用压力平方法解释煤层气藏气-水两相渗流试井  

Application of Quadratic Pressure Method in Well Test Interpretation of Gas-water Two-phase Flow in Coal Seam

作　　者：胡小虎[1] 郑世毅[2] 胡素明[3] 张冬玲 翟雨阳[5] 

机构地区：[1]中石化石油勘探开发研究院,北京100083 [2]Heriot-Watt大学 [3]中国石油大学(北京)石油工程学院,北京102249 [4]中石油煤层气有限责任公司,北京100028 [5]中联煤层气国家工程研究中心有限责任公司,北京100095

出　　处：《石油天然气学报》2011年第2期118-122,167,共5页Journal of Oil and Gas Technology

基　　金：国家科技重大专项(2009ZX05038-005);国家"973"规划项目(2009219606)

摘　　要：煤层气井在投产前,主要采用注入-压降法进行试井,以保证在测试期间不发生解吸,保持单相渗流。但煤层气藏在很长的排采期内,气-水两相将同时存在,因此,研究气-水两相渗流时的试井解释方法也具有重要意义。目前,直接使用油藏的多相渗流试井解释方法来解释煤层气井气-水两相渗流时还具有一定的局限性:综合流度法需要忽略压力及含气饱和度的梯度,拟压力法所需的相渗数据很难获取,压力平方法虽然可在没有相渗曲线的情况下完成试井解释,但不能直接用于煤层气藏试井解释。该论文参照油藏的压力平方法,建立了适合煤层气藏的气-水两相渗流试井解释方法。用该方法对煤层气数值模拟的试井数据进行了解释,得出的气、水相的渗透率和表皮系数等数值,与输入数值模拟软件的数值基本一致,表明该方法准确可靠。Before production was started in coal-bed methane wells,well test was carried out by using injection/draw down method to maintain single phase flow by preventing adsorbed gas from desorption.However,in a long period of water drainage in the coal seams,gas and water phases existed simultaneously,thus,studying well test interpretation method for two-phase flow in CBM reservoir was very important.At present,well test analysis methods for multi-phase flow in oil reservoirs still had a certain limitation for interpreting two-phase flow in coal seams.For example,the total mobility method is applicable only if the gradients of pressure and gas saturations are neglected;the pseudo pressure method needs relative permeability data,which are really difficult to be obtained.Quadratic pressure method is valid even without relative permeability,but it still cannot be used for well test interpretation of coal seam two-phase flow.Referring to the quadratic pressure method for oil reservoirs,a similar method feasible for CBM reservoirs is established,and this method is used to interpret well test data given by reservoir simulator,the result of gas-water-phase permeability and skin factor are almost the same as input data.

关 键 词：煤层气 两相渗流 试井解释 压力平方法 

分 类 号：TD842[矿业工程—煤矿开采]