钙华的形成环境与特征及在油气储集方向的探讨

Overview of the Formation Environment and Characteristics of Travertines and Discussion on the Direction of Oil and Gas Reservoir

钙华是一种特殊的化学或生物化学沉积,它们在大陆内部广泛地分布且含有重要的地质信息,是一种特殊的油气储集体。影响钙华沉积的因素复杂多样,在调研钙华的形成过程及分类的基础上,从气候环境、水文地质条件、水体物理化学条件、生物活动及构造活动五个方面讨论钙华形成的控制因素;并从沉积环境与模式、沉积速率等方面将新疆塔北地区的钙华与国外钙华沉积体进行类比,发现塔北钙华沉积体在温暖湿润的环境下表现出良好的季节性分层,五道班地区钙华在沉积时汇入了大量的陆源碎屑,受生物活动影响较大;硫磺沟地区的钙华沉积则是伴随断裂活动所形成热液上涌的产物。通过对比发现,塔北露头缝洞内充填的钙华内部孔隙发达、连通性较好,并有良好的含油显示,故钙华具备一定的储集能力。

A travertine is a special chemical or biochemical deposition.They are widely distributed in the interior of the continent and contain important geological information and are special reservoirs of oil and gas.The factors that affect the deposition of travertines are complex and diverse.Based on the investigation of the formation process and classification of travertines,this article discusses the controlling factors of travertine formation from five aspects:climate environment,hydrogeological conditions,physical and chemical conditions of water bodies,biological activities,and structural activities.Then,the travertine in the Tabei area of Xinjiang province is compared with foreign travertine deposits in terms of depositional environment,model,and deposition rate.The travertine deposits show good seasonal stratification under a warm and humid environment in north Tarim.The travertine in Wudaopan area was deposited into a large amount of terrigenous debris and greatly affected by biological activities.In Liuhuanggou,travertines are a product of hydrothermal upwellings resulting from fault activity.By comparing and summarizing the findings,the travertine that filled in the fractured caves in Tabei has well-developed internal pores,good connectivity,and good oil content display.Therefore,the travertine has a certain storage capacity.