Early-diagenetic Carbonate Nucleation Cementation in Cenozoic Sandstones,Northern Tarim Basin：Evidences from High-resolution Electric Borehole Images
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摘要: 早期碳酸盐胶结作用是库车坳陷新生界浅埋藏河流相砂岩内除机械压实外目前正在进行的主要成岩作用,高分辨率电阻率成像测井资料为研究其特征及成因提供了重要的地球物理证据。在电阻率成像测井图像上,早期碳酸盐胶结物呈圆形、椭圆形或不规则斑块状、葡萄状等形态出现,多数顺层理方向分布,其产状有孤立状或分散状斑块、断续胶结纹层和连续胶结纹层等。它们可以发育于砂岩层顶部或底部,也可以与疏松未胶结或弱胶结砂岩呈互层或夹层状交替分布。早期碳酸盐胶结物的沉淀采取核心式胶结模式,即胶结物首先围绕少数核心沉淀,呈斑块状逐渐向外增生,直至从各个核心生长出来的碳酸盐胶结斑块相互靠近和连生导致砂岩层被完全胶结为止。砂体或砂层被碳酸盐胶结的过程遵循由外向内 (由砂体边缘向砂体中心 )、由高渗透纹层向低渗透纹层、由局部胶结核心向周围孔隙增生的规律.Abstract: Carbonate ccmcntation is the main diagcnctic process except for compaction in shallow-burial(shallower than 700 metcrs) Ncogcnc-Quatcrnarv fluvial sandstoncs of northern Tarim Basin.High-resolution electric borcholc images provide valuable information on the gcomctrv and occurrence of carbonate concretions in these sandstoncs. Carbonate concretions in the sandstoncs are characterized with white high-resistive features in both static and dynamic images.The shape of these concretions is round clliptoid or irregular. They may occur as isolate patches scattered in poorcemented sandstones, or appear in group as spiccato or continuous carbonate-cemented laminae intcrbcddcd with poor-cemcntcd sandstone laminae. Strong selectivity of carbonate ccmcntation at different scales is observed on the images of these sandstoncs.On scale of sandstone beds, carbonate concretions preferentially developed at the upper and/or lower parts, where ion materials needed for carbonate cement precipitation are believed to be more easily available from adjacent clay sediments.On scale of beddings,carbonate concretions usually aligned parallel to bedding surfaces.In most cases, they intcrbcddcd with poor-ccmcnted sandstone laminae as spiccato or continuous carbonate-cemented laminae which may be resulted from the texture and hence permeability differences between laminae.On laminae scale, carbonate cements selectively precipitate around some nuclei then enlarge outwards as cemented patches.when the patches grow closer or merge together spiccato or continuous cemented laminae form. fragments, which are the The selectivity of ccmcntation some relation to the,listrihution of elastic carbonate common gram components in these sandstones. Based on interpertation of electric images,this paper concluded a growth of early-diagenetic carbonate cements in these sandstoncs.They were developed following the sequences from the top and/or the middle of the sandstone beds, from high-permeable laminae to low-permeable laminae, and from some local nuclei to their vicinity.
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Key words:
- sandstone /
- cementation /
- carbonate mineral /
- electric borehole imaging /
- Tarim basin
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[1] 1 刘宝王君，张锦泉主编. 沉积成岩作用[M]. 北京：科学出版社，1992.65 ~ 92，237 ~ 257
2 James W C. Early diagenesis，Atherton Formation（Ouaternary）：a guide for understanding early cement distribution and grain modifications in non-marine deposits [J]. Journal of Sedimentary Petrology，1985，55：135 ~ 146
3 Wilkinson M. The concretions of the Bearreraig Sandstone Formation：geometry and geochemistry[J]. Sedimentology，1991，38（5）：899 ~ 912
4 McBride E F，Picard M D，Fork R L. 0riented concretions，lonian coast，ltaly：evidence of groundwater fIow direction[J]. Journal of Sedimentary Research，1994，64：535 ~ 540
5 Rider M H. The geological interpretation of well logs（2nd edition）[M].Houston：Gulf Publishing Company，1996. 199 ~ 225
6 Serra 0. Schlumberger Formation MicroScanner image interpretation[M].Houston：Schlumberger Educational Services，1989. 15 ~ 96
7 Harker S D，McGann G J，Bourke L T，Adams J T. Methodology of Formation MicroScanner image interpretation in Claymore and Scapa fields（North Sea）[A]. In：Hurst A，Lovell M A，Morton A C ，eds. Geological applications of wireline logs. Geological Society of London Special Publication，No.48：11 ~ 25
8 Carr D L ，Johns R A. High-resolution reservoir characterization of Midcontinent sandstones using wireline resistivity imaging，Boonsville（Bend congIomerate）gas field，Fort Warth Basin，Texas[J]. The Log AnaIyst，1997，38（6）：54 ~ 70
9 V 恩格尔哈特. 沉积物和沉积岩成因[M]. 王东坡，何起祥，汪碧华译. 北京：地质出版社，1982. 170 ~ 187
10 Berner R A. Early diagenesis：a theoretical approach. Princeton[M]. New Jersey：Princeton University Press. 1980. 241
11 F J 佩蒂庄，P E 波特，R 西弗. 砂和砂岩[M]. 北京：科学出版社，1977. 38 ~ 40，99 ~ 100，303 ~ 306，318 ~ 319
12 Beard D C，Weyl D K. Influence of texture on porosity and permeability of unconsolidated sand[J]. AAPG Bulletin，1973，57：349 ~ 369
13 Ftchtbauer H. 沉积相对砂岩成岩作用的控制[A]. 见：贾振远，万静萍，袁柄存等译. 沉积物的成岩作用[C]. 武汉：中国地质大学出版社，1989. 141 ~ 149
14 Ftrsich F T. Rhythmic bedding and shell bed formation in the Upper Jurassic of GreenIand[A]. In：EinseIe G，Seilacher A ，eds. Cyclic and eventstratification[C]. Berlin：Springer-VerIag，1982，208 ~ 222
15 Bryant I D，Kantorowicz J D，Love C F. The origin and recognition of Iaterally continuous carbonate-cemented horizons in the Upper Lias Sands of southern England[J]. Marine and Petroleum Geology，1988，5（2）：108 ~133
16 Bj!rkum P A，Walderhaug 0. Geometrical arrangement of calcite cementation within shallow marine sandstones[J]. Earth-Science Reviews，1990，29：145 ~ 161
17 Kantorowicz J D，Bryant I D，Dawans J M. Controls on the geometry and distribution of carbonate cements in Jurassic sandstones：Bridport Sands，southern EngIand and Virking Group，Troll FieId，Norway[A]. In：Marshal J M，ed. Diagenesis of sedimentary seguences. Blackwell Scientific Publications，1987，103 ~ 118
18 McBride E F. Contrasting diagenetic histories of concretions and host rock，Lion Mountain Sandstone（Cambrian），Texas[J]. Geological Society of American Bulletin，1988，100（11）：1 803 ~ 1 810
19 McBride E F，MiIIiken K L，Cavazza W，et al. Heterogeneous distribution of calcite cement at the outcrop scale in Tertiary Sandstones，northern Apennines，Italy[J]. AAPG Bulletin，1995，79（7）：1 044 ~ 1 063
20 Bj!rkum P A，Walderhaug 0. Isotopic composition of a calcite-cemented Iayer in the Lower Jurassic Bridport Sands，southern England：implications for formation of Iaterally extensive calcite-cemented Iayers[J]. Journal ofSedimentary Petrology，1993，63（4）：678 ~ 682 -
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