黄骅坳陷大港探区下古生界碳酸盐岩潜山差异演化及优质储层成因

Differential evolution and origin of high-quality reservoirs in the Lower Paleozoic carbonate buried hills in Dagang prospecting area, Huanghua Depression

程鑫 周立宏 操应长 金凤鸣 付立新 李宏军 楼达 远光辉

Xin Cheng Lihong Zhou Yingchang Cao Fengming Jin Lixin Fu Hongjun Li Da Lou Guanghui Yuan

碳酸盐岩潜山储层成因及分布的复杂性制约了该类油藏的勘探。综合利用地震资料、岩心-薄片观察、测-录井分析、地化分析以及埋藏史分析等技术方法，从构造演化差异性角度对大港探区下古生界碳酸盐岩潜山进行分类，并开展了储集差异性和优质储层成因研究。大港探区下古生界碳酸盐岩潜山可以划分为残丘山、间断侵蚀断块山、断块山、挤压褶皱山和重力滑动褶皱山5种类型。残丘山为晚期大气水淋滤型储层，储集空间以岩溶孔、洞为主，发育少量裂缝；间断侵蚀断块山为中期大气水淋滤-深部溶蚀共控型储层，溶孔和裂缝均较发育；断块山、挤压褶皱山和重力滑动褶皱山未经历中、晚期表生淋滤，储层成因与断裂和埋深密切相关，可分为断裂破碎-深部溶蚀共控和断裂沟通-TSR溶蚀共控2种成因类型。前者在靠近基底断裂部分发育孔、洞、缝复合型储层，随着距基底断层距离增加，逐渐变为裂缝主导型储层，溶孔含量降低；后者主要发育在地温较高（>140 ℃）的深埋区，储集空间以裂缝为主，发育部分溶蚀孔、洞。上古生界缺失区、基底断层发育区和发育上古生界的深埋高温区（>140 ℃）可作为优质储层预测的有利指向。

The exploration for carbonate reservoirs in buried hills has been hampered by a poor understanding of their distribution and genesis.With a combination of seismic profile interpretation, core and thin section observation, logging analysis as well as geochemical and burial history analysis, the types of the Lower Paleozoic buried hills, reservoir characteristics and genesis of high-quality reservoirs in Dagang prospecting area were studied from the perspective of evolutional difference.The buried-hills in the area can be classified into five categories: monadnock, intermittently eroded fault-block buriedhill, fault-block buried hill, compressional folded buried hill and gravitational sliding folded buried hill.The monadnock resulted from a late-stage meteoric water leaching is dominated by dissolution pores and cavities, followed by some fissures.The intermittently eroded fault-block, a result of middle-stage meteoric water leaching and deep burial dissolution, is full of dissolution pores and tectonic fissures.The last three buried hills that shunned the middle- or late-stage meteoric water leaching contain reservoirs linked to faulting and deep burial and formed either by fault-related shattering-deep burial dissolution or by fault connection-TSR related dissolution.The former forms mostly composite reservoirs with dissolution pores, cavities and fissures in areas close to basement faults and would gradually turn into tectonic fissure-dominated reservoirs as they migrate away from the basement faults.The latter forms reservoirs commonly seen in deep buried formations with very high temperatures (higher than 140 ℃).These reservoirs are mainly composed of fissures, followed by some dissolution pores and cavities.It is therefore suggested that high-quality reservoirs are most probably developed in areas with the Upper Paleozoic strata heavily eroded or basement faults well developed or with the Upper Paleozoic strata developed against a high temperature setting (higher than 140 ℃).

10.11743/ogg20210313