地学前缘 ›› 2023, Vol. 30 ›› Issue (6): 329-340.DOI: 10.13745/j.esf.sf.2023.2.13

• 海相深层-超深层碳酸盐岩油气动态成藏和聚集 • 上一篇    下一篇

塔里木盆地北部奥陶系超深层液态烃演化与保存机制:来自模拟实验的证据

陈强路1,2(), 马中良1,2,*(), 黎茂稳1,2, 席斌斌1,2, 郑伦举1,2, 庄新兵2, 袁坤1,2, 马晓潇1, 许锦1,2   

  1. 1.中国石化油气成藏重点实验室, 江苏 无锡 214126
    2.中国石化石油勘探开发研究院 无锡石油地质研究所, 江苏 无锡 214126
  • 收稿日期:2023-01-05 修回日期:2023-02-07 出版日期:2023-11-25 发布日期:2023-11-25
  • 通讯作者: * 马中良(1984—),男,博士,高级工程师,主要从事成烃成藏物理模拟与常规-非常规油气地质研究工作。E-mail: mazl.syky@sinopec.com
  • 作者简介:陈强路(1969—),男,博士,高级工程师,主要从事沉积学及油气成藏综合研究工作。E-mail: chenql.syky@sinopec.com
  • 基金资助:
    国家自然科学基金企业创新发展联合基金项目“海相深层油气富集机理与关键工程技术基础研究(U19B6003);中国石油化工集团科技部项目“海相深层高温高压条件下烃类转化与保持机制(P9032)

Mechanisms of liquid hydrocarbon evolution and preservation in ultra-deep Ordovician reservoirs, northern Tarim Basin: Insights from laboratory simulation experiments

CHEN Qianglu1,2(), MA Zhongliang1,2,*(), LI Maowen1,2, XI Binbin1,2, ZHENG Lunju1,2, ZHUANG Xinbing2, Yuan Kun1,2, MA Xiaoxiao1, XU Jin1,2   

  1. 1. Key Laboratory of Petroleum Accumulation Mechanisms, SINOPEC, Wuxi 214126, China
    2. Wuxi Research Institute of Petroleum Geology, Exploration and Production Research Institute, SINOPEC, Wuxi 214126, China
  • Received:2023-01-05 Revised:2023-02-07 Online:2023-11-25 Published:2023-11-25

摘要:

塔里木盆地北部寒武系—奥陶系超深层发现一批油藏和挥发性油藏,拓展了石油(液态烃)勘探的深度下限和规模增储领域。深层、超深层跨越多个构造期,经历了复杂的构造、埋藏和热演化历史,油气成藏有其特殊性,超深层油气藏的形成与保持机制仍需深入探讨。前人在重点层系埋藏热演化史、油气成藏定年、含烃包裹体和原油稳定性等方面开展了研究,但超深储层中烃类与矿物基质、地层水的相互作用对油气演化和保存的影响作用还需深化研究。本文以塔里木盆地顺托果勒地区奥陶系埋藏-热演化史和古压力变化为约束条件,开展油藏演化系列模拟实验,在逼近地下储层油气赋存状态、上覆压力、地层流体性质和压力条件下,重建了烃类热演化过程。结果表明,温度是原油裂解的主动力,油藏经历的最高古地温及持续时间是控制现今油气相态的决定性因素,而在VRo<2.0%时,地层水、灰岩储层介质环境等延缓了原油的裂解,有利于油藏的保存。对顺托果勒地区早期充注原油的保存能力进行了初步评价,早期充注原油在顺北地区保存指数为67%~100%,顺南地区为17%~50%,推测顺北地区液态烃大量消亡的深度下限在10 000 m左右。

关键词: 超深层, 液态烃, 保存机制, 模拟实验, 塔里木盆地

Abstract:

A number of oil and volatile oil reservoirs have been discovered in the Cambrian-Ordovician in the northern Tarim Basin expanding the depth scale of hydrocarbon-liquid window. The deep and ultra-deep reservoirs span multiple tectonic periods and have undergone complex tectonic, burial and thermal evolution. To understand the mechanisms of liquid hydrocarbon formation and maintenance, the burial history of key stratigraphic sequences, oil and gas formation and dating, hydrocarbon inclusions and crude oil stability have been investigated. However, in-depth studies on the interactions between hydrocarbons and mineral matrix/formation water and their effects on reservoir evolution and preservation are still lacking. In this paper, laboratory simulation experiments are carried out using constrains from the burial, thermal and paleopressure history of the Shuntuo Guole region, Tarim Basin, and the thermal history of reservoir fluids is reconstructed under conditions mimicking the natural occurrence state, overburden pressure, fluid properties and pressure regimes of the underground reservoirs. The results show that the reservoir temperature controls crude oil cracking, where the highest paleo-temperature and duration of hydrocarbon accumulation dictate the phase behavior of reservoir fluids today. When VRo is less than 2.0%, crude oil cracking is delayed under effects of formation water and limestone matrix, which is conducive to liquid hydrocarbon preservation in a reservoir. Based on preliminary evaluation, the estimated Oil Preservation Indexes (OPI) for early filled crude oil in Shunbei and Shunnan are 67%-100% and 17%-50%, respectively, which suggests the depth limit for significant hydrocarbon accumulation in Shunbei can be extended to ~10000 m.

Key words: ultra-deep sequence, liquid hydrocarbon, preservation mechanism, simulation experiment, Tarim Basin

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