吉木萨尔凹陷芦草沟组页岩油开发难点及对策

为实现吉木萨尔凹陷芦草沟组页岩油资源的有效动用和高效开发,推动中国陆相页岩油的规模化建产,通过详细对比国内外页岩油储集层地质特征,分析了中国陆相页岩油与北美海相页岩油的地质差异,结合吉木萨尔凹陷芦草沟组页岩油勘探开发的探索与实践,形成了吉木萨尔凹陷芦草沟组页岩油高效开发的技术对策体系。研究结果表明,吉木萨尔凹陷芦草沟组页岩油具有储集层埋深大、物性差、非均质性强等特征,开发过程中面临的难点主要体现在甜点识别标准不完善、整体有效可动用程度低、开发技术参数不明确、降本增效难度大等。通过开展以下工作有效解决了目前面临的开发技术难题:①综合储集层、测井、录井、地震和基础力学实验研究,建立“甜点”评价标准,优选地质和工程有利区;②开展地质工程一体化研究,结合现场井距试验和生产动态资料分析,优选井网部署参数、优化合理工作制度;③基于原油流动性实验分析,明确原油流动性主要影响因素为黏度,采用CO2前置压裂可有效降黏增效;④推动大平台批钻批压,降低压裂窜扰、套损等问题对规模建产的影响,奠定降本增效技术攻关方向。吉木萨尔凹陷页岩油开发过程中形成的技术对策,对中国陆相页岩油资源的规模建产具有积极的示范作用。

Difficulties and Countermeasures of Shale Oil Development in Lucaogou Formation of Jimsar Sag

To realize the effective producing and development of the shale oil resources in the Lucaogou formation of Jimsar sag and to push the scaled productivity construction of China’s terrestrial shale oil,the paper detailedly compares the geological characteristics of the shale oil reservoirs in China and abroad,analyzes the geological differences between China’s terrestrial shale oil and the marine shale oil in north America,and establishes a series of technical countermeasures for high efficient development of the shale oil in the Lucaogou formation of Jimsar sag based on the researches and practices of the exploration and development in the formation.The study results show that the shale oil in the Lucaogou formation of Jimsar sag is characterized by deep burial,poor physical properties and serious heterogeneity etc.,and the difficulties encountered during the development mainly include incomplete criterion of sweet spot identification,low degree of overall effective producing,uncertain technical parameters for development and lots of difficulties in cost decreasing and benefit increasing,the following work has been carried out to overcome the difficulties encountered during development:1)Based on the studies of reservoir,logging,mud log,seismic and fundamental mechanics experiment,a set of criterion of“sweet spot”evaluation has been established to optimize favorable geological and engineering area;2)The study on geology-engineering integration has been performed to optimize well pattern deployment parameters and reasonable working system based on field well-spacing test and production performance analysis.3)The main factor influencing crude oil fluidity is determined as the viscosity based on the analysis of crude oil fluidity experiment,and then PadCO2 fracturing technology can be used to effectively reduce viscosity and increase efficiency.4)The large-scaled platform batch drilling and fracturing processes have been applied to reduce the impacts of fracturing interference and casing failure on scaled productivity construction,and then to determine the technological direction for decreasing cost and increasing efficiency.The countermeasures formed during the shale oil development in Jimsar sag have a good demonstration effect on large-scaled production of the shale oil resources in China.