杭州湾富浅层气区工程超前排气井井距优化研究  

STUDY ON A SPACING OPTIMIZATION METHOD OF ADVANCED EXHAUST WELLS FOR SHALLOW GAS IN HANGZHOU BAY AREA

作　　者：郭江涛 王勇[2] 贾鹏飞[1] 张军杰 陈成[2] GUO Jiangtao;WANG Yong;JIA Pengfei;ZHANG Junjie;CHEN Cheng(State Key Laboratory of Continental Dynamics,Department of Geology,Northwest University,Xi'an 710069,China;State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan 430071,China;China Railway Major Bridge Reconnaissance&Design Institute Co.,Ltd.,Wuhan 430051,China)

机构地区：[1]西北大学地质学系大陆动力学国家重点实验室,西安710069 [2]中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室,武汉430071 [3]中国中铁大桥勘测设计集团有限公司,武汉430051

出　　处：《工程地质学报》2024年第1期194-205,共12页Journal of Engineering Geology

基　　金：国家自然科学基金项目(资助号:51979269,52127815)。

摘　　要：对遭遇浅层气灾害地质的工程,一般防治措施多为建设前期布设超前排气井进行控制性排气。深入了解排气过程中气藏内部的气水运移规律,对于排气井井距的设计和高效率排气有重要意义。基于非饱和土两相渗流原理和杭州湾富浅层气区的典型概化地质模型,利用数值模拟方法研究了有控排气条件下气藏内部气水界面运移过程,探讨了影响超前排气井布设的因素,提出一种井距优化方法,并在实际工程中应用。结果表明:不同井口排气速率下,气藏内部气水分布形态与气体排放效果显著不同;工程超前排气井井距的设置可以淹井时间最长和剩余气藏厚度最小进行优化;原始气藏压力是影响井距优化的最显著因素,而储气层下部渗水系数、气藏厚度等并不影响最优井距的确定;调节井距对改善竖向排气井的排气效果随原始气藏压力系数减小而减弱;原始气藏压力系数大,井距适当减小,反之,可适度增加;对于气藏压力系数小的工程,建议发展水平排气井布设技术,以改善排气效果。此外,工程超前排气井的井距设置还应考虑与建(构)筑物的合理安全距离,达到高效、安全和避免投资浪费的目的。For engineering constructions encountering shallow gas geological disasters,laying advanced exhaust wells is an effective method to control hazards.To deeply understand the shallow gas and water transport law in a gas reservoir during the exhausting process is of great significance for designing wells to efficiently exhaust harmful gas.Based on the two-phase seepage principle of unsaturated soil and a typical geological model of shallow gas buried in Hangzhou Bay,the migration process of the gas-water interface in the gas reservoir under controlled exhaust conditions was studied using the numerical simulation method,and the factors affecting the layout of advanced exhaust wells were discussed.A spacing optimization method for the exhausting wells was proposed and applied in practical engineering.Results show that the gas-water distribution patterns and gas emission effects in a gas reservoir are significantly different at different gas emission rates.The spacing setting of engineering advanced exhaust well can be reasonably optimized according to the longest flooding time and the minimum remaining gas reservoir thickness.The original pressure in the gas reservoir is the most significant factor affecting the optimal layout of exhaust wells.However,the water permeability coefficient of the soil below the gas reservoir and the thickness of the original gas reservoir have no obvious influences on the optimal value.The effect of adjusting well spacing to improve the exhaust effect of vertical exhaust wells weakens as the pressure coefficient of the gas reservoir decreases.If the pressure coefficient is large,the well spacing should be appropriately reduced;otherwise,it should be moderately increased.For engineering constructions encountering shallow gas geology with small gas pressure,developing the technology of laying horizontal exhaust wells is conducive to improving the exhaust effect.In addition,a safe and reasonable distance from surrounding buildings(structures)should also be considered in the designing of adva

关 键 词：浅层气 非饱和土 排气井 气水运移 淹井时间 剩余气藏厚度 

分 类 号：TE37[石油与天然气工程—油气田开发工程]