马朗凹陷条湖组致密油藏成藏特征与主控因素

Reservoir-forming Features and Main Controlling Factors of Tight-oil Reservoir in Tiaohu Formation,Malang Depression

三塘湖盆地二叠系条湖组致密油勘探主要集中在马朗凹陷,相继发现多个含油气构造。根据勘探经验,以非常规油气勘探地质理论为指导,通过解剖已知油藏,系统分析烃源岩、储集层、盖层等油气藏形成的基本要素,研究表明,条湖组致密油藏储集层岩性为沉凝灰岩,储集层具有中高孔、特低渗特征,含油饱和度高,油藏受控于宽缓的构造背景和沉积微相,大面积分布的优质烃源岩是该层系致密油藏形成的物质基础。并认为:马朗凹陷牛圈湖鼻隆构造南部斜坡—马中构造西部斜坡区成藏条件优越,勘探前景广阔,是下步致密油勘探的有利区带。

In Santanghu Basin, an exploration to the Permian Yiaohu Formation tight oil is grouped mainly on Malang depression, and some hydrocarbon-bearing structures have been discovered one after another. Guided by geologic theory of unconventional oil and gas, many fundamental factors to form oil and gas reservoirs, including source rock, reservoir, and caprock, were analyzed. Results show that（1）Tiaohu Formation is composed of depositional tuff;（2）it is characterized by middle to high porosity, extra-low permeabili-ty, and high oil saturation;（3）it is controlled by gently structural setting and sedimentary microfacies; and（4）widespread and highquality source rock is the material base to form tight-oil reservoirs.In addition, it is deemed that in this basin, an area between two slopes of southern Niuquanhu nose structure and western Mazhong structure not only has good conditions to form reservoir, but also is the favorable zone for further tight-oil exploration because of bright prospect.