碳酸盐胶结物形成机制及其对渤海海域C12和Q17构造中生界碎屑岩储层的影响

doi:10.11743/ogg20190611

摘要/Abstract

摘要： 采用薄片鉴定、X-衍射、扫描电镜、元素分析、盆模软件和激光微区碳氧同位素等分析手段，对C12和Q17构造碳酸盐胶结类型、赋存状态、不同期次碳酸盐胶结物形成机理及其对储层物性的影响进行了对比研究。结果表明，碳酸盐胶结物的差异导致了储层物性的差异，而碳酸盐胶结物的成因和分布主要受埋藏条件、淋滤作用、构造条件和成岩环境差异4个因素的影响。C12构造碳酸盐胶结物含量高，早期和晚期胶结物充填孔隙，且早期胶结物后期未发生溶蚀，仅在中生界顶部不整合面附近发育次生孔隙。这是由于C12构造受反复深埋藏、封闭成岩环境、辫状河的强烈蒸发环境以及早期断层活动的构造条件影响，导致本区碳酸盐胶结强烈，储层致密。Q17构造碳酸盐胶结也较为普遍，但仅在局部细粒砂岩段存在早期胶结物富集段，而在原始沉积条件好的厚层粗砂岩段碳酸盐本身含量低，或发生早期碳酸盐溶蚀，并出现零星铁白云石胶结，物性相对较好。这是由于Q17构造为浅埋藏、开放的成岩环境和断层持续活动的构造条件，淋滤作用影响的范围广、深度大。而晚期铁白云石的出现，与地层水流体活动、油气侵位有关。根据这一现象，提出了差异成岩作用的观点，并从宏观构造和微观成岩的角度进行了探讨。

关键词: 淋滤作用, 成岩作用, 埋藏条件, 差异成岩, 碳酸盐胶结, 构造环境, 中生界, 渤海海域

Abstract: Carbonate cements were pervasively developed in deep clastic strata of the Mesozoic formations in the Bohai Bay Basin.Based on results through thin section identification,X-ray diffraction,Scanning Electron Microscopy (SEM),elements analysis,and numerical basin modeling and laser micro-sampling analysis for carbon and oxygen isotopes,we made a comparative study on the types,occurrences,and genetic mechanisms of carbonate cements of various periods,and their impacts on reservoir physical properties in the C12 and Q17 structures.The results show that the differences of carbonate cements of the two structures have led to different reservoir physical properties,and the generation and distribution of carbonate cements were mostly under the control of burial period,leaching,tectonic conditions,and diagenetic settings.The C12 structure features high content of carbonate cements,and its reservoir pores are filled with both early and later generated carbonate cements.Furthermore,the cements of early generation experienced no dissolution at later stages,while secondary pores developed only near the top Mesozoic unconformity.The reason lies in the impact of repeated deep burial processes,sealing diagenetic conditions,and intensive evaporation of the braided rivers,as well as the early faulting,which resulted in the intense carbonate cementation and then the initiation of reservoir tightening in the C12 structure.In comparison,the Q17 structure is relatively good in reservoir physical properties.Although the carbonate cementation is also intensive in the structure,characterized by early-stage carbonate cement concentration in local intervals of fine-grained sandstones,the thick-bedded coarse-grained sandstone intervals of better original sediment facies have usually low carbonate content or experienced carbonate dissolution at early stages,resulting in sporadic cements of ferron dolomite.This is due to its shallow burial history,open diagenetic settings,continuous fault activities,and wide-spread leaching.The occurrence of ferron dolomite was associated with formation water flows and hydrocarbon charging on the sandstones.Based on these observations,we proposed a concept of differential diagenesis,and discussed its mechanism from both the macro-structure and micro-diagenesis perspectives.

Key words: leaching, diagenesis, burial condition, differential diagenesis, carbonate cementation, tectonic environment, Mesozoic, Bohai Sea

中图分类号:

TE121.3

卢欢,徐长贵,王清斌,等. 碳酸盐胶结物形成机制及其对渤海海域C12和Q17构造中生界碎屑岩储层的影响[J]. 石油与天然气地质, 2019, 40(6): 1270-1280. doi: 10.11743/ogg20190611 Lu Huan,Xu Changgui,Wang Qingbin,et al. Genetic mechanism of carbonate cements and its impact on the Mesozoic clastic reservoir quality of the C12 and Q17 structures,Bohai Sea Area[J]. Oil & Gas Geology, 2019, 40(6): 1270-1280. doi: 10.11743/ogg20190611

参考文献 17

[1]	蔡雄飞,王德辉,章泽军.陆相残余盆地的主要类型、特点及研究方法[J].世界地质,2004,23(3):222-226. Cai Xiongfei,Wang Dehui,Zhang Zejun.Types,features and studying method of continental relict basins[J].World Geology,2004,23(3):222-226.
[2]	王连进,叶加仁.残余盆地特征及研究方法[J].天然气地球科学,2000,11(3):8-12. Wang Lianjin,Ye Jiaren.Characteristics of remnant basin and its study methodology[J].Natural Gas Geoscience,2000,11(3):8-12.
[3]	吴智平,李伟,任拥军,等.济阳坳陷中生代盆地演化及其与新生代盆地叠合关系探讨[J].地质学报,2003,77(2):280-286. Wu Zhiping,Li Wei,Ren Yongjun.Basin evolution in the Mesozoic and Superposition of Cenozoic Basin in the area of the Jiyang depression[J].Acta Geologica Sinica,2003,77(2):280-286.
[4]	黄可可,黄思静,佟宏鹏.长石溶解过程的热力学计算及其在碎屑岩储层研究中的意义[J].地质通报,2009,28(4):474-482. Huang Keke,Huang Sijing,Tong Hongpeng.Thermodynamic calculation of feldspar dissolution and its significance on research of clastic reservoir[J].Geological Bulletin of China,2009,28(4):474-482.
[5]	黄思静,黄可可,冯文立,等.成岩过程中长石、高岭石、伊利石之间的物质交换与次生孔隙的形成:来自鄂尔多斯盆地上古生界和川西凹陷三叠系须家河组的研究[J].地球化学,2009,38(5):498-506. Huang Sijing,Huang Keke,Feng Wenli,et al.Mass exchanges among feldspar,kaolinite and illite and their influences on secondary porosity formation in elastic diagenensis:a case study on the Upper Paleozoic,Ordos Basin and Xujiahe Formation,western Sichuan depression[J].Geochimica,2009,38(5):498-506.
[6]	Aagaard P,Jahren J S,Egeberg P K.North Sea clastic diagenesis and formation water constraints[A].In Kharaka and Maest (eds.),Water-rock interaction:Rotterdam,Balkema[C].1992,2:147-152.
[7]	张善文.成岩过程中的"耗水作用"及其石油地质意义[J].沉积学报,2007,25(5):701-707. Zhang Shanwen."Water consumption" in diagenetic stage and its petroleum geological significance[J].Acta Sedimentological Sinica,2007,25(5):701-707.
[8]	刘四兵,沈忠民,刘昊年,等.川西坳陷中段上三叠统须家河组水岩相互作用机制[J].石油学报,2013,34(1):47-58. Liu Sibing,Shen Zongming,Liu haonian,et al.Mechanism of water-rock interaction of the Upper Triassic Xujiahe Formation in the middle part of western Sichuan depression[J].Acta Petrolei Sinica,2013,34(1):47-58.
[9]	张金亮,刘宝,毛凤鸣,等.苏北盆地高邮凹陷北斜坡阜宁组成岩作用及储层特征[J].石油学报,2003,24(2):43-49. Zhang Jinliang,Liu Baojun,Mao Fengming.Clastic diagenesis and reservoir characteristics of Funing Formation in north slope of Gaoyou Depression in Subei Basin[J].Acta Petrolei Sinica,2003,24(2):43-49.
[10]	Jones LM,Taylor A R,Winter D L,et al.The use of the laser microprobe for preparation in stable isotope mass spectrometry(abstract)[J].Terra Congita,1986,6:263.
[11]	Smalley P C,Maile C N,Coleman M L,et al.LASSIE (laser ablation sampler for stable isotope extraction)applied to carbonate minerals[J].Chemical Geology,1992,101:43-52.
[12]	Dickson J A D,Smalley P C,Raheim A,et al.Intracrystaiiine carbon and oxygen isotope variation in cal-cite revealed by laser microsampling[J].Geology,1990,18:809-811.
[13]	Beaudoin G and Taylor B E.MILES laser microprobe.Part 2:Preliminary assessment of precision and accuracy of suiphur isotope analysis[C].Current Research,PartD;Geological survey of Canada,Paper 93-1D.
[14]	Franchi I A,Wright I P,Gibson E K,et al.The laser microprobe:A technique for extracting carbon,nitrogen,and oxygen from solid samples for isotopic measurements[M].Journal of Geophysical Research,1986,91:514-524.
[15]	Aagaard P,Helgeson H C.Activity/composition relations among silicates and aqueous solutions;Ⅱ,chemical and thermodynamic consequences ideal mixing of atoms on homological sites in mont-morillonites,illites,and mixed-layer[J].Clays and Clay Minerals,1983,30(3):207-217.
[16]	王大锐.油气稳定同位素地球化学[M].北京:石油工业出版社,2000. Wang Darui.Petroleum geochemistry study of stable isotopes[M].Beijing:Petroleum Industry Press,2000.
[17]	Keith M L,Weber J N.Carbon and oxygen isotopic composition of selected limestones and fossils[J].Geochimica et Cosmochimica Acta,1964,28(10-11):1786-1816.