Murphy C.A.,Bell Geospace Ltd |
Dickinson J.,Bell Geospace Ltd
72nd European Association of Geoscientists and Engineers Conference and Exhibition Incorporating SPE EUROPEC 2010, Workshops | Year: 2010
Exploration play models are employed by mineral and hydrocarbon exploration companies to establish and help explain the geological setting of their targeted resource. Such models are routinely enhanced through the deployment of geophysical technologies to better improve the understanding of the geological setting and size, shape and depths of the target. FTG Gravity data offers an additional layer of information to consider the fortunes of many exploration play models from salt, fault block closure and igneous intrusion models to more mainstream fault mapping. Many have been confirmed or tweaked through direct involvement of the FTG data into their exploration workflow and are a testament to the acceptance of this innovative technology by leading exploration companies. This paper will present data examples demonstrating the usefulness of FTG Gravity when investigating the prospectivity of exploration play models. Examples from survey work targeting fault block structural closures and igneous intrusives will be shown.
Salem A.,GETECH |
Salem A.,University of Leeds |
Masterton S.,GETECH |
Campbell S.,GETECH |
And 4 more authors.
Geophysical Prospecting | Year: 2013
Full Tensor Gravity Gradiometry (FTG) data are routinely used in exploration programmes to evaluate and explore geological complexities hosting hydrocarbon and mineral resources. FTG data are typically used to map a host structure and locate target responses of interest using a myriad of imaging techniques. Identified anomalies of interest are then examined using 2D and 3D forward and inverse modelling methods for depth estimation. However, such methods tend to be time consuming and reliant on an independent constraint for clarification. This paper presents a semi-automatic method to interpret FTG data using an adaptive tilt angle approach. The present method uses only the three vertical tensor components of the FTG data (Tzx, Tzy and Tzz) with a scale value that is related to the nature of the source (point anomaly or linear anomaly). With this adaptation, it is possible to estimate the location and depth of simple buried gravity sources such as point masses, line masses and vertical and horizontal thin sheets, provided that these sources exist in isolation and that the FTG data have been sufficiently filtered to minimize the influence of noise. Computation times are fast, producing plausible results of single solution depth estimates that relate directly to anomalies. For thick sheets, the method can resolve the thickness of these layers assuming the depth to the top is known from drilling or other independent geophysical data. We demonstrate the practical utility of the method using examples of FTG data acquired over the Vinton Salt Dome, Louisiana, USA and basalt flows in the Faeroe-Shetland Basin, UK. A major benefit of the method is the ability to quickly construct depth maps. Such results are used to produce best estimate initial depth to source maps that can act as initial models for any detailed quantitative modelling exercises using 2D/3D forward/inverse modelling techniques. © 2013 European Association of Geoscientists & Engineers.
Dickinson J.L.,Bell Geospace Ltd. |
Wijns C.,First Quantum Minerals Ltd. |
Murphy C.A.,Bell Geospace Ltd.
73rd European Association of Geoscientists and Engineers Conference and Exhibition 2011: Unconventional Resources and the Role of Technology. Incorporating SPE EUROPEC 2011 | Year: 2011
Full tensor gravity gradiometry (FTG) measures the complete gravity field; because of this we are able to realign the axes of the tensor to better image geology. Consequently we are able to design surveys based on optimal acquisition and safety parameters, then realign during the interpretation stage to focus on geological strike direction. This is also a powerful technique for interpreting surveys with more than one dominant strike trend. The realignment technique is demonstrated using a dataset from Mauritania, acquired in 2010.
Dickinson J.L.,Bell Geospace Ltd. |
Murphy C.A.,Bell Geospace Ltd. |
Robinson J.W.,Bell Geospace Ltd.
72nd European Association of Geoscientists and Engineers Conference and Exhibition 2010: A New Spring for Geoscience. Incorporating SPE EUROPEC 2010 | Year: 2010
Full Tensor Gravity Gradiometry (FTG) has proven to be an effective tool for both the Oil and Gas and Mineral exploration industries since it was introduced in the late 1990s. The multi component gravity surveying technology provides a rich source of information that lends itself ideally suited to imaging and delineating key geological structure. New techniques involving invariant analysis have been developed that facilitate quick and efficient imaging to extract detailed geological information. This paper presents these imaging techniques applied to data collected over the Vinton Dome in Louisiana. © 2010, European Association of Geoscientists and Engineers.