石油学报 ›› 2013, Vol. 34 ›› Issue (2): 201-218.DOI: 10.7623/syxb201302001

• 地质勘探 •    下一篇

塔里木盆地库车坳陷和塔西南坳陷油气地质特征类比及勘探启示

何登发 1   李德生 2   何金有 1   吴晓智 2   

  1. 1.中国地质大学(北京)能源学院 北京 100083; 2.中国石油勘探开发研究院 北京 100083
  • 收稿日期:2012-08-11 修回日期:2012-12-15 出版日期:2013-03-25 发布日期:2013-01-31
  • 通讯作者: 何登发
  • 作者简介:何登发,男,1967年12月生,1989年获西北大学学士学位,1996年获北京石油勘探开发科学研究院博士学位,现为中国地质大学(北京)能源学院教授、博士生导师,长期从事沉积盆地构造分析与油气勘探研究工作。
  • 基金资助:

    国家自然科学基金重点项目(No.40739906)、国家重点基础研究发展计划(973)项目(2011CB201101)和国家重大科技专项(2011ZX05008-001)资助。

Comparison in petroleum geology between Kuqa depression and Southwest depression in Tarim Basin and its exploration significance

HE Dengfa 1   LI Desheng 2   HE Jinyou 1   WU Xiaozhi 2   

  1. School of Energy Resources, China University of Geosciences
  • Received:2012-08-11 Revised:2012-12-15 Online:2013-03-25 Published:2013-01-31

摘要:

塔里木盆地西南坳陷已有近60年的油气勘探历史,目前已发现了柯克亚、巴什托普、亚松迪、和田河、阿克莫木5个油气田和山1井、柯东1井2个油气藏。对于该一直被寄予厚望的地区,如何深入认识其油气地质条件,加快勘探进程,获得更多的油气发现,始终是石油地质学家与油气勘探家努力追求的目标。塔里木盆地库车坳陷的天然气勘探近10年来取得重大突破。进行2个坳陷的石油地质类比研究是解剖与揭示西南坳陷油气地质条件的重要方法之一。本文立足于库车与西南坳陷已有的油气勘探资料和现有认识,从比较大地构造学与石油地质学的角度深入剖析二者的相似性与差异性。二者虽然在盆-山边界具有逆冲、走滑-逆冲性质,具有现今陆内前陆盆地结构,为不同性质的盆地转换、叠加形成,坳陷内部具有“分块、分带、分层”的特点,油气聚集受断裂带控制明显等方面具有相似性,但更多地体现出彼此的差异性。差异性主要表现在:大地构造背景,深部地质结构,基底性质,构造演化,地质结构,构造变形,烃源岩及其演化,储盖组合,含油气系统,油气成藏机理与成藏模式,油气分布规律等12个方面。其中,大地构造背景差异(库车坳陷与古亚洲洋相关,西南坳陷与特提斯体系相关)及地质结构特点的不同(库车坳陷主体为新生界与中生界叠加,西南坳陷主体为新生界与古生界叠加)是决定其油气成藏差异性的根本因素。石油地质类比表明,西南坳陷的油气勘探需要新的石油地质学理论与新的勘探思维。新的石油地质学理论要明确阐述“古老烃源岩生成的油气在后期强烈构造活动中保存的部位、状态、类型与可能机制”;新的勘探思维迫切需要建立新的三维地质结构概念,整体、动态的勘探观与立体勘探思维,既重视山前带的复杂构造圈闭,也要重视斜坡带的隐蔽圈闭如奥陶系潜山、泥盆系-石炭系地层-岩性圈闭,同时要密切关注逼近寒武系烃源岩的白云岩圈闭。

关键词: 大地构造背景, 地质结构, 油气分布, 石油地质类比, 库车坳陷, 西南坳陷, 塔里木盆地

Abstract:

Petroleum exploration in the southwest Tarim Basin has a history more than sixty years. Up to now, five oil and gas fields and two oil and gas reservoirs have been discovered, namely Kekeya, Bashituopu, Yasongdi, Hetianhe, Akemomu, and the Shan-1 well and Kedong-1 well. Petroleum geologists and explorationists have cherished high hopes for these favorable and prospecting areas and all along pursued goals how to understand their petroleum geological conditions in detail, to accelerate exploration activities, and to get much more discoveries. In addition, a great breakthrough has been made in gas exploration of Kuqa area in Tarim Basin since 2000. Therefore, the petroleum geologic comparison between these two depressions is one of the important methods to analyze and uncover key petroleum geologic conditions of Southwest depression. Based on available exploration data and the current knowledge of these two depressions, we compared the very similarities and differences between them from the point of view of comparative tectonics and petroleum geology. Both of them share the following common points: (1) boundaries between the basin and mountains are characteristic of overthrusting or strike-slipping-overthrusting; (2) they have the intra-continental foreland basin structures at present; (3) they are formed by the transformation and superimposition of different proto-type basins; (4) basin structures are characterized by segmentation, zonation and stratification; and (5) fault zones play a major role in controlling hydrocarbon accumulation. However, differences between these two depressions are also much more remarkable in twelve aspects, such as geo-tectonic settings, deep geological structures, basement properties, tectonic evolution, geological framework, structural deformation, source rocks and their thermal evolution, reservoir-seal rock associations, petroleum systems, oil and gas accumulation mechanisms and preservation patterns, and oil and gas distributions. Of which the overwhelming important factors that control the oil and gas reservoir-formation are the geo-tectonic background and geological structures. The former shows that Kuqa depression is tightly related to the Paleo-Asian Ocean tectonic system, while Southwest depression to the Tethyan Ocean tectonic system. The latter indicates that Kuqa depression is formed predominantly by the superimposition of Cenozoic strata upon Mesozoic strata, while Southwest depression chiefly by the superimposition of Cenozoic strata upon Paleozoic strata. The above-mentioned comparison shows clearly that exploration in Southwest depression must be supported by a new theory of petroleum geology and exploration philosophy. This new theory needs to definitely disclose the exact locations, status, types, and possible mechanisms of the oil and gas sealed and preserved under late-period extensive structural movements, which have been sourced from old and lower-seated source rocks. It is urgent for this new exploration philosophy to establish new concepts of 3D geological structures, ideas of unitary and dynamic exploration, and also the stereoscopic thinking, which strengthen not only complex structural traps in foreland belts, but also subtle traps in slope zones, i.e. Ordovician buried-hills and Devonian-Carboniferous stratigraphic-lithologic traps, as well as dolomitic traps adjacent to Cambrian source rocks.

Key words: geotectonic setting, geological framework, oil and gas distribution, comparison of petroleum geological factors, Kuqa depression, Southwest depression, Tarim Basin