渤海湾盆地辽河坳陷稠油分布特征及主控因素

Characteristics and controlling factors of heavy oil distribution in Liaohe Depression, Bohai Bay Basin

陈星州 邵建欣 孙转 韩宏伟 郭强 尹宜鹏 孙新宇

CHEN Xingzhou SHAO Jianxin SUN Zhuan HAN Hongwei GUO Qiang YIN Yipeng SUN Xinyu

中国石油 辽河油田分公司 勘探开发研究院, 辽宁 盘锦 124010 中国石油 辽河石油勘探局有限公司, 辽宁 盘锦 124010

Research Institute of Petroleum Exploration and Development, Liaohe Oilfield Company, CNPC, Panjin, Liaoning 124010, China Liaohe Petroleum Exploration Bureau Co., Ltd., CNPC, Panjin, Liaoning 124010, China

渤海湾盆地辽河坳陷原油类型多样，但以稠油为主，其油气储量和产量均占该坳陷总量的50%以上。研究辽河坳陷油藏稠变的成因机理，进而搞清稠油的分布规律，对后继勘探开发具有重要的意义。依据辽河油田多年稠油油藏勘探开发形成的系统认识，对稠油油藏的“边、浅、松、早、降、失、盖”等地质特征开展研究；并从构造格局、储层特征、油藏埋深、地下流体、封盖条件和氧化及生物降解作用等方面对稠油分布和稠变原因进行探讨，厘清辽河坳陷油藏稠变机理及主控因素。研究发现，构造格局是控制稠油分布的决定因素，储层、埋深、地下流体和盖层等地质条件是控制原油稠变的重要因素，生物降解和氧化作用是稠变的必要条件。辽河坳陷油气藏具有明显的环洼分布规律，围绕生油洼陷由内向外存在3个环带，内带以天然气、凝析油为主，埋深一般大于3 500 m；中带以稀油为主，局部富集天然气及稠油，埋深在1 700~3 500 m；外带以稠油为主，埋深一般小于1 700 m。

There are various types of crude oil in the Liaohe Depression, Bohai Bay Basin, among which heavy oil accounts for more than 50% of the oil and gas reserves and production. Therefore, it is of great significance for future exploration and development to study the main controlling factors of oil densification in the Liaohe Depression and to understand the distribution pattern of heavy oil. Based on the systematic understanding of heavy oil reservoir exploration and development in Liaohe oilfield for decades of years, and by aiming at the geological characteristics of heavy oil reservoirs such as "edge, shallow, unconsolidated, early, falling, loss, capping", this paper discusses the distribution and densification reasons of heavy oil from six aspects, including structural pattern, reservoir characteristics, reservoir burial depth, underground fluid, capping conditions, oxidation and biodegradation. The densification mechanism and controlling factors of heavy oil reservoirs in the Liaohe Depression are basically clarified. Through the study of heavy oil densification factors, it is found that structural pattern is the main factor controlling heavy oil distribution, geological conditions such as reservoir, burial depth, underground fluid and cap rocks are important factors controlling heavy oil densification, while biodegradation and oxidation are the keys for heavy oil densification. Oil and gas reservoirs accumulate around sags in the Liaohe Depression. There are three rings around the oil-generating sags from the inside to the outside. The inner zone is dominated by natural gas and condensate gas, and the buried depth is generally more than 3 500 m. The middle zone is dominated by light oil, partially enriched with natural gas and heavy oil, with a buried depth of 1 700-3 500 m. The outer zone is dominated by heavy oil, and the buried depth is generally less than 1 700 m.

国家科技重大专项 2016EX05006005;中国石油集团公司重大科技专项 2017E-16

https://doi.org/10.11781/sysydz202302317