裂缝气藏气井产能特征及产能方程修正方法研究

Research on Productivity Characteristics and Correction of Productivity Equations of Gas Wells in Fractured Gas Reservoirs

李晓平 李裕民 邵剑波 段华庭 朱松柏

LIXiaoping LIYumin SHAOJianbo DUANHuating ZHUSongbai

西南石油大学石油与天然气工程学院, 四川 成都 610500 中国石油塔里木油田公司, 新疆 库尔勒 841000

Petroleum Engineering School, Southwest Petroleum University, Chengdu, Sichuan 610500, China Tarim Oilfield Company, PetroChina, Korla, Xinjiang 841000, China

裂缝性气藏具有地质储量丰富和单井产能高的特点，目前常规理论二项式产能方程在裂缝性气藏中的适用性较差，理论计算得到的紊流项远小于实测结果。针对上述问题，以塔里木盆地克深气田为例，从地质认识、测试资料、渗流规律和数值模拟等方面总结了裂缝性气藏的产出特征。分析表明，井筒与天然裂缝相交处是天然气的主要产出井段，气体在天然裂缝的聚集增大了裂缝性气藏气井生产过程中的紊流效应，导致高速非达西效应明显，理论二项式产能方程不能准确评价其产能。在理论二项式产能方程的基础上，回归克深气田理论与实际非达西流系数的关系，建立了裂缝性气藏二项式产能方程修正方法，并用实测数据验证了产能模型的可靠性。实例分析表明，克深气田气井开采过程中绝大部分能量都消耗在紊流效应上，因此，裂缝性气藏开发时需要控产降低压力损失。将理论计算得到的结果代入到“一点法”经验公式中，结果表明，较低的生产压差条件下计算得到的气井产能远高于实际结果，建议合理测试生产压差为地层压力的4%～10%为宜。

Fractured gas reservoirs are characterized by abundant reserves and high gas well productivity. The binomial productivity equation of conventional theory has bad applicability in fractured gas reservoirs, and the turbulence flow coefficient obtained by theoretical model is far less than the measured results. Taking Keshen Gas Field as an example, we summarize natural gas production characteristics in fractured natural gas reservoirs based on geological cognition, test data, percolation theory and numerical simulation. The analysis results show that intersection of wellbore and natural fractures is the main production well section, and the accumulation of gas in natural fractures increases the turbulence effect during production, resulting in obvious highspeed nonDarcy effect, and the theoretical binomial productivity equation cannot accurately evaluate its productivity. Secondly, the binomial productivity equation correction method for fractured gas reservoirs is established by regressing the relationship between the theory of Keshen Gas Field and the actual nonDarcy flow coefficient. The reliability of the productivity model is verified by the measured data. The case analysis shows that most of the energy consumed in the production process of Keshen gas well is turbulent effect, so it is necessary to control production for reducing pressure loss in fractured gas reservoir. Finally, the calculation value of production is tested with the singlepoint productivity formula. The computed result shows that the gas well productivity calculated under the condition of low production pressure difference is much higher than the actual results, and the reasonable test production pressure difference should be between 4% and 10% of the formation pressure.

10.11885/j.issn.1674-5086.2022.07.26.04