延长气田一点法产能评价模型

Productivity evaluation model based on single point method used for Yanchang Gasfield

乔向阳 李元生 冯婷婷 冯东

QIAO Xiangyang LI Yuansheng FENG Tingting FENG Dong

陕西延长石油(集团)有限责任公司研究院 中海石油(中国)有限公司上海分公司研究院 中国石油大学(北京)石油工程教育部重点实验室

Research Institute, Shaanxi Yanchang Petroleum (Group) Co.Ltd., Xi'an 710075, Shaanxi, China Research Institute, CNOOC China Limited Shanghai Branch, Shanghai 200300, China Key Laboratory of Petroleum Engineering Education Ministry, China University of Petroleum (Beijing), Beijing 102249, China

经验数是一点法评价气井产能的重要参数，如何优选方法求解经验数，对提高一点法的准确性具有重要的意义。以延长气田为例，利用最优化方法（实际无阻流量与计算无阻流量之间的方差之和最小）优选经验数，并建立了经验数与地层系数之间的关系式。研究结果表明：最优化方法计算得到压力平方法下的经验数为0.94，无阻流量平均误差为5.7%；拟压力法下的经验数为0.8，无阻流量平均误差为7.8%，两种方法的误差均远小于常规方法，且前者更优；同时研究还发现延长气井的经验数大都大于0.8，地层渗流主要为达西流动，高速非达西所消耗的压力降较小，其测井地层系数（kH）与经验数满足：当kH < 29 D·m时，地层系数与经验数满足线性关系，且随着地层系数增大，经验数增大；当kH≥29 D·m时，经验数为0.94。

Empirical coefficient is the important parameter of single point method for gas well productivity evaluation, so how to select the empirical coefficient solving method is of great significance to improve the accuracy of single point method.In this paper, Yanchang Gas Field was taken as an example.Its empirical coefficient was selected by means of optimization method (the sum of the variance between the actual absolute open flow (AOF) and the calculated one is minimum), and the relational expression between empirical coefficient and formation capacity was established.It is shown that the empirical coefficient and AOF average error of pressure squared method which are calculated by means of the optimization method are 0.94 and 5.7% and those of pseudo-pressure method are 0.8 and 7.8%.The errors of both methods are lower than that of conventional methods, and the former is much better.And it is also indicated that the empirical coefficients of gas wells in Yanchang Gas Field are all higher than 0.8.The porous flow in the formation is mainly Darcy flow, the pressure drop consumed by high-speed non-Darcy flow is less, and its logging formation capacity () and empirical coefficient satisfy the following conditions, i.e., in the case of < 29 D∙m, it is linear relationship between formation capacity and empirical coefficient and empirical coefficient increases with the increase of formation capacity, while in the case of≥29 D∙m, empirical coefficient is 0.94.

10.13639/j.odpt.2018.01.014