Effect of Gas Cap and Aquifer Strength on Optimal Well Location for Thin-Oil Rim Reservoirs

Iyare, U. C.; Silva, Jill K. Marcelle-de

doi:10.2118/158544-ms

Cited by 7 publications

(4 citation statements)

References 24 publications

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“…These factors did not incorporate major operational and reservoir parameters, and the estimation of oil recovery is based on sensitivity analysis. Oil rim recovery has been documented by few authors such as Iyare and Marcelle-De Silva (2012) by initiating sensitivity analysis on important uncertainties that affect oil rim productivity. The results obtained from these methods are from a randomly selected production scheme and static uncertainties.…”

Section: Introductionmentioning

confidence: 99%

“…Experimental designs were used by Olamigoke and Peacock (2012) to suggest and validate effective screening models for optimizing oil and gas recovery in oil rim reservoirs. Kabir et al (2002) and Obah et al (2012) both designed an experiment with limited uncertainties to develop a response surface model to estimate oil recovery in oil rim reservoirs. Although their work did not include a Pareto analysis, the higher the number of these parameters, the more effective the Pareto analysis of significant parameters.…”

Section: Introductionmentioning

confidence: 99%

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Effect of water and gas injection schemes on synthetic oil rim models

Olabode

2020

J Petrol Explor Prod Technol

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Oil recovery in oil rim reservoirs is usually affected by reservoir and operational parameters. An experiment was designed to develop various types of oil rims with a broader range of uncertainties. Mensuration analysis was used to create the basic grid designs, while the Eclipse software was used to incorporate pressure, volume and temperature and reservoir fluid properties to create a black oil model for oil rims. The reservoir models were conditioned to a simultaneous production scheme through which a response surface model was generated to represent oil recovery for all the models. The models were later classified into drive mechanisms based on the results from the Pareto analysis. Various secondary injection schemes were carried out based on reservoir geometry to investigate their response on oil recovery. Results show that for single injection schemes, oil recovery from water down-dip (6.5%) and water up-dip (4.37%) was higher than gas scheme injection for reservoir model 10. Oil recovered from up-dip and down-dip water injection (7.1%) was higher than gas up-dip and down-dip injection (0.03%) for reservoir model 10, and for the same model, an oil recovery of 7.7% and 5.63% was recorded for gas up-dip and water down-dip injection and gas down-dip and water up-dip injection, respectively. The final analysis shows that there is an appreciable increase in oil recovery when injection rates are increased as seen in water down-dip and up-dip injection with 15.43% recovery for reservoir model 10.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of water and gas injection schemes on synthetic oil rim models

Olabode

2020

J Petrol Explor Prod Technol

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“…They highlighted the impact of force balance changes (coning tendency) by increasing the viscous withdrawal with the use of horizontal wells, coupled with gas re-injection to obtain higher recovery efficiency. Iyare and Marcelle-de Silva (2012) carried out an investigation on well placement using a single-well numerical simulator to study the effect of gas cap and aquifer sizes on the production of a thin oil rim reservoir. Their results indicated that placement of the horizontal well below the water-oil-contact (WOC) is more favorable for a large gas cap reservoir; and the well should be placed above gas-oilcontact (GOC) for a reservoir with a small gas cap and large aquifer.…”

Section: Introductionmentioning

confidence: 99%

Integrated reservoir management in a Niger Delta oil rim field

2020

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Several hundred million barrels of oil and trillions standard cubic feet of gas are enclosed within the oil rim reservoirs in the Niger Delta. The low recovery from these reservoirs can be attributed to the excessive early water and gas breakthrough at the wells which requires immediate attention. However, the majority of oil rims are thinly bedded and exist between strong aquifers and large gas caps which make preventing water and gas coning a very difficult task. The best approach to optimize production from these oil rims is effective reservoir management which involves evaluation, monitoring, goal setting, and revision of a few strategies for efficient field development. Current strategies to lessen these problems are limited due to their complexities and low recovery factor. This paper presents an integrated reservoir management approach for improved exploitation of an oil rim reservoirs in the Niger Delta. Seven development strategies were evaluated using Net-Present Value (NPV), Internal Rate of Return (IRR), and Discounted Payout Period (DPOP) criteria. In all these strategies, well placement, number of years of production, and production cycle were considered uncertain. The results show that well placement has a significant impact on efficient oil rims development. Therefore, by using a 1500 ft horizontal well, and a concurrent ABOUT THE AUTHORS

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“…Note that in most cases the optimal recovery rate falls between the critical rate and the maximum recoverable rate for that well. Optimization in this sense is necessary because the critical rate is usually not economical and producing at very high rates leads to early fluid breakthrough which also leads to high production cost or early abandonment of the well, thereby leaving behind large volumes of oil in the reservoir [13,14]. In view of this, a balance must be created between the cost of production (which is a function of years of production before abandonment), the volume of fluid recovered (which is a function of the production rate), and volume of fluid left in the reservoir as a result of abandonment due to coning [15].…”

Section: Introductionmentioning

confidence: 99%

Mathematical Approach to Determination of Optimum Oil Production Rate in Oil Rim Reservoirs

Julian¹,

Toochukwu²,

Ohia³

et al. 2019

PSE

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Oil rim reservoirs present unique problems during production. This is because of the proximity of the water and/or gas to the oil in the pay zone leading to phase distortion due to pressure disequilibrium during production of the oil. The resultant effect is early water/gas breakthroughs which ultimately lead to increased well operational cost, damage to production equipment and eventually to early loss of the well. Production rate becomes crucial as it directly or indirectly affects the overall recovery efficiency from the well. Low rate production signifies longer well production period due to delayed breakthrough time but at the expense of higher well operational cost per unit volume of oil produced, while higher rate production signifies higher oil volume per unit cost of well operation but with increased risk of losing the well due to water/gas breakthrough. Operators produce at a rate deemed economic in order to make profits. Most economic rates are higher than the critical rate which is the rate considered that coning would be maximally delayed. To optimize production, it is necessary to recover most of the fluid from the reservoir before abandonment. Higher recovery factors means that less volume of fluid is left in the reservoir at abandonment. The optimum oil production rate is the best economic oil rate that would result to the highest recovery factor obtainable from that well. The question is what rate is considered optimal and how can it be calculated? This work presents a mathematical model solution for the calculation of the optimum oil production rate. It takes cognizance of the recovery factor and the time value of money and present an analytical model to calculate the optimum oil production rate. From the work the optimum oil production rate was calculated to be 918.63stb/d while the critical oil rate was calculated to be 20.17stb/d.

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Effect of Gas Cap and Aquifer Strength on Optimal Well Location for Thin-Oil Rim Reservoirs

Cited by 7 publications

References 24 publications

Effect of water and gas injection schemes on synthetic oil rim models

Effect of water and gas injection schemes on synthetic oil rim models

Integrated reservoir management in a Niger Delta oil rim field

Mathematical Approach to Determination of Optimum Oil Production Rate in Oil Rim Reservoirs

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