石油学报 ›› 2014, Vol. 35 ›› Issue (4): 664-672.DOI: 10.7623/syxb201404006

• 地质勘探 • 上一篇    下一篇

柯坪—巴楚露头区蓬莱坝组白云岩特征及孔隙成因

郑剑锋1,2, 沈安江1,2, 乔占峰1,2, 吴兴宁2, 张天付1,2   

  1. 1. 中国石油天然气集团公司碳酸盐岩储层重点实验室 浙江杭州 310023;
    2. 中国石油天然气股份有限公司杭州地质研究院 浙江杭州 310023
  • 收稿日期:2014-01-04 修回日期:2014-04-25 出版日期:2014-07-25 发布日期:2014-08-05
  • 通讯作者: 郑剑锋,男,1977年7月生,2001年获江汉石油学院学士学位,2004年获长江大学硕士学位,现为中国石油天然气股份有限公司杭州地质研究院高级工程师,主要从事碳酸盐岩沉积、储层研究。Email:zhengjf_hz@petrochina.com.cn
  • 作者简介:郑剑锋,男,1977年7月生,2001年获江汉石油学院学士学位,2004年获长江大学硕士学位,现为中国石油天然气股份有限公司杭州地质研究院高级工程师,主要从事碳酸盐岩沉积、储层研究。Email:zhengjf_hz@petrochina.com.cn
  • 基金资助:

    国家重大科技专项(2011ZX05004-002)资助。

Characteristics and pore genesis of dolomite in the Penglaiba Formation in Keping-Bachu outcrop area

Zheng Jianfeng1,2, Shen Anjiang1,2, Qiao Zhanfeng1,2, Wu Xingning2, Zhang Tianfu1,2   

  1. 1. CNPC Key Laboratory of Carbonate Reservoir, Zhejiang Hangzhou 310023, China;
    2. PetroChina Hangzhou Research Institute of Geology, Zhejiang Hangzhou 310023, China
  • Received:2014-01-04 Revised:2014-04-25 Online:2014-07-25 Published:2014-08-05

摘要:

塔里木盆地下奥陶统蓬莱坝组白云岩是重要的潜在勘探领域,但因其勘探、研究程度低,导致目前的认识无法满足油气勘探需求,而其孔隙成因及发育规律是非常重要的制约因素之一。通过对柯坪水泥厂剖面及巴楚达坂塔格剖面的精细岩石特征描述,发现研究区蓬莱坝组白云岩孔隙主要发育于细—粗晶白云岩中,孔隙类型以晶间孔、晶间溶孔为主,且相对均质,一般孔隙度3%~5%。微量元素、稀土元素及氧、碳、锶同位素特征反映白云石化作用主要发生于早—中埋藏期,局部受到晚埋藏期热液的改造,白云石化流体主要为海源地层水。在对重点白云岩层段进行精细岩相、高频层序地层分析及利用显微、荧光技术恢复白云岩原岩结构的基础上,认为蓬莱坝组白云岩孔隙的发育具有成层性和旋回性,台内高能滩是孔隙发育的优势相带,六级或五级高频旋回向上变浅序列的上部为有利孔隙发育位置。白云石化作用并不直接产生孔隙,而是使原岩孔隙得到继承,并起保护孔隙的作用。

关键词: 柯坪—巴楚地区, 蓬莱坝组, 露头, 白云岩, 孔隙成因, 下奥陶统

Abstract:

Dolomite of Penglaiba Formation in Tarim Basin provides a potentially important exploration field. With low degree of relevant exploration and research, the current understandings cannot meet the needs for dolomite exploration in Penglaiba Formation, and study on the genesis and distribution of dolomite is one of the important limiting factors. This study detailed the characteristics of dolomite in Keping and Dabantage sections, indicating that pores mainly exist in fine-coarse crystalline dolomite, including the major types of intercrystalline pore and intercrystalline solution pore (average porosity, approx. 3% ~5%). Trace elements, rear earth elements, and oxygen, carbon, and strontium isotope elements were analyzed, and the results reflected that dolomitization mainly took place in the early-middle buried stage and was partially modified by hydrothermal fluid in the later buried stage, with formation water of sea source as the main dolomitization fluid. Additionally, the lithofacies and high frequency sequence stratigraphy of selected dolomite intervals were analyzed and the original dolomite rock structure was reconstructed by microscopy and fluorescence technique. It was found that the development of dolomite pores featured stratification and cyclicity, for which high energy platform shoal was the favorable facies and the top of sixth- or fifth-order cycle was the favorable place. Dolomitization did not product pores directly but mainly inherited and protected the pores from the original rocks.

Key words: Keping-Bachu area, Penglaiba Formation, outcrop area, dolomite, pore genesis, Lower Ordovician

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