Depletion oil recovery for systems with widely varying initial composition

Singh, Kameshwar; Fevang, Øivind; Whitson, Curtis Hays

doi:10.1016/j.petrol.2005.01.008

Cited by 7 publications

(2 citation statements)

References 6 publications

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“…In addition, the interpretation of these nearcritical systems as connected or compartmentalized can have a significant impact on development plan (Singh et al 2005). Figure 11 is the map-based corollary of the schematic cross-sections presented in Figure 8a, b, with pre-and post-production interpretations.…”

Section: Discussionmentioning

confidence: 99%

Compartmentalization or gravity segregation? Understanding and predicting characteristics of near-critical petroleum fluids

Páez

Lawerence

Zhang

2010

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Compartmentalized reservoirs can be identified based on a variety of criteria most commonly using structural geometries and stratigraphic barriers. This paper reviews several case studies from West African fields in which an additional variable, fluid chemistry, is used to identify compartmentalization at an early stage in the production history. Fluid characterization is important to constrain productivity, connectivity, facilities planning, and commercial value. Near-critical, single-phase fluids offer a case in which underestimation fluid PVT behaviour and variability can have a significant impact on all of these elements – resulting in incorrect interpretations of resource type and distribution.

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Section: Discussionmentioning

confidence: 99%

Compartmentalization or gravity segregation? Understanding and predicting characteristics of near-critical petroleum fluids

Páez

Lawerence

Zhang

2010

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“…Singh et al (2005) studied depletion recovery for synthetic reservoirs with a wide range of initial compositions and found that the recovery for a fluid near critical point was lower than those from volatile oil and gas condensate reservoirs. Condensate liquid drops out in the reservoir when the reservoir pressure falls below the dew point pressure and gets trapped in the reservoir.…”

Section: Development Strategymentioning

confidence: 99%

Subsurface Appraisal and Field Development Planning of the Gas Condensate Field GVLA

et al. 2013

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The Greater Vanza Longui Area (GVLA) field is located in Area B of the offshore Cabinda, Angola Block 0 concession. GVLA is a multi field development and will target hydrocarbon resources in the Cretaceous Pinda formation that contain reservoirs with rich gas condensates and underlying volatile oil rims.The objective of this paper is to demonstrate the rigorous subsurface evaluation process employed for developing a large offshore gas condensate field. The strength of the reservoir evaluation is the large amount of good quality appraisal data gathered and used to benchmark subsurface inputs. There have been 6 reservoir penetrations, 4 DSTs and 3 full reservoir cores and multiple fluid samples.A structured workflow was followed to identify and incorporate the uncertainties in the subsurface assessment. Probabilistic forecasts helped to fully characterize and realistically assess the uncertainties. The uncertainties were grouped mainly into static and dynamic categories.The impact of the static uncertainties was assessed using 3-D geological models. Geologic models were built upon a corebased sequence stratigraphic framework for the Pinda formation. The facies, petrophysical properties and top depth of reservoir were varied to capture the uncertainty ranges seen in the GVLA wells and analogue fields. These models captured the net-to-gross uncertainty which has the largest impact on hydrocarbons in-place and connectivity.The dynamic uncertainties were assessed using statistical design of experiments. Monte Carlo simulations were employed to generate the probabilistic estimates. Reservoir simulation with the compositional formulation was used as the primary forecasting method. Robust equation-of-state models were built to appropriately quantify natural gas liquids (LPGs) which were value drivers for the project. Various development alternatives (primary depletion, gas injection) were evaluated and detailed economic analysis were performed for concept selection. The production forecasts were verified with material balance models, analogues. OTC 24108developed using an FPSO for LPG sales, which provided a potential outlet for the discovered GVLA resource. Further appraisal of GVLA in 2008-2010 was completed by drilling the G6, G2 and G3 wells. The results of these wells, and their integration into the new reservoir models removed the geologic risk, reduced subsurface uncertainties, and confirmed hydrocarbon resources similar to pre-drill estimates. Regional GeologyThe GVLA development is comprised of five adjacent Pinda fault blocks. Longui Main is the large horst block on the western side of GVLA; Longui East is a down-thrown graben to the east of Longui Main; 79-B is comprised of a series of tilted and rotated horst blocks that dip to the east; Vanza is a northwest-southeast oriented horst block that along with the 80-E fault block forms the eastern edge of GVLA (see Fig. 2). Oil and gas are trapped by dip closure against bounding normal and listric faults that provide a seal along the boundaries of the individual fa...

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