大牛地低渗透气藏产水气井动态优化配产方法

Study on dynamic production optimization for water produced gas wells in Daniudi low permeability gas reservoirs

传统气井配产方法应用于大牛地低压、低渗、低产致密砂岩气藏产水气井时,气井的携液潜能得不到充分发挥,累计排水采气量大,最终采收率低。基于产水气藏物质平衡原理、气井产能、井筒压力温度分布预测理论,应用节点系统分析方法建立了产水气井生产动态预测方法,该方法能动态预测地层压力、井底流压、井口油压、产量、采收率随时间的变化;结合连续携液理论提出了产水气井配产新方法,该方法所配气量高于井口临界携液气量,且随时间动态递减,而不是保持不变。大牛地DK3井实例计算表明,新方法能更长时间维持气井连续携液生产,降低了累计排水采气量,提高了最终采收率。

Applying traditional production allocation method to water produced gas wells in Daniudi field, characterized with low pressure, low permeability, and low production, can not fully use liquid removing potential, leading to large accumulative production of deliquification and finally low ultimate recovery. The paper theoretically set up a dynamic prediction model for water produced gas well, by nodal system analysis, based on material balance principle, well productivity and flowing pressure and temperature drop theories. The model can predict reservoir pressure, bottom hole flowing pressure, wellhead flowing pressure, production rate, and recovery varying with time. A new production allocation method was proposed, considering continues liquid removing theory. The allocated production dynamically decreases with time, and is always larger than critical gas rate for liquid removal, which avoids lower ultimate recovery. Daniudi DK3 well was used as an example to be compared with published method, and the results show that the new method can reduce the accumulative production of deliquification, and enhance ultimate recovery..