气田水回注井可注量计算方法

A Calculation Method of Water Injection Volume for Reinjection Gas Well

为避免气田水回注过程中由于注入量太大引发井筒完整性破坏和发生地层窜漏,开展了气田水回注可注量评价研究。通过建立注入流体-套管-井壁-地层耦合的有限元力学分析模型进行注水井井筒受力分析;利用现代试井分析理论中的最优化拟合方法拟合注水过程中井底流压数据并获取注入流体波及半径,结合注入层段河道砂体展布确定波及面积;根据物质平衡原理计算可注量,形成气田水高压回注可注量评价方法。以L地区气田水回注井可注量评价为例进行分析,该方法考虑的因素客观全面,可以为气田水回注精细化管理提供定量指标和依据。

In order to avoid the destruction of wellbore integrity and formation leakage caused by the overload of water reinjection in gas field, the researchers carried out the quantity evaluation of gas field water injection. The injected fluid casing and borehole and formation coupling finite element mechanics analysis model was established to analyze the water injection wellbore stress. The optimal fitting method in the modern well testing analysis theory was adopted to predict the flowing pressure data in the water bottom hole and acquirethe injected fluid spreading radius, which was combined with the injected layer channel sand body distribution to determine the affected area. According to the material balance principle,the amount of water reinjection can be calculated, which contributes to forming the evaluation method of high pressure gas field water injection. In the case of evaluating water injection volume for reinjection gas well in the L area, the proposed method considers factors comprehensively and objectively, and can provide a quantitative index and basis for the fine management of gas field water reinjection.