水驱砂岩气藏型地下储气库长岩心注采实验研究　

Long core injection-production experiments study on water flooding sandstone gas reservoir type underground gas storage

张建国 刘锦华 何磊 薛云龙 石磊

ZHANG Jianguo LIU Jinhua HE Lei XUE Yunlong SHI Lei

低渗透油气田勘探开发国家工程实验室，陕西西安　710018 中国石油长庆油田分公司勘探开发研究院，陕西西安　710018 中国石油长庆油田分公司对外合作部，陕西西安　710018 中国石油勘探开发研究院廊坊分院，河北廊坊　065007

National Engineering Laboratory for Low-Permeability Petroleum Exploration and Development, Xi’an 710018, China Exploration and Development Research Institute of Changqing Oilfield Company, CNPC, Xi’an 710018, China International Cooperation Department of Changqing Oilfield Company, CNPC, Xi’an 710018, China Research Institute of Petroleum Exploration and Development, CNPC, Langfang 065007, China

水驱砂岩气藏型地下储气库通过注气驱水扩容，但是受储层非均质性以及水侵等因素的影响，实际运行过程中的库容量和工作气量大多低于设计值。为进一步优化气库注采效果，开展了多轮次的长岩心注采实验，分析注采过程中压力场分布及库容动用特征，研究影响扩容效果的因素。研究结果表明：随着注采轮次增加，注气排驱难度加大，排驱效果逐渐变差，趋于最大库容量；远井地区储层不能有效参与气库运行，注气后气库平衡压力低于上限压力，采气后气库平衡压力高于下限压力，导致实际库容量和工作气量达不到设计值；受储层孔喉分布非均质性、气驱压力梯度的限制以及采气循环边水的影响，排驱扩容增加的库容有限，注采模拟结束后，库容动用率仅为30%，工作气量占比也仅有21.6%。研究结果为水驱砂岩气藏储气库方案设计提供技术支持。

The capacity expansion of underground gas storage in water flooding sandstone gas reservoir form can be realized through water flooding. But influenced by the reservoir heterogeneity and water invasion, the storage capacity and the working gas volume is mostly less than the designed value during the actual operation process. In order to optimize the injection production effect of gas storage, multi-rounds long core water-gas mutual flooding experiments were carried out to analyze the pressure field distribution and capacity utilization characteristics during the process, and to study the factors that affect the expansion. The study shows that with the more rounds of injection, gas displacement becomes more difficult, and the displacement result gradually becomes poorer, tending to the maximum storage capacity. The reservoirs located in far well area cannot effectively participate in storage operation. The storage equilibrium pressure is less than the upper limit pressure after the injection; and it is more than the lower limit pressure after gas recovery, which causes the actual storage capacity and the working gas volume is always less than the designed value. Restricted by the reservoir pore throat heterogeneity and gas drive pressure gradient, and influenced by side water cycle, the capacity expansion increased by the displacement is limited. After injection-production simulation, the capacity utilization rate is only 30%, and the working gas volume ratio is also only 21.6%.