Rock physics templates modeling for time-lapse seismic analysis of reservoir M1 in Moremi Field, Offshore Niger Delta Basin.

2019 ◽  
Author(s):  
John Onayemi ◽  
Ahmad Adeniji ◽  
Anuoluwa Osinaike
Keyword(s):  
Niger Delta ◽  
Seismic Analysis ◽  
Rock Physics ◽  
Time Lapse ◽  
Niger Delta Basin

scholarly journals Lithology and fluid discrimination using rock physics-based modified upper Hashin–Shtrikman bound: an example from onshore Niger Delta Basin

2021 ◽  
Vol 11 (2) ◽  
pp. 569-578
Author(s):  
C. G. Okeugo ◽  
K. M. Onuoha ◽  
A. C. Ekwe
Keyword(s):  
Upper Bound ◽  
Acoustic Impedance ◽  
Niger Delta ◽  
Rock Physics ◽  
Time Lapse ◽  
Successful Prediction ◽  
Niger Delta Basin ◽  
Reservoir Connectivity ◽  
4D Seismic ◽  
Gas Bearing

AbstractThe Ozifa reservoir is proven reservoir that cuts across the Northern and Greater Ughelli depo-belts of the Niger Delta Basin. This reservoir possesses heterogenous character southward of the field, making elastic properties, lithologies and fluid types difficult to describe accurately. In this study, rock physics template was applied to porosity and acoustic impedance (AI) crossplot clusters to illustrate rock–fluid relationships using modified Hashin–Shtrikman upper bound, Voigt upper bound and Reuss lower bound, as an input in the template. Values of acoustic impedance and porosity were used as lithofacies classification parameters for discrimination of lithofacies and fluid types. Our result showed that modified Hashin–Shtrikman upper bound line when applied in acoustic impedance (AI) and porosities (φ) crossplot domain discriminated gas-filled reservoirs from brine filled reservoirs and shale effectively. Similarly, results from crossplot showed clear separation of shale, heteroliths filled with brine and gas bearing sand, which was not plausible using conventional petrophysical analysis. This approach was successfully applied in analysing lithofacies and fluid relationship in different well locations and serves as a model for successful prediction of different lithology and fluid types, a major requirement for determining effects of geological variables such as sorting, clay distributions on the reservoir connectivity and optimum production using time-lapse (4D) seismic interpretation.

scholarly journals Time-Lapse Seismic Monitoring of Onshore Reservoirs in Niger Delta, Field ‘K’ as a Case Study

2017 ◽  
Vol 1 (1) ◽  
pp. 23-27 ◽  
Author(s):  
A. Ogbamikhumi ◽  
T. Tralagba ◽  
E. E. Osagiede
Keyword(s):  
Seismic Data ◽  
Acoustic Impedance ◽  
Niger Delta ◽  
Rock Physics ◽  
Time Lapse ◽  
Seismic Survey ◽  
Impedance Change ◽  
Data Set ◽  
Reservoir Fluid ◽  
4D Seismic

Field ‘K’ is a mature field in the coastal swamp onshore Niger delta, which has been producing since 1960. As a huge producing field with some potential for further sustainable production, field monitoring is therefore important in the identification of areas of unproduced hydrocarbon. This can be achieved by comparing production data with the corresponding changes in acoustic impedance observed in the maps generated from base survey (initial 3D seismic) and monitor seismic survey (4D seismic) across the field. This will enable the 4D seismic data set to be used for mapping reservoir details such as advancing water front and un-swept zones. The availability of good quality onshore time-lapse seismic data for Field ‘K’ acquired in 1987 and 2002 provided the opportunity to evaluate the effect of changes in reservoir fluid saturations on time-lapse amplitudes. Rock physics modelling and fluid substitution studies on well logs were carried out, and acoustic impedance change in the reservoir was estimated to be in the range of 0.25% to about 8%. Changes in reservoir fluid saturations were confirmed with time-lapse amplitudes within the crest area of the reservoir structure where reservoir porosity is 0.25%. In this paper, we demonstrated the use of repeat Seismic to delineate swept zones and areas hit with water override in a producing onshore reservoir.

scholarly journals Rock physics attribute analysis for hydrocarbon prospectivity in the Eva field onshore Niger Delta Basin

2020 ◽  
Vol 10 (8) ◽  
pp. 3127-3138
Author(s):  
Alexander Ogbamikhumi ◽  
Nosa Samuel Igbinigie
Keyword(s):  
Feasibility Study ◽  
Niger Delta ◽  
Poisson Ratio ◽  
Rock Physics ◽  
Plot Analysis ◽  
Attribute Analysis ◽  
Geological Conditions ◽  
Niger Delta Basin ◽  
Ratio Versus

Abstract Direct hydrocarbon indicator (DHI) expressions observed on seismic could arise due to various geological conditions. Such expression could lead to misinterpretation as hydrocarbon presence if not properly analyzed. This study employs rock physics attributes analysis to evaluate an identified prospect in the undrilled area of the studied reservoir. Prospect identification was actualized by analyzing structural and amplitude maps of the reservoir, which revealed a possible roll over anticline at both the exploited and prospective zone, with a very good amplitude support that conforms to structure. Well-based cross-plot analysis adopted four cross-plot techniques for feasibility study to test the applicability of rock physics for prospect evaluation in the field; Lambda-Rho versus Lambda-Rho/Mu-Rho ratio; Mu-Rho versus Lambda-Rho; and Poisson Ratio versus P-impedance. The result presented Poisson ratio, Lambda-Rho and Lambda/Mu-Rho ratio as good fluid indicator and Mu-Rho as a viable lithology indicator. As such, they were selected for seismic-based attribute and cross-plot analysis to validate the identified prospect. The results from seismic-based analysis showed consistency in the expression of the analyzed attribute at both the exploited and prospective zone. The seismic-based cross-plot analysis result was similar to the well-based analysis and was able to confirm that the observed amplitude expression in the exploited zone is an indication of hydrocarbon-bearing sand.

scholarly journals Correction to: Lithology and fluid discrimination using rock physics-based modified upper Hashin–Shtrikman bound: an example from onshore Niger Delta Basin

2021 ◽  
Author(s):  
C. G. Okeugo ◽  
K. M. Onuoha ◽  
A. C. Ekwe
Keyword(s):  
Niger Delta ◽  
Rock Physics ◽  
Original Publication ◽  
Niger Delta Basin

In the original publication of the article, table 2 and some of the figures were incorrectly published.

scholarly journals Application of rock physics parameters for lithology and fluid prediction of ‘TN’ field of Niger Delta basin, Nigeria

2018 ◽  
Vol 27 (4) ◽  
pp. 853-866 ◽  
Author(s):  
Chukwuemeka Patrick Abbey ◽  
Emele Uduma Okpogo ◽  
Ifeyinwa Obiageli Atueyi
Keyword(s):  
Niger Delta ◽  
Rock Physics ◽  
Niger Delta Basin

scholarly journals Quantitative seismic analysis of a thin layer of CO2 in the Sleipner injection plume

Geophysics ◽  
2012 ◽  
Vol 77 (6) ◽  
pp. R245-R256 ◽  
Author(s):  
Gareth Williams ◽  
Andrew Chadwick
Keyword(s):  
Thin Layer ◽  
Seismic Analysis ◽  
Rock Physics ◽  
Time Lapse ◽  
Thin Layers ◽  
Single Frequency ◽  
Small Scale ◽  
Seismic Reflection Data ◽  
Initial Application ◽  
Topmost Layer

Time-lapse seismic reflection data have proved to be the key monitoring tool at the Sleipner [Formula: see text] injection project. Thin layers of [Formula: see text] in the Sleipner injection plume show striking reflectivity on the time-lapse data, but the derivation of accurate layer properties, such as thickness and velocity, remains very challenging. This is because the rock physics properties are not well-constrained nor are [Formula: see text] distributions on a small scale. However, because the reflectivity is dominantly composed of interference wavelets from thin-layer tuning, the amplitude and frequency content of the wavelets can be diagnostic of their temporal thickness. A spectral decomposition algorithm based on the smoothed pseudo Wigner-Ville distribution has been developed. This enables single frequency slices to be extracted with sufficient frequency and temporal resolution to provide diagnostic spectral information on individual [Formula: see text] layers. The topmost layer of [Formula: see text] in the plume is particularly suitable for this type of analysis because it is not affected by attenuation from overlying [Formula: see text] layers and because there are areas in which it is temporally isolated from deeper layers. Initial application of the algorithm to the topmost layer shows strong evidence of thin-layer tuning effects. Analysis of tuning frequencies on high-resolution 2D data suggests that layer two-way temporal thicknesses in the range 6 to 11 ms can be derived with an accuracy of c. 2 ms. Direct measurements of reflectivity from the top and the base of the layer permit calculation of layer velocity, with values of around [Formula: see text], in reasonable agreement with existing rock physics estimates. The frequency analysis can, therefore, provide diagnostic information on layer thicknesses in the range of 4 to 8 ms. The method is currently being extended to the full 3D time-lapse data sets at Sleipner.

scholarly journals Hydrocarbon Prospectivity in the undrilled area of AIMA Field in the Niger Delta Basin, Nigeria.

2021 ◽  
Vol 6 (1) ◽  
pp. 34-41
Author(s):  
Alexander Ogbamikhumi ◽  
John Elvis Ighodalo
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Niger Delta ◽  
Water Saturation ◽  
Poisson Ratio ◽  
Rock Physics ◽  
Reservoir Properties ◽  
Field Development ◽  
Seismic Reservoir ◽  
Niger Delta Basin

Field development is a very costly endeavor that requires drilling several wells in an attempt to understanding potential prospects. To help reduce the associated cost, this study integrates well and seismic based rock physics analysis with artificial neural network to evaluation identified prospects in the field.  Results of structural and amplitude maps of three major reservoir levels revealed structural highs typical of roll over anticlines with amplitude expression that conforms to structure at the exploited zone where production is currently ongoing. Across the bounding fault to the prospective zones, only the D_2 reservoir possessed the desired amplitude expression, typical of hydrocarbon presence. To validate the observed amplitude expression at the prospective zone, well and seismic based rock physics analyses were performed. Results from the analysis presented Poisson ratio, Lambda-Rho and Lambda/Mu-Rho ratio as good fluid indicator while Mu-Rho was the preferred lithology indicator.  These rock physics attributes were employed to validate the observed prospective direct hydrocarbon indicator  expressions on seismic. Reservoir properties maps generated for porosity and water saturation prediction using Probability Neural Network gave values of 20-30% and 25-35% for water saturation and porosity respectively, indicating  the presence of good quality hydrocarbon bearing reservoir at the prospective zone.

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