辽河东部地区梨树沟组页岩气富集条件及有利区优选

Enrichment condition of Lishugou Formation shale gas and favorable area selection in eastern area of Liaohe

辽河东部地区中生界下白垩统梨树沟组泥页岩地层厚度大,分布面积广,发育稳定;泥页岩有机碳质量分数高,热演化程度适中,干酪根类型主要为Ⅱ型,生烃强度大,具备页岩气富集的基本条件;泥页岩孔隙类型以残余粒间孔、微孔及溶孔为主,孔渗性较好,石英、长石等脆性矿物质量分数高,有利于页岩气储集及后期的储层改造,具有与延长油田三叠系已发现的陆相页岩气相类似的地质和地化条件,页岩气富集潜力大。文中采用综合信息叠合法对该区下白垩统梨树沟组页岩气富集有利区进行初步预测,认为有利区主要沿营口—佟二堡断裂呈带状分布。

The thickness of shale reservoir for Lower Cretaceous l,ishugou Formation in eastern area of Liaohe is great, with wide and stable distribution. TOC of shale is high and degree of thermal evolution is moderate. The kerogens are mainly Type Ⅱ, mainly by gas generation with great intensity of hydrocarbon generation, having the basic condition of shale enrichment. The pore types of shale are mainly residual intergranular pores, microporous pores and solution pores. The porosity and permeability are good. The content of brittle minerals such as quartz and feldspar is high, which is beneficial to shale gas storage and later reservoir stimulation. Its geologic and geochemical characteristics are similar to Triassic shale in Yanchang oilfield, in which continental facies shale gas has been found. The enrichment potential of shale gas is great. Using the method of superposition for comprehensive information, this paper preliminarily predicts the favorable area of Lower Cretaceous Lishugou Formation shale gas enrichment. It is considered that the favorable area is mainly distributed as a belt-shaped region along Yingkou-Tongerpu.