济阳陆相断陷湖盆泥页岩细粒沉积层序初探  

A Study on Fine Sedimentary Sequence of Shale in the Continental Rift Basin of Jiyang Depression

作　　者：王勇[1] WANG Yong(Research Institute of Exploration and Developmen, Shengli Oilfield Company, SINOPEC, Dongying, Shandong 257015, China)

机构地区：[1]中国石化胜利油田分公司勘探开发研究院,山东东营257015

出　　处：《西南石油大学学报（自然科学版）》2016年第6期61-69,共9页Journal of Southwest Petroleum University(Science & Technology Edition)

基　　金：国家重点基础研究发展计划(973计划)(2014CB239104)

摘　　要：综合运用地球化学元素、沉积环境恢复指标、岩性及伽马能谱测井响应演化规律,对济阳拗陷沙四上—沙三下亚段泥页岩细粒沉积层序研究表明,在细粒沉积层序的形成过程中,受沉积环境和沉积作用的影响,层序界面处往往表现为高碎屑物源供给,高Ti、Fe、Al、Na、K、Co、Cr、Cd、Mn元素丰度,低碳酸盐岩含量、Ca元素、腐泥组含量,以及发育代表水动力条件较强的冲刷面、交错层理等沉积构造和古环境指标出现较大的转折变化特征。准层序组往往代表一个较大湖进和湖退的过程,TOC或Sr大值段往往对应湖进与湖退的转化面。细粒沉积由于颗粒细小,沉积缓慢,且富含有机质,对K、U、Th等放射性元素具有很强的吸附性,有利于K、U、Th等放射性元素富集,最终表现为GR测井对细粒泥页岩的分辨率往往高于其他岩性。济阳拗陷沙四上—沙三下亚段GR测井响应纵向规律明显,在全区范围内有较好的可对比性,可利用GR曲线纵向演化规律进行细粒沉积层序地层全区对比追踪。Integrating the geochemical elements, sedimentary environment restoration indicators, lithology and gamma spectroscopylogging response, we studied the fine shale sedimentary sequence on the Es4 s Es3x of Jiyang Depression, and theresults show that, during the formation process of fine-grained sedimentary sequence, the sequence boundary, affected by depositionalenvironment and depositional effects, displays characteristics as follows: high supply of detritus source, high abundancesof Ti, Fe, Al, Na, K, Co, Cr, Cd and Mn, low content of carbonate rocks, Ca elements and sapropel group, and greatvariations in sedimentary structures and paleoenvironmental indicators of scour surface and cross-bedding which representstrong hydrodynamic conditions. Parasequence group often represents a process of large scale progradation and retrogradation,with great value segment of TOC or Sr corresponding with the transformed surface. Due to small particles, slow depositionprocess, and abundant organic matter, the fine-grained sediments have strong adsorption on K, U, Th and other radioactiveelements, which contributes to the enrichment of these radioactive elements, and better performance of GR logging on fineshale resolution than other lithologies. The GR logging response bears obvious longitudinal regulationand is of good contrasttracking feature on the Es4 s Es3x of Jiyang Depression, so we can use the vertical evolution of GR curve to contrast and tracethe fine-grained sedimentary sequence in the whole region.

关 键 词：化学元素 沉积环境 伽马能谱 细粒沉积 层序 

分 类 号：TE121[石油与天然气工程—油气勘探]