摘要
2018年底,中国石油西南油气田分公司部署的第1口以火山岩储层为目的层的永探1井在二叠系火山岩测试获气22.5×10~4 m^3/d,展示出四川盆地火山岩气藏良好的勘探潜力。为快速建立火山岩测井岩性识别方法,综合运用岩心、薄片、常规测井、元素扫描测井和成像测井技术对永探1井火山岩岩性进行识别。结果表明:①按岩石结构特征,永探1井火山岩岩性可分为火山熔岩和火山碎屑熔岩,火山岩碎屑熔岩根据角砾含量的多少可细分为含角砾凝灰熔岩和角砾熔岩;②岩性扫描测井可以定量提供地层主要造岩矿物元素的含量,结合TAS图版有效判断火山岩化学成分,经过剔除异源的角砾矿物成分后的岩性扫描测井结果分析,永探1井火山岩地层按化学成分主要为基性的碱玄武岩和玄武岩;③永探1井整体以基性火山岩为主,放射性低,自然伽马无法区分岩性,但密度、补偿声波和电阻率曲线对岩性敏感,利用密度与声波时差和密度与深电阻率交会法可有效区分火山岩岩性;④通过常规测井识别岩性成分和成像测井识别结构及构造特征,可以有效评价火山岩岩性。
At the end of 2018, gas at the rate of 22.5×104 m3/d during the test was produced from the Permian volcanic rocks of Yongtan 1 well, which is the first one deployed by PetroChina Southwest Oil & Gasfield Company to treat these volcanic reservoirs as the target, also revealing good exploration potential for volcanic-rock gas reservoirs in Sichuan Basin. So, the lithology of volcanic rocks in this well was identified by some data from core analysis, thin-section identification, and conventional, elemental scanning, and image logging in order to quickly develop some methods of logging-based lithologic identification. Results show that,(1) these rocks are mainly composed of volcanic lava and volcaniclastic lava. And in terms of breccia content, the latter may be also subdivided into tuffaceous lava with breccia and breccia lava;(2) lithoscanner logging can be used to quantitatively determine the content of major rock-forming mineral elements. And combined with TAS chart, it can discriminate rock chemical composition effectively. Results from lithoscanner logging demonstrate, after the removal of heterogeneous breccia mineral components, on the basis of chemical composition, these rocks can be divided into basic alkali basalt and basalt;(3) volcanic rocks in Yongtan 1 well are mainly dominated by basic ones with low radioactivity. And the lithology cannot be distinguished via GR logging whereas sensitive to density, compensated sonic, and resistivity logging. As a result, the crossplots of both DEN-AC and DEN-Rt may be adopted to identify lithology;and (4) volcanic- rock lithology can be evaluated effectively by means of conventional logging to identify its composition, and image logging for structural and tectonic characteristics, respectively.
作者
吴煜宇
赖强
谢冰
刘鑫
Wu Yuyu;Lai Qiang;Xie Bing;Liu Xin(Exploration and Development Research Institute,PetroChina Southwest Oil & Gasfield Company,Chengdu,Sichuan610041,China)
出处
《天然气勘探与开发》
2019年第1期21-27,共7页
Natural Gas Exploration and Development
基金
中国石油天然气股份有限公司重大科技专项"西南油气田天然气上产300×10~8 m~3关键技术研究与应用"(编号:2016E-0604)
关键词
永探1井
火山岩
岩性识别
岩性扫描测井
成像测井
四川盆地
Yongtan 1 well
Volcanic rock
Lithologic identification
Lithoscanner logging
Image logging
Sichuan Basin
