鄂尔多斯盆地马五白云岩储层特征及主控因素

Characteristics and Controlling Factors of Dolomite Reservoirs in the Ma5 Sub-member of Ordovician in Majiagou, Ordos Basin

杨西燕 包洪平 任军峰 马占荣

YANGXiyan BAOHongping RENJunfeng MAZhanrong

成都理工大学沉积地质研究院, 四川 成都 610059 西南石油大学地球科学与技术学院, 四川 成都 610500 中国石油长庆油田公司勘探开发研究院, 陕西 西安 710018

Insititue of Sedimentary Geology, Chengdu University of Technology, Chengdu, Sichuan 610059, China School of Geoscience and Technology, Southwest Petroleum University, Chengdu, Sichuan 610500, China Research Institute of Exploration and Development, Changqing Oilfield Company, PetroChina, Xi'an, Shaanxi 710018, China

在大量钻井岩芯观察、测井分析、薄片、扫描电镜鉴定、物性分析的基础上，研究了鄂尔多斯盆地马五亚段白云岩储层特征及主控因素。认为马五亚段储集岩类型以泥粉晶白云岩和粉晶白云岩为主；储集空间类型主要为晶间（溶）孔和溶蚀孔洞；属于低孔低渗储层。发育云坪、灰质洼地、云质洼地、云灰灰云洼地微相，微相控制白云岩的分布，分布面积最广、白云岩厚度最大、物性最好的是靖边西云坪白云岩带。白云化作用决定优质储层的形成，准同生期白云化作用形成少量白云石晶间微孔、准同生期后白云化作用形成白云石晶间孔、埋藏期白云化作用形成白云石晶间孔和溶蚀孔；白云化亚相决定有效储层的分布，边缘过渡亚相是最有利的白云化亚相；表生岩溶和埋藏溶蚀作用提供大部分储集空间，但渗流粉砂、方解石、石英等充填作用破坏储集空间。

In this study, we analyzed the characteristics and controlling factors of dolomite reservoirs based on core survey, well logging analysis, thin section and SEM identification, and analysis of physical properties. We found that the reservoir rock mainly consists of siltcrystal dolomites and siltcrystal-micrite dolomites. The main types of reservoir spaces are intercrystalline pores and dissolution pores-caves with low porosity and low permeability. At Ma5, dolomitic flat, lime mud depression, dolomitic depression, and dolomitic-lime mud depression facies are developed. The dolomite belt of the dolomitic flat is controlled by sedimentary microfacies, with the thickest dolomites of the best physical properties widely distributed in Jinbian County. The location of high quality reservoir is controlled by dolomitization:some intercrystal micro-pores were formed by penecontemporaneous dolomitization; intercrystal pores were formed after penecontemporaneous dolomitization; and intercrystal pores and emposieu by buried dolomitization. Reservoir effectiveness is controlled by dolomitization subfacies; the best subfacies are boundary-interim subfacies. Most reservoir spaces formed by epigenic karstification and burial dissolution are filled by vadose silt, calcite, and quartz.

10.11885/j.issn.1674-5086.2015.09.07.01