Author Affiliations
1Hanshan Normal University, Chaozhou 521014, China2Shenhua Geological Exploration Ltd., Beijing 102211, China3China University of Petroleum (Beijing), Beijing 102249, Chinashow less
Fig. 1. Schematic diagram of the interaction process between neutrons and strata
Fig. 2. Structural diagram of the GEM element capture spectrum logging tool
Fig. 3. Core analysis and mineral components calibration chart of GEM in the Niutitang Formation of the BY2 Well
Fig. 4. Distribution of clay minerals in the Niutitang Formation of the BY2 Well (3 102.39~3 170.5 m, color online)
Fig. 5. Logging curves of GEM element capture of the Niutitang Formation in the BY2 Well
Fig. 6. Identification of major elements in the tectonic background of the source area(a) Fe+Mg—Ti diagram, (b) Fe+Mg—Al/Si diagram
Fig. 7. Source characteristics of the Niutitang Formation (a) Al—Ti diagram, (b) Fe/(Fe+Mg)—Si diagram
Fig. 8. Geochemical index profile of the Niutitang Formation
Fig. 9. Photographs of the Niutitang Formation core in the BY2 Well (a) Carbonaceous mudstone in the lower part of the Niutitang Formation, (b) Siliceous rock at the bottom of Niutitang Formation, (c) Phosphorus nodules develop at the bottom layer of the Niutitang Formation, (d) The upper part of the Niutitang Formation is composed of muddy limestone mixed with black mudstone
| 元素 Element | 矿物 Mineral |
|---|
| 硅 Si | 石英Quartz | | 钙 Ca | 方解石、白云石Calcite, dolomite | | 硫 S | 石膏、黄铁矿Gypsum, pyrite | | 铁 Fe | 黄铁矿、菱铁矿Pyrite, siderite | | 铝 Al | 蒙脱石、伊利石Montmorillonite, illite | | 钛 Ti | 黏土矿物Clay minerals | | 钆 Gd | 黏土矿物、重矿物 Clay minerals, heavy minerals |
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Table 1. Relationship between major elements and minerals
| 测量指标 Measurement range |
|---|
| 最大耐压Max Pressure / MPa | 137 | 最大耐温 Max temperature / ℃ | 177 | | 硬件参数Hardware parameters | | 放射源类型Type of radiation source | 55.5×1010 Bq镅铍中子源55.5×1010 Bq americium beryllium neutron source | | 晶体类型Crystal type | BGO闪烁计数器 BGO scintillation counter | | 采样间隔Sampling interval / point∙m-1 | 10个 Ten points | | 测量参数Measurement parameters | | 伽马测量能级范围Gamma measurement energy level range / MeV | 0.6~9.5 | 纵向分辨率 Vertical resolution / mm | 457.2 | 探测范围 Detection range / mm | 152.4 | 初始测量曲线 Initial measurement curve | H、C、O、Mg、Al、Si、S、Cl、K、Ca、Ti、Mn、Fe和Gd等元素的产额 H, C, O, Mg, Al, Si, S, Cl, K, Ca, Ti, Mn, Fe, Gd element yield | 解谱处理方法 Spectral analysis processing method | 通过氧化物闭合模型计算的Mg、Al、Si、S、K、Ca、Ti、Mn、Fe和Gd等元素的质量百分比 Mass percentages of elements such as Mg, Al, Si, S, K, Ca, Ti, Mn, Fe, and Gd calculated using the oxide closure model |
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Table 2. Technical parameters of the GEM element capture spectrum logging tool
| 系System | 统Series | 组Group | 代号Code | 底深Bottom depth / m | 厚度Thickness / m | 岩性描述 Lithology description | 沉积相Sedimentary facies |
|---|
寒武系 Cambrian | 下统 Lower series | 清虚洞组 Qingxudong | Є 1q | 2 173 | 162 | 深灰色灰岩、泥质灰岩、云质灰岩 Dark gray limestone, muddy limestone, and cloudy limestone | 台地陆棚 Platform shelf | 石牌组 Shipai | Є 1s | 3 071 | 898 | 深灰、灰黑色泥岩夹深灰色砂质泥岩、含灰泥岩，底部灰黑色泥岩、含碳泥岩 Dark gray, grayish black mudstone mixed with dark gray sandy mudstone, containing limestone, bottom grayish black mudstone, containing carbon mudstone | 浅海陆棚 Shallow sea shelf | 牛蹄塘组 Niutitang | Є 1n | 3 114 | 43 | 深灰色泥质灰岩、灰质泥岩Dark gray argillaceous limestone, calcareous mudstone | 滞流盆地缓坡 Slow slope of stagnant basin | | Є 1n | 3 171.5 | 57.5 | 灰黑色碳质泥岩，底部含磷结核Grey black carbonaceous mudstone with phosphorus nodules at the bottom | 滞流盆地 Stagnant basin | 震旦系 Sinian | 上统 Upper series | 留茶坡组 Liuchape | Z2l | 3 239 | 67.5 | 灰黑、深灰色硅质岩夹少量炭质泥岩 Grey black, dark gray siliceous rock with a small amount of carbonaceous mudstone | 滞流盆地 Stagnant basin | 陡山坨组（未穿） Doushantue (TD) | Z2d | 3 275.0 | 36 | 灰色灰质云岩 Gray gray limestone | 滞流盆地 Stagnant basin |
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Table 3. Comparison of GEM logging stratification in the BY2 Well
| 地层名称Formation | 井深Depth / m | 铝 Al | 钙 Ca | 铁 Fe | 钾 K | 镁 Mg | 锰 Mn | 硅 Si | 硫 S | 钛 Ti | 岩性 Lithology | 沉积相Sedimentary facies |
|---|
| 组Group | 段Section |
|---|
| 牛蹄塘组Niutitang Є1n | 上段 Upper | 3 071~3 114 | 0.020 1 | 0.158 5 | 0.026 9 | 0.015 1 | 0.021 1 | 0.000 2 | 0.189 7 | 0.016 3 | 0.003 7 | 灰色泥质灰岩Gray argillaceous limestone | 滞流盆地缓坡 Slow slope of stagnant basin | 下段 Lower | 3 114~3 171.5 | 0.041 5 | 0.027 2 | 0.032 1 | 0.018 3 | 0.002 7 | 0.000 2 | 0.344 1 | 0.017 8 | 0.002 4 | 黑色泥页岩 Black shale | 滞流盆地 Stagnant basin |
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Table 4. Average layered distribution of GEM element weight ratios in the BY2 Well (decimal format)
判别指标 Identification index | 沉积环境指标Sedimentary environmental index | 牛蹄塘组Niutitang group |
|---|
低值 Low value | 中等 Middle value | 高值 High value | 上段 Upper section | 下段 Lower section | 平均 Average |
|---|
物源分析Provenance analysis | ω(Al)/ ω(Al+Fe+Mn) | 0.10~0.40 大洋中脊沉积物 Midocean ridge sediments | 0.40~0.70远洋盆地 Ocean basin | 0.50~0.9大陆边缘 Continental margin | 0.43 | 0.56 | 0.50 | | 沉积情况Sedimentation situation | ω(Fe/Ti) | <20 正常沉积 Normal sedimentation | | >20 热水参与 Hot water participation | 7.27 | 13.38 | 10.33 | | ICV | <1 再循环沉积 Recirculating deposition | | >1 首次沉积 First sedimentation | 11.22 | 2.16 | 6.69 |
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Table 5. Sedimentary environment identification indicators
| 澳大利亚Australia PAAS | 中国 China | 牛蹄塘组 Niutitang group |
|---|
鄂尔多斯盆地 Ordos Basin | 珠江 The Pearl River | 黄河 Yellow River | 长江 Yangtze River | 上段Upper section | 下段Lower section |
|---|
| Al/Ti | 14 | 18.75 | 15.59 | 15.6 | 16.8 | 5.43 | 17.2 | 数据来源 Data sources | 太古宙页岩 Archaean shale | 神东矿区延安组煤层岩心 Core of Yanan Formation coal seam in Shendong mining area | 南海北部表层 Surface layer in the northern South China Sea | 黄海岩心 Yellow Sea core | 东海岩心 Donghai Sea core | 元素测井 GEM | 元素测井 GEM |
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Table 6. Al/Ti ratio of shale in the Niutitang Formation
