Estimation Of Height Of Oil -Water Contact Above Free Water Level Using Capillary Pressure Method For Effective Classification Of Reservoirs In The Niger Delta

Okolie, EC; Ujanbi, O

doi:10.4314/njphy.v19i2.38146

Cited by 2 publications

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“…The oil-water contact is the surface in a subsurface reservoir separating the oil from the water. According to Okolie and Ujanbi (2007), evaluation of oil-water contact within the Niger Delta reservoir is difficult due to the presence of interbedded shale layers in the reservoir. In this study, the oil water contacts across the four wells in Fig.…”

Section: Well Log Analysismentioning

confidence: 99%

Reservoir characterization and volumetric estimation of reservoir fluids using simulation and analytical methods: a case study of the coastal swamp depobelt, Niger Delta Basin, Nigeria

Kurah

Shariatipour

Itiowe³

2021

J Petrol Explor Prod Technol

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Suites of wireline well logs and three-dimensional (3D) seismic data were integrated to characterise the reservoir and estimate the hydrocarbon in Otigwe field, coastal swamp depositional belt, Niger Delta. The 3D seismic data were used to generate seismic sections through which fourteen faults and two horizons of interest were mapped across four wells. Depth structural map generated from the mapped faults and horizons of interest shows that the trapping mechanism within the field is fault-supported anticlinal structural trap. The four available wells were correlated using lithostratigraphic correlation to establish two reservoir continuities (Reservoir A and B). The estimated reservoir fluid volume at surface condition using reservoir simulation and modelling software is 59 MMstb for reservoir A and 25.70 MMstb for reservoir B. On the other hand, the estimated reservoir fluid volume at surface condition using analytical method is 52.58 MMstb for reservoir A and 18.85 MMstb for reservoir B. Using reservoir simulation and modelling software, the average net-to-gross ratio and shale volume for reservoir A range from 0.86 to 0.89 and 0.11 to 0.14, respectively, while for reservoir B the range is between 0.69 to 0.82 and 0.18 to 0.31, respectively. On the flipside using the analytical method, the average net-to-gross ratio and shale volume for reservoir A is 0.78 and 0.22, respectively. The results from the volumetric estimation of reservoir fluids showed close values using both methods and reservoir A is more prolific compare to B.

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Section: Well Log Analysismentioning

confidence: 99%

Reservoir characterization and volumetric estimation of reservoir fluids using simulation and analytical methods: a case study of the coastal swamp depobelt, Niger Delta Basin, Nigeria

Kurah

Shariatipour

Itiowe³

2021

J Petrol Explor Prod Technol

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“…Two non-miscible fluids sharing the same porous space tend to occupy different positions depending on their density contrast (Glover 2000;Pascoal 2015). Vavra et al (1992), Hartmann and Beaumont (1999), Larsen et al (2000), Sarwaruddin et al (2001), Kumar et al (2002), Wiltgen et al (2003), Johan and Svein (2005), Okoli and Ujanbi (2007), Jamiolahmady et al (2007), Zhao et al (2008), Renzo et al (2010) and Goda (Sam) et al (2011) have employed a different approach to analyse the oil transition zone and saturation height above free water level using semi-empirical relationship from Leverett (1941), Skelt and Harrison (1995), Christiansen (2001), Wu (2004), amongst others, with special core analysis (SCAL) under laboratory conditions. Hydrocarbon saturation in a reservoir can be overestimated when the effect of mobile water occurring in the transition zones within the reservoir is not accounted for while estimating reserves (Fig.…”

Section: Introductionmentioning

confidence: 99%

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

Abiola

Obasuyi

2019

J Petrol Explor Prod Technol

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Capillary 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 × 10 6 and 406 × 10 6 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 × 10 6 and 256 × 10 6 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.Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

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Estimation Of Height Of Oil -Water Contact Above Free Water Level Using Capillary Pressure Method For Effective Classification Of Reservoirs In The Niger Delta

Cited by 2 publications

References 0 publications

Reservoir characterization and volumetric estimation of reservoir fluids using simulation and analytical methods: a case study of the coastal swamp depobelt, Niger Delta Basin, Nigeria

Reservoir characterization and volumetric estimation of reservoir fluids using simulation and analytical methods: a case study of the coastal swamp depobelt, Niger Delta Basin, Nigeria

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

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