塔里木盆地塔河油田中西部奥陶系油气成藏主控因素与动态成藏过程

Main constrains and dynamic process of Ordovician hydrocarbon accumulation, central and western Tahe Oil Field, Tarim Basin

赵永强 云露 王斌 耿峰 李海英 顾忆 刘永立

ZHAO Yongqiang YUN Lu WANG Bin GENG Feng LI Haiying GU Yi LIU Yongli

中国石化 油气成藏重点实验室, 江苏 无锡 214126 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 中国石化 西北油田分公司, 乌鲁木齐 830011

SINOPEC Key Laboratory of Petroleum Accumulation Mechanisms, Wuxi, Jiangsu 214126, China Wuxi Research Institute of Petroleum Geology, SINOPEC, Wuxi, Jiangsu 214126, China Northwest Oil Company, SINOPEC, Urumqi, Xinjiang 830011, China

塔里木盆地塔河油田中西部奥陶系油气资源类型多样，纵向整体含油，成藏过程极其复杂。从多元成藏要素及其时空动态配置关系角度出发，综合典型油藏解剖、烃源岩热演化生烃史、古构造演化、成藏期和输导体系等研究，以古构造与走滑断裂叠加控储、控藏、控聚的思路重新认识塔河油田中西部油气成藏动态过程，建立了复式成藏模式。研究区油气成藏主控因素为烃源岩长期生排烃、多期充注成藏及混合改造、古构造控制运聚方向、走滑断裂垂向输导与侧向调整、多类型缝洞储集体大规模发育。油气成藏动态过程具有早期"垂向输导、侧向汇聚、古隆控富"，晚期"原地烃源、纵向运聚、断裂控富"的特征。不同期次、不同性质的油气混合成藏，造就了奥陶系现今复杂的油气面貌。重质油区以早期成藏为主，与加里东中晚期古构造高部位有关，后期充注较弱；而轻质油区以晚期成藏为主，主要受走滑断裂垂向输导和近距离侧向调整控制，在NNE向断裂带及与NNW向断裂的交会部位最为富集。

Diversified types of oil and gas resources have been discovered in the Ordovician strata of central and western parts of the Tahe Oil Field, Tarim Basin. The formation contains oil in the vertical direction as a whole, and its accumulation process appeared to be extremely complicated. The dynamic process of oil and gas accumulation in the central and western parts of Tahe Oil Field were re-studied on the basis of combination of approaches including perspective of multiple reservoir-forming factors and their temporal and spatial dynamic configuration relationships, the discussion of typical reservoir profiles, thermal evolution of source rocks and consequent hydrocarbon generation history, paleo-structural evolution, hydrocarbon accumulation period and transport system, thus, a model of compound accumulation was established following an idea that paleo-structures and strike-slip faults together constrained reservoir formation and hydrocarbon generation as well as accumulation. Studies have shown that the main constrains for hydrocarbon accumulation in the study area includes the long-term hydrocarbon generation and expulsion from source rocks, multi-stage charging and accumulation and mixing transformation, paleo-structural controlling the migration and accumulation direction, vertical conduction and lateral adjustment by strike-slip faults, and multiple types of fractures and caves. The dynamic process of hydrocarbon accumulation has the characteristics of "vertical transportation, lateral accumulation, paleo-uplift controlling enrichment" in the early stage, and "in-situ hydrocarbon source, vertical migration and accumulation, and fault controlling enrichment" in the late stage. The mixed accumulation of oil and gas of different stages and different properties has created the present complex oil and gas appearance of the Ordovician strata. The heavy oil area was dominated by early accumulation, which was related to the high paleo-structures in the middle and late Caledonian periods, and the later charging was relatively weaker. The light oil area was dominated by late accumulation, mainly constrained by the vertical transport and short-range lateral adjustment of strike-slip faults. It is most developed in the NNE-trending fault zone and the intersection with the NNW-trending fault.

中国石化科技部科技攻关项目 P18095-2

https://doi.org/10.11781/sysydz202105758