鄂尔多斯盆地铝土岩天然气新领域勘探发现与理论技术进展  

Exploration achievements and technological progress in new fields of bauxite natural gas in Ordos Basin

作　　者：李明瑞 张雷[2,3] 张三[1,2] 曹茜 章辉若[1,2] 李涵 LI Mingrui;ZHANG Lei;ZHANG San;CAO Qian;ZHANG Huiruo;LI Han(Exploration Division of PetroChina Changqing Oilfield Company,Xi'an 710018,China;National Engineering Laboratory for Exploration and Development of Low Permeability Oil and Gas Fields,Xi'an 710018,China;Research Institute of Exploration and Development,PetroChina Changqing Oilfield Company,Xi'an 710018,China)

机构地区：[1]中国石油长庆油田分公司勘探事业部,陕西西安710018 [2]低渗透油气田勘探开发国家工程实验室,陕西西安710018 [3]中国石油长庆油田分公司勘探开发研究院,陕西西安710018

出　　处：《天然气地球科学》2024年第8期1339-1350,共12页Natural Gas Geoscience

基　　金：中国石油“十四五”前瞻性基础性重大科技项目“致密气新区新领域资源潜力与富集规律研究”(编号:2021DJ2101)资助.

摘　　要：在梳理总结勘探成果、理论技术进展的基础上,系统评价鄂尔多斯盆地铝土岩气藏资源潜力,提出未来铝土岩气藏的发展方向。鄂尔多斯盆地铝土岩气藏是蕴藏在含铝岩系地层中的特殊气藏类型,该套含铝岩系在盆地广泛分布,位于下古生界风化壳与上古生界沉积地层之间,其成因属于喀斯特型。铝土岩气藏主体位于庆阳古陆东翼古地貌斜坡区的含铝岩系地层中,从岩性组合及矿物特征分析认为其分布与微古地貌和沉积相明显相关,具有原地堆积与二次搬运2种沉积建造特征,可进一步划分出高地潜坑型、斜坡阶地型、封闭潟湖型3种铝土岩气藏类型,且在平面上具有一定的分区性。勘探分别落实L47、CT3、L68、HT14、HT7等5个有利含气区,其中L47井区铝土岩具有连续“透镜状”分布特征。首口铝土岩水平井试气达353.4×10^(4)m^(3)/d,创盆地上古生界单井最高产量,气藏具有单体厚、点群式的“鸡窝状”分布特征,直井试气最高产量达100×10^(4)m^(3)/d以上,综合评价有利勘探面积为7000 km^(2),天然气资源量约为5000×10^(8)m^(3)。研究表明:鄂尔多斯盆地西南部特殊的古陆背景、湿热气候环境、长期风化淋滤作用是形成铝土岩气藏的优越条件;不同于其他类型储层,铝土岩储层在表生期、成岩期、成藏期均具有一定的变化,且在表生期已基本定型,优质储层分布主要受垂向岩溶作用和横向泄水通道发育程度控制;攻关形成的三维地震预测识别与测井评价技术、多组分耦合活性酸加砂压裂技术是发现铝土岩高效气藏的重要保障。自2021年铝土岩气藏发现以来勘探成效显著,更加明确了铝土岩作为高效气藏勘探的前景十分广阔,坚定了在古陆周边寻找铝土岩气藏规模储量的认识,同时积极完善新类型气藏配套技术,为高质量动用铝土岩气藏积累丰富技术经验。The resource potential of bauxite gas reservoirs in Ordos Basin is evaluated systematically on the basis of careful summary of exploration results and theoretical and technical progress,and the development direction of bauxite gas reservoirs in the future is proposed.The bauxite gas reservoir in Ordos Basin is a special type of gas reservoir in aluminum-bearing rock series,which is widely distributed in the basin between the Lower Paleozoic weathering crust and the Upper Paleozoic sedimentary strata,and its genesis belongs to karst type.The bauxite gas reservoir is mainly located in the aluminium-bearing rock series in the paleogeomorphic slope area of the eastern wing of Qingyang ancient land,and its distribution is obviously related to micropaleogeomorphic and sedimentary facies according to lithology combination and mineral characteristics.It has two sedimentary construction characteristics of in-situ accumulation and secondary transport,and can be further divided into three types of bauxite gas reservoirs:upland sunken pit type,slope terrace type and closed lagoon type.The exploration has been carried out in L47,CT3,L68,HT14,HT7,and other favorable gas bearing areas.Among them,the bauxite in the L47 well area has a continuous“lenticular”distribution.The first bauxite horizontal well gas test reached 3.534×10^(6) m^(3)/d,the highest single well production in the Upper Paleozoic of the basin.Exploration and development in CT3 and L68 well areas are integrated.The gas reservoir has the characteristics of“chicken nest”distribution with single thickness and point group.The gas test in vertical wells is up to more than 1×10^(6) m^(3)/d.Comprehensive evaluation shows a favorable exploration area of 7000 km^(2) and a natural gas resource of approximately 500 billion cubic meters.The results show that the special paleocontinental background,hot and humid climate and long-term weathering leaching are the favorable conditions for the formation of bauxite gas reservoirs in the southwest of Ordos Basin.Different

关 键 词：铝土岩系 微古地貌 庆阳古陆 勘探发现 资源潜力 

分 类 号：TE132.1[石油与天然气工程—油气勘探]