河东煤田北部典型砂岩体沉积演化特征  

Sedimentary evolution features of typical sandstones in the northern Hedong Coalfield,Ordos Basin

作　　者：李勇[1] 汤达祯[1] 许浩[1] 孟艳军[1] 曲英杰[2] 

机构地区：[1]中国地质大学(北京)能源学院 [2]中国石化国际石油勘探开发有限公司

出　　处：《天然气工业》2013年第2期22-27,共6页Natural Gas Industry

基　　金：国家科技重大专项课题(编号:2011ZX05062-01)

摘　　要：河东煤田北部是鄂尔多斯盆地煤层气和致密砂岩气勘探开发的重点地区,为理清含煤地层中砂岩体的发育情况和天然气成藏潜力,基于区域地层对比、层序地层划分、沉积相等分析,结合前人的研究成果,对石炭—二叠系太原组的晋祠砂岩、桥头砂岩和北岔沟砂岩3套典型砂岩体的空间展布特征进行了精细刻画,探讨了砂岩体沉积演化过程,建立了砂岩体沉积模式。最终获得以下认识:①3套砂岩体垂向厚度大,具正粒序旋回,古流向由北向南,波及范围渐次增大;晋祠砂岩、桥头砂岩由太原期海退时低弯度曲流河沉积形成,属陆表海背景下快速侵入的河流相沉积,北岔沟砂岩为山西期陆相河流沉积,形成的砂岩体分布区域更大。②该区地势在晋祠砂岩和桥头砂岩沉积时期由北高南低,过渡为南高北低,又过渡为北高南低,构造隆升和沉降幅度反复变化;海侵期间形成的泥炭沼泽在全区发育,形成覆盖全区的煤层,具一定的填平补齐作用。③3套砂岩体与煤层相互叠置,地层中泥岩和石灰岩广泛发育,为致密砂岩气成藏提供了良好的生储盖条件,使得该区具备良好的天然气勘探潜力。The northern Hedong Coalfield is an important target area for exploration and development of coalbed methane and tight gases in the Ordos Basin. In order to learn about the development of sandbodies and tight gas potentials of the sandbodies in coalbearing strata in this area, we described in detail the spatial distribution of 3 sets of typical sandbodies in the Permo-Carboniferous Taiyuan Formation including the Jinci, Qiaotou and Beichagou sandstones, discussed their sedimentary evolution process, and estab- lished their sedimentation models through regional stratigraphic correlation, sequence stratigraphic division and analysis of sedimen- tary facies and in combination with the previous study results. The following conclusions were obtained. （1） These 3 sets of sand- boides have huge thickness and normal grading. The paleostreams flowed from north to south and their sweep areas got enlarged pro- gressively in this direction. The Jinci and Qiaotou sandstones are low sinuosity channel deposits formed during the marine regression in the Taiyuan period, and belong to fluvial deposits formed in epicontinental sea environment. In contrast, the Beichagou sandstones are continental fluvial deposits formed in the Shanxi period, and are more widely distributed. （2） During the deposition of Jinci and Qiaotou sandstones, the palaeogeomorphology of the study area was converted from high in the north and low in the south to high in the south and low in the north, and then converted back again with the amplitudes of uplifting and subsidence changed repeatedly. The peat swamp formed during transgression occurred in the whole area, which leads to the formation of extensive coal layers cover- ing the whole area. （3） The said three sets of sandbodies were overlapped with coal layers, among which the extensively developed mudstones and limestones provided favorable conditions for generation, accumulation and preservation of tight gas, which makes a large exploration potential in the study area.

关 键 词：河东煤田 石炭 二叠纪 沉积模式 致密砂岩气 沉积演化 空间展布 勘探潜力 鄂尔我斯盆地 

分 类 号：P618.13[天文地球—矿床学]