Free Surface Multiple Removal Using 3D Surface Related Multiple Elimination Technique on 3D Seismic Data from Offshore Niger Delta

The basic theory of surface-related multiple elimination (SRME) can be formulated easily for 3D seismic data. However, because standard 3D seismic acquisition geometries violate the requirements of the method, the practical implementation for 3D seismic data is far from trivial. A major problem is to perform the crossline-summation step of 3D SRME, which becomes aliased because of the large separation between receiver cables and between source lines. A solution to this problem, based on hyperbolic sparse inversion, has been presented previously. This method is an alternative to extensive interpolation and extrapolation of data. The hyperbolic sparse inversion is formulated in the time domain and leads to few, but large, systems of equations. In this paper, we propose an alternative formulation using parabolic sparse inversion based on an efficient weighted minimum-norm solution that can be computed in the angular frequency domain. The main advantage of the new method is numerical efficiency because solving many small systems of equations often is faster than solving a few big ones. The method is demonstrated on 3D synthetic and real data with reflected and diffracted multiples. Numerical results show that the proposed method gives improved results compared to 2D SRME. For typical seismic acquisition geometries, the numerical cost running on 50 processors is [Formula: see text] per output trace. This makes production-scale processing of 3D seismic data feasible on current Linux clusters.

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Evaluation of seismic attributes for reservoir characterization over Edi field, Niger delta, Nigeria using 3d seismic data

International Journal of Advanced Geosciences ◽

10.14419/ijag.v8i2.31043 ◽

2020 ◽

Vol 8 (2) ◽

pp. 168

Author(s):

Nyeneime O. Etuk ◽

Mfoniso U. Aka ◽

Okechukwu A. Agbasi ◽

Johnson C. Ibuot

Keyword(s):

Seismic Data ◽

Niger Delta ◽

Reservoir Characterization ◽

Seismic Attributes ◽

3D Seismic ◽

Root Mean Square Amplitude ◽

Phase Gradient ◽

Major Fault ◽

Seismic Sections ◽

3D Seismic Data

Seismic attributes were evaluated over Edi field, offshore Western Niger Delta, Nigeria, via 3D seismic data. Manual mappings of the horizons and faults on the in-lines and cross-lines of the seismic sections were done. Various attributes were calculated and out put on four horizons corresponding to the well markers at different formations within the well were identified. The four horizons identified, which includes: H1, H2, H3 and H4 were mapped and interpreted across the field. The operational agenda was thru picking given faults segments on the in–line of seismic volume. A total of five faults coded as F1, F2, F3, F4 and F5, F1 and F5 were the major fault and were observed as extending through the field. Structural and horizon mappings were used to generate time structure maps. The maps showed the various positions and orientations of the faults. Different attributes which include: root mean square amplitude, instantaneous phase, gradient magnitude and chaos were run on the 3D seismic data. The amplitude and incline magnitude maps indicate direct hydrocarbon on the horizon maps; this is very important in the drilling of wells because it shows areas where hydrocarbons are present in the subsurface. The seismic attributes revealed information, which was not readily apparent in the raw seismic data.

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Preliminary structural evaluation of an X-Field Onshore Niger Delta using 3D seismic data

International Journal of the Physical Sciences ◽

10.5897/ijps2016.4508 ◽

2016 ◽

Vol 11 (12) ◽

pp. 149-156 ◽

Cited By ~ 1

Author(s):

N Ehirim C ◽

A E Abbey M

Keyword(s):

Seismic Data ◽

Niger Delta ◽

3D Seismic ◽

Structural Evaluation ◽

3D Seismic Data

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Structure of the footwall of a listric fault system revealed by 3D seismic data from the Niger Delta

Basin Research ◽

10.1111/j.1365-2117.2011.00514.x ◽

2011 ◽

Vol 24 (1) ◽

pp. 107-123 ◽

Cited By ~ 6

Author(s):

Dominic Maloney ◽

Richard Davies ◽

Jonathan Imber ◽

Stephen King

Keyword(s):

Seismic Data ◽

Niger Delta ◽

Fault System ◽

3D Seismic ◽

Listric Fault ◽

3D Seismic Data

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Transition zones analysis using empirical capillary pressure model from well logs and 3D seismic data on ‘Stephs’ field, onshore, Niger Delta, Nigeria

Journal of Petroleum Exploration and Production Technology ◽

10.1007/s13202-019-00814-2 ◽

2019 ◽

Vol 10 (3) ◽

pp. 1227-1242

Author(s):

O. Abiola ◽

F. O. Obasuyi

Keyword(s):

Capillary Pressure ◽

Seismic Data ◽

Niger Delta ◽

Time Structure ◽

Well Logs ◽

3D Seismic ◽

Seismic Section ◽

Transition Zones ◽

Mobile Water ◽

3D Seismic Data

AbstractCapillary pressure is an important characteristic that indicates the zones of interaction between two-phase fluids or fluid and rock occurring in the subsurface. The analysis of transition zones (TZs) using Goda (Sam) et al.’s empirical capillary pressure from well logs and 3D seismic data in ‘Stephs’ field, Niger Delta, was carried out to remove the effect of mobile water above the oil–water contact in reservoirs in the absence of core data/information. Two reservoirs (RES B and C) were utilized for this study with net thicknesses (NTG) ranging from 194.14 to 209.08 m. Petrophysical parameters computed from well logs indicate that the reservoirs’ effective porosity ranges from 10 to 30% and the permeability ranges from 100 to > 1000 mD, which are important characteristics of good hydrocarbon bearing zone. Checkshot data were used to tie the well to the seismic section. Faults and horizons were mapped on the seismic section. Time structure maps were generated, and a velocity model was used to convert the time structure maps to its depth equivalent. A total of six faults were mapped, three of which are major growth faults (F1, F4 and F5) and cut across the study area. Reservoir properties were modelled using SIS and SGS. The capillary pressure log, curves and models generated were useful in identifying the impact of mobile water in the reservoir as they show the trend of saturating and interacting fluids. The volume of oil estimated from reservoirs B and C without taking TZ into consideration was 273 × 106 and 406 × 106 mmbbls, respectively, and was found to be higher than the volume of oil estimated from the two reservoirs while taking TZ into consideration which was 242 × 106 and 256 × 106 mmbbls, respectively. The results have indicated the presence of mobile water, which have further established that conventionally recoverable hydrocarbon (RHC) is usually overestimated; hence, TZ analysis has to be performed for enhancing RHC for cost-effective extraction and profit maximization.

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