气井近井储层污染对高速非达西渗流的影响

Effect of formation damage near wellbore on high-velocity non-Darcy flow of gas well

藤赛男 李相方 李元生

中国石化上海海洋油气分公司研究院，上海 200120 中国石油大学石油工程教育部重点实验室，北京 102249

Research Institute of Shanghai Offshore Petroleum Company, SINOPEC, Shanghai 200120, China MOE Key Laboratory of Petroleum Engineering, China University of Petroleum, Beijing 102249, China

高速非达西渗流效应是气井生产的一个重要特征。在钻、完井及生产作业过程中，近井地带储层污染不仅会产生真实表皮，增大近井地带压力降，而且会影响气井的高速非达西渗流，进而影响气井产能。为此，文中提出了近井地带储层污染对高速非达西渗流产生影响的影响系数。基于渗流理论，通过将渗流区域划分为储层物性改变区和未改变区，推导得出影响系数的表达式。影响系数的敏感性及理论公式分析结果表明：近井地带污染所产生的正表皮会加强高速非达西渗流，而酸化等措施所形成的负表皮会减弱高速非达西渗流；当表皮系数为正且污染区域半径小于1 m时，气井的高速非达西渗流受近井污染带参数变化的影响显著。该研究使非达西渗流表皮系数的计算和产能预测结果更加准确。

Abstract: High-velocity non-Darcy flow is an important characteristics of gas production. The formation damage near the wellbore not only causes a true skin and increases pressure drop, but also affects non-Darcy flow and the production of gas well. Therefore, this paper puts forward the influence coefficient to show its influence on non-Darcy flow. Through dividing the flow region into damaged area and undamaged area, the expression of influence coefficient has been derived based on flow seepage theory. The results of sensitivity analysis and theoretical analysis of influence coefficient show that the positive skin caused by damage will enlarge the non-Darcy flow, but the negative skin caused by the measurements such as acidification will recede the non-Darcy flow. When the skin factor is positive and the radius of damage area is smaller than 1 m, the parametric change of damage area will affect the high-velocity non-Darcy flow significantly. The study makes the calculation of non-Darcy flow skin factor and the prediction of productivity more accurately.

10.6056/dkyqt201401015