深层煤层气保压取心技术及应用研究

Research on pressure maintaining and core sampling technology for deep coalbed methane and its application

摘要:

煤层气取心过程中，压力发生变化，会直接造成煤层岩心含气量及孔隙度等参数发生改变，这对煤层气体含量探测及煤层气成藏理论研究造成偏差。目前煤层气资源勘探取心采用的保压取心工具，保压能力低于50 MPa，不能满足深层煤层气资源精确勘查的需求。针对这一问题，研发了一种深层煤层气保压取心工具，保压能力60 MPa，单回次取心长度6.5 m，并通过理论分析、数值模拟、室内试验等方法验证了该工具的强度和安全性。在内蒙古某煤层气勘探井进行保压取心作业，共进行3筒保压取心，累计进尺9.4 m，收获岩心总长9.12 m，平均岩心收获率97%，保压成功率100%。研究结果表明：研制的深层煤层气保压取心工具性能可靠，可为煤层气、页岩气等非常规油气资源精确探测提供新的工具方法支撑。

Abstract:

During the coring process of coalbed methane， changes in pressure can directly cause changes in parameters such as gas content and porosity of the coalbed core， which can lead to deviations in the detection of coalbed gas content and theoretical research on coalbed methane reservoir formation. At present， the pressure holding coring tool used for coalbed methane resource exploration has a pressure holding capacity of less than 50MPa， which cannot meet the precise exploration needs of deep coalbed methane resources. In response to this problem， a deep coalbed methane pressure holding coring tool has been developed with a pressure holding capacity of 60MPa and a single core length of 6.5m. The strength and safety of the tool have been verified through theoretical analysis， numerical simulation， indoor testing and other methods. Three pressure holding coring operations were carried out in a coalbed methane exploration well in Inner Mongolia， with a cumulative footage of 9.4m and a total core length of 9.12m. The average core recovery rate was 97%， and the pressure holding success rate was 100%.The research results indicate that the developed deep coalbed methane pressure holding coring tool has reliable performance and can provide new tool and method support for precise detection of unconventional oil and gas resources such as coalbed methane and shale gas.