GABATLAS - Birkhead-Walloon Aquitard - Thickness and Extent

## **Abstract** \n\nThis dataset and its metadata statement were supplied to the Bioregional Assessment Programme by a third party and are presented here as originally supplied.\n\nThe Birkhead-Walloon Aquitard - Thickness and Extent data sets, are part of a set that represents the hydrostratigraphic units of the Great Artesian Basin, which include five major aquifers, four intervening aquitards, and the Cenozoic cover to the GAB.\n\n\n\nThere are five layers in the Birkhead-Walloon Aquitard map data.\n\n\n\nA: Formation Extent\n\nB: Outcrop extent\n\nC: Isopach Raster\n\nD: Isopach Contours\n\nE: Data Point Locations\n\n\n\nThe datasets have been derived from the lithostratigraphic intercepts in drillhole data from petroleum exploration wells, water bores, and stratigraphic wells. Seismic correlation and assessment of hydrogeological character based on electrofacies have not been used. The working datasets for this study has been derived primarily from the following databases:\n\n\n\n1.\tPEPS-SA (Petroleum Exploration and Production System - South Australia) (Department of Primary Industries and Regions SA, 2011)\n\n2.\tWaterConnect Groundwater database (Govt. of SA, 2011)\n\n3.\tQPED (Queensland Petroleum exploration database) (Geological Survey of Queensland, 2010).\n\n4.\tGABLOG (Great Artesian Basin Well Log Dataset) (Habermehl, 2001)\n\n5.\tAdditional supplementary information was derived from published reports listed in the following section.\n\n\n\nThis is a regional interpretation for mapping at approximately 1:1 000 000 to produce a broad scale overview, and examination of small areas by collecting extra data is most likely to produce results that differ from this regional interpretation.\n\n\n\nThis dataset and associated metadata can be obtained from www.ga.gov.au, using catalogue number 81681.\n\n\t\n\nAssociated report reference:\n\nRansley, T., Radke, B., Feitz, A., Kellett, J., Owens, R., Bell, J. and Stewart, G., 2014. Hydrogeological Atlas the Great Artesian Basin. Geoscience Australia. Canberra. \\[available from www.ga.gov.au using catalogue number 79790\\]\n\n\n\nREFERENCES:\n\nReferences - main data sources\n\n\n\n\\*\tDepartment of Primary Industries and Regions SA (2011). Petroleum Exploration and Production System - South Australia (PEPS-SA). Version 2011-06-15. Retrieved from http://www.pir.sa.gov.au/petroleum/access_to_data/peps-sa_database\n\n\\*\tGeological Survey of Queensland (2010). Queensland Petroleum Exploration Data (QPED) database. Retrieved 25 September 2011, from http://mines.industry.qld.gov.au/geoscience/geoscience-wireline-log-data.htm.\n\n\\*\tGeoscience Australia, 2013. Mesozoic Geology of the Carpentaria and Laura Basins (dataset). Scale 1:6000000. Geoscience Australia, Canberra. \\[available from www.ga.gov.au using catalogue number 75840\\]\n\n\\*\tGovt. of South Australia (2011). WaterConnect Groundwater database \\[available at https://www.waterconnect.sa.gov.au\\].\n\n\\*\tHabermehl, M. A. and J. E. Lau (1997). Hydrogeology of the Great Artesian Basin Australia (Map at scale 1:2,500,000). Canberra, Australian Geological Survey Organisation.\n\n\\*\tO'Brien, P. E. (2011). The eastern edge of the Great Artesian Basin: relationships between the Surat and Clarence-Moreton basins. Internal report. Canberra, Geoscience Australia.\n\n\\*\tWells, A.T. , O'Brien, P.E. 1994 Lithostratigraphic framework of the Clarence-Moreton Basin IN Wells, A.T. and O'Brien, P.E. (eds.) "Geology and Petroleum Potential of the Clarence-Moreton Basin, New South Wales and Queensland" Australian Geological Survey Organisation. Bulletin 241 p4-47\n\n## **Dataset History** \n\nSOURCE DATA: \n\nData was obtained from a variety of sources, as listed below:\n\n\\*\tWaterConnect Groundwater database (Govt. of SA, 2011)\n\n\\*\tGreat Artesian Basin Well Log Dataset (GABLOG) (Habermehl, M. A., 2001).\n\n\\*\tPetroleum Exploration and Production System - South Australia (PEPS-SA) (Department of Primary Industries and Regions SA, 2011).\n\n\\*\tQueensland Petroleum Exploration Database (QPED) (Geological Survey of Queensland, 2010).\n\n\\*\tWell completion and drill log reports (see references in abstract)\n\n\\*\tOther reports (see references in abstract)\n\n\\*\tSeismic surveys and associated reports (see seismic references section in abstract)\n\n\n\nMETHOD:\n\nFormation Extent\n\nThe extent was based on 1:500k mapping of Wells & O'Brien (1994) and drillhole data (see References for main data sources).\n\n\n\nExtent lines were adjusted to envelop all borehole intercepts of the Hydrostratigraphic unit. This produced some varied and irregular shapes, some patchy regions, and required some interpretation to establish the most likely extent boundary. \n\n\n\nOutcrop Extent\n\nOutcrop extents were taken from Hydrogeology of the Great Artesian Basin Australia (Habermehl & Lau, 1997) for the Eromanga and Surat sub-basins. For the Carpentaria Basin, Mesozoic Geology of the Carpentaria and Laura Basins (Geoscience Australia, 2013) was used. \n\n\n\nIsopach Raster\n\nDrillhole intercepts in Clarence-Moreton from O'Brien (2011) were used to calculate isopach values by using the depth to top and bottom values of formations within the drillhole database attributes, and adding them together to form the isopach values for each data point across the whole aquifer/aquitard. These values were extrapolated using the ESRI ANUDEM Topo-To-Raster surface modeller tool to generate the isopach raster grid (thickness). Zero thickness constraints were applied at the known extent of the aquifer/aquitard, except in cases where the formation extends beyond the GAB boundary (for example the Precipice formation on the eastern side of the GAB, where the formation is quite thick and is exposed as a cliff). In these cases, constraints were not applied and the software was allowed to model a thickness right up to the GAB boundary. Resulting grids were modified using the ESRI Grid Calculator to set the minimum thickness to 0, and clipped to the aquifer/aquitard extent.\n\n\n\nIsopach Contours\n\nIsopach contours were calculated from the Birkhead Walloon Aquitard thickness grid (generated from drillhole intercepts in Clarence-Moreton from O'Brien (2011)) using the ESRI Contour Tool. These were calculated at 50m intervals. In most cases the zero contour lines generated by the tool were replaced by the extent of the aquifer due to the erratic nature of the generated lines. In cases where the aquifer/aquitard is thick at the extent, the zero isoline is outside the extent and is not mapped in that area. Isopachs were clipped to the aquifer/aquitard extent.\n\n\n\nData Point Locations\n\nData Point Locations have been derived from the bore hole data collected for this project. Only the location has been included.\n\n\n\nSOFTWARE:\n\nAll modifications/edits and geoprocessing were performed using ESRI ArcGIS 10 software.\n\n\n\nQAQC:\n\nData sets were searched for errors such as negative thickness, missing data, incorrectly calculated thickness, aquifers/aquitards with missing formations, and false XY data.\n\nThe data was given a second Q&A after the thickness grids had been calculated. This involve plotting the points and the thickness grid and looking carefully for bad values. Sometimes a false outlier value would cause a 'bullseye' effect on the grid. To check the veracity, nearby data would be compared, and if necessary the original data would be searched check the value. Some petroleum fields would have wildcat picks at certain bore holes and these were compared with nearby boreholes and adjusted or deleted.\n\nAdditionally, if whole subregions had suspect values the data was check to ensure the relevant data had all been included. Finally, data sets were also checked to ensure the bore whole data recorded the full thickness of the Aquifer. In many cases water bores only go down until a suitable water source is found and often will not penetrate the whole aquifer. This data was considered on a case by case basis, in areas where plenty of suitable data was available they were removed, and in areas of sparse borehole data they were included to establish the occurrence of the formation albeit as a minimum thickness value.\n\n\n\nData has undergone a QAQC verification process in order to capture and repair attribute and geometric errors.\n\n## **Dataset Citation** \n\nGeoscience Australia (2015) GABATLAS - Birkhead-Walloon Aquitard - Thickness and Extent. Bioregional Assessment Source Dataset. Viewed 07 December 2018, http://data.bioregionalassessments.gov.au/dataset/a5912292-10cd-42e2-aefe-49aae2eead4b.

## **摘要**

本数据集及其元数据声明由第三方提供给生物区域评估计划（Bioregional Assessment Programme），并按原始提供形式呈现于此。

伯克黑德-瓦隆隔水层（Birkhead-Walloon Aquitard）厚度与分布数据集是代表大自流盆地（Great Artesian Basin）水文地层单元的数据集之一，该盆地包含五个主要含水层、四个间插隔水层以及覆盖大自流盆地（GAB）的新生代地层。

伯克黑德-瓦隆隔水层地图数据包含五个图层：

A：地层分布

B：出露范围

C：等厚线栅格

D：等厚线等值线

E：数据点位置

本数据集源自石油勘探井、水井和地层井钻孔数据中的岩石地层截距。未使用基于电相的地震对比及水文地质特征评估。本研究的工作数据集主要来源于以下数据库：

1. PEPS-SA（南澳大利亚石油勘探与生产系统，Petroleum Exploration and Production System - South Australia）（南澳大利亚初级产业与地区部，2011）

2. WaterConnect地下水数据库（南澳大利亚政府，2011）

3. QPED（昆士兰石油勘探数据库，Queensland Petroleum Exploration Database）（昆士兰地质调查局，2010）

4. GABLOG（大自流盆地测井数据集，Great Artesian Basin Well Log Dataset）（Habermehl，2001）

5. 其他补充信息源自下文列出的已发表报告。

本数据集是针对约1:100万比例尺制图的区域解释，旨在提供大范围概览；通过收集额外数据对小区域进行详细考察，所得结果很可能与本区域解释存在差异。

本数据集及相关元数据可通过目录号81681从www.ga.gov.au获取。

相关报告引用：

Ransley, T., Radke, B., Feitz, A., Kellett, J., Owens, R., Bell, J.及Stewart, G.，2014年。《大自流盆地水文地质图集》。澳大利亚地质科学局（Geoscience Australia），堪培拉。[可通过目录号79790从www.ga.gov.au获取]

参考文献：

主要数据源参考文献

* 南澳大利亚初级产业与地区部（2011）。南澳大利亚石油勘探与生产系统（PEPS-SA）。版本2011-06-15。获取自http://www.pir.sa.gov.au/petroleum/access_to_data/peps-sa_database

* 昆士兰地质调查局（2010）。昆士兰石油勘探数据库（QPED）。2011年9月25日获取自http://mines.industry.qld.gov.au/geoscience/geoscience-wireline-log-data.htm。

* 澳大利亚地质科学局，2013年。《卡奔塔利亚与劳拉盆地中生代地质学》（数据集）。比例尺1:6000000。澳大利亚地质科学局，堪培拉。[可通过目录号75840从www.ga.gov.au获取]

* 南澳大利亚政府（2011）。WaterConnect地下水数据库[可通过https://www.waterconnect.sa.gov.au获取]。

* Habermehl, M.A.及J.E. Lau（1997）。《澳大利亚大自流盆地水文地质学》（比例尺1:250万地图）。堪培拉，澳大利亚地质调查组织。

* O'Brien, P.E.（2011）。《大自流盆地东缘：苏拉特与克拉伦斯-莫顿盆地的关系》。内部报告。堪培拉，澳大利亚地质科学局。

* Wells, A.T.及O'Brien, P.E. 1994。《克拉伦斯-莫顿盆地岩石地层框架》，载于Wells, A.T.及O'Brien, P.E.（编）《新南威尔士州与昆士兰州克拉伦斯-莫顿盆地地质与石油潜力》，澳大利亚地质调查组织公报241，第4-47页

## **数据集历史**

源数据：

数据来源于多种渠道，如下所列：

* WaterConnect地下水数据库（南澳大利亚政府，2011）

* 大自流盆地测井数据集（GABLOG）（Habermehl, M.A.，2001）

* PEPS-SA（南澳大利亚石油勘探与生产系统，2011）

* QPED（昆士兰石油勘探数据库，2010）

* 井完井报告与钻井日志（参见摘要参考文献）

* 其他报告（参见摘要参考文献）

* 地震勘探及相关报告（参见摘要地震参考文献部分）

方法：

地层分布

地层分布基于Wells & O'Brien（1994）的1:50万制图及钻孔数据（参见主要数据源参考文献）。

分布线经过调整，以包围水文地层单元的所有钻孔截距。这产生了一些多样且不规则的形状、部分斑块区域，需要通过解释来确定最可能的分布边界。

出露范围

出露范围取自《澳大利亚大自流盆地水文地质学》（Habermehl & Lau，1997）中伊罗曼加和苏拉特次盆地的数据；针对卡奔塔利亚盆地，则使用《卡奔塔利亚与劳拉盆地中生代地质学》（澳大利亚地质科学局，2013）。

等厚线栅格

使用O'Brien（2011）中克拉伦斯-莫顿盆地的钻孔截距，通过钻孔数据库属性中的地层顶底深度值计算等厚值，并累加得到整个含水层/隔水层各数据点的等厚值。这些值通过ESRI ANUDEM Topo-To-Raster表面建模工具外推，生成等厚线栅格（厚度）。在含水层/隔水层已知分布范围处应用零厚度约束，但当地层延伸至大自流盆地边界之外时（例如大自流盆地东侧的Precipice地层，其厚度较大且以悬崖形式出露）除外；此类情况下不应用约束，允许软件建模至大自流盆地边界的厚度。最终栅格通过ESRI栅格计算器修改，将最小厚度设为0，并裁剪至含水层/隔水层分布范围。

等厚线等值线

等厚线等值线通过ESRI Contour工具从伯克黑德-瓦隆隔水层厚度栅格（源自O'Brien（2011）中克拉伦斯-莫顿盆地的钻孔截距）计算得出，间隔为50米。多数情况下，工具生成的零等值线被含水层分布范围取代，因生成的线条具有不稳定性。当地层在分布范围处厚度较大时，零等值线位于分布范围之外，该区域不绘制此线。等厚线裁剪至含水层/隔水层分布范围。

数据点位置

数据点位置源自本项目收集的钻孔数据，仅包含位置信息。

软件：

所有修改/编辑及地理处理均使用ESRI ArcGIS 10软件完成。

质量控制：

数据集经过错误排查，包括负厚度、缺失数据、厚度计算错误、含水层/隔水层地层缺失及错误XY数据等。

厚度栅格计算完成后，数据经过二次质量审核。这包括绘制数据点与厚度栅格，并仔细检查异常值。有时虚假异常值会在栅格上造成‘靶心’效应；为验证真实性，会对比邻近数据，必要时检索原始数据核查数值。部分油田的野猫井数据会与邻近钻孔对比，进行调整或删除。此外，若整个子区域数值可疑，则核查相关数据是否全部纳入。最后，还检查钻孔数据是否记录了含水层的完整厚度：多数情况下，水井仅钻至合适水源处，往往未穿透整个含水层；此类数据根据具体情况处理——在数据充足区域予以剔除，在钻孔数据稀疏区域则保留，以确定地层存在性（尽管仅为最小厚度值）。

数据已通过QAQC验证流程，以捕获并修复属性及几何错误。

## **数据集引用**

澳大利亚地质科学局（2015）GABATLAS - 伯克黑德-瓦隆隔水层 - 厚度与分布。生物区域评估源数据集。查阅于2018年12月7日，http://data.bioregionalassessments.gov.au/dataset/a5912292-10cd-42e2-aefe-49aae2eead4b。