石油学报 ›› 2022, Vol. 43 ›› Issue (8): 1049-1064.DOI: 10.7623/syxb202208002

• 地质勘探 • 上一篇    下一篇

库车坳陷东部迪北地区侏罗系阿合组致密砂岩气勘探重大突破及地质意义

王清华1, 张荣虎2, 杨宪彰1, 余朝丰2, 徐振平1, 周露1, 王珂2, 张亮1   

  1. 1. 中国石油塔里木油田公司 新疆库尔勒 841000;
    2. 中国石油杭州地质研究院 浙江杭州 310023
  • 收稿日期:2022-07-09 修回日期:2022-07-27 出版日期:2022-08-25 发布日期:2022-09-05
  • 通讯作者: 张荣虎,男,1976年9月生,2013年获中国石油勘探开发研究院博士学位,现为中国石油勘探开发研究院教授级高级工程师,主要从事碎屑岩沉积储层、成藏与天然气地质综合研究工作。Email:zrh_hz@petrochina.com.cn
  • 作者简介:王清华,男,1968年8月生,2007年获浙江大学博士学位,现为中国石油塔里木油田公司教授级高级工程师,主要从事油气勘探研究工作。Email:wqh-tlm@petrochina.com.cn
  • 基金资助:
    国家科技重大专项"深层-超深层油气成藏过程与勘探新领域"(2017ZX05008-004)和中国石油天然气集团有限公司"十四五"上游领域前瞻性基础性项目(2021DJ0302)资助。

Major breakthrough and geological significance of tight sandstone gas exploration in Jurassic Ahe Formation in Dibei area,eastern Kuqa depression

Wang Qinghua1, Zhang Ronghu2, Yang Xianzhang1, Yu Chaofeng2, Xu Zhenping1, Zhou Lu1, Wang Ke2, Zhang Liang1   

  1. 1. PetroChina Tarim Oilfield Company, Xinjiang Korla 841000, China;
    2. PetroChina Hangzhou Research Institute of Geology, Zhejiang Hangzhou 310023, China
  • Received:2022-07-09 Revised:2022-07-27 Online:2022-08-25 Published:2022-09-05

摘要: 库车坳陷东部迪北地区下侏罗统阿合组致密气资源潜力巨大,是塔里木盆地天然气增储上产的重要接替领域。受制于地质条件复杂,该地区的油气富集规律认识不清、储层甜点预测难度大,制约了致密气的有效勘探与开发。基于构造演化、烃源岩、沉积储层、生-储-盖组合及勘探实践的系统分析,探讨了阿合组天然气成藏新模式。迪北地区发育多条4级高角度逆冲断裂,其中Ⅲ、Ⅳ级断裂的伴生裂缝发育,构造整体表现为自南向北阶梯式抬升,局部发育断背斜和断鼻构造,主要形成于中新世-第四纪逆冲推覆期;阿合组储层以辫状河三角洲平原亚相辫状河道巨厚层状(含砾)粗砂岩为主,多尺度、多成因的微裂缝可有效沟通微孔隙和长石粒内溶孔等储集空间,有利于规模储层甜点的发育。阿合组致密气藏的生-储-盖组合表现为"三明治"式,其中,三叠系暗色泥岩和煤层是致密气藏的主力烃源岩。阿合组致密气成藏演化具有"先致密后成藏"的特征,早期注入油、减孔致密,喜马拉雅晚期(18~1 Ma)断裂和构造缝发育,利于天然气沿断裂-裂缝带充注成藏。迪北5井采用常规钻井工程和常规压裂工艺实现了阿合组超深层致密油气效益勘探突破,证实了迪北地区整体含气,以烃源岩发育区、优势储层分布区、Ⅲ-Ⅳ级断裂-裂缝带的油气最为富集。重新刻画了效益勘探有利区的面积为1 030 km2、天然气资源量为7 210×108m3、石油资源量为3 090×104t。

关键词: 侏罗系, 致密砂岩气, 储层甜点, 迪北气藏, 库车坳陷

Abstract: The Lower Jurassic Ahe Formation in Dibei area,eastern Kuqa depression has a great potential of tight gas resource,which is an important replacement field for increasing natural gas reserves and production in Tarim Basin.Limited by the complex geological conditions,the hydrocarbon enrichment law in this area is still unknown,and it is difficult to predict reservoir sweet spots,thus restricting the effective exploration and development of tight gas.Based on the systematic analysis of tectonic evolution,source rock,sedimentary reservoir,source-reservoir-cap rock association and exploration practice,this paper explores the new gas accumulation mode of Ahe Formation.Several four-grade high-angle thrust faults are developed in Dibei area,of which grade III-IV faults are developed and associated with fractures.On the whole,the tectonic structure show a stepped uplift from south to north,and fault anticline and fault nose-shaped structure are developed in regional areas,mainly formed in the Miocene-Quaternary thrust-nappe period;the reservoirs of Ahe Formation are mainly composed of ultra-thick layered (gravel-bearing) coarse sandstone in the braided channels of the braided delta plain subfacies.The multi-scale and polygenetic microfractures can effectively communicate the reservoir spaces such as micropores and the intragranular dissolved pores of feldspar,which is conducive to the development of large-scale reservoir sweet spots.The source-reservoir-cap rock association of the tight gas reservoir in Ahe Formation presents a sandwich pattern,in which the Triassic dark mudstone and coal seam are the main source rocks of the tight gas reservoir.The accumulation evolution of tight gas in Ahe Formation is characterized by "first compaction and then accumulation".Both injecting oil and reducing pores for compaction in the early stage as well as the development of Himalayan faults and tectonic fractures in the late stage are conducive to the charging and accumulation of gas along the fault-fracture zone.A breakthrough in the exploration of ultra-deep tight oil and gas in Ahe Formation was made in Well Dibei 5 by conventional drilling engineering and fracturing technique,based on which it is confirmed that the overall Dibei area has gas resource and the oil and gas are most enriched in the source rock development area,the dominant reservoir area and the zone of grade III-IV faults and fractures.The favorable exploration area is re-determined as 1 030 km2,the amount of natural gas resource and oil resource is 7 210×108m3 and 3 090×104t,respectively.

Key words: Jurassic system, tight sandstone gas, reservoir sweet spot, Dibei gas reservoir, Kuqa depression

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