石油与天然气地质 ›› 2011, Vol. 32 ›› Issue (4): 577-583，592.doi: 10.11743/ogg20110411

• 石油与天然气地质 • 上一篇    下一篇

大型高原内陆咸化湖盆油气特殊成藏条件分析及勘探意义——以柴达木盆地柴西地区为例

  

  • 出版日期:2011-08-28 发布日期:2011-09-26

Special reservoir formation conditions and their exploration significance of the large saline lacustrine basin of inland plateautaking the western Qadam Basin for example

  • Online:2011-08-28 Published:2011-09-26

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摘要：

摘要：提出了诸如柴西地区这种大型的高原内陆咸化湖盆4大特殊成藏条件：1）相似于现代青海湖，其具有多物源、小体系、窄相带、多类型的特殊沉积条件；2）受其独特的地质背景及水介质的影响，具有统一生烃坳陷，多个主力生烃中心共存的格局；3）区别于其他大型内陆湖盆单一的油气运移势（诸如鄂尔多斯盆地），其具有多方向发散式的优势油气运移势；4）高海拔活动区油气藏具有“自我封闭”成藏的特征。基于以上特殊成藏条件，提出了柴西地区岩性油气藏勘探除了局限于传统的三角洲前缘相带之外，滩坝砂、藻灰岩及地震引起的滑塌、浊积体成为岩性油气勘探的3大主要接替领域。这种多个主力生烃中心共存的格局和多方向发散式油气运移势的特点，决定了柴西地区的油田将呈现出近源成藏、分散聚集、油气田小而多的特点。因而勘探部署应在老区精细勘探的基础上积极实施低勘探区的石油预探，尤其要加强紧邻主力生烃中心且处于优势油气运移势指向区的阿尔金山前带、甘森及红沟子一带的石油预探。同时，这种“自我封闭”成藏的认识，明确了盆缘稳定抬升区将成为盆地下一步实施储量增长高峰期的主要领域。

关键词: 关键词：特殊油气成藏条件, 高原内陆咸化湖盆, 勘探意义, 柴西地区

Abstract:

Abstract: The author proposed four major special conditions for hydrocarbon accumulation in large saline lacustrine basins of inland plateau (such as the western Qaidam area). First, their sedimentary environment is similar to that of modern Qinghai Lake, featuring in unique deposition conditions such as multisource, small systems, narrow facies belt and multiple types. Secondly, controlled by unique geological background and water medium, they share the pattern of one hydrocarbongeneration depression with a number of kitchens. Thirdly, different from other large inland lake (such as the Ordos Basin) with a single hydrocarbon migration potential, they have the advantage of multidirectional migration potential of oil and gas. Finally, reservoirs in active regions at higher altitude show a “selfclosed” pooling pattern. Based on the above four specific reservoiring conditions, the author proposed that oil and gas exploration in western Qadam Basin shall not only focus on delta front deposits, but also on the following three targets: beach bar sand, algal limestone as well as slump and turbidite sandbody caused by earthquakes. In addition, the abovementioned features determine that the oil fields in western Qaidam have the characteristics of nearsource accumulation, wide distribution, small but numerous oil/gas fields. Thus the exploration should be mainly brought before areas close to the main kitchens, such as Altun, Gansen and along Honggouzi. Meanwhile, the understanding of socalled “selfclosed” reservoiring pointed out that the uplifted basin margin be the main areas for future reserve growth.

Key words:  , Key words： special hydrocarbon accumulation condition, saline lacustrine basin of inland plateau, exploration significance, western Qaidam Basin