摘要
为了消除压力计位置对非均质气藏产能的影响,提出了压力计下入的位置或者压力的校正位置应该是地层系数为总地层系数的一半时的井底深度Hm处而不是储层中部,并且将压力计位置的井底压力校正到井底深度Hm处的压力,发现校正后的压降由重力压降和摩阻压降组成,并在此基础上推导了对压力校正到Hm处的产能方程。从校正的产能方程发现,重力压降的影响并入到了井底流压中,而油气在井筒中的流动摩阻压降系数的影响并入到系数B上。与压力计处于储层中部时产能方程相比,推导产能方程系数A没变,但是系数B由地层中的非达西系数和井筒中的摩阻压降系数组成。如果没有考虑方程的校正,当压力计处于储层上部时,生产压差偏小,摩阻压降增大,会使得系数B减小甚至可能出现负斜率,最终会高估了气井的产能;当压力计处于储层下部时,生产压差偏大,摩阻压降减小,使得系数B增大,最终会低估了气井的产能,这与该文的模拟结果是一致的。提出了考虑压力计位置影响的试井资料处理方法,该方法能够很好的评价气井的产能。
In order to eliminate the impact of pressure gauge position on the deliverability of heterogeneous gas reservoir, this paper proposed that pressure gauge should be descended to（or the pressure should be corrected to） the depth of Hm whose permeability ca- pacity is half of the whole permeability capacity, not the middle depth of reservoirs. After the correction of the bottom hole pressure near pressure gauge to the pressure of H,, depth, it was found that the pressure drop after correction consisted of gravity pressure drop and friction resistence pressure drop, and further more deliverability equation was derived considering pressure corrected to the depth of H,~. In the corrected deliverability equation, the effects of gravity pressure drop and pressure drop coefficients of flow- ing friction resistence of the oil ＆ gas in wellbore were added to bottom hole flowing pressure and coefficient B respectively. There- fore compared with the deliverability equation before correction, in the deliverability equation derived in this paper, coefficient A didn＇ t change while coefficient B consisted of non-Darcy flow coefficient and wellbore friction resistence coefficient. Despite of the correction of deliverability equation, when pressure gauge position was above the depth of Hm, producing pressure difference got smaller and pressure drop of friction resistence got bigger, making coefficient B reduce even turn negative, and finally the capacity of gas well could be overestimated; when pressure gauge position was below the depth of H,,, producing pressure difference got big- ger and pressure drop of friction got smaller, making coefficient B bigger, and finally the capacity of gas well could be underestimat- ed. These results are consistent with simulation results in this paper. What＇ s finally more, this paper provided well testing data pro- cessing method considering pressure gauge position, which could effectively evaluate the capacity of gas wells.
出处
《油气藏评价与开发》
2011年第6期25-28,34,共5页
Petroleum Reservoir Evaluation and Development
基金
国家重点基础研究发展计划("973"计划)项目"低渗透碎屑岩天然气藏有效储层分布与渗流规律"(2007CB209506)资助
关键词
非均质气藏
压力计
产能方程
校正方法
压力系统
heterogeneous gas reservoir, pressure gauge, deliverability equation, correction method, pressure system
作者简介
李元生（1986-），男，中国石油大学（北京）油气日开发工程在读硕士，石油天然气开发研究。
