鄂尔多斯盆地东缘非常规天然气勘探实践及发展方向——以临兴-神府气田为例

Practices and development trend of unconventional natural gas exploration in eastern margin of Ordos Basin:Taking Linxing-Shenfu gas field as an example

鄂尔多斯盆地东缘临兴-神府气田早期一直以煤层气勘探为主,并且缺乏系统的成藏理论认识和关键的开发技术手段,致密气勘探开发工作几乎停滞。近年来,通过转变区域工作重心(从煤层气走向致密气)、深化成藏理论研究和创新地质工程一体化技术,成功指导了中国海油陆上第一个千亿方大气田的发现。基于期间致密气勘探开发实践,系统总结了区域致密气勘探开发理论进展和技术成果,并提出了未来中国海油陆上非常规天然气发展方向。研究认为:(1)鄂尔多斯盆地东缘非常规油气资源十分丰富,致密砂岩、煤层、铝土岩、碳酸盐岩等多种储层类型发育,具备立体成藏和多气共存条件。(2)创新提出鄂东盆缘“源-储-断”三控影响下的差异成藏富集模式,形成了地质工程“双甜点”定量识别技术,实践了全流程一体化的压裂增产改造技术,建立了沉积-成岩双协同的储层综合评价技术,有力支持了海油陆上非常规天然气产业的快速发展,目前已基本探明致密气地质储量近3000亿方,建成年产能20亿方。(3)提出了“双碳”目标引领下中国海油陆上超级大气群(万亿级规模)的战略构想,制定了“立足致密气、突破深煤层、兼顾新领域(铝土岩与碳酸盐岩)”的勘探目标,形成“整体部署、分类突破、多气协同”的一盘棋理念,采用“致密气勘探定深煤层气甜点,深煤层气勘探助力致密气开发,铝土岩等新领域接替动用”的勘探开发一体化模式。在上述技术成果、理论认识和勘探策略的研究下,揭示了中国海油陆上非常规天然气巨大的勘探前景。

Since Linxing-Shenfu gas field in the eastern margin of Ordos Basin has been dominanted by coalbed methane exploration in the early stage,and lacks systematic theoretical understanding of reservoir formation and key development techniques,the exploration and development of tight gas has almost been stagnant.In recent years,it has successfully guided the discovery of CNOOC’s first onshore gas field of 100 billion cubic meters by virtue of changing the regional work focus(from coalbed methane to tight gas),deepening the theoretical research of reservoir formation and innovating the integrated technology of geological engineering.Based on the practice of tight gas exploration and development during this period,the theoretical progress and technical achievements of regional tight gas E&P are systematically summarized,and the future development direction of onshore unconventional natural gas in CNOOC is put forward.The results show that:(1)the eastern margin of Ordos Basin is rich in unconventional oil and gas resources,and developed with tight sandstone,coal seam,bauxite,carbonate rock and other reservoir types,showing the stereoscopic reservoir formation and multi gas coexistence conditions.(2)It has innovated the theory of differential reservoir formations and enrichment under the control of“source-reservoir-fault”in the Eastern Hubei basin margin,formed the“dual sweet spot”quantitative identification and transformation technology of geological engineering integration,and a series of technologies of quantitative identification of water bearing gas reservoirs,which strongly supports the rapid increase of reserves and production of unconventional natural gas.At present,the annual productivity has reached 2 billion cubic meters.(3)put forward the exploration strategy of“based on tight gas,breaking through deep coal seams,taking into account the new fields of bauxite and carbonate rock”,strengthen the integration of exploration and development of“overall deployment,classification breakthrough,and coordination of three gas types”,and adopt the integrated E&P mode of“tight gas exploration determines coalbed methane sweet spot,and coalbed methane exploration helps tight gas development,and bauxite and other new resources are replaced”.Under the research of the above technical achievements,theoretical understanding and exploration strategy,the huge exploration prospect of CNOOC’s onshore unconventional natural gas reservoir is revealed.