0塔里木盆地志留纪地层_沉积特征与岩相古地理

文章编号:1671-1505(2006)03-0339-14　

3中国石油塔里木油田公司勘探生产项目(2004)的部分研究成果收稿日期:2005-11-10 改回日期:2006-01-10

塔里木盆地志留纪地层、沉积特征与岩相古地理

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贾进华1　张宝民1　朱世海2　朱运成2　李占银2

1中国石油勘探开发研究院,北京1000832中原石油勘探局地质录井处,河南濮阳457001

摘　要　近年来塔里木盆地志留系油气勘探的发现,使志留系研究重新受到重视,但仍存在一些制约勘探的基础地质问题需要深入研究。本文在塔里木盆地志留系野外露头、井下地层岩性段划分对比的基础上,详细研究了不同岩性段的沉积体系、沉积相和微相特征,恢复了塔里木盆地志留纪不同时期的岩相古地理格局。根据志留纪地层发育和沉积特征,塔里木盆地志留系可分为柯坪—塔中和塔东地层分区,并进一步划分为柯坪、巴楚、塔中、塔北、满东和英吉苏6个地层小区。塔里木盆地志留系主要发育碎屑潮坪(夹风暴)沉积体系、无障壁滨岸海滩—陆棚沉积体系、碎屑潮坪—滨岸砂坝复合沉积体系和辫状河三角洲沉积体系4种类型,经历了海域范围逐渐缩小、古气候由温暖潮湿向炎热干旱过渡的过程。盆地整体地势呈南高北低,物源主体来自塔东和塔东南地区。平面上西部水体较浅而开阔,东部较闭塞,海侵方向来自北部和西北部。塔里木盆地志留纪古环境和古地理特征反映了在沿海岸带附近发育潮下潮道与砂坝砂体,尽管单砂体厚度较薄,但多套单砂体纵向上叠置可以形成砂体相对富集的砂层组,具有形成岩性—地层圈闭的地质条件。

关键词　塔里木盆地　志留纪　地层　沉积特征　岩相古地理

第一作者简介　贾进华,男,1965年生,1993年毕业于中国地质大学(北京),获博士学位,现为中国石油勘探开发研究院高级工程师,主要从事含油气盆地沉积学和储层地质学研究。

中图分类号:P51212 文献标识码:A

Stratigraphy ,sedimentary characteristics and lithofacies

palaeogeography of the Silurian in T arim B asin

Jia Jinhua 1　Zhang Baomin 1　Zhu Shihai 2　Zhu Yuncheng 2　Li Zhanyin 2

1Research Institute of Pet roleum Ex ploration &Development ,Pet roChina ,Beijing 1000832Geologic L ogging Depart ment of Zhongyuan Pet roleum Ex ploration B ureau ,Puyang 457001,Henan

Abstract A great attention has been repaid to the study of the Silurian in the Tarim Basin due to the discovery of petroleum in the interval ,but there still exists some basic geologic problems which hinder the exploration 1Based on the division and correlation of different lithologic members between the field outcrops and the wells ,the depositional systems and sedimentary facies and microfacies of these members have been studied in detail 1Then ,the lithofacies palaeogeographic evolution of the Sil 2urian in the Tarim Basin has been reconstructed 1According to the stratigraphic and sedimentary devel 2oping features ,the Silurian in the Tarim Basin can be divided into Keping 2Tazhong and Tadong strati 2

第8卷　第3期2006年　8月

古地理学报

JOURNAL OF PALAEO GEO GRAPHY

Vol 18　No 13

Aug 1　2006

graphic regions ,and be subdivided into six stratigraphic sub regions including Keping ,Bachu ,Tazhong ,Tabei ,Mandong and Y ingjisu 1Mainly four types of depositional systems were developed in the Silurian in the Tarim Basin 1They were the shore 2neritic shelf system ,detrital tidal flat (interca

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lated tempestites ),detrital tidal flat 2shore composite and braided delta systems 1Sedimentary facies are dominated by detrital tidal flat ,shore beach ,offshore subaqueous sand bar ,neritic shelf and braided delta 1The Tarim Basin experienced a process of marine domain gradually decreasing and paleo 2climate changing from warm and humid to hot and dry during the Silurian 1The topography of the Sil 2urian basin was higher in the south and lower in the north and the sediments mainly came from Tadong and Tadongnan areas 1There were a relatively shallow and extensive waterbody in western area ,and a relatively euxinic body in eastern area 1Marine transgression was from the north and northwest 1The palaeoenvironmental and palaeogeographic characters show that subtidal channel and bar sandbodys were developed along the shore 2line 1Although the single sandbody was thin ,relatively abundant sand 2body assemblages can be formed by the vertical stacking of many sets of single sandbodys 1Thus the ge 2ologic conditions for forming litho 2stratigraphic traps are favorable 1

K ey w ords Tarim Basin ,Silurian ,stratigraphy ,sedimentary characteristics ,lithofacies palaeogeography

About the f irst author Jia Jinhua ,born in 1965,graduated from China University of G eo 2sciences (Beijing )and obtained a doctoral degree in 19931Now he is a senior engineer in Research In 2stitute of Petroleum Exploration and Development ,PetroChina ,and is engaged in sedimentology ,reservoir geology of petroliferous basin 1

1　引言

在塔里木盆地最初的油气勘探中,志留系并未受到足够的重视,但随着近几年在志留系砂岩中获得越来越多的油气发现和不同级别的油气显示,志留系重新引起了勘探家们的关注。1994年12月塔中11井在志留系砂岩中首次获得工业油气流,2001年发现了塔中47井志留系油藏,2003年在塔

中东部发现了大面积的志留系含油砂岩,同年又在满东地区的满东1井喜获工业气流。除此之外,塔里木盆地志留系广泛分布的沥青砂岩更是引人注目

(刘洛夫等,2001;张俊等,2004)。以上重要的勘探发现表明塔里木盆地志留系蕴藏着巨大的油气勘探潜力。目前,志留系已经成为塔里木盆地继东河砂岩之后又一个重要的海相砂岩储集层位。尽管如此,针对志留系的研究中仍然存在一些制约勘探研究认识的难题,其中最关键的是储集砂体的评价预测和油气藏分布规律问题,因此需要进一步详细地研究志留纪的地层与沉积特征,并确定其岩相古地理分布。

中国石油塔里木油田公司对志留纪的地层和沉

积相特征已进行了较多的研究(朱筱敏,1995;顾家裕等,1996;贾进华等,1997;侯会军等,1997;钟广法等,1997;朱爱国等,1998;朱筱敏等,2001,2002;刘家铎等,2004;朱如凯等,2005),但这些基本是分地区、分区块或分层段的

研究,较少从全盆地角度进行系统研究。同时,对沉积相的认识,也存在多种看法,甚至存在矛盾,

如对塔中地区柯坪塔格组上段沉积相的认识(贾进华等1997;钟广法等,1997;朱筱敏等,2001,2002;朱如凯等,2005)、对岩相古地理及海侵和物源方向的认识等。在2004年4月塔里木盆地志留系研讨会中,由生产和科研人员进行了共同研究,就志留系的地层划分对比与沉积相分析达成了初步共识。

根据2004年塔里木盆地志留系最新地层划分对比方案Ξ,结合地震剖面解释资料,以单井与连井沉积相分析为基础,通过对盆地覆盖区30余口井志留系不同岩性段的沉积相和微相研究,及其与

Ξ塔里木盆地志留系研讨会会议纪要.20041内部资料.

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