苏丹Muglad盆地6区基岩储层发育特征及其勘探意义

doi:10.3969/j.issn.1672-7703.2020.04.014

摘要/Abstract

摘要： 在邻区多个盆地基岩潜山勘探陆续获得突破的背景下，苏丹Muglad 盆地基岩勘探备受关注。基于盆地勘探实际，充分利用Muglad 盆地6 区钻井、测井、测试和三维地震等资料对基底岩性和储层发育特征进行研究，并分析其勘探意义。盆地基底岩石由长石、石英、角闪石和云母等矿物组成，其原岩属于长英质花岗岩或花岗闪长岩，并经历了不同程度区域变质或动力变质，属低级—中级变质程度的变质岩。研究区内基岩储层具有双层结构，浅层属风化淋滤带，中—深层以裂缝发育带为主。风化淋滤带主要发育在隆（凸）起表层，厚度较小，通常不足50m，以风化淋滤作用为主，多见岩石破碎和矿物溶蚀，孔洞发育；裂缝发育带厚度一般较大，但区域分布不均，在盆缘和坳— 隆过渡带较发育，是盆地基底主要储层类型。富油气坳陷（或凹陷）边缘陡坡带、坳—隆过渡带等裂缝发育区应是未来基岩勘探的优先方向。

关键词: 苏丹, Muglad 盆地6 区, 盆地基底, 岩石类型, 储层特征, 勘探意义

Abstract: Basement exploration in the Muglad Basin in Sudan has attracted a lot of attention following recent breakthroughs in the exploration of basement buried hill in several adjacent basins. This study analyzes the basement lithology and reservoir development characteristics in the basin and considers its significance as an exploration target. Analysis is based on exploration practice, using drilling, well logging, testing, and 3D seismic data from block-6 of the basin. The basement rock is composed of feldspar, quartz, hornblende, and mica. The protolith is felsic granite or granodiorite, which experienced varying degrees of regional metamorphism or dynamic metamorphism, so that the basement rocks are metamorphic rocks of low to intermediate metamorphism. Basement reservoirs in the study area have double-layer structures: shallow layers of weathering crust and middle- deep layers primarily composed of fracture zones. The weathering crusts are usually of small thickness (less than 50 m) and are mostly developed on the surfaces of uplifts (bulges). Weathering and leaching have resulted in widespread broken rocks and dissolved minerals, with vugs developed. The fracture zones are generally thick, but distribution is uneven. It is evident in the basin margin and in the transition zone between depression and uplift that fracture zones form the principal reservoir type in the basin basement. Fracture development areas such as the steep-slope zones at the edge of petroleum-rich depressions (or sags) and depression-uplift transition zones should be priority targets for basement exploration in the future.

中图分类号:

赵健, 张光亚, 刘爱香, 客伟利, 史艳丽, 邹荃, 程顶胜, 郑永林, 於拥军. 苏丹Muglad盆地6区基岩储层发育特征及其勘探意义[J]. 中国石油勘探, 2020, 25(4): 133-142.

Zhao Jian, Zhang Guangya, Liu Aixiang, Ke Weili, Shi Yanli, Zou Quan, Cheng Dingsheng, Zheng Yonglin, Yu Yongjun. Development characteristics and exploration significance of basement reservoirs in block-6 of the Muglad Basin, Sudan[J]. China Petroleum Exploration, 2020, 25(4): 133-142.

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