塔里木盆地古城地区奥陶系鹰三段硅质岩地球化学特征及成因

  • 王珊 , 1 ,
  • 曹颖辉 1 ,
  • 张亚金 2 ,
  • 杜德道 1 ,
  • 徐兆辉 1 ,
  • 杨敏 1 ,
  • 赵一民 1
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  • 1. 中国石油勘探开发研究院,北京 100083
  • 2. 大庆油田有限责任公司勘探开发研究院,黑龙江 大庆 163712

王珊(1986-),女,河北保定人,工程师,硕士,主要从事碳酸盐岩沉积储层研究. E-mail:.

收稿日期: 2020-03-26

  修回日期: 2020-04-20

  网络出版日期: 2020-05-27

Origin and geochemical characteristics of siliceous rocks in the third Member of Yingshan Formation in Gucheng area, Tarim Basin

  • Shan WANG , 1 ,
  • Ying-hui CAO 1 ,
  • Ya-jin ZHANG 2 ,
  • De-dao DU 1 ,
  • Zhao-hui XU 1 ,
  • Min YANG 1 ,
  • Yi-min ZHAO 1
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  • 1. PetroChina Research Institute of Petroleum Exploration & Development, Beijing 100083, China
  • 2. PetroChina Daqing Oilfield Company, Daqing 163712, China

Received date: 2020-03-26

  Revised date: 2020-04-20

  Online published: 2020-05-27

Supported by

The 13th Five-Year Plan of CNPC(2019B-04)

The Major Science and Technology Project of CNPC(2016E-0204)

本文亮点

奥陶系鹰三段是塔里木盆地古城地区的主力储集层段,但硅质岩发育,导致储层变差。镜下观察揭示研究区硅质岩主要为残余结构硅质岩;地球化学分析结果显示硅质岩在Al—Fe—Mn三角图中位于热液沉积区域,且Al/(Fe+Mn+Al)值、(Fe+Mn)/Ti值、Y/Ho—Th/U关系、ΣREE值、LREE/HREE值、δCe值及δEu值均与热液成因的硅质岩地球化学指标相吻合;同时Si同位素、O同位素及其相关关系与交代成因的硅质岩和成岩石英的地球化学指标相吻合。以上特征表明,研究区硅质岩为成岩后的热液交代成因。结合区域地质资料,研究区早加里东期发育断穿基底的NE向断裂,为热液流体提供了运移通道。二叠纪末期,塔里木盆地发生大规模的火山活动,为碳酸盐岩的硅化提供了热液和硅质来源。硅质热液沿NE向断裂及其伴生裂缝广泛进入鹰三段与碳酸盐岩发生反应,硅质热液交代碳酸盐岩沉积物并沉淀形成硅质岩。

本文引用格式

王珊 , 曹颖辉 , 张亚金 , 杜德道 , 徐兆辉 , 杨敏 , 赵一民 . 塔里木盆地古城地区奥陶系鹰三段硅质岩地球化学特征及成因[J]. 天然气地球科学, 2020 , 31(5) : 710 -720 . DOI: 10.11764/j.issn.1672-1926.2020.04.017

Highlights

The 3rd Member of Yingshan Formation is a main reservoir section in Gucheng area of Tarim Basin, but the development of siliceous rock destroyed the reservoir to a certain extent. The siliceous rocks in the study area are mainly residual structural rocks. The results of geochemical analysis show that the siliceous rocks are located in the hydrothermal sedimentary area in the Al-Fe-Mn diagram, and the values of Al/(Fe+Mn+Al), (Fe+Mn)/Ti, Y/Ho-Th/U, ΣREE, LREE/HREE, δCe and δEu are consistent with the geochemical indexes of hydrothermal sedimentary siliceous rocks. The Si isotopes, O isotopes and their correlation are consistent with the geochemical indexes of metasomatic siliceous rocks and diagenetic quartz. The above characteristics indicate that the siliceous rocks of the 3rd Member of Yingshan Formation in the study area are formed by hydrothermal metasomatism after diagenesis. Combined with the regional geological data, the NE trending faults that break through the basement developed in Early Caledonian Period, providing a migration channel for the hydrothermal fluid. At the end of Permian, large-scale volcanic activities took place in Tarim Basin, which provided hydrothermal and siliceous sources for silicification of carbonate rocks. The siliceous hydrothermal fluid entered the 3rd Member of Yingshan Formation along NE-trending faults and its associated fractures and reacted with carbonate rocks. The siliceous hydrothermal fluid replaced carbonate sediments and precipitated to form siliceous rocks.

0 引言

硅质岩是指由生物化学作用、火山作用、热水作用等形成的富含SiO2的岩石(SiO2质量分数一般>70%),也包括盆地内经过机械破碎再沉积的岩石,统称为硅质岩[1]。硅质岩结构较致密,受后期成岩作用影响小,其地球化学特征可以较好地反映其成因、来源、沉积环境等信息[2,3,4,5,6]
在碳酸盐岩油气储层方面,硅化热液是影响储层发育的重要因素,已经引起人们的广泛关注。前人[7,8]研究表明,携带硅质的热液既能溶蚀碳酸盐岩改善储层,又能沉淀硅质封堵孔隙破坏储层,总体上对储层发育具有双重影响。
塔里木盆地奥陶系是油气勘探的主力层段,已发现了多个深层碳酸盐岩大油气田[9],其中,古城地区奥陶系鹰三段储层发育,但是与塔北和塔中不同[10,11],古城地区各井碳酸盐岩层中常见硅质岩薄层。前人[12,13,14,15,16]对塔里木盆地硅质岩成因做过相关研究,主要集中在对寒武系硅质岩的成因、沉积环境方面的分析,对于奥陶系硅质岩研究相对较少[17,18,19],对于研究区硅质岩的研究尚且未见。
本文以古城地区鹰三段硅质岩为研究对象,在岩心薄片观察的基础上,结合元素、同位素等地球化学特征,对其成因机制及对碳酸盐岩储层的影响进行探讨。

1 地质背景

塔里木盆地古城低凸起是塔中隆起向东延伸的末端,北部邻满西低凸起,东为塔东隆起带,西南部以塔中I号断裂与塔中隆起相邻(图1),总体呈NW倾向的大型宽缓鼻状构造,面积约为6 100 km2
图1 古城地区区域简图[23](a)及奥陶系综合地层柱状图(b)

Fig.1 Location map, faults distribution[23] (a) and Ordovician stratigraphic histogram(b) of Gucheng area

古城地区主要发育NE向、NNE向和NW向共3组断裂[20,21,22]。吴斌等[20]厘定出该区断裂活动主要有3期,包括加里东早期、加里东中期和加里东晚期—海西早期。
古城地区奥陶系自下而上发育蓬莱坝组、鹰山组、一间房组、吐木休克组和却尔却克组共5套地层。鹰三段厚度在200~350 m之间,以白云岩沉积为主,夹灰岩薄层(图1),是主力储集层。测井资料揭示硅质岩在研究区鹰三段发育较为普遍(图2),在单井上显示为薄层状。
图2 古城地区奥陶系鹰三段地层对比 (剖面位置见图1)

Fig.2 Stratigraphic correlation profile of 3rd Member of Yingshan Formation in Gucheng area(see Fig.1 for section location)

2 硅质岩岩石学特征

研究区鹰三段硅质岩在岩心上呈中灰色,形态多样,见角砾状[图3(a)]、条带状[图3(b)]、团块状[图3(c)]及结核状[图3(d)]等,可见原始的沉积构造,如纹层[图3(a)]。微观上,硅质岩主要为残余结构硅质岩,包括残余纹层结构[图3(e),图3(f)]和残余颗粒结构[图3(g)—图3(l),图3(o),图3(p)],均由隐晶质石英组成,与交代残余的白云岩或灰岩共存[图3(e)—图3(h)]。在原始粒间孔或溶蚀孔洞中,硅质岩表现为充填晶粒状[图3(i)—图3(l)]、环带状[图3(m),图3(n)]或放射状[图3(o),图3(p)]特征。
图3 古城地区鹰三段硅质岩岩石学特征

(a)GC8井,2-5/7,硅质岩,上部为角砾状,下部为纹层状,岩心;(b) GC 9井,1-2/3,条带状硅质岩,岩心;(c) GC15井,6 355.6 m,团块状硅质岩,岩心;(d) GC15井,6 354.5 m,结核状硅质岩,岩心;(e)—(f) GC8井,2-5/7,残余纹层结构硅质岩,暗色纹层为交代残余白云石、方解石,铸体薄片,e(-),f(+);(g)—(h)GC15井,6 354.5 m,残余颗粒结构硅质岩,见交代残余砂屑灰岩,铸体薄片,g(-),h(+);(i)—(j) GC15井,6 354.5 m,残余颗粒结构硅质岩,颗粒部分为隐晶质石英,颗粒间为结晶状石英,铸体薄片,i(-),j(+); (k)— (l)GC15井,6 436 m,残余颗粒结构硅质岩,颗粒部分为隐晶质石英,颗粒间为结晶状石英,铸体薄片,k(-),l (+);(m)—(n)GC9井,1-2/3,硅质岩,基质为隐晶质石英,孔洞中石英呈充填环带状,铸体薄片,m(-),n(+); (o)—(p) GC15井,6 355.6 m,残余颗粒结构硅质岩,颗粒部分为隐晶质石英,颗粒间为放射状石英充填o(-),p(+)

Fig.3 Petrological characteristic of siliceous rocks in 3rd Member of Yingshan Formation in Gucheng area

3 地球化学分析

3.1 分析方法

本研究选送硅质岩样品共计5块,均为岩心样品,分别来自GC9井、GC8井和GC15井。所有样品在进行地球化学分析之前均磨制铸体薄片用于镜下观察。主微量元素分析在南京宏创地质勘查技术服务有限公司完成,检测方法为电感耦合等离子质谱(ICP-MS)分析法,分析仪器为Agilent 7700x等离子体质谱仪。硅、氧同位素分析在核工业北京地质研究院完成,分析方法分别为DZ/T 0184.22—1997《硅同位素组成的测定》和DZ/T 0184.17—1997《碳酸盐矿物或岩石中碳、氧同位素组成的磷酸法测定》,分析仪器为MAT-253气体同位素质谱计。

3.2 分析结果

分析结果见表1表2表3
表1 主量元素、硅氧同位素分析结果

Table 1 Results of major elements and isotopes

样品 编号 井号 岩性 含量/%

δ18O

/‰(V-SMOW)

δ30Si/‰ (V-NBS28)
SiO2 TiO2 Al2O3 Fe2O3 MnO MgO CaO Na2O K2O P2O5 LOI
GC9-1 古城9 硅质岩 76.15 0.03 0.63 1.30 0.003 3.60 8.14 0.04 0.12 0.01 9.60 19.8 2.3
GC15-1 古城15 硅质岩 73.15 0.02 0.27 1.20 0.005 0.17 14.13 0.15 0.03 0.01 10.98 21.9 2.9
GC15-2 古城15 硅质岩 66.79 0.01 0.23 1.00 0.005 0.18 17.59 0.03 0.03 0.01 13.84 21.8 2.7
GC15-3 古城15 硅质岩 91.12 0.01 0.22 0.57 0.002 0.73 3.51 0.03 0.02 0.01 3.46 19.8 2.2
GC8-1 古城8 硅质岩 69.72 0.03 0.78 1.45 0.008 0.32 15.13 0.01 0.24 0.01 11.81 20.7 /
表2 微量元素分析结果

Table 2 Results of trace element concentrations

样品编号 井号 岩性 含量/(10-6
Li Be Sc Ti V Cr Mn Co Ni Cu Zn Ga Rb Sr Y
GC9-1 古城9 硅质岩 4.78 0.10 0.29 130.63 5.83 6.30 49.09 0.86 75.47 5.33 1.19 0.77 2.76 47.32 0.82
GC15-1 古城15 硅质岩 3.33 0.04 0.16 45.67 2.13 3.97 37.99 0.40 2.62 2.21 0.21 0.39 0.65 39.23 0.36
GC15-2 古城15 硅质岩 5.69 0.08 0.27 67.26 2.39 6.98 65.77 0.64 3.43 4.14 1.00 0.63 1.16 63.79 0.63
GC15-3 古城15 硅质岩 4.39 0.06 0.22 57.27 5.31 5.10 31.05 0.37 1.92 3.16 0.14 0.56 0.62 24.74 0.43
GC8-1 古城8 硅质岩 10.44 0.20 0.72 172.91 5.91 8.97 81.36 1.94 41.88 10.53 1.20 1.36 5.77 64.96 1.05
样品编号 井号 岩性 含量/(10-6 Y/Ho Th/U La/Ho
Zr Nb Mo Cs Ba Hf Ta Pb Th U La Ho
GC9-1 古城9 硅质岩 3.93 1.04 9.95 0.13 84.67 0.11 0.09 22.16 0.50 1.93 0.90 0.03 28.00 0.26 0.81
GC15-1 古城15 硅质岩 1.47 0.71 3.01 0.05 63.52 0.04 0.02 20.83 0.29 1.54 0.53 0.01 27.80 0.19 1.07
GC15-2 古城15 硅质岩 3.96 0.99 8.31 0.10 98.72 0.09 0.08 19.06 0.58 6.21 1.02 0.02 30.04 0.09 1.29
GC15-3 古城15 硅质岩 3.75 0.44 3.11 0.05 31.62 0.09 0.02 5.12 0.31 1.82 0.81 0.02 26.72 0.17 1.34
GC8-1 古城8 硅质岩 5.43 1.48 20.92 0.24 101.84 0.14 0.05 28.42 1.01 7.70 1.62 0.04 26.59 0.13 1.08
表3 稀土元素分析结果

Table 3 Results of rare earth element contents

样品编号 井号 岩性 含量/(10-6
La Ce Pr Nd Sm Eu Gd Tb Dy Ho
GC9-1 古城9 硅质岩 0.899 1.735 0.193 0.745 0.158 0.031 0.141 0.023 0.139 0.029
GC15-1 古城15 硅质岩 0.529 1.002 0.105 0.401 0.083 0.021 0.070 0.010 0.063 0.013
GC15-2 古城15 硅质岩 1.024 1.938 0.205 0.757 0.140 0.035 0.134 0.017 0.101 0.021
GC15-3 古城15 硅质岩 0.815 1.594 0.173 0.652 0.116 0.028 0.104 0.013 0.078 0.016
GC8-1 古城8 硅质岩 1.620 3.185 0.359 1.319 0.258 0.062 0.215 0.034 0.190 0.039
样品编号 井号 岩性 含量/(10-6 LREE/HREE δEu δCe
Er Tm Yb Lu ΣREE ΣLREE ΣHREE
GC9-1 古城9 硅质岩 0.086 0.014 0.098 0.015 4.31 3.76 0.54 6.90 0.98 0.96
GC15-1 古城15 硅质岩 0.038 0.006 0.040 0.006 2.39 2.14 0.25 8.70 1.31 0.98
GC15-2 古城15 硅质岩 0.065 0.010 0.078 0.012 4.54 4.10 0.44 9.38 1.18 0.97
GC15-3 古城15 硅质岩 0.044 0.007 0.045 0.007 3.69 3.38 0.31 10.74 1.17 0.98
GC8-1 古城8 硅质岩 0.117 0.019 0.136 0.020 7.57 6.80 0.77 8.83 1.22 0.96
主量元素分析结果表明,古城地区鹰三段硅质岩样品的SiO2含量分布范围为66.79%~91.12%,平均为75.38%,低于纯硅质岩(91%~99.8%)[24]。其他成分中CaO含量最高,变化范围为3.51%~17.59%,平均为11.7%,其次为Fe2O3,含量变化范围为0.57%~1.45%,平均为1.1%。硅质岩样品的SiO2含量随烧失量的增大而降低,与其含有较多的碳酸盐岩矿物有关。总体来看,硅质岩主要由硅质与白云石或方解石组成,其含量总和为SiO2+CaO+MgO+LOI,其变化范围为96.98%~98.81%,平均为98.02%,其他元素的含量均较低。
稀土元素组成上,硅质岩稀土元素总量较低,变化范围为(2.39~7.57)×10-6,平均为4.50×10-6,在稀土元素PAAS标准化分配图上,硅质岩表现为近水平的分布特征。LREE/HREE较小,分布范围为6.9~10.74,平均为8.91。样品总体表现出Eu正异常,δEu值为0.98~1.31,平均为1.17。所有样品均表现出弱的Ce负异常,δCe值为0.96~0.98,平均为0.97。
Si、O同位素分析结果表明,硅质岩δ30Si值分布范围为2.2‰~2.9‰,平均为2.5‰,δ18O值分布范围为19.8‰~21.9‰,平均为20.8‰。

4 成因探讨

硅质岩的成因问题主要涉及SiO2的来源及其形成方式。SiO2的来源一般认为有生物、陆源和热液共3种[25]。硅质岩的形成方式概括起来包括生物或生物化学成因[26,27]、火山—生物成因[28,29,30]、热水直接沉积成因[31,32,33]、与上升流有关的(生物)成因[34]、以及交代成因[35]。利用主微量元素、硅氧同位素可对其成因进行判识。

4.1 主量元素

硅质岩中 Fe、Mn 的富集与热液的参与有关,Al、Ti的富集多与陆源物质的输入有关[36]。不同成因硅质岩的 Al/(Fe+Mn+Al)值不同,海相沉积物中Al/(Fe+Mn+Al)值大于0.4反映其生物成因,小于0.4则为热液成因[37],该值在0.01(纯热液成因)至0.6(纯生物成因)之间变化[36,38]
研究区硅质岩Al/(Fe+Mn+Al)值介于0.14~0.29之间,平均为0.21,均小于0.4,表明为热液成因。前人提出利用Al—Fe—Mn三角图判别硅质岩成因[38],目前这种方法已被广泛应用。将本文研究数据投到该三角图解(图4)中,可见数据全部落于图解富Fe端,表明硅质岩为热液成因。
图4 古城地区鹰三段硅质岩Al—Fe—Mn成因判别图解(底图据ADACHI等[38]

Fig.4 Al-Fe-Mn diagram of siliceous rocks of 3rd Member of Yingshan Formation in Gucheng area(after ADACHI et al.[38])

现代海洋典型热水沉积物Fe/Ti>20[39],(Fe+Mn)/Ti>20±5[39]。本文研究的Fe/Ti值分布范围为54.39~89.67,平均为68.16,(Fe+Mn)/Ti值分布范围为54.72~90.17,平均为68.48,均与热水沉积物的分布范围相吻合,揭示了硅质岩为热液成因。

4.2 微量元素

钍/铀(Th/U)值反映了硅质岩形成时下地壳或上地幔的深部物源加入程度[40,41]。当硅质岩为海相沉积时,Th/U值较高;当硅质流体来自深部地壳或上地幔时,Th/U值非常低[40,41]。Y/Ho值可以指示岩石中元素的物质来源。正常海相沉积硅质岩Y/Ho值小于28,火成岩和碎屑岩的平均Y/Ho值约为28左右[42],陈永权等[14]运用Th/U—Y/Ho关系来区分硅质岩成因:高Th/U值、低Y/Ho值为海水沉积特征;高Y/Ho值、低Th/U值为深部热液特征。
研究区硅质岩Y/Ho—Th/U关系(图5)显示,所有样品均落入“交代区”。其Y/Ho值为26.59~30.04,平均值为27.83,与球粒状陨石Y/Ho值(约为28)相近;Th/U值为0.09~0.26,平均值为0.17。二者均揭示了深部热液的加入。
图5 古城地区鹰三段硅质岩Th/U—Y/Ho关系(底图据陈永权等[14]

Fig.5 Th/U-Y/Ho relationship diagram of siliceous rocks of 3rd Member of Yingshan Formation in Gucheng area(after CHEN et al.[14]

La/Ho值是衡量热水来源和运移的指标[43]。陈红汉等[17]利用La/Ho—Y/Ho关系来判定硅质流体的来源:较高的Y/Ho值为海水来源和同生卤水来源的沉积特征;较低的Y/Ho值和La/Ho值为富SiO2上升热液的沉积特征;2种流体的混合热流体形成了硅质岩,随着硅化程度增加,La/Ho值急剧下降、Y/Ho值略有下降。将本研究数据点投到图版上(图6),可以看出,数据点La/Ho值极低(0.81~1.34,平均值为1.12),反映了研究区硅质岩硅化程度高,硅化流体具有混合热流体的特征。
图6 古城地区鹰三段硅质岩La/Ho—Y/Ho关系(底图据陈红汉等[17])

Fig.6 La/Ho-Y/Ho relationship diagram of siliceous rocks of 3rd Member of Yingshan Formation in Gucheng area(after CHEN et al.[17])

4.3 稀土元素

稀土元素对硅质岩成因和形成环境具有很好的指示意义[44,45,46]。硅质岩的沉积环境不同,其稀土元素总量ΣREE值具有较大的差异,总体上,硅质岩的ΣREE值在受陆源影响的环境中含量较高,而热液成因的硅质岩ΣREE含量往往偏低。本研究中,硅质岩稀土元素含量低,ΣREE值为(2.39~7.57)×10-6,平均为4.5×10-6,与热水沉积的硅质岩(ΣREE<200×10-6[47])特征吻合。
与正常海水沉积物相比,海相热水沉积物PAAS标准化曲线呈现近水平或左倾的分配特征,Ce有明显负异常,LREE/HREE值较小[48]。本研究稀土元素PAAS标准化曲线表现为近水平的分布特征(图7)。所有样品均表现出弱的Ce负异常,且LREE /HREE值较小(平均为8.91),均反映了热水沉积的特征。
图7 古城地区鹰三段硅质岩稀土元素配分图

Fig.7 REE distribution of siliceous rocks of 3rd Member of Yingshan Formation in Gucheng area

Eu异常是反映热液沉积的重要标志。正常海水沉积和生物成因的硅质岩无明显的Eu正异常,还原的酸性热液流体常以显著的Eu正异常为标志,δ Eu越大反映硅质岩与热液关系越密切[49]。研究区5个样品中仅有一个样品Eu无明显异常,为0.98,其余4个样品均表现出了明显的正异常,δEu值为1.17~1.31,平均为1.22,表现出了热液成因的特征。

4.4 硅、氧同位素

硅同位素数值的变化是由SiO2沉淀过程中硅同位素动力学分馏引起的,SiO2沉淀速度越慢,其动力分馏越大,δ30Si值就越高。当环境温度越高时,SiO2结晶越缓慢,其同位素动力分馏较大,导致δ30Si值高[50],另外,硅化岩的硅同位素值与水/岩值有关,水/岩值越高,硅化过程中选择性越好,导致δ30Si值越高。因此可用δ30Si判别硅质岩成因及硅质来源。变质岩和火成岩δ30Si值在-1‰~0.5‰之间,生物成因硅质岩的δ30Si值为-1.1‰~1.7‰[51],交代成因硅质岩δ30Si 值为1.4‰~3.8‰[52],热液石英δ30Si值为-2.1‰~0‰[53]
不同来源的石英具有不同的O同位素特征。火成岩中石英δ18O值一般为8‰~12‰;变质石英δ18O值一般为11‰~17‰;热泉华石英δ18O值一般为12‰~23‰,成岩石英δ18O值一般分布在13‰~30‰之间[54]
根据以上δ30Si与δ18O成因判识关系,作出δ30Si—δ18O关系图版(图8),将本研究数据投到该图版上,可以更加直观地判识硅质岩的成因。研究区硅质岩δ30Si值分布范围为2.2‰~2.9‰,平均为2.5‰,与图版上交代成因硅质岩Si同位素特征一致,表明硅质岩为交代成因,这与薄片上观察到的硅质交代现象相吻合;δ18O值分布范围为19.8‰~21.9‰,平均为20.8‰,该值同时对应热泉华和成岩石英O同位素分布范围,可能指示了成岩后受到来自深部的高SiO2浓度的热液交代成因。
图8 古城地区鹰三段硅质岩硅氧同位素组成关系

Fig.8 δ18O30Si relationship diagram of siliceous rocks of 3rd Member of Yingshan Formation in Gucheng area

综合硅质岩岩石学特征及主微量元素、硅氧同位素特征可以得出,研究区鹰三段硅质岩为热液交代成因,即由后期硅质热液流体对先驱碳酸盐岩沉积物的交代而形成。

4.5 硅质岩对储层的意义

研究区早加里东期发育断穿基底的NE向断裂,为热液流体提供了运移通道。二叠纪末期,塔里木盆地发生大规模的火山活动,为碳酸盐岩的硅化提供了热液和硅质来源。硅质热液沿NE向断裂和其伴生裂缝广泛进入鹰三段碳酸盐岩沉积物中,与围岩发生水岩反应,部分围岩被溶蚀改造形成优质储层,同时硅质岩交代原岩且在孔洞缝中沉淀破坏储层[20,21]。可见热液硅化作用对碳酸盐岩储层的发育具有双重影响,硅质岩的沉淀破坏储层,但指示了优质储层的分布情况。从图2中可以看出,在硅质岩极不发育的地层中(如GC8井、GC14井鹰三段上段),储层不发育,在硅质岩极发育的层段(如GC12井中段、GC13井底部),储层也不发育;根据徐兆辉等[55]的研究,在平面上,硅质岩与储层也具有一定的伴生关系,硅质岩过厚和过薄的地区,储层均不发育,而在硅质岩由厚转薄的地区,储层厚度有增大的趋势。总体来看,优质储层在硅质岩普遍发育的背景下,与硅质岩分布呈近似相反的关系,主要分布在硅质岩相对不发育的层段。
究其原因,硅质岩不发育说明地层原始物性差,围岩致密,硅质热液流体难以进入地层对其进行改造。硅质岩极发育说明地层原始孔隙度好,硅质热液流体易进入地层对其进行溶蚀改造,但是由于硅质大量沉淀,封堵孔隙,破坏了储层。硅质岩相对不发育说明地层原始物性较好,有利于硅质热液流体对其进行溶蚀改造提升储层物性,同时又有一定的硅质沉淀,但是沉淀的硅质岩量少,不会大规模封堵溶蚀孔洞,对储层破坏较弱,而其存在恰恰指示了储层的发育层段与分布范围。前人研究认为[14],可通过评价不同区域硅化程度来评价其储层的发育状况,但是如何厘定优质储层的硅化程度仍需要进一步研究。

5 结论

(1)研究区鹰三段硅质岩主要为残余结构硅质岩,地球化学分析结果显示硅质岩在Al—Fe—Mn三角图中位于热液沉积区域,且Al/(Fe+Mn+Al)值、(Fe+Mn)/Ti值、Y/Ho—Th/U关系、ΣREE值、LREE/HREE值、δCe值及δEu值均与热液成因的硅质岩地球化学指标相吻合;同时Si同位素、O同位素以及其相关关系与交代成因的硅质岩和成岩石英的地球化学指标相吻合。以上特征表明,研究区鹰三段硅质岩为成岩后的热液交代成因。
(2)研究区早加里东期发育的断穿基底的NE向断裂为热液提供了运移通道,硅质热液流体沿断裂进入鹰三段地层与碳酸盐岩发生反应,硅质流体交代碳酸盐岩沉积物并沉淀形成硅质岩。
(3)硅质岩的沉淀破坏储层,但适量的硅质岩沉淀指示了储层的分布。
1
曾允孚,夏文杰.沉积岩石学[M].北京:地质出版社,1986,1-190.

ZENG Y F, XIA W J. Sedimentary Petrology[M].Beijing: Geological Publishing House,1986:1-190.

2
杨海生,周永章,杨志军,等.热水沉积硅质岩地球化学特征及意义:以华南地区为例[J].中山大学学报:自然科学版,2003,42(6):111-115.

YANG H S, ZHOU Y Z, YANG Z J, et al. Geochemical characteristics and significance of hydrothermal cherts:A case study of South China[J]. Acta Scientiarum Naturalium Universitatis Sunyatseni, 2003,42(6):111-115.

3
杨志军,周永章,张澄博,等.硅质岩组构信息研究及其意义[J].矿物岩石地球化学通报,2003,22(3):255-258.

YANG Z J, ZHOU Y Z, ZHANG C B, et al. The research of fabric information in the siliceous rock and its significance[J]. Bulletin of Mineralogy, Petrology and Geochemistry,2003,22(3):255-258.

4
冯胜斌,周洪瑞,燕长海,等.东秦岭二郎坪群硅质岩地球化学特征及其沉积环境意义[J].现代地质,2007,21(4):675-682.

FENG S B, ZHOU H R, YAN C H, et al. The geochemical characteristics of cherts of Erlangping Group in east Qinling and their sedimentary environment importance[J].Geoscience,2007,21(4):675-682.

5
冯彩霞,刘家军.硅质岩的研究现状及其成矿意义[J].世界地质,2001,20(2):119-123.

FENG C X, LIU J J. The investive actuslity and mineralization significance of cherts[J]. World Geology, 2001,20(2):119-123.

6
崔春龙.硅质岩研究中的若干问题[J].矿物岩石,2001,21(3):100-104.

CUI C L. Some problems in the study of the siliceous rock[J]. Journal of Mineralogy and Petrology, 2001, 21(3): 100-104.

7
康玉柱.塔里木盆地古生代海相碳酸盐岩储集岩特征[J].石油实验地质,2007,29(3):217-223.

KANG Y Z. Reservoir rock characteristics of Paleozoic marine facies carbonate rock in the Tarim Basin[J]. Petroleum Geology & Experiment, 2007,29(3):217-223.

8
赵宗举,王招明,吴兴宁, 等.塔里木盆地塔中地区奥陶系储层成因类型及分布预测[J].石油实验地质,2007,29(1):40-46.

ZHAO Z J, WANG Z M, WU X N, et al. Genetic types and distribution forecast of available carbonate reservoirs in Ordovician in the central area of Tarim Basin[J]. Petroleum Geology & Experiment, 2007,29(1):40-46.

9
ZHU G Y, MILKOV A, ZHANG Z Y, et al. Formation and preservation of a large, super-deep ancient carbonate reservoir, the Halahatang Oilfield in the Tarim Basin, China[J]. AAPG Bulletin, 2019,103: 1703-1743.

10
ZHU G Y, ZHANG Y, ZHOU X X, et al. TSR, deep oil cracking and exploration potential in the Hetianhe Gas Field, Tarim Basin, China[J]. Fuel, 2019, 236:1078-1092.

11
ZHU G Y, ZHANG Z Y, MILKOV A, et al. Diamondoids as tracers of late gas charge in oil reservoirs: Example from the Tazhong area, Tarim Basin, China[J]. Fuel, 2019, 253:998-1017.

12
杨瑞东,张传林,罗新荣,等.新疆库鲁克塔格地区早寒武世硅质岩地球化学特征及其意义[J].地质学报, 2006,80(4):598 -605.

YANG R D, ZHANG C L, LUO X R, et al. Geochemical characteristics of Early Cambrian cherts in Quruqtagh, Xinjiang, West China[J]. Acta Geologica Sinica, 2006,80(4):598 -605.

13
于炳松,陈建强,李兴武,等.塔里木盆地肖尔布拉克剖面下寒武统底部硅质岩微量元素和稀土元素地球化学及其沉积背景[J].沉积学报, 2004,22(1):59-66.

YU B S, CHEN J Q, LI X W, et al. Rare earth and trace element patterns in bedded-cherts from the bottom of the Lower Cambrian in the northern Tarim Basin, Northwest China: Implication for depositional environments[J]. Acta Sedimentologica Sinica, 2004,22(1):59-66.

14
陈永权,蒋少涌,周新源,等.塔里木盆地寒武系层状硅质岩与硅化岩的元素、δ30Si、δ18O地球化学研究[J].地球化学, 2010,39(2):159-170.

CHEN Y Q, JIANG S Y, ZHOU X Y, et a1. δ30Si,δ18O and elements geochemistry on the bedded siliceous rocks and cherts in dolostones from Cambrian strata, Tarim Basin[J]. Geochimica, 2010,39(2):159-170.

15
杨宗玉,罗平,刘波,等.塔里木盆地阿克苏地区下寒武统玉尔吐斯组硅质岩分类及成因[J].地学前缘,2017,24(5):245-264.

YANG Z Y, LUO P, LIU B, et al. Analysis of petrological characteristics and origin of siliceous rocks during the earliest Cambrian Yurtus Formation in the Aksu area of the Tarim Basin in northwest China[J]. Earth Science Frontiers,2017,24(5):245-264.

16
杨宗玉,罗平,刘波,等.塔里木盆地阿克苏地区下寒武统玉尔吐斯组两套黑色岩系的差异及成因[J].岩石学报, 2017, 33(6) : 1893-1918.

YANG Z Y, LUO P, LIU B, et al. The difference and sedimentation of two black rock series from Yurtus Formation during the earliest Cambrian in the Aksu area of Tarim Basin, Northwest China[J]. Acta Petrologica Sinica, 2017, 33(6) : 1893-1918.

17
陈红汉,鲁子野,曹自成,等.塔里木盆地塔中地区北坡奥陶系热液蚀变作用[J].石油学报,2015,37(1):43-63.

CHEN H H, LU Z Y, CAO Z C, et al. Hydrothermal alteration of Ordovician reservoir in northeastern slope of Tazhong Uplift, Tarim Basin[J]. Acta Petrolei Sinica, 2015, 37(1): 43-63.

18
李映涛,叶宁,袁晓宇,等.塔里木盆地顺南4 井中硅化热液的地质与地球化学特征[J].石油与天然气地质,2015,36(6):934-944.

LI Y T, YE N, YUAN X Y, et al. Geological and geochemical characteristics of silicified hydrothermal fluids in Well Shunnan 4, Tarim Basin[J]. Oil & Gas Geology, 2015,36(6):934-944.

19
刘永立,尤东华,高利君,等.塔河油田塔深6井蓬莱坝组硅质岩成因及其地质意义[J].石油与天然气地质,2020,41(1):83-91.

LIU Y L, YOU D H, GAO L J, et al. Genesis and geological significance of siliceous rock in Penglaiba Formation in Well Tashen 6, Tahe Oilfield[J]. Oil & Gas Geology,2020,41(1):83-91.

20
吴斌,何登发,孙方源.塔里木盆地古城低凸起下古生界的断裂特征及成因机制[J].天然气地球科学,2015,26(5):871-879.

WU B, HE D F, SUN F Y. Fault characteristic and genetic mechanism of the Lower Paleozoic in Gucheng lower uplift, Tarim Basin[J]. Natural Gas Geoscience, 2015, 26(5): 871-879.

21
冯子辉,李强,张亚金,等.古城低凸起奥陶系油气成藏条件与分布规律[J].大庆石油地质与开发,2019,38(5):87-93.

FENG Z H, LI Q, ZHANG Y J, et al. Accumulating conditions and distribution laws of Ordovician hydrocarbon in Gucheng low uplift[J]. Petroleum Geology & Oilfield Development in Daqing,2019,38(5):87-93.

22
李昂,鞠林波,张丽艳.塔里木盆地古城低凸起古—中生界构造演化特征与油气成藏关系[J].吉林大学学报:地球科学版,2018,48(2):545-555.

LI A, JU L B, ZHANG L Y. Relationship between hydrocarbon accumulation and Paleo-Mesozoic tectonic evolution characteristics of Gucheng lower uplift in Tarim Basin[J].Journal of Jilin University:Earth Science Edition,2018,48(2):545-555.

23
周波,曹颖辉,齐井顺,等.塔里木盆地古城地区下奥陶统储层发育机制[J].天然气地球科学,2018,29(6):773-783.

ZHOU B, CAO Y H, QI J S, et al. The development mechanism of Lower Ordovician reservoir in the Gucheng area, Tarim Basin, China[J].Natural Gas Geoscience,2018,29(6):773-783.

24
MURRAY R W, BUCHHOLTZ TEN BRINGK M R, GERLACH D C, et al. Rare earth, major, and trace element composition of Monterey and DSDP chert and associated host sediment: Assessing the influence of chemical fractionation during diagenesis[J].Geochimica et Cosmochimica Acta, 1992. 56(7) : 2657-2671.

25
MALIVA R G, KNOLL A H, SIMONSON B M. Secular change in the Precambrian silica cycle: Insights from chert petrology[J].Geological Society of America Bulletin, 2005, 117(7): 835.

26
孔庆玉,龚与觑.安徽巢县下二叠统硅质岩的成因[J].石油与天然气地质,1986,7(2):171-174.

KONG Q Y, GONG Y Q. Origin of the Lower Permain siliceous rocks in Chaoxian County, Anhui[J].Oil & Gas Geology,1986,7 (2) : 171-174.

27
YAO L B, GAO Z M, YANG Z S, et al. Origin of seleniferous cherts in Yutangba Sedeposit, Southwest Enshi, Hubei Province[J].Science in China:Series D,2002,45(8):741-754.

28
田云涛,冯庆来,李琴.桂西南柳桥地区上二叠统大隆组层状硅质岩成因和沉积环境[J]. 沉积学报,2007,25 (5) : 671-677.

TIAN Y T, FENG Q L, LI Q. The petrogenesis and sedimentary enviroment of the bedded cherts from Upper Permian Dalong Formation, southwest Guangxi[J]. Acta Sedimentologica Sinica,2007,25 (5) :671-677.

29
林良彪,陈洪德,朱利东.重庆石柱吴家坪组硅质岩地球化学特征[J].矿物岩石,2010,30(3): 52-58.

LIN L B, CHEN H D, ZHU L D. Geochemical characteristics of silicalites from Wujiaping Formation in Shizhu, Chongqing[J]. Journal of Mineralogy and Petrology,2010,30 (3) : 52-58.

30
CHEN H, XIE X N, HU C Y, et al. Geochemical characteristics of Late Permian sediments in the Dalong Formation of the Shangsi section, northwest Sichuan Basin in South China: Implications for organic carbon-rich siliceous rocks formation[J]. Journal of Geochemical Exploration,2012,11: 35-53.

31
夏邦栋,钟立荣,方中,等.下扬子区早二叠世孤峰组层状硅质岩成因[J].地质学报,1995,69(2): 125-137.

XIA B D, ZHONG L R, FANG Z, et al. The origin of cherts of the Early Permian Gufeng Formation in the Lower Yangtze area, eastern China[J]. Acta Geologica Sinca,1995,69 (2) : 125-137.

32
冯彩霞,刘家军,刘燊,等.渔塘坝富硒硅质岩成因及沉积环境探讨硅、氧、碳和硫同位素证据[J].岩石学报,2009,25(5):1253-1259.

FENG C X, LIU J J, LIU S, et al. Petrogenetics and sedimentary environment of the chert from Yutangba, western Hubei Province: Evidence from silicon, oxygen, carbon and sulfur isotopic compositions[J]. Acta Petrologica Sinica, 2009, 25(5):1253-1259.

33
付伟,周永章,杨志军,等.湘中南二叠系孤峰组硅质岩的成因属性及其地球动力学指示意义[J].矿物岩石地球化学通报,2004,23 (1) : 292-300.

FU W, ZHOU Y Z, YANG Z J, et al. Petrogenesis of the bedded chert from the Gufeng Formation and its implications to Early Permian geodynamic background in South China[J]. Bulletin of Mineralogy, Petrology and Geochemistry,2004,23(1) : 292-300.

34
杨玉卿,冯增昭.华南下二叠纪层状硅岩的形成及意义[J].岩石学报,1997,13 (1) : 111-120.

YANG Y Q, FENG Z Z. Formation and significance of the bedded siliceous rocks of the Lower Permian in south China[J]. Acta Petrologica Sinica,1997,13 (1) :111-120.

35
曹秋香,郭福生,刘向铜,等.浙江江山丁家山组层状硅质岩阴极发光特征及成因探讨[J].沉积学报,2008,26 (5) : 797-803.

CAO Q X, GUO F S, LIU X T, et al. Origin of bedded chert from Dingjiashan Formation in Jiangshan region, Zhejiang Province: Evidence from cathodeluminescence[J]. Acta Sedimentologica Sinica,2008,26 (5) : 797-803.

36
YAMAMOTO K. Geochemical characteristics and depositional environments of cherts and associated rocks in the Franciscan and Shimanto terranes[J]. Sedimentary Geology,1987,52(1/2):65-108.

37
BOSTROM K, KRAAEMER T, GARTNER S. Provoenance and accumulation rates of opaline silica, Al, Ti, Fe, Mn, Cu, Ni and Co in Pacific pelagic sediments[J]. Chemical Geology,1973,11: 132-148.

38
ADACHI M, YAMAMOTO K, SUGISAKI R. Hydrothermal chert and associated siliceous rocks from the northern Pacific, their geological significance as indication of ocean ridge activity[J]. Sedimentary Geology,1986,47: 125-148.

39
RONA P A. Hydrothermal mineralization at oceanic ridges[J]. Canadian Mineralogist, 1988, 26: 431-465.

40
MCLENNAN S M, TAYLOR S R. Th and U in sedimentary rocks: Crustal evolution and sedimentary recycling[J].Nature,1980,285(5767):625-624.

41
MCLENNAN S M, TAYLOR S R. Sedimentary rocks and crustal evolution: Tectonic setting and secular trends[J].Journal of Geology,1991,99(1):1-21.

42
BAU M. Controls on the fractionation of isovalent trace elements in magmatic and aqueous systems: Evidence from Y/Ho, Zr/Hf, and lanthanide tetrad effect[J].Contributions to Mineralogy and Petrology,1996,123(3):323-333.

43
BAU M, DULSKI P. Comparative study of Yttrium and rare earth element behaviors in fluorine-rich hydrothermal fluids[J]. Contributions to Mineralogy and Petrology,1995,119(2/3):213-223.

44
王卓卓,陈代钊,汪建国.广西南宁地区泥盆系硅质岩地球化学特征及沉积环境[J].沉积学报,2007,25(2):239-246.

WANG Z Z, CHEN D Z, WANG J G. Element geochemistry and depositional setting of the chert in Devonian, Nanning area, Guangxi[J]. Acta Sedimentologica Sinica, 2007,25(2):239-246.

45
戢兴忠,李楠,张闯,等.勉略构造带硅质岩元素地球化学特征及其形成环境[J].岩石学报,2014,30(9):2619-2630.

JI X Z, LI N, ZHANG C, et al. Elemental geochemistry characteristics and forming environment of cherts in the Mianlue tectonic zone[J].Acta Petrologica Sinica,2014,30(9):2619-2630.

46
刘浩,徐大良,牛志军,等.湖北竹山杨家堡组硅质岩成因及沉积环境分析[J].沉积学报,2015,33(6):1087-1096.

LIU H, XU D L, NIU Z J, et al. Petrogenesis and sedimentary environment of siliceous rocks of Yangjiabao Formation in Zhushan area, northwestern Hubei[J]. Acta Sedimentologica Sinica, 2015,33(6):1087-1096.

47
MURRAY R W, BUCHHOLTZ TEN BRINK M R, GERLACH D C, et al. Rare earth, major, and trace elements in chert from the Franciscan Complex and Monterey Group, California: Assessing REE sources to fine-grained marine sediments[J]. Geochimica et Cosmochimica Acta, 1991,55(7): 1875-1895.

48
李胜荣,高振敏.湘黔地区牛蹄塘组黑色岩系稀土特征:兼论海相热水沉积稀土模式[J]. 矿物学报,1995,15(2) :225 -229.

LI S R, GAO Z M. REE characteristics of black rock series of the Lower Lambrian Niutitang Formation in Hunan-Guizhou Provinces, China, with a discussion on the REE patterns in marine hydrothermal sediments[J]. Acta Mineralogica Sinica, 1995, 15(2) :225-229.

49
FRIMMEL H E. Trace element distribution in Neoproterozoic carbonates as palaeoenvironmental indicator[J]. Chemical Geology,2009,258(3/4):338-353.

50
邓碧平,刘显凡,朱建军,等.壳幔混染成矿机制的稀有气体同位素及硅同位素证据: 以滇西富碱斑岩型多金属矿区为例[J].吉林大学学报:地球科学版, 201444(6): 1856-1866.

DENG B P, LIU X F, ZHU J J, et al. Noble gas isotope and silicon isotope evidences of crust-mantle mixing ore-formation mechanism: Examplified by the Alkali-Rich porphyry polymetallic deposits in Western Yunnan, China[J]. Journal of Jilin University: Earth Science Edition, 2014, 44(6): 1856-1868.

51
马文辛,刘树根,黄文明,等.渝东地区震旦系灯影组硅质岩结构特征与成因机理[J].地质学报,2014,88(2):239-253.

MA W X, LIU S G, HUANG W M, et a1. Fabric characteristics and formation mechanism of chert in Sinian Dengying Formation,eastern Chongqing[J].Acta Geologica Sinica, 2014,88(2):239-253.

52
吕志成,刘丛强,刘家军,等.北大巴山下寒武统毒重石矿床赋矿硅质岩地球化学研究[J].地质学报,2004,78(3):390-406.

LV Z C, LIU C Q, LIU J J, et al. Geochemical study on the Lower Cambrian witherite-bearing cherts in the northern Daba Mountains[J]. Acta Geologica Sinica, 2004,78(3):390-406.

53
丁悌平,蒋少涌,万德芳.硅同位素地球化学[M].北京:地质出版社,1994:17-88.

DING T P, JIANG S Y, WAN D F. Silicon Isotope Chemistry[M]. Beijing: Geological Publishing House, 1994:17-88.

54
何俊国,周永章,杨志军,等.藏南硅质岩地质地球化学特征及其成矿效应[J].矿产与地质, 2004,18(5):405-409.

HE J G, ZHOU Y Z, YANG Z J, et al. Geological and geochemical characteristics and related mineralization of cherts in South Tibet[J]. Mineral Resources and Geology, 2004,18(5):405-409.

55
徐兆辉,王露,曹颖辉,等. 塔里木盆地古城地区鹰三段硅质含量分布预测与主控因素分析[J].天然气地球科学202031(5):612-622.

XU Z H, WANG L, CAO Y H, et al. Quantitative prediction of siliceous content and its controlling factor in the third member of Yingshan Formation in Gucheng area,Tarim Basin[J]. Natural Gas Geoscience, 2020, 31(5): 612-622.

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