The impact of seismic amplitudes on prospect risk analysis

Roden, Rocky; Forrest, Mike

doi:10.1190/1.2148278

Cited by 3 publications

(3 citation statements)

References 2 publications

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“…While evaluating Direct Hydrocarbon Indicator (DHI) characteristics, an understanding of geological setting is crucial as an expected DHI response is dependent on it. The presence of a DHI in seismic data aids in de-risking of a prospect and has a significant impact on reserve calculation (Hilterman 2001;Roden et al 2005Roden et al , 2012Hanafy et al 2018). AVO analysis is a deterministic way to predict hydrocarbon presence from seismic data (Smith and Gidlow 1987;Rutherford and Williams 1989;Hilterman 1990;Castagna and Smith 1994;Smith and Sutherland 1996;Castagna et al 1998;Figueiredo et al 2019;Fawad et al 2020).…”

Section: Direct Hydrocarbon Indicator and Analysis Of Pre-stack Gathersmentioning

confidence: 99%

Post-drill geophysical characterization of two deep-water wells of Cauvery Basin, East Coast of India

Mishra¹,

Patidar

2022

J Petrol Explor Prod Technol

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The depth of the reservoir causes an increase in the degree of uncertainty in the prediction of reservoir quality. High frequency is suppressed with depth because Earth functions as a low-pass filter. The seismic amplitudes observed at various interfaces are influenced by spherical divergence, transmission losses, mode conversions, and inter-bed multiples. Seismic data have numerous essential components that must be thoroughly examined during hydrocarbon prospect identification and maturation, including post-critical reflections, events coherency (in near and far offsets), mode conversion, and interbed multiples. Seismic amplitudes are typically derived from 2D/3D seismic data and utilized directly or indirectly for reservoir interpretation and better prediction of subtle geological and geophysical information. To accurately depict subsurface geological features, stratigraphic architecture, and reservoir facies, it should be used in conjunction with the existing paleoenvironment data. When employed alone, the subsurface geophysical data may lead to erroneous interpretation of subsurface lithologies and inaccurate reservoir property predictions. Understanding these factors could help interpreters make better use of seismic data while maturing and de-risking the prospectivity. This study examines the post-drill geophysical characterization of two exploratory wells that were drilled in the deep-water area of the Cauvery Basin, East Coast of India. Analysis and correlation with a discovery well is done to understand the sediment depositional heterogeneity and corresponding seismic amplitude response, primarily for the cemented reservoir (dry well). To discover prospects and subsequently de-risk the existing prospect inventory, a dashboard checklist for in-depth study of seismic and well data has been developed. The top-down geophysical analytical approach that has been presented will aid in defining reservoir characteristics generally, estimating deliverability, and subsequently raising the geological probabilities and chance of success (COS) of any exploration project. The findings of this study allow critical analysis of seismic data to distinguish between softer/slower/possibly better reservoir rocks and hard/fast/tight rocks.

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Section: Direct Hydrocarbon Indicator and Analysis Of Pre-stack Gathersmentioning

confidence: 99%

Post-drill geophysical characterization of two deep-water wells of Cauvery Basin, East Coast of India

Mishra¹,

Patidar

2022

J Petrol Explor Prod Technol

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“…Gas reservoirs across the Gulf of Mexico have been designated as Class 1, 2, 3, or 4, depending on their P-P amplitude-versus-angle (AVA) response Roden et al, 2005). The P-P AVA behaviors on which that classification scheme is based are shown as generalized curves in Figure 18.…”

Section: Class 2 Reservoirsmentioning

confidence: 99%

“…Figure 20 displays well-log data across the Alba reservoir target. Modified from Roden et al, 2005. V S = 1370 m/s, and r b = 2.10 gm/cm 3 . The upper seal layer of the reservoir was assigned log-averaged properties: V P = 2470 m/s, V S = 915 m/s, and r b = 2.16 gm/cm 3 .…”

Section: Class 2 Reservoirsmentioning

confidence: 99%

Methods and Applications in Reservoir Geophysics

Johnston¹

2010

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Integrated Prospect Evaluation and Characterization Using Pre-Stack Seismic Data, Mansoura Area, onshore Nile Delta, Egypt

Fathy¹,

Shams²

2017

Day 3 Wed, May 10, 2017

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In 2003, an aggressive drilling program started in Mansoura area in the onshore Nile Delta, with high success ratio. The program benefited from the direct hydrocarbon indicators provided by the post stack seismic data. After proving hydrocarbon presence in the field many reservoirs explored, however some challenges appeared lately. The most important challenges are the lithology and fluid discrimination due to the shale behavior, furthermore, the delineation of different reservoir properties like clay content, water saturation, and porosity proved to be challenging. Analysis of pre-stack seismic data for different reservoir properties prediction is commonly used for reservoir characterization. To enhance pre-stack seismic data quality some seismic gathers preconditioning flowcharts have been applied on the pre-stack data. The wavelet spectral analysis has been performed after conditioning the data then different techniques like the AVO simultaneous inversion, AVO analysis and density inversion have been applied on both west Dikirnis and west Khilala fields. Building rock physics model was carried out in the onshore Nile Delta to link the elastic properties and the reservoir properties. The model implemented in the unexplored areas within the concession to minimize the drilling risk of the delineated prospects. The rock physics model built in the area of study helped significantly to discriminate between wet sand, shale and gas sands. The middle and late Messinian are typically sand rich sections with excellent reservoir quality encountered in the drilled wells within both fields. Different reservoir properties predicted using the advanced inversion techniques in addition to the well data showing strong correlation at the well locations. The reliability of the far and ultra-far seismic data was encouraging. The cross-plot of the acoustic impedance versus shear impedance represents a useful technique in the onshore Nile Delta for sand and shale discrimination. Using Elastic impedance logs we can discriminate the water bearing sand, hydrocarbon sand and shale especially at the ultra-far angle.

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The impact of seismic amplitudes on prospect risk analysis

Cited by 3 publications

References 2 publications

Post-drill geophysical characterization of two deep-water wells of Cauvery Basin, East Coast of India

Post-drill geophysical characterization of two deep-water wells of Cauvery Basin, East Coast of India

Methods and Applications in Reservoir Geophysics

Integrated Prospect Evaluation and Characterization Using Pre-Stack Seismic Data, Mansoura Area, onshore Nile Delta, Egypt

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