Enhanced Prospect Definition Using Well and 4D Seismic Data in a Niger Delta Field

Dagogo, Tamunonengiyeofori; Ehirim, C. N.; Ebeniro, J. O.

doi:10.4236/ijg.2016.78074

Cited by 10 publications

(6 citation statements)

References 8 publications

(7 reference statements)

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“…This makes Lambda-Rho a better fluid indicator than Mu-Rho which is a matrix indicator that helps to provide direct geological meaningful information about reservoirs [10]. The hydrocarbon zone showed the gas zone lower in Lambda-Rho and density responses than the oil zone [2,10,[39][40][41]. The plot indicates that λρ is more robust than μρ in the analysis of fluids in the field of study and that μρ values are relatively low for the reservoir sand according to [2,3,10].…”

Section: Lambda-rho Against Mu-rhomentioning

confidence: 99%

Fluid and Lithology Discrimination for Reservoir Characterization of HAX Field, Offshore Niger Delta

Umeadi

Balogun

2023

AJR2P

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Fluid and lithology discrimination for reservoir characterization of HAX field, offshore Niger Delta was carried out in this study. Three reservoir intervals, R_4500, R_5500, and R_6500 were picked, identified, and correlated across the four wells; but only the R_5500 reservoir was analyzed. The cross-plot analysis of elastic rock properties with reservoir properties such as Vp/Vs ratio against Acoustic Impedance, Lambda-Rho against Vp/Vs, Mu-Rho against Density, and Lambda-Rho against Mu-Rho colour-coded by gamma ray, water saturation, and density respectively was carried out for fluid and lithology discrimination. The result of these elastic rock properties when colour-coded with gamma ray distinguished reservoir R_5500 into the sand zone and shale zone for the four wells, these results depict lithology discrimination as predominantly found in the Niger Delta basin. Consequently, when colour–coded by water saturation reservoir R_5500 was distinguished into three zones namely the hydrocarbon bearing zone, brine sand zone and shale zone indicative of both lithology and fluid discrimination. From these cross-plots, the clusters with the least water saturation correspond to highly charged hydrocarbon saturation sand while clusters with maximum water saturation correspond to non-hydrocarbon zone (brine sand and shale). Finally, when colour–coded by density reservoir R_5500 was distinguished into four zones namely gas sand zone and oil sand zone, brine sand zone, and shale zone indicating fluid types. The result shows relatively lower Acoustic Impedance, Vp/Vs ratio, lambda-rho, mu-rho, and density (as the colour-code) values indicating hydrocarbon bearing sand while the relatively higher Acoustic Impedance, Vp/Vs ratio, lambda-rho, mu-rho and density (as the colour-code) values are associated with non-hydrocarbon zone (shale and brine sand). This study has been able to discriminate hydrocarbon reservoirs using the cross-plots of elastic rock properties in the zone of interest and proven that the HAX field is viable in terms of hydrocarbon prospects and highly economical for production.

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Section: Lambda-rho Against Mu-rhomentioning

confidence: 99%

Fluid and Lithology Discrimination for Reservoir Characterization of HAX Field, Offshore Niger Delta

Umeadi

Balogun

2023

AJR2P

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“…Withdraw of mass (hydrocarbon) is expected to result in compaction and pressure changes in the reservoir. [2] demonstrated that changes in the rock derived attributes (density, lambda-rho, impedance) indicated change in reservoir properties of a Niger Delta Field (pore saturation and pressure). Similarly, ground subsidence due to hydrocarbon extraction was inferred from evaluating density, lambda-rho and acoustic impedance changes [3].…”

Section: Introductionmentioning

confidence: 98%

Rock Physics Models and Seismic Inversion in Reservoir Characterization, “MUN” Onshore Niger Delta Field

Munyithya¹,

Ehirim²,

Dagogo³

2019

IJG

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Rock Physics Modelling and Seismic Inversion were carried out in an Onshore Niger Delta Field for the purpose of characterizing a hydrocarbon reservoir. The aim of the study was to integrate rock physics models and seismic inversion to improve the characterization of a selected reservoir using well-log and 3D seismic data sets. Seven reservoir sands were delineated using suite of logs from three wells. In this study, the sand 4 reservoir was selected for analysis. The result of petrophysical evaluation shows that the sand 4 reservoir is relatively thick (62 ft) with low water saturation (0.33), shale volume (0.11) and high porosity (0.32). These results indicate reservoir of good quality and producibility. Cross-plot of property pairs (acoustic impedance (I p) vs. lambda-rho (λρ) and mu-rho (µρ) vs. lambda-rho (λρ) color-coded with reservoir properties reveals three distinct probable zones: hydrocarbon sand, brine sand and shale. Results show that low I p , λρ and µρ associated with hydrocarbon charged sands correspond to low S w and V sh and high ϕ. The integration of rock physics models and inverted rock attributes effectively delineated and improved understanding of already producing reservoirs, as well as other hydrocarbon charged sands of low S w , V sh , and high ϕ to the east of existing well locations, which indicate possible bypassed hydrocarbon pays. The results of this work can assist in forecasting hydrocarbon prospectivity and lessen chances of drilling dry holes in MUN onshore Niger delta field.

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“…Estimation of geomechanical properties in the Niger Delta Basin using prestack timemigrated seismic data and well log requires great skill and immense understanding of seismic inversion technique as this is the key to unraveling geomechanical properties from seismic data. Seismic inversion method provides the most detailed view of the earth's subsurface and its applications in the Niger Delta over the years have yielded increase in oil production (Dagogo et al 2016;Akpan et al 2020a, b).…”

Section: Introductionmentioning

confidence: 99%

Application of pre-stack seismic waveform inversion and empirical relationships for the estimation of geomechanical properties in Ruby field, central swamp depobelt, Onshore Niger Delta, Nigeria

Ugbor

Odong

Akpan

2021

J Petrol Explor Prod Technol

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Pre-stack seismic inversion, well log analysis approach and empirical relations were adopted in this study to better estimate geomechanical properties of Ruby field with minimum error. The use of conventional well log empirical method alone to evaluate geomechanical properties in oil/gas fields sometimes becomes problematic. Geomechanical properties were divided into: elastic moduli [Young’s modulus, shear modulus, bulk modulus and Poisson ratio (PR)] and rock mechanical strength properties (closure stress ratio (CSR), brittleness (BRI) and compressibility). Four geomechanical earth models (CSR, BRI, Young’s modulus and PR) were generated from the inversion analysis to understand the distribution of rock strength properties across the field. The results deciphered high Young’s, shear and bulk modulus in the reservoir zone compared to the cap/seal rocks and a decrease in PR. This implies that, the cap/seal are more ductile and less compressible than the reservoir rocks, indicating that the reservoirs are highly brittle. CSR result reveals high in cap/seal indicating that the cap/seal rock are harder to fracture and has a greater chance to withstand higher compressive stress before failing as opposed to reservoir rocks. The inverted earth model shows that, Young’s modulus and brittleness increase toward the northeastern part of the field, while CSR and PR increase toward the southwestern part of the field. These results suggest that harder, stiffer, highly compressible and easily fractured rocks are found in the northern and eastern part of the field as opposed to the southern to western part of the field that is ductile.

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Enhanced Prospect Definition Using Well and 4D Seismic Data in a Niger Delta Field

Cited by 10 publications

References 8 publications

Fluid and Lithology Discrimination for Reservoir Characterization of HAX Field, Offshore Niger Delta

Fluid and Lithology Discrimination for Reservoir Characterization of HAX Field, Offshore Niger Delta

Rock Physics Models and Seismic Inversion in Reservoir Characterization, “MUN” Onshore Niger Delta Field

Application of pre-stack seismic waveform inversion and empirical relationships for the estimation of geomechanical properties in Ruby field, central swamp depobelt, Onshore Niger Delta, Nigeria

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