澳大利亚博文盆地煤层气富集规律和勘探策略研究——以博文区块Moranbah煤层组为例  

Study on coalbed methane enrichment laws and exploration strategies in the Bowen Basin,Australia–a case of Moranbah coal measures in the Bowen block

作　　者：李铭 孔祥文[1] 夏朝辉[1] 夏明军[1] 王林 崔泽宏[1] 刘玲莉[1] Li Ming;Kong Xiangwen;Xia Zhaohui;Xia Mingjun;Wang Lin;Cui Zehong;Liu Lingli(PetroChina Research Institute of Petroleum Exploration&Development;China National Oil and Gas Exploration and Development Corporation Ltd.)

机构地区：[1]中国石油勘探开发研究院,100083 [2]中国石油国际勘探开发有限公司

出　　处：《中国石油勘探》2020年第4期65-74,共10页China Petroleum Exploration

基　　金：国家科技重大专项“海外重点探区目标评价与未来领域选区选带研究”(2016ZX05029-005)。

摘　　要：澳大利亚的博文盆地是典型的弧后前陆聚煤盆地。博文盆地博文区块地质条件复杂,尽管已开展了大量的煤层气勘探工作,但是控制煤层气富集的地质因素众多,对该区块的煤层气富集规律一直认识不清。结合博文盆地的煤层发育特征、构造特征、水文地质特征、应力特征以及煤层含气性和渗透率等地质特征,以该地区发育的Moranbah煤层组为例,提出“沉积控煤、构造控气、水文控藏、应力控带、局部高部位和边缘斜坡富集高产”的煤层气富集高产规律:沉积相控制煤层分布、煤层储层物性,河流冲积平原、上三角洲平原煤层较厚,下三角洲平原煤层较薄;构造控制含气量及富集带,向斜构造有利于煤层气的富集高产,局部高部位形成煤层气富集高产区;水文地质条件控制煤层气成藏,位于弱径流—承压区成藏条件好,当地表径流和地层倾向一致时,成藏条件较有利;应力场控制煤层高渗带,埋深增加,有效应力增加,煤层割理裂隙闭合造成渗透率降低。在煤层气富集规律的基础上,厘定了煤层气资源规模、控气因素、可采性三级有利区评价指标体系,圈定了研究区块的甜点区、有利区和不利区。基于澳大利亚煤层气区块管理政策,提出了甜点区申请开发许可优先投入试产开发评价、有利区申请潜在商业区勘探保地、不利区申请退地的勘探策略。The Bowen Basin in Australia is a typical back-arc foreland coal-accumulation basin.The geological conditions of Bowen block in the Bowen Basin are complex.Although a lot of coalbed methane(hereinafter referred to as CBM)exploration work has been carried out,the CBM enrichment laws in this block are not clear due to they are controlled by many geological factors.Combined with the coal seam development characteristics,structural characteristics,hydrogeological characteristics,stress characteristics,and other geological characteristics such as gas-bearing properties and permeability of coal seams in the Bowen Basin,and taking the Moranbah coal measures developed in the block as an example,this paper puts forward the CBM enrichment and high-production laws,which is that“coal development is controlled by sedimentary facies,gas-bearing property is controlled by structure,gas accumulation is controlled by hydrology,CBM plays are controlled by stress,and the enrichment and high-production zones are the local-high position and marginal slope”.The sedimentary facies control the coal seam distribution and reservoir physical properties.The coal seams in river alluvium plain and upper delta plain are thicker,and those in lower delta plain are thinner.The structures control the gas content and enrichment zones.Syncline structures are conductive to the CBM enrichment and high production.The CBM enrichment and high production zones are at local high positions of syncline.Hydrogeological conditions control the CBM accumulation,where they are good in the weak runoff-confi ned area.When the direction of surface runoff is consistent with that of formation dip,the CBM accumulation conditions are favorable.The stress fi eld controls the high permeability zones of coal seams.With the increase of burial depth,the effective stress increases,and the coal seam cleat fractures are closed,results in the decrease of permeability.Based on the CBM enrichment laws,the evaluation index system of 3-level favorable areas is determined,that is,

关 键 词：煤层气富集规律 高分辨率层序 含气量 渗透率 甜点区 区块管理 勘探策略 

分 类 号：TE122.2[石油与天然气工程—油气勘探]