Anisotropic Avo Analysis for Reservoir Characterization in Derby Field Southeastern Niger Delta

Ehirim, C. N.; Chikezie, Nnamdi Ogbonna

doi:10.9790/4861-0901016773

Cited by 3 publications

(4 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Reflection coefficients contain valuable information about the local medium properties on both sides of an interface. Therefore, analysis of amplitude variations with incidence angle or offset (AVA/AVO) is often used in reservoir characterization (Mallick and Frazer 1991;Avseth et al 2001;Break et al 2006;Ehirim and Chikezie 2017;Avseth and Lehocki 2021).…”

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

View full text Add to dashboard Cite

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.

show abstract

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

View full text Add to dashboard Cite

show abstract

“…The Agbada Formation (Eocenerecent) overlies the Akata Formation and consists of paralic siliciclastics over 3,700 meters thick [9]. This Formation is divided into an upper unit which consists of sandstoneshale alternations with the former predominating over the latter and a lower unit in which the shales predominate.…”

Section: Agbada Formationmentioning

confidence: 99%

“…Deductions from this study show that Heri sand was deposited in a coeval period within the late Miocene epoch under three distinct depositional environments (distributary channel, barrier bar, and mouth bar) in differing bathymetric regimes ranging from inner neritic, middle neritic, and outer neritic setting [21][22][23][24][25][26][27][28][29][30].…”

Section: Unit Cmentioning

confidence: 99%

Geoscience Assessment of Declined Production Rate and Recovery from a Reservoir in “ANDA” Field, Onshore Southwestern Niger Delta

Udoinyang

Ekere

George

2021

CJAST

View full text Add to dashboard Cite

Declined production rates in wells producing from common reservoirs are enigmatic and generally viewed as phenomenal in some fields worldwide. The challenge posed by such discordant production trends forecloses the preponderance of totally and partially abandoned production, especially in aging fields. This study assesses possible factors associated with varying well production trends from a common reservoir in a field in the onshore western Niger Delta, by integrating multi-geoscience parameters including formation evaluation, 3D quantitative seismic analyses, paleoenvironmental diagnoses, paleobathymetric studies, and reservoir petrophysics to unravel the complexity of the reservoir. Composite well logs were collected from five wells selected for the study. Gamma-ray and SP logs were combined to delineate the depositional environment of "Heri sand" based on Schlumberger's (1985) log motif classification. The results were applied and found useful to develop an optimum recovery production plan for the study field. It has been revealed from this study that declined production performances of the Heri sand reservoir are attributed to the deposition of the reservoir in three distinct paleoenvironments under different bathymetric settings within a coeval period. These factors constitute strong influences on the petrophysics of the reservoir which invariably influences’ the production performance of the reservoir. Having realized the cause of the declined rate of the reservoir in the Anda field, the reservoir can be revitalized by well injection and fracturing.

show abstract

“…These formations vary in age of deposition and composition. The Benin Formation overlies the Agbada Formation and comprises the unconsolidated sands and sandstones with thicknesses ranging from 0 to 2100 m (11) . The Agbada Formation underlies the Benin Formation and ranges from Eocene to recent.…”

Section: Location and Geology Of The Study Areamentioning

confidence: 99%

Assessment of updated low frequency model in delineating bypassed hydrocarbon reservoir: A 4D seismic study of ’X’ - field, offshore, Niger Delta, Nigeria

Akpan¹

2020

IJST

View full text Add to dashboard Cite

Aim/objectives: The aim of this research is, to use Time lapse (4D) seismic and investigate the influence of low frequency update in deterministic model-based seismic inversion employed in delineating a prospect saturated with bypassed hydrocarbon accumulation. Method: The dataset employed in this study incorporates 4D seismic volumes with fifteen (15) years production, interval between 2001 baseline and 2016 monitor seismic vintages. The inversion was carried out using full bandwidth of the updated low frequency and bandpass filtered low frequency approaches. The seismic vintages (baseline and monitor) were simultaneously inverted into acoustic impedance volumes for the two approaches. The formation fluid and lithology were discriminated through fluid replacement modelling (FRM) based on the colour separation between brine and gas saturation scenarios. Findings: The two inversion methods employed reveal six (6) zones suspected to be saturated with bypassed hydrocarbons. The delineated bypassed zones are masked in the full bandwidth approach,depicting the effect of the updated low frequency model. Meanwhile, the bandpass filtered approach result presents a better delineated bypassed reservoir as the zones are more pronounced when compared with the full bandwidth approach. Porosity estimate reveals that the bandpass filtered approach is characterized with excellent porosity in the suspected bypassed zones. The results equally gave more reliable and full delineated bypassed zones. Originality and novelty: The dataset employed in this study were obtained from a producing hydrocarbon field which, interest is to maximize the production of oil/gas. The study will bridge the inherent gab observed in using model-based seismic inversion approach to analyse and interpret seismic data in order to delineate hydrocarbon prospects. The research reveals that,the model-based seismic inversion method is still very effective in delineating hydrocarbon prospect when the updated low frequency is bandpass filtered to remove the model effect which influences the inverted acoustic impedance results. Keywords: Porosity; frequency; bypassed; reservoir and impedance

show abstract

Anisotropic Avo Analysis for Reservoir Characterization in Derby Field Southeastern Niger Delta

Cited by 3 publications

References 12 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

Geoscience Assessment of Declined Production Rate and Recovery from a Reservoir in “ANDA” Field, Onshore Southwestern Niger Delta

Assessment of updated low frequency model in delineating bypassed hydrocarbon reservoir: A 4D seismic study of ’X’ - field, offshore, Niger Delta, Nigeria

Contact Info

Product

Resources

About