底水气藏大斜度井开发优化设计研究

Optimization of development of highly deviated well in gas reservoir with bottom water

大斜度井开发底水气藏遇到的最大问题就是底水锥进。以数值模拟技术为手段,建立底水气藏大斜度井地质概念模型。区别于常规单参数局部优化,采用极差法分析大斜度井开发底水气藏时复合参数的交互影响,从而能够又快又准地得出更合理的全局最优结果。同时,为准确模拟开采特征,利用多段井模拟技术并考虑气藏渗流与井筒流体流动的耦合及摩阻的影响,采用示踪剂追踪法精确模拟底水见水时间,使得指标优化更加合理可靠。结果表明,斜井段趾端避水高度对见水时间及无水采出程度均产生影响,而斜井段长度和生产压差则对预测期末采出程度起主要作用。该项研究对底水气藏大斜度井的高效开发具有一定的指导作用。

The most important matter on the development of highly deviated well in gas reservoir with bottom water is water coning. A basic model of highly deviated well in gas reservoir with bottom water was established by means of numerical simulation methods. Applying orthogonal design method to analyze the interaction of compound parameters during highly deviated well developing the gas reservoir with bottom water can quickly and accurately obtain a more reasonable holistic optimization result different from the conventional local optimization with single parameter. Meanwhile, for the sake of accurate simulating of development features, used multi-segment well model to consider the effect of the friction and flow coupling between formation and well bore, and applied tracers to accurately simulate water breakthrough time of bottom water, which make the index optimization more reasonable and reliable. The result shows that the height of water avoidance at the toe of deviated segment can affect water breakthrough time and water-free recovery percent obviously, and the length of deviated segment and producing pressure drop play a major role on the recovery percent in the final prediction.This study has importance in guiding efficient development of highly deviated well in gas reservoir with bottom water.