海相油气地质2024，Vol.29Issue(2)：125-135,11.DOI:10.3969/j.issn.1672-9854.2024.02.002
鄂尔多斯盆地东北部奥陶系马四段白云岩储层特征及主控因素
Characteristics and main controlling factors of dolomite reservoir in the fourth member of the Ordovician Majiagou Formation in the northeast of Ordos Basin
摘要
Abstract
Multiple exploration wells including well Mitan 1 have obtained high production natural gas flow in the dolomite of the fourth member of the Ordovician Majiagou Formation(O1m4)in the northeast of Ordos Basin,demonstrating that the O1m4 of the region has good exploration prospects.However,there is still controversy over whether large-scale dolomite reservoirs are developed in the O1m4 in the northeastern basin,and the unclear distribution of dolomite reservoirs restricts the next exploration deployment.Based on comprehensive data such as core,thin sections,field emission scanning electron microscopy and geochemical characteristics,a systematic study is conducted on the characteristics and development controlling factors of the O1m4 dolomite reservoir in the northeast of Ordos Basin.On this basis,the distribution of the O1m4 dolomite reservoir in the northeast of the basin is predicted.The research results indicate that:(1)Tidal flat type dolomite reservoir,mound-shoal type dolomite reservoir and bioturbation type dolomite reservoir are developed in the O1m4 in the northeast of Ordos Basin.The storage space of the three types of dolomite reservoir is mainly intergranular pores with a small number of micro cracks,and the average porosity is 4.77%,5.12%and 2.52%respectively.(2)The formation of dolomite reservoirs is related to mound-shoal complex,bioturbation and dolomitization.The development of tidal flat type dolomite reservoir is related to dolomitization,which is the key to the formation of intergranular pores in such reservoirs.The development of the mound-shoal type dolomite reservoir is controlled by the mound-shoal complex and dolomitization.The mound-shoal complex is the material basis for reservoir development,and the dolomitization further enhances the compressive capacity of the reservoir,which is conducive to the preservation of intergranular pores.Bioturbation and dolomitization control the development of bioturbation type dolomite reservoir.The burrows formed by bioturbation lay the foundation for reservoir development.Dolomitization forms intergranular pores and is beneficial for pore preservation.(3)The Shenmu-Jingbian area in the northeast of the basin is located on a low uplift belt during the O1m4 period,which is conducive to the development of shoal-mound bodies,biological disturbance and dolomitization.The developed dolomite reservoirs can provide a large-scale storage space for natural gas enrichment.关键词
白云石化作用/生物扰动作用/丘滩体/白云岩储层/马四段/鄂尔多斯盆地东北部Key words
dolomitization/bioturbation/mound-shoal complex/dolomite reservoir/the fourth member of Majiagou Formation/northeast of Ordos Basin分类
能源科技引用本文复制引用
苏文杰,鲁慧丽,乔德民,李辉,石磊,罗开通..鄂尔多斯盆地东北部奥陶系马四段白云岩储层特征及主控因素[J].海相油气地质,2024,29(2):125-135,11.基金项目
本文受中国石油天然气集团有限公司攻关性应用性科技专项"碳酸盐岩油气富集规律及有利区带研究"(2023ZZ16YJ01)和长庆油田公司重大科技专项"鄂尔多斯盆地中元古界—奥陶系构造沉积演化、成源机制与勘探新领域研究"(ZDZX2021)联合资助 （2023ZZ16YJ01）
