海拉尔-塔木察格盆地南贝尔凹陷下白垩统火山碎屑岩储集层成岩演化及控制因素

应用普通薄片、铸体薄片、扫描电镜、黏土矿物X射线衍射等多种测试手段，对海拉尔-塔木察格盆地南贝尔凹陷下白垩统铜钵庙组和南屯组火山碎屑岩储集层成岩演化特征进行了系统研究，并探讨了成岩演化的控制因素。研究认为，储集层成岩作用类型主要有熔结作用、压实作用、脱玻化作用、蚀变作用、胶结作用和溶蚀溶解作用，所处成岩作用阶段主要为中成岩阶段A期。储集层经历了同生成岩阶段-中成岩阶段A期的演化过程，局部储集层还经历了表生成岩阶段的演化过程。各成岩演化阶段特点均有所不同，其中，同生成岩阶段以熔结作用和弱胶结作用为特点，早成岩阶段A期以较强压实、弱胶结为特点，早成岩阶段B期的特点为较强压实、弱胶结、弱溶蚀，中成岩阶段A期为中等压实、较强胶结、较强溶蚀，表生成岩作用阶段以大气水淋滤作用为特点。成岩演化过程主要受成岩环境以及构造作用和火山活动的控制。储集层成岩环境大致经历了弱碱性-弱酸性-酸性-碱性的演化过程，酸性成岩环境以溶蚀溶解作用为主，碱性成岩环境胶结作用明显。构造作用和火山活动通过控制火山碎屑物质的来源、裂缝的产生、热流体活动以及表生成岩阶段的进行等来影响储集层的成岩演化。

Diagenetic evolution and controlling factors of pyroclastic reservoirs of the Lower Cretaceous in Nanbeier Sag, Hailar-Tamtsag Basin

Through various measurements，such as analyses of normal thin-sections，cast thin-sections，scanning electron microscope and X-ray diffraction of clay minerals，this paper systematically studies the diagenetic evolution and controlling factors of pyroclastic reservoirs from the Tongbomiao and Nantun Formations of Lower Cretaceous in Nanbeier Sag of Hailar-Tamtsag Basin.It is considered that the diagenesis types of the reservoirs include weldition，compaction，devitrification，alteration，cementation and dissolution.The main diagenesis stage is the middle diagenetic stage A.The reservoirs undergo the evolution process from syngenesis diagenetic stage to middle diagenetic stage A，part of which experience the evolution process of epidiagenetic stage.Different diagenetic evolution stages have different characteristics.The syngenesis diagenetic stage is characterized by weldition and weak cementation.While the early diagenetic stage A is featured by strong compaction and weak cementation.The early diagenetic stage B has strong compaction，weak cementation and weak dissolution.When it comes to middle diagenetic stage A，compaction becomes moderate，on the other side，compaction and dissolution get stronger.The epidiagenetic stage differs from others by meteoric water leaching.The diagenetic evolution process is controled by diagenesis environment，tectonism and volcanic activities.The diagenetic environments undego the evolution process from weak alkali to weak acidic，then acidic to alkali environments.In the acidic diagenetic environment，dissolution takes place.While，in the alkali diagenetic environment，cementation dominates.Tectonism and volcanic activities influences the diagenetic evolution process by controlling the origin of pyroclastic components，the occurrence of fractures，thermal fluid activities and the evolution of epidiagenetic stage.