辽东湾坳陷斜坡型太古界潜山储层特征及主控因素——以锦州25￣A构造为例

Reservoir characteristics and main controlling factors of slope-type Archean buried hill in Liaodongwan Depression: a case study of Jinzhou 25-A structure

王茂桢 王冰洁 杨传超 郝轶伟 张江涛 于雯汀

王茂桢1，王冰洁1，杨传超1，郝轶伟1，张江涛1，于雯汀2

1.Bohai Oil Research Institute, Tianjin Branch of CNOOC Ltd., Tianjin 300459, China; 2.Oilfield Production Department, China Oilfield Services Limited, Tianjin 300451, China

针对斜坡型太古界变质岩潜山储层非均质性强、储层空间分布规律及主控因素认识不清等问题，以渤海海域锦州25￣A构造太古界潜山为研究对象，基于岩心、井壁取心、测井、地震及实测物性资料，明确了太古界潜山储层类型及其成储模式。结果表明：1）变质岩潜山储层以构造裂缝为主，沿构造裂缝发育溶蚀孔，为典型的双孔介质型储层，孔隙度介于3.5%~13.3%，渗透率介于0.01×10-3~15.32×10-3 μm2。2）构造活动、风化作用以及矿物组成共同控制了潜山储层的空间分布，燕山末期走滑压隆带应力集中，储层发育厚度可超过100 m；风化作用导致潜山顶部100 m以内发生强溶蚀，孔隙度较内幕裂缝带提高3倍，渗透率可提高近100倍；储层的发育具有矿物选择性，脆性矿物质量分数超过80%的变质花岗岩脆性强且具有更多的可溶矿物，是最主要的成储岩性。3）斜坡型变质岩潜山具有“构造主导，风化￣矿物联控”的优质储层发育模式，燕山期走滑压隆带是最优储层发育区，该模式对未来斜坡型太古界潜山的勘探具有重要的指导意义。

 Aiming at the problems of strong heterogeneity, unclear spatial distribution law and controlling factors in the slope-type Archean metamorphic buried hill reservoir, taking Jinzhou 25?鄄A Archaean buried hill in Bohai Sea area as an example, based on core, wall core, logging, seismic and measured physical property data, reservoir type and its reservoir formation models of Archean buried hill are made clear. The results show that the metamorphic buried hill reservoir is dominated mainly by structural fractures, along which corrosion pores are developed. It is a typical double-porosity medium reservoir with porosity ranging from 3.5% to 13.3% and permeability ranging from 0.01×10-3￣15.32×10-3 μm2. It reveals that tectonic activity, weathering and mineral composition jointly control the spatial distribution of buried hill reservoir. In the late Yanshan period, the stress in the strike slip uplift zone is concentrated, and the reservoir development thickness is large than 100 m. Weathering leads to strong dissolution within 100 m of the top of buried hill, with porosity 3 times higher than that of internal fracture zone and permeability 100 times higher. The development of reservoir has mineral selectivity. Metamorphic granite with more than 80% of brittle minerals content is the most important reservoir formation lithology because of its strong brittleness and more soluble minerals. The reservoir development model of slope-type buried hill is established, which is characterized by "tectonic dominance, weathering and mineral joint control". The strike-slip uplift area in Yanshanian period is the best reservoir development area. This model has important guiding significance for the future exploration of slope-type Archean buried hill.

10.6056/dkyqt202304014