石油学报 ›› 2011, Vol. 32 ›› Issue (6): 949-958.DOI: 10.7623/syxb201106004

• 地质勘探 • 上一篇    下一篇

塔中地区志留系柯坪塔格组砂岩输导层量化表征及有效性评价

赵  健 1  罗晓容 1  张宝收 2  赵风云 2  雷裕红 1   

  1. 1中国科学院地质与地球物理研究所中国科学院油气资源研究重点实验室  北京  100029; 2中国石油塔里木油田公司勘探开发研究院  新疆库尔勒  841000
  • 收稿日期:2011-04-15 修回日期:2011-07-20 出版日期:2011-11-25 发布日期:2012-01-17
  • 通讯作者: 赵 健
  • 作者简介:赵 健,男,1982年8月生,2006年毕业于中国地质大学(武汉),现为中国科学院地质与地球物理研究所在读博士研究生,主要从事石油地质专业油气成藏动力学研究。
  • 基金资助:

    国家重点基础研究发展规划(973)项目(2011CB201105和2006CB202305)资助。

A quantitative characterization and effectiveness evaluation on sandstone carrier beds of the Silurian Kalpintag Formation in the Tazhong area, Tarim Basin

ZHAO Jian 1  LUO Xiaorong 1  ZHANG Baoshou 2  ZHAO Fengyun 2  LEI Yuhong 1   

  • Received:2011-04-15 Revised:2011-07-20 Online:2011-11-25 Published:2012-01-17

摘要:

量化表征砂岩的输导性能正成为砂岩输导体研究新的发展方向。以塔中地区志留系柯坪塔格组砂岩为研究对象,从油气运移角度对砂体在地质历史时期的连通、物性条件进行了分析,利用砂地比判别模型分析砂体几何连通特征;在有效区分不同期次原油的基础上,选择晚期原油作为关键指示物,分析了砂体在海西期油气成藏时流体连通特征。结果表明,志留系沥青砂岩在晚期油气成藏时不仅几何空间上相互连通,而且流体连通性良好,仍是油气运移的有效通道。根据砂体成岩作用及其与油气充注的关系,定量恢复了沥青砂岩在油气成藏时的古物性,并采用渗透率量化表征了其输导性能。结合前人关于志留系油气成藏模式及主要控烃断层启闭性认识,建立了塔中地区志留系油气运聚复合输导格架,并在此基础上,数值模拟分析了海西期末油气运聚成藏过程。结果表明,塔中地区志留系油气运聚成藏受砂岩输导性影响显著,输导性偏差的西北部地区油气主要富集在断裂带附近,而输导性较好的中南部区域油气侧向运移明显。

关键词: 塔中地区, 柯坪塔格组, 砂岩输导层, 几何连通性, 流体连通性, 数值模拟

Abstract:

Compared with the traditional sandstone description, a quantitative characterization of the geometric connectivity of sandstone carrier beds and the fluid connectivity has become an innovatory trend in studies of sandstone carrier beds because a numerical simulation that becomes increasingly necessary and important in carrier-bed studies can be achieved by this approach. The present paper took a sandstone carrier member of the Silurian Kalpintag Formation in the Tazhong area as an example to study the connectivity and physical properties of sandstones in geological history in terms of hydrocarbon migration. The sandstone carrier member of the Silurian Kalpintag Formation is made up of two separated oil-gas migration units, so it would be proper to divide the member into two sets of sandstone carriers: the upper and lower sandstone carrier sub-members. The geometric connectivity of these two carrier sub-members was quantitatively characterized using a sandstone ratio calculation model and based on effectively distinguishing oils into different episodes the late-stage oil was taken as a key indicator to investigate the fluid connectivity of sandstones during the Hercynian hydrocarbon accumulation. The result revealed that that Silurian sandstones had a good capacity of fluid connectivity besides the geometric connectivity, thus they remained a potential oil-gas carrier bed. According to the relationship between sandstone diagenesis and hydrocarbon charging, the paleo-porosity and paleo-permeability of sandstone carrier beds in hydrocarbon accumulations were quantitatively reconstructed and then the quantified paleo-permeability was applied as a key parameter to characterize the carrier capacity of sandstones. As another important migration pathway, the hydrocarbon carrier capacity of critical faults was also evaluated. These faults combined together with sandstone carriers formed a compound framework for hydrocarbon migration and accumulation. Based on previous studies on Silurian hydrocarbon accumulation models and the behavior of major faults in hydrocarbon migration, the geometric distribution and direction of hydrocarbon migration pathways in Silurian asphalt sandstones in the Tazhong area were obtained using numerical simulation and the process of hydrocarbon migration and accumulation at the end of Hercynian was investigated as well. The result revealed that oil-gas migration and accumulation in the Silurian were strongly influenced and even controlled by the carrier capacity of Silurian sandstones. In the northwestern Tazhong area, hydrocarbons mainly accumulated around fault belts due to a relatively poor carrier capacity of sandstones there, while the lateral migration of hydrocarbons occurred mainly in the central and southern Tazhong area because of a better carrier capacity of sandstones. Therefore, structural reservoirs may be the next exploration goal in the northwestern Tazhong area, while lithologic reservoirs should be given special attention in the central and southern Tazhong area.

Key words: Tazhong area, Kalpintag Formation, sandstone carrier bed, geometric connectivity, fluid connectivity, numerical simulation