam pressure, permeability, porosity, relative permeability, critically analytic stress. Gas reservoir engineering factors include bottom-hole flowing pressure, skin factor, boundary radius and fracture parameters.