Magnus WAG Pattern Optimization Through Data Integration

Erbas, Demet; Dunning, Matthew; Nash, Timothy M.; Cox, D. C.; Stripe, John A.; Duncan, Euan

doi:10.2118/169167-ms

Cited by 3 publications

(1 citation statement)

References 7 publications

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“…It can be concluded that North Sea is the offshore leader of worldwide WAG applications. Erbas et al (2014) reported that Magnus tertiary miscible gas injection which was started in 2002 through a WAG scheme, took the recovery factor close to 56% of the OOIP. Magnus has a Magnus sandstone member (MSM) and a lower Kimmeridge Clay Formation (LKCF).…”

Section: Water Alternating Gas (Wag) Methodsmentioning

confidence: 99%

A review of gas enhanced oil recovery schemes used in the North Sea

Gbadamosi

Kiwalabye

Junin

et al. 2018

J Petrol Explor Prod Technol

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The rate of replacement of produced oil and gas reserves by new discoveries is in a state of steady decline. Instead of searching for rare new oil fields, it is more economically justified to improve production from the existing and known fields. This is often achieved using enhanced oil recovery (EOR) technologies. The application of EOR in the North Sea dates to the mid-1970's with most of the fields being flooded with gas due to their light oils. Following a critical review of relevant published literature, the EOR methods in the past five decades are: water alternating gas (WAG), miscible gas injection (MGI), foam assisted water alternating gas (FAWAG), simultaneous water and gas (SWAG), and microbial enhanced oil recovery. The first part of this paper explores the advantages and limitations of the field implementation of gas EOR methods in North Sea oil fields. In the second part, new screening criteria of WAG, SWAG, MGI and FAWAG were developed by performing statistical analysis of the data from the past field experiences, especially in the North Sea. The screening criteria of the future methods are clearly documented in the literature and therefore not covered in this study. From the screening criteria, it has been identified that most North Sea fields qualify for WAG. This explains why WAG has been the most common scheme in the North Sea. FAWAG should also be implemented either after WAG or SWAG when the residual oil saturation is < 20%.

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Section: Water Alternating Gas (Wag) Methodsmentioning

confidence: 99%

A review of gas enhanced oil recovery schemes used in the North Sea

Gbadamosi

Kiwalabye

Junin

et al. 2018

J Petrol Explor Prod Technol

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Optimize a WAG Field Development Plan, Use Case of Carbonate Ultra-Deep Water Reservoir

et al. 2015

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The low recovery factor associated with carbonate reservoir and the availability of affordable gas has drawn new attention to a Water Alternative Gas (WAG) strategy to enhance hydrocarbon recovery for reservoir at early stage of production. The use of WAG allows to improve sweep efficiency limiting fingering and hydrocarbon trapping at macroscopic (Water injection -WI) and microscopic (pore) (Gas Injection -GI) level.The purpose of this work is twofold: present a new field development plan optimization formulation generalized for continuous and/or WAG injection and its suggested application to a real reservoir test case. Optimum field development plans for different strategies are presented and the advantages of a WAG strategy as opposite to a continuous water injection are further discussed. The proposed optimization problem covers well placement, control, schedule and gas lift under uncertainty. This problem is formulated as Mixed Integer Nonlinear Programing (MINLP) with non-linear constrains in order to take into account operational restrictions.A carbonate deep water reservoir at the early stages of its exploitation has been used to evaluate this new workflow. An in-house Particle Swarm Optimization (PSO) algorithm has been used to solve this nonlinear optimization problem. The use of a real field as test bench poses additional strength on the robustness of the formulation in presence of a large number of decision variables and constrains. Special care has been taken in the field development plan selection, taking into account the optimal solution as well as additional objectives and sentiments added by the decision makers which increase the realism of the final solution.The optima selected were compared to a WAG base case adjusted using standard commercial tools according to best practice. The results obtained for the current reservoir highlight key performances of the optimization algorithm applied to the WAG strategy. WAG increases the recovery factor and enhance an early production (paramount to improve the NPV according to the economic model) with respect to a continuous WI. The optimization of WAG cycles allows to find the best hydrocarbon production under the constrain imposed by the facilities and the gas availability. The optimum inter-well-distance and schedule results from the compromise between a strong sweep yet avoiding an early water breakthrough and reducing interference among producers. The well layout is therefore an output of the NPV optimization, the carbonate geological characterization and the operation risk. The optimal field development plan has shown a 35% of increment in NPV compared to the base case.This workflow presented and discussed presents an innovative and general formulation for the optimization of a WAG and/or continuous injection for real reservoir under uncertainty. The optimization algorithm allows fast convergence and accurate results. The extension to multiple objective functions and the inclusion of the human decision in the optimization process is also considered.

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An Integrated Rejuvenation Project in the UK. From Gas Disposal Issue to WAG Opportunity

Manotti

Renna

Mattei

et al. 2016

Day 1 Mon, March 21, 2016

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Despite the increase of hydrocarbons exploitation from green fields in the last decades, the majority of the global production is still sustained by brown fields contribution. Rejuvenation of mature assets, as the one described in this work, plays a crucial role in current low oil price scenario, improving production with limited investments and risks.Object of this work is an offshore oil field in the UK area in production since 1996. The field is developed by means of water injection for pressure maintenance and gas injection for disposal, with current water-cut higher than 90% and gas-breakthrough in wells close to the disposal area. After the acquisition of the operatorship in 2014, an asset rejuvenation project started, involving an integrated analysis of the field, based on the review of all available static and dynamic data. Combination of basic reservoir engineering tools and advanced modeling simulators was the key element of the performed analysis. This paper shows how an integrated workflow, combining skills from different professional families, allowed to find low cost opportunities with short time-to-market.Production data analysis highlighted low efficiency of current water injection: majority of the injected volume is produced without displacing additional oil. Moreover, the new reservoir compositional model showed presence of by-passed oil in the crestal part of the field not displaced due to gravitational segregation effect.Thanks to the better understanding of the field characteristics and fluids movement, different actions were planned in order to maximize oil recovery. In particular, a screening of possible IOR/EOR techniques showed immiscible WAG as the most promising one to recover un-swept attic oil. Several sensitivities were performed on water and gas injection rates, cycles duration and gas composition, in order to properly evaluate and maximize the expected additional recovery. Based on modeling results, two currently shut-in injectors were selected for a WAG pilot phase. The feasibility study highlighted that only minor plant changes were required, due to the availability of both water and gas injection facilities. This aspect drove the project economics into favorable evaluation. Moreover, moving gas injection from disposal to WAG mitigates well production problems in the disposing area, turning gas injection from an issue to opportunity extending field life. This paper gives a detailed description of the rejuvenation project ongoing on an UK field which main outcome is the start-up of a WAG project. Advanced workflow, combining streamlines and conventional simulators, was used for waterflooding assessment and optimization. This integrated project was carried out with short time to market and minimal expenditure, showing how EOR processes can be an opportunity for field rejuvenation even in a low oil price environment.

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Magnus WAG Pattern Optimization Through Data Integration

Cited by 3 publications

References 7 publications

A review of gas enhanced oil recovery schemes used in the North Sea

A review of gas enhanced oil recovery schemes used in the North Sea

Optimize a WAG Field Development Plan, Use Case of Carbonate Ultra-Deep Water Reservoir

An Integrated Rejuvenation Project in the UK. From Gas Disposal Issue to WAG Opportunity

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