黄陵矿区煤矿井下围岩喷涌气体致灾机理及防治措施

鄂尔多斯盆地南缘黄陵矿区黄陵一号等煤矿在采掘过程中出现井下围岩大量气体喷涌现象,导致矿井停采停掘,对煤矿安全生产构成严重威胁。为了揭示喷涌气体的成因及致灾机理,以地面钻孔补充勘探和钻探资料及围岩气体地球化学参数测试数据为基础,采用气样地球化学特征分析、热演化史模拟、烃源岩对比、运移通道识别等多种方法,查明围岩气体的砂岩储集层平面及剖面分布特征,研究区内异常致灾围岩气体的成因类型和来源,分析围岩气体异常喷涌的致灾机理,建立以顶底板砂岩探抽为主的分源综合立体抽采防治模式。研究结果表明:(1)该区煤矿井下围岩气体喷涌具有突发性、隐蔽性、涌出集中和涌出量大等特点,涌出气体主要成分为甲烷,气体主要来源于围岩;(2)顶、底板围岩气体主要为原油伴生热解成因的油型气,生气源岩为上三叠统延长组长7等段腐泥型主力烃源岩,经燕山运动形成的北东向基底断层及其周围大规模垂直裂缝运移而来;(3)油型气主要储集砂岩层呈区带式分布,受构造和岩性双重控制;(4)针对围岩油型气以游离态储集在砂岩中、由采动裂隙导通涌出的特点,采用分源综合立体抽采的防治模式进行围岩气灾害治理,取得了良好的治理效果。

Disaster-causing mechanism of surrounding rock gas flowing underground in the Huangling coal mine and prevention measures

In the mining process of coal mines (e.g. No.1 Huangling Coal Mine) in the Huangling mining area along the southern margin of the Ordos Basin, a great amount of gas flows from the surrounding rocks underground, leading to mining suspension and serious threat to the safe production of coal mines. In order to reveal the origin and disaster-causing mechanism of flowing gas, the areal and sectional distribution characteristics of sandstone reservoirs of surrounding rock gas were investigated, the genetic type and origin of abnormal disaster-causing surrounding rock gas in the study area were studied, and the disaster-causing mechanism of the abnormal flowing of surrounding rock gas was analyzed based on the supplementary exploration and drilling data of surface drilling and the geochemical parameter test data of surrounding rock gas by means of geochemical characteristic analysis of gas sample, thermal evolution history simulation, source rock comparison, migration pathway identification and other methods. Then, the prevention and control mode of multi-source comprehensive three-dimensional extraction with the extraction of roof and floor sandstone as the dominant part was established. And the following research results were obtained. First, the flowing of surrounding rock gas underground in this area is abrupt, hidden, concentrated and considerable, and the gas is mainly composed of methane and is mainly derived from surrounding rocks. Second, the surrounding gas in the roof and floor is mainly the pyrogenic oil-type gas associated with crude oil. And its source rocks are sapropel-type principal source rocks, e.g. Chang 7 Member of Yanchang Fm, Upper Triassic, and its migration pathway is acted by the NE trending basement faults formed by the Yanshan movement and the large-scale vertical fractures around them. Third, the main reservoir sandstones of oil-type gas are distributed in the pattern of zoning controlled by structure and lithology jointly. Fourth, the surrounding rock oil-type gas is stored in a free state in sandstones and it flows out through mining-induced fractures, so the prevention and control mode of multi-source comprehensive three-dimensional extraction is adopted to control the disaster caused by surrounding rock gas with a good effect.