本溪组砂岩致密化的三种成因类型及预测  

Three genetic types and prediction of sandstone densificationin the Benxi Formation

作　　者：万永平 宋明 折印楠 蒲仁海[2] 周文娟 WAN Yongping;SONG Ming;SHE Yinnan;PU Renhai;ZHOU Wenjuan(Natural Gas Research Institute,Shaanxi Yanchang Petroleum〔Group〕Co.,Ltd.,Yan’an 716000,China;Department of Geology,Northwest University,Xi’an 710069,China;State Key Laboratory of Deep Oil and Gas,China University of Petroleum〔East China〕,Qingdao 266580,China)

机构地区：[1]陕西延长石油〔集团〕有限责任公司气田公司,陕西延安716000 [2]西北大学地质学系,陕西西安710069 [3]中国石油大学〔华东〕深层油气全国重点实验室,山东青岛266580

出　　处：《西北大学学报(自然科学版)》2025年第2期223-234,共12页Journal of Northwest University(Natural Science Edition)

基　　金：国家自然科学基金(41390451);陕西省重点研发计划项目(2022GY-140)。

摘　　要：鄂尔多斯盆地延安地区上石炭统本溪组是重要的天然气产层之一,储层主要为障壁、潮道和浅滩微相砂岩。研究区大部分钻井砂岩产气,但部分本溪组砂岩因致密化变为干层。查清砂岩致密成因与分布,有效规避干层成为开发井位部署的重要问题之一。该研究将砂岩岩心、沉积微相、显微特征与测井响应等相结合,研究砂岩致密成干层的成因和预测方法。结果表明,研究区干层砂岩存在3种类型:凝灰质基底式胶结砂岩、碳酸盐岩基底式胶结砂岩和紧密压实型砂岩。第一种干层砂岩沿古火山口集中局限在靖边南古潮道附近;第二种干层砂岩分布在上覆太原组灰岩相对增厚区;第三种干层砂岩分布于孤立的小型浅滩砂岩中,可能与成藏期酸性流体和油气没有进入储层形成溶蚀孔有关。该研究对有效储层形成机理及“甜点”分布预测具有重要意义。The Benxi Formation of the Upper Carboniferous in the Yanchang field of the Ordos Basin is one of the important natural gas production layers,with reservoirs mainly composed of barrier,tidal channel,and shoal microfacies sandstones.Most of the drilled sandstones produce gas,but some of the drilled Benxi Formation sandstones have become dry layers due to densification.Identifying the origin and distribution of tight sandstone and effectively avoiding dry layers has become one of the important issues in the deployment of production wells.This article combines sandstone cores,sedimentary microfacies,microscopic characteristics,and logging responses to study the genesis and prediction methods of tight dry sandstone layers.The results indicate that there are three types of dry sandstone:tuffaceous basal cemented sandstone,carbonate basal cemented sandstone,and tightly compacted sandstone.The first type is concentrated and limited along the ancient volcanic crater near the ancient tidal channel of southern Jingbian;The second type is distributed in the relatively thickened area of the overlying Taiyuan Formation limestone;The third type is distributed in isolated small shoal sandstones,which may result in the lack of dissolution pores during the reservoir formation period which needs acidic fluids and oil and gas to enter the reservoir.This understanding is of great significance for the formation mechanism of effective reservoirs and the prediction of"sweet spot"distribution.

关 键 词：本溪组 干层成因分类 显微特征 测井特征 跨尺度识别 

分 类 号：P618.11[天文地球—矿床学]