从成岩角度看鄂尔多斯马家沟组碳酸盐岩中的裂缝及其储集意义

DIAGENESIS OF THE CARBONATE ROCKS OF THE MAJIAGOU FORMATION IN THE ORDOS BASIN:FRACTURES AND THEIR IMPLICATIONS FOR OIL AND GAS STORAGE

鄂尔多斯盆地奥陶系马家沟组碳酸盐岩中裂缝非常发育，本文从成岩角度对它们进行了研究。依据裂缝间切割关系、裂缝与成岩组构间关系、裂缝内充填物类型和地球化学特征，将裂缝分为七期。并通过有机质成熟演化历史与裂缝形成历史的匹配分析，认为燕山运动形成的第Ⅵ期裂缝和喜山运动形成的第Ⅶ期裂缝可成为有效储渗裂缝。

Fractures are well developed in the carbonate rocks of the Ordovician Majiagou Formation in the Ordos Basin.In this paper,the fractures investigated are interpreted as the products of diagenesis,and underwent seven stages of evolution,which have been distinguished in terms of the crosscutting relationships between the fractures,relationships between fractures and diagenetic fabrics, types and geochemical characteristics of the fillings within the fractures.Viewed from the history of the fracture formation,matching with that of organic matter maturation,the Ⅵ and Ⅶ stages of fractures created by Yanshanian and Himalayan Movements,respectively may become valid fractures for oil and gas storage,and play an important part in the migration and accumulation of oil and gas in the central part of the basin and the Tertiary faulted trough areas.