Time Lapse Gravity Gradiometry for Reservoir Monitoring

DiFrancesco, Dan; Talwani, Manik

doi:10.3997/2214-4609-pdb.5.h007

Cited by 2 publications

(2 citation statements)

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“…It was de-classified and applied to exploration in 1997. The two members of the Lockheed family of gradiometers including Lockheed Martin Air Full Tensor Gradiometer (FTG) by Bell Geospace [8] and FALCON TM Airborne Gravity Gradiometer (AGG) developed by the collaboration of BHP Billiton from Australia [9]. The Falcon TM system measures the components T UV and T NE depending on a gravity gradiometer instrument mounted in an inertial platform at a noise level of 3.3 E [10], while the Air-FTG system measures the acceleration of gravity in all directions of the field depending on three gravity gradiometer instruments at a noise level of 4-6 E [11].…”

Section: Introductionmentioning

confidence: 99%

Integration of Residual Terrain Modelling and the Equivalent Source Layer Method in Gravity Field Synthesis for Airborne Gravity Gradiometer Test Site Determination

Yang,

Li,

Feng

et al. 2023

Remote Sensing

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To calibrate airborne gravity gradiometers currently in development in China, it is urgent to build an airborne gravity gradiometer test site. The site’s selection depends on the preknowledge of high-resolution gravity and gradient structures. The residual terrain modelling (RTM) technique is generally applied to recover the short-scale gravity field signals. However, due to limitations in the quality and resolution of density models, RTM terrain generally assumes a constant density. This assumption can introduce significant errors in areas with substantial density anomalies and of reggued terrain, such as volcano areas. In this study, we promote a method to determine a high-resolution gravity field by integrating long-wavelength signals generated by EGM2008 with short-wavelength signals from terrain relief and shallow density anomalies. These short wavelength signals are recovered using the RTM technique with both constant density and density anomalies obtained through the equivalent source layer (ESL) method, utilizing sparse terrestrial gravity measurements. Compared to the recovery rate of 54.62% using the classical RTM method, the recovery rate increases to 86.22% after involving density anomalies. With this method, we investigate the gravity field signals over the Wudalianchi Volcano Field (WVF) both on the Earth’s surface and at a flight height of 100 m above the terrain. The contribution of each part and their attenuation characters are studied. In particular, the 5 km × 5 km area surrounding Bijiashan (BJS) and Wohushan (WHS) volcanos shows a strong gravity signature, making it a good candidate for the test site location. This study gives the location of the airborne gravity gradiometer test site which is an essential step in the instruments’ development. Furthermore, the method presented in this study offers a foundational framework for future data processing within the test site.

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Section: Introductionmentioning

confidence: 99%

Integration of Residual Terrain Modelling and the Equivalent Source Layer Method in Gravity Field Synthesis for Airborne Gravity Gradiometer Test Site Determination

Yang,

Li,

Feng

et al. 2023

Remote Sensing

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“…He also reported that the RAGG output fluctuation was less than 2 E in a stability experiment of 18 h and the instrument bias trend was about 2.2 × 10 −3 E/h [14,15,16]. However, the scale factor calibration had not been reported and the output unit of RAGG was directed to E. Hofmeyer et al, who focused on the intrinsic noise of the RAGGs and proved an achievable sensitivity below 3 E/√Hz for stationary measurements using the eight-accelerometer gravity gradiometer and the performance has been improved through optimization in the gradiometer measurement [17,18,19]. Although the sensitivity has been tested and calculated by E/√Hz instead of V/√Hz, the scale factor calibration of RAGG has still not been released.…”

Section: Introductionmentioning

confidence: 99%

Scale Factor Calibration for a Rotating Accelerometer Gravity Gradiometer

Deng

Huang

et al. 2018

Sensors

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Rotating Accelerometer Gravity Gradiometers (RAGGs) play a significant role in applications such as resource exploration and gravity aided navigation. Scale factor calibration is an essential procedure for RAGG instruments before being used. In this paper, we propose a calibration system for a gravity gradiometer to obtain the scale factor effectively, even when there are mass disturbance surroundings. In this system, four metal spring-based accelerometers with a good consistency are orthogonally assembled onto a rotary table to measure the spatial variation of the gravity gradient. By changing the approaching pattern of the reference gravity gradient excitation object, the calibration results are generated. Experimental results show that the proposed method can efficiently and repetitively detect a gravity gradient excitation mass weighing 260 kg within a range of 1.6 m and the scale factor of RAGG can be obtained as (5.4 ± 0.2) E/μV, which is consistent with the theoretical simulation. Error analyses reveal that the performance of the proposed calibration scheme is mainly limited by positioning error of the excitation and can be improved by applying higher accuracy position rails. Furthermore, the RAGG is expected to perform more efficiently and reliably in field tests in the future.

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Time Lapse Gravity Gradiometry for Reservoir Monitoring

Cited by 2 publications

References 0 publications

Integration of Residual Terrain Modelling and the Equivalent Source Layer Method in Gravity Field Synthesis for Airborne Gravity Gradiometer Test Site Determination

Integration of Residual Terrain Modelling and the Equivalent Source Layer Method in Gravity Field Synthesis for Airborne Gravity Gradiometer Test Site Determination

Scale Factor Calibration for a Rotating Accelerometer Gravity Gradiometer

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