GABATLAS - Evergreen-Poolowanna Aquitard and Equivalents - 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. The Evergreen-Poolowanna Aquitard and Equivalents - 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 Evergreen-Poolowanna Aquitard and Equivalents map data\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 datasest for this study has been derived primarily from the following databases:\n\n\\*\tPEPS-SA (Petroleum Exploration and Production System - South Australia) (Department of Primary Industries and Regions SA, 2011)\n\n\\*\tWaterConnect Groundwater database (Govt. of SA, 2011)\n\n\\*\tQPED (Queensland Petroleum exploration database) (Geological Survey of Queensland, 2010).\n\n\\*\tGABLOG (Great Artesian Basin Well Log Dataset) (Habermehl, 2001)\n\n\\*\tAdditional supplementary information was derived from published reports listed in the following section.\n\n\n\nInterpretations by O'Brien & Wells, (1994); and O'Brien 2011 were used in generating the isopach data (thickness surface and contours) along the boundary of the Surat and Clarence-Moreton Basins.\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\n\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\\*\tGibson, D. L., B. S. Powell & Smart, J. (1974). Shallow stratigraphic drilling, northern Cape York Peninsula, 1973. Record 1974/76. Australia, Bureau of Mineral Resources.\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\n\nReferences - Seismic Surveys\n\n\\*\tnone\n\n\n\nReferences - Well Completion Reports and drilling logs\n\n\\*\tnone\n\n## **Dataset History** \n\nThis dataset and associated metadata can be obtained from www.ga.gov.au, using catalogue number 81683.\n\nSOURCE DATA: \n\nData was obtained from a variety of sources, as listed below:\n\n1.\tWaterConnect Groundwater database (Govt. of SA, 2011)\n\n2.\tGreat Artesian Basin Well Log Dataset (GABLOG) (Habermehl, M. A., 2001).\n\n3.\tPetroleum Exploration and Production System - South Australia (PEPS-SA) (Department of Primary Industries and Regions SA, 2011).\n\n4.\tQueensland Petroleum Exploration Database (QPED) (Geological Survey of Queensland, 2010).\n\n5.\tWell completion and drill log reports (see references in abstract)\n\n6.\tOther reports (see references in abstract)\n\n7.\tSeismic surveys and associated reports (see seismic references section in abstract)\n\n\n\nMETHOD:\n\nFormation Extent\n\nExtents were based on drill hole data (listed above).\n\n\n\nExtent lines were adjusted to envelop all drill hole 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 sourced and extracted 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\nSource point thickness values calculated from drillhole intercepts 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.\n\nThese values were extrapolated using the ESRI ANUDEM Topo-To-Raster surface modeller tool to create grid surface. 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 Evergreen-Poolowanna Aquitard and equivalents thickness grid 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 - Evergreen-Poolowanna Aquitard and Equivalents - Thickness and Extent. Bioregional Assessment Source Dataset. Viewed 07 December 2018, http://data.bioregionalassessments.gov.au/dataset/b9c0d451-e7f0-4810-95eb-51fa6d9f552b.

## **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。Evergreen-Poolowanna弱透水层及等效层——厚度与分布数据集，是表征大自流盆地（Great Artesian Basin，GAB）水文地层单元的数据集之一，该盆地包含5个主要含水层、4个夹层弱透水层以及覆盖GAB的新生代地层。

Evergreen-Poolowanna弱透水层及等效层地图数据包含5个图层：

A：地层分布

B：出露分布

C：等厚线栅格

D：等厚线

E：数据点位置

该数据集源自石油勘探井、水井及地层井的岩性地层截距数据，未使用基于电相的地震对比与水文地质特征评估结果。本研究的工作数据集主要来自以下数据库：

* 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）

* WaterConnect地下水数据库（南澳大利亚政府，2011）

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

* GABLOG（大自流盆地井日志数据集，Great Artesian Basin Well Log Dataset）（Habermehl，2001）

* 补充信息源自下一节列出的已发表报告。

在生成Surat与Clarence-Moreton盆地边界处的等厚数据（厚度面与等厚线）时，采用了O'Brien & Wells（1994）及O'Brien（2011）的解释结果。

本数据集为区域尺度解释成果，适用于约1:100万比例尺制图，旨在提供宏观概览；若通过收集额外数据对小区域进行详细分析，所得结果很可能与本区域解释存在差异。

相关报告引用：

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

参考文献：

参考文献——主要数据源

* 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。检索自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）。检索日期：2011年9月25日，来源http://mines.industry.qld.gov.au/geoscience/geoscience-wireline-log-data.htm。

* 澳大利亚地球科学局（2013）。Carpentaria与Laura盆地中生代地质（数据集）。比例尺1:6000000。澳大利亚地球科学局，堪培拉。[可通过目录号75840从www.ga.gov.au获取]

* Gibson, D. L., B. S. Powell & Smart, J. (1974). 约克角半岛北部浅层地层钻探（1973）。记录1974/76。澳大利亚矿产资源局。

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

* Habermehl, M. A. and J. E. Lau (1997). 《澳大利亚大自流盆地水文地质》（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：Surat与Clarence-Moreton盆地的关系。内部报告。堪培拉，澳大利亚地球科学局。

* Wells, A.T. , O'Brien, P.E. 1994 Clarence-Moreton盆地的岩性地层框架，收录于Wells, A.T.与O'Brien, P.E.（编）《Clarence-Moreton盆地的地质与石油潜力》（新南威尔士州与昆士兰州），澳大利亚地质调查组织。公报241，第4-47页。

参考文献——地震勘探

* 无

参考文献——完井报告与钻井日志

* 无

## **数据集历史**

本数据集及相关元数据可通过目录号81683从www.ga.gov.au获取。

源数据：

数据源自以下多种来源：

1. WaterConnect地下水数据库（南澳大利亚政府，2011）

2. 大自流盆地井日志数据集（GABLOG）（Habermehl, M. A., 2001）

3. 南澳大利亚石油勘探与生产系统（PEPS-SA）（南澳大利亚初级产业与地区部，2011）

4. 昆士兰石油勘探数据库（QPED）（昆士兰地质调查局，2010）

5. 完井报告与钻井日志（见摘要参考文献）

6. 其他报告（见摘要参考文献）

7. 地震勘探及相关报告（见摘要地震参考文献部分）

方法：

地层分布

分布范围基于上述钻井数据确定。

分布线经调整以包围水文地层单元的所有钻井截距。这产生了一些形状各异的不规则区域及零散斑块，需通过解释确定最可能的分布边界。

出露分布

Eromanga与Surat子盆地的出露分布源自《澳大利亚大自流盆地水文地质》（Habermehl & Lau，1997）并从中提取。Carpentaria盆地的出露分布则使用《Carpentaria与Laura盆地中生代地质》（澳大利亚地球科学局，2013）。

等厚线栅格

源点厚度值通过钻井数据库属性中的地层顶底深度值计算得出，将各数据点的地层厚度相加得到整个含水层/弱透水层的等厚值。

这些值通过ESRI ANUDEM Topo-To-Raster表面建模工具进行外推，生成栅格表面。在含水层/弱透水层已知分布范围内施加零厚度约束，但当地层延伸至GAB边界以外时（例如GAB东侧的Precipice地层，其厚度较大且以悬崖形式出露）除外；此类情况下不施加约束，允许软件建模至GAB边界处的厚度。生成的栅格通过ESRI栅格计算器修改，将最小厚度设为0，并裁剪至含水层/弱透水层分布范围。

等厚线

Evergreen-Poolowanna弱透水层及等效层厚度栅格的等厚线通过ESRI Contour工具计算得出，间隔为50米。多数情况下，工具生成的零等高线因线条不稳定而被含水层分布范围替代。当地含水层/弱透水层在分布边界处较厚时，零等值线位于分布范围外，该区域不绘制零等值线。等厚线裁剪至含水层/弱透水层分布范围。

数据点位置

数据点位置源自为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。

质量保证与质量控制（QAQC）：

对数据集进行错误排查，包括负厚度（negative thickness）、数据缺失（missing data）、厚度计算错误（incorrectly calculated thickness）、含水层/弱透水层地层缺失以及XY数据错误等。

厚度栅格计算完成后，对数据进行二次质量检查。这包括绘制数据点与厚度栅格，仔细查找异常值。有时虚假异常值会在栅格上造成“靶心”效应，需通过对比邻近数据验证真实性，必要时查阅原始数据核对数值。部分油田的野猫井数据会与邻近钻孔对比，若存在偏差则进行调整或删除。

此外，若整个子区域数据可疑，需检查是否包含所有相关数据。最后，验证钻孔数据是否记录了含水层的完整厚度：许多水井仅钻至合适水源处，往往未穿透整个含水层。此类数据需逐案评估——在数据充足区域剔除，在钻孔稀疏区域保留（作为最小厚度值）以确定地层存在性。

数据集已通过QAQC验证流程，以捕获并修复属性与几何错误。

## **数据集引用**

澳大利亚地球科学局（Geoscience Australia）（2015）GABATLAS——Evergreen-Poolowanna弱透水层及等效层：厚度与分布。生物区域评估源数据集。查阅日期：2018年12月7日，http://data.bioregionalassessments.gov.au/dataset/b9c0d451-e7f0-4810-95eb-51fa6d9f552b。