Li Chuanming, Wu Yong, Ding Xuefeng, Xie Xiankui, Luo Tianxiang, Zhang Jianwu, Sun Yaping, Xia Chuangtuo
Exploration Division of PetroChina Changqing Oilfield Company, Xi'an, 710018, People's Republic of China.
National Engineering Laboratory for Exploration and Development of Low Permeability Oil and Gas Fields, Xi'an, 710018, People's Republic of China.
Sci Rep. 2025 Jul 1;15(1):22093. doi: 10.1038/s41598-025-06582-w.
Carbonates, the main components of oil shale that influence oil and gas accumulation, are becoming increasingly significant in oil shale studies. This paper aims to examine the formation mechanisms of various carbonate minerals in shale and their impact on oil enrichment. In the Dongying Depression, two predominant types of carbonate minerals have been identified: micritic carbonate and grain carbonate. Micritic carbonate primarily forms through biogenic processes, where alternating carbonate and clay mineral laminae result from the periodic stratification of lacustrine water bodies. These layers are relatively thin. Micritic carbonate rocks contain low organic matter and predominantly feature narrow slit-like pores, leading to a tight pore structure that hinders oil shale accumulation. In contrast, grain carbonate formation is governed by diagenetic processes. Influenced by deep fluids, these carbonate laminae are mainly composed of lens-shaped, coarsely crystalline calcite and exhibit significant thickness. Grain carbonate rocks have a relatively high organic matter content, with pore spaces primarily consisting of bottleneck- and slit-shaped throats. This configuration enhances reservoir capacity and creates favorable conditions for oil shale accumulation.
碳酸盐是油页岩的主要成分，对油气聚集有影响，在油页岩研究中变得越来越重要。本文旨在研究页岩中各种碳酸盐矿物的形成机制及其对石油富集的影响。在东营凹陷，已识别出两种主要类型的碳酸盐矿物：微晶碳酸盐和粒状碳酸盐。微晶碳酸盐主要通过生物作用形成，湖相水体的周期性分层导致碳酸盐和粘土矿物层交替出现。这些层相对较薄。微晶碳酸盐岩含有低有机质，主要特征是狭窄的狭缝状孔隙，导致孔隙结构致密，阻碍油页岩聚集。相比之下，粒状碳酸盐的形成受成岩作用控制。受深部流体影响，这些碳酸盐层主要由透镜状、粗晶方解石组成，厚度较大。粒状碳酸盐岩有机质含量相对较高，孔隙空间主要由瓶颈状和狭缝状喉道组成。这种结构增强了储集能力，为油页岩聚集创造了有利条件。
