|
|||||
|
|
| 二连盆地巴音都兰凹陷下白垩统湖相云质岩成因研究 | |
| 引用本文： | 王会来,高先志,杨德相,李浩,张志遥,王旭,张丽. 二连盆地巴音都兰凹陷下白垩统湖相云质岩成因研究[J]. 沉积学报, 2014, 32(3): 560-567 |
| 作者姓名： | 王会来 高先志 杨德相 李浩 张志遥 王旭 张丽 |
| 作者单位： | 中国石油大学(北京)地球科学学院;中国石油大学(北京)油气资源与探测国家重点实验室;中国石油华北油田分公司勘探开发研究院;中国石化石油勘探开发研究院无锡石油地质研究所;中国石油华北油田分公司地球物理勘探研究院; |
| 基金项目： | 中石油重大研究课题“二连盆地富油凹陷深化勘探潜力与方向研究”(编号:HBYT-YJY-2011-JS-406)资助 |
| 摘 要： | 巴音都兰凹陷下白垩统发育的云质岩是一套具有特殊成因的重要标志层，且近年来在其中发现大量油气显示，但目前对这套云质岩成因研究程度较低。为此，通过岩芯观察、薄片鉴定、全岩分析、微量元素和碳氧同位素测定等方法，综合研究了云质岩的岩石学特征、古水介质、成因类型等。研究认为，本区古水介质为淡水-微咸水，而白云石中铁含量高，是埋藏白云化作用的产物，发生白云化作用的母质是凝灰物质，凝灰物质蚀变作用形成大量的斜长石和镁、铁离子，并在二氧化碳参与下发生水解，形成铁白云石，其中二氧化碳主要来源于埋藏条件下的有机质甲烷化作用。 |
| 关 键 词： | 云质岩 凝灰物质 埋藏白云化作用 下白垩统 巴音都兰凹陷 二连盆地 |
| 收稿时间： | 2013-10-12 |
Genesis of Dolomitic Rock within the Lower Cretaceous Lacustrine Facies in Bayindulan Sag,Erlian Basin |
|
| Abstract: | The dolomite rocks of the Lower Cretaceous are formed under special geologic conditions, and are the key horizon that can be correlated with the whole basin. In recent years, abundant hydrocarbon shows have been found in the dolomitic rocks, but there is little research on the dolomitization of this deposit. The genesis of dolomite in the study area is related to hydrolysis of volcanic material. Bulk rock and microscopic petrologic features analysis indicate that the specific suite of rocks is rich in volcanic ash which contains a large amount of Ca2+ and Mg2+. Dolomites, which originated from the reaction of CO2, Ca2+ and Mg2+, replace volcanic material to fill pores and fractures. Crystal structures of dolomite observed under microscope, can be classified as porphyritic crystal, micritic crystal and fine-powder crystal. Dolomite with porphyritic crystal behaves dispersire state and shows irregular shape. Additionally, the size of porphyritic crystal is relatively large, with an average diameter of about 0.2mm. Dolomite with micritic crystal is characterized of laminated and agglomerate feature. The difference between porphyritic and micritic structure is related to the liquidity of pore fluids. Dolomites with fine-powder crystal concentrate in reservoir pores or fractures as cement. The problem about origin of the CO2 is as important as that of Mg2+ to the specific dolomitization. Analysis of carbon isotope show that CO2 used to hydrolysis is related to the methanation of organic matters. The carbons within original organic material are transformed to methane and bicarbonate by methanation in the absence of oxygen. The enrichment of 12C in methane results in the concentration of 13C in bicarbonate and a slightly positive of δ13C in dolomite. |
| Keywords: | |
| 本文献已被 CNKI 等数据库收录！ | |
| 点击此处可从《沉积学报》浏览原始摘要信息 | |
| 点击此处可从《沉积学报》下载全文 | |