Field investigation of surface casing vent flow and gas migration around leaky petroleum wells

漏油井是石油和天然气行业最大的环境负担之一。此外，当水井成为“孤儿”(即不存在有法律责任或经济能力的一方来管理废弃)时，这一责任可以转移到公共财政，在当前的经济气候下，这种情况发生得更频繁。漏水井可能会出现地表套管通风流，即气体(主要是甲烷)在井筒内泄漏(S)，和/或气体运移(GM)，即气体从目标或中间带，或通过井筒中某个深度的孔，运移到地面。特别是，转基因的程度没有得到很好的描述，气体运输途径没有得到很好的理解，补救努力很少在第一次尝试(或第二次或第三次)就成功。显然有必要进行研究，以便i)增加关于气体在地下如何运动的知识，ii)制定最佳做法，以监测和指导泄漏井周围的补救尝试。**与行业合作伙伴和天然气输送服务提供商合作，该项目将包括对选定的泄漏井点进行一系列调查，从大范围开始(在5-6口井进行非侵入性调查)，然后集中在一个井点，根据以前的调查情况进行全面的详细研究。根据各个天然气输送服务提供商的管理做法，该项目的第一部分将采用多种天然气输送评估方法，以便在提供SCVF/GM数据的同时，比较各种方法和技术。然后，这些信息将被用于进行详细的地下调查，包括钻井、取心、地球物理、广泛的地下水采样等。最终结果将是一个地下天然气运输的综合概念模型(这是第一个)，并为监测和补救泄漏井的最佳管理做法开发一个数值模型和指南。

Leaky wells represent one of the greatest environmental liabilities to the oil and gas industry. Furthermore, this liability can be transferred to the public purse when wells become "orphaned" (i.e. no legally responsible or financially able party exists to manage abandonment), which is occurring more frequently in the current economic climate. Leaky wells can exhibit surface casing vent flow (SCVF), where gas (primarily methane) leaks inside the well casing(s), and/or gas migration (GM), where gas migrates from the target or intermediate zone, or through a hole in the well casing at some depth, to the ground surface. In particular, the extent of GM is not well delineated, gas transport pathways are not well understood, and remediation efforts are rarely successful on the first attempt (or second or third). There is a clear need for research to i) increase knowledge about how gas moves in the subsurface and ii) to develop best practices to monitor and guide remediation attempts around leaky wells.**In collaboration with industry partners and gas migration service providers, this project will comprise a series of investigations at select leaky well sites, starting broad in scope (non-intrusive investigations at 5-6 wells) before focusing on one well site to conduct a comprehensive detailed study informed by the previous investigations. A variety of gas migration assessment approaches will be employed in the first part of the project, as per management practices of individual gas migration service providers, which will allow comparison of methods and techniques while providing data on SCVF/GM. This information will then be used to conduct a detailed subsurface investigation, including drilling, coring, geophysics, extensive groundwater sampling, among others. The end result will be a comprehensive conceptual model of subsurface gas transport (the first of its kind) as well as the development of a numerical model and guidelines for best management practices regarding monitoring and remediation of leaky wells.************