北非克拉通盆地古生界碎屑岩储层特征与成储机制

Characteristics and formation mechanisms of the clastic reservoirs in the Paleozoic cratonic basins of North Africa

吕雪雁 曹喆 杨光庆 张玉银 刘静静 李晋 张忠民

Xueyan LU Zhe CAO Guangqing YANG Yuyin ZHANG Jingjing LIU Jin LI Zhongmin ZHANG

古生界广泛发育的碎屑岩是北非地区克拉通盆地主要的油气勘探开发层系。不同地区的储层成岩演化和后期改造不同，储层品质差别很大。基于IHS数据库中的北非地区8个构造单元492个油气藏的储层资料，结合储层埋藏史、地温史和成岩演化史，研究了不同时代和地区古生界碎屑岩储层特征差异，提出了优质储层发育主控因素，预测了有利储层发育地区。研究认为：①北非地区古生界寒武系、奥陶系和泥盆系砂岩储层是北非克拉通盆地的主力储层，主要为河流相、滨海-近岸相和浅海相碎屑岩沉积。储层分布范围广，连续性好。②储层经历两类埋藏史，构造演化差异导致不同地区、不同时代储层成岩演化不同。成岩过程中压实作用和石英次生加大胶结作用对储层物性起破坏作用。长石溶解和多期构造裂缝改造对储层物性起建设性作用。③寒武系-下奥陶统有利储层普遍发育于受海西运动影响较大的隆起区。上奥陶统优质储层主要发育于霍加尔地盾周边的莫祖克盆地、伊利兹盆地和阿赫奈特盆地。下泥盆统优质储层分布范围更广，主要分布在伊利兹盆地、阿赫奈特盆地、蒂米蒙盆地、里甘盆地以及古达米斯盆地北部隆起和斜坡区。

The widely distributed Paleozoic clastic rocks are identified as the primary target for hydrocarbon exploration and production in the cratonic basins of North Africa. The diagenetic evolution and late-stage modification vary greatly in different regions across North Africa， resulting in significantly different reservoir quality. Based on the data from 492 hydrocarbon reservoirs across eight tectonic units in North Africa， sourced from IHS Markit， as well as the burial， geothermal， and diagenetic evolution histories of these reservoirs， we investigate the differences in the characteristics of the Paleozoic clastic reservoirs across different epochs and regions in North Africa. Furthermore， the major factors controlling the development of high-quality reservoirs are clarified and the favorable areas for reservoir development are predicted. The results indicate that the Cambrian， Ordovician， and Devonian sandstone reservoirs of the Paleozoic are major pay zones in the cratonic basins of North Africa. These reservoirs consist primarily of fluvial， littoral-nearshore， and neritic clastic rock deposits with extensive distribution and high continuity. Two types of burial history occurred in these reservoirs， leading to varying diagenetic processes of reservoirs across different regions and epochs with differential tectonic evolution. The compaction and secondary overgrowth and cementation of quartz during diagenesis are detrimental to the physical properties of reservoirs， while feldspar dissolution， and modifications by multi-stage tectonic fractures are of constructive effects on their physical properties. The favorable Cambrian-Lower Ordovician reservoirs generally occur in the uplifted areas that have been significantly influenced by the Hercynian movement. The high-quality reservoirs of the Upper Ordovician are principally distributed in the Murzuq， Illizi， and Ahnet basins near the Hoggar Shield. The high-quality reservoirs of the Lower Devonian exhibit more extensive distribution， primarily found in the Illizi， Ahnet， Timimoun， and Reggane basins， as well as the northern uplift and slope areas of the Ghadames Basin.

10.11743/ogg20250316