Analysing Full Tensor Gravity Data with Intuitive Imaging Techniques

Dickinson, Jade L.; Murphy, Colm; Robinson, James W.

doi:10.3997/2214-4609.201400717

Cited by 20 publications

(9 citation statements)

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“…Airborne FTG data were acquired over the Vinton Salt Dome, Louisiana, USA in 2008 as part of a test program for the newly acquired BT67 aircraft by Bell Geospace (Dickinson et al 2010). The airborne FTG data were flown with N-S flight lines with a spacing of 150 m at an average altitude of 75 m. The data were enhanced by band-pass filtering all components between 500-2500 m spatial wavelengths.…”

Section: F I E L D E X a M P L E S Vinton Salt Domementioning

confidence: 99%

“…The airborne FTG data were flown with N-S flight lines with a spacing of 150 m at an average altitude of 75 m. The data were enhanced by band-pass filtering all components between 500-2500 m spatial wavelengths. The advantage of the filtering process is to emphasize the signal associated with the salt body hosting high-density cap rock (Dickinson et al 2010). Figure 8(a-d) shows the filtered vertical tensor gravity components (T zx , T zy , and T zz ) and the computed adaptive tilt angle with a = 1.…”

Section: F I E L D E X a M P L E S Vinton Salt Domementioning

confidence: 99%

“…It measures the derivative of all the three gravity components in all three directions and provides a rich source of informa- * E-mail: asks@getech.com tion for defining edges of geological structures at both local and regional scales (Dickinson, Murphy and Robinson 2010). It measures the derivative of all the three gravity components in all three directions and provides a rich source of informa- * E-mail: asks@getech.com tion for defining edges of geological structures at both local and regional scales (Dickinson, Murphy and Robinson 2010).…”

Section: Introductionmentioning

confidence: 99%

“…Full Tensor Gravity Gradiometry (FTG) has proven to be an effective tool in both oil and gas and mineral exploration. It measures the derivative of all the three gravity components in all three directions and provides a rich source of informa- * E-mail: asks@getech.com tion for defining edges of geological structures at both local and regional scales (Dickinson, Murphy and Robinson 2010). Several developments in imaging techniques have been presented (Murphy and Brewster 2007;Dickinson et al 2009) and enable greater insight into a subsurface structure through the utilization of full tensor components.…”

Section: Introductionmentioning

confidence: 99%

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Interpretation of tensor gravity data using an adaptive tilt angle method

Salem

Masterton

Campbell

et al. 2013

Geophysical Prospecting

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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.

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Section: F I E L D E X a M P L E S Vinton Salt Domementioning

confidence: 99%

Section: F I E L D E X a M P L E S Vinton Salt Domementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Interpretation of tensor gravity data using an adaptive tilt angle method

Salem

Masterton

Campbell

et al. 2013

Geophysical Prospecting

View full text Add to dashboard Cite

show abstract

“…The airborne FTG data were flown with N-S flight lines with a spacing of 150 m at an average altitude of 75 m. The data were enhanced by band pass filtering all components between 500 m and 2500 m spatial wavelengths. The advantage of the filtering process is to better capture the signal associated with the salt body hosting the high density cap rock (Dickinson et al, 2010). Figure 2 shows the filtered vertical tensor gravity components (T zx , T zy , and T zz ) and the computed adapted tilt angle with a =1.…”

Section: Depth Estimation Of Ftg Datamentioning

confidence: 99%

Depth estimating Full Tensor Gravity data with the Adaptive Tilt Angle method

Murphy¹,

Dickinson²,

Salem

2012

ASEG Extended Abstracts

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Depth estimation procedures for potential field data are well recognised techniques. Both Euler and Werner methodologies are typically used as a series of automated steps and applied to both gridded and profile data. The Tilt Derivative Depth method works on gridded data and has been used extensively on magnetic data. Its advantage is its ability to produce a focused set of solutions and is now being commonly adopted for potential field data. This paper describes an Adaptive Tilt Angle method for depth estimating Full Tensor Gravity data. The method is an adaptation of the Tilt Derivative depth estimation procedure adopted for magnetic data. The procedure works on 4 of the independently measured Tensor components and produces sets of solutions that are more easily interpreted. The tilt angle method is defined as a ratio of the Tensor components in each of the X, Y and Z directions and assumes a vertical contact geological setting. The implementation of a scaling factor allows the technique to work on horizontal contacts. The scaling factor is essentially similar to the concept of a Structural Index as used with Euler depth estimation methods. The technique was tested successfully on an Air-FTG® survey data set over a shallow salt feature onshore USA and is now being routinely deployed. The benefits of the direct depth estimation technique are immense in that it not only provides constraint on other interpretative processing techniques, but quickly establishes a starting depth model for any detailed forward / inverse modelling exercises.

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