石油与天然气地质 ›› 2011, Vol. 32 ›› Issue (4): 512-521.doi: 10.11743/ogg20110404

• 石油与天然气地质 • 上一篇    下一篇

塔里木盆地S76井与TZ62井奥陶系礁滩相储层发育差异性对比

  

  • 出版日期:2011-08-28 发布日期:2011-09-26

Differences of the Ordovician reefbank reservoirs in S-76 and TZ-62 well in the Tarim Basin

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

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摘要：

摘要：塔里木盆地奥陶系一间房组和良里塔格组礁滩相带是重要的油气勘探领域。塔河地区S76井一间房组礁滩处于台内缓坡之上，属于台内礁滩相；而塔中地区TZ62井良里塔格组礁滩处于陡坡型台地边缘，为台缘礁滩相。通过准层序类型分析，认为两口井有六种准层序样式，但是处于不同构造位置。相比S76井而言，TZ62井的准层序对海平面变化的响应更迅速，准层序厚度更小。而通过层序结构分析，认为S76井的台内礁滩相主要发育在准层序组的高位体系域内，即基准面下降半旋回；而TZ62井台缘礁滩相处于准层序组的海侵体系域，即基准面上升半旋回。正因为如此，S76井的礁滩相呈进积式增长，礁滩厚度薄、沉积相相变速率快；而TZ62井沉积可容纳空间较稳定，礁滩相呈加积式增长，礁滩厚度大、沉积相相变速率变慢。两口井目的层段均处在一个三级层序的基准面上升旋回中，岩石类型分别以颗粒灰岩为主和以泥灰岩为主。因此，通过台内礁滩相和台缘礁滩相的岩性组合、沉积相和层序地层的相互比较可以得出，由于受构造位置和受海平面影响，不同相带的礁滩在层序地层中发育模式不同，从而导致不同礁滩的岩性、厚度以及发育规模存在差异。

关键词: 关键词：礁滩, 层序地层, 基准面, 奥陶系, 碳酸盐岩, 塔里木盆地

Abstract:

Abstract: Reefbank facies belts in the Ordovian Yijianfang and Lianglitage Formations are important target for hydrocarbon exploration in Tarim Basin. In Well S76 in Tahe area, the reefbank reservoirs of the Yijianfang Formation are developed in the intraplatform ramp and belong to intraplatform reefbank facies. In contrast, in Well TZ-62 in Tazhong area, the reefbank reservoirs of the Lianglitage Formation are developed on the margin of steep platform and are of platformmargin reefbank facies. By analyzing subsequence patterns, six types of subsequence can be identified in both wells, but occur at different structural locations. Compared with Well S-76, the subsequences of Well TZ-062 were more sensitive to fluctuation of sea level thus are smaller in thickness. Analysis of sequence structures reveals that the intraplatform reefbank facies in Well S-76 were mostly developed in highstand system tract, i.e. the falling semicycle of the base level. In contrast, the platform margin reefbank facies in Well TZ-62 were developed in transgressive system tract, i.e. the rising semicycle of the base level. Therefore, the reefbank facies of Well S-76 feature in progradational growth, small thickness and rapid change of sedimentary facies. On the contrary, the reefbank facies of Well TZ-62 are characterized by aggradational growth, larger thickness and slow change of sedimentary facies due to the relatively stable accommodation space. The targets in both wells are located in the rising cycle of the base level of a thirdorder sequence and are dominated by grainstone and marl respectively. Comparisons of lithological association, sedimentary facies and sequence stratigraphy of these two kinds of reefbank facies reveal that the development patterns of reefbank reservoirs in different facie belts are different due to the impacts of structural locations and sea level fluctuation, resulting in the differences of lithology, thickness and scale of different reefbank facies. 

Key words:  , Key words： reefbank, sequence stratigraphy, base level, Ordovician, carbonate rock, Tarim Basin