Production Decline Behavior Analysis of a Vertical Well with a Natural Water Influx/Waterflood

Wei, Mingqiang; Ren, Keyi; Duan, Yunlong; Chen, Qingxuan; Dejam, Morteza

doi:10.1155/2019/1683989

Cited by 8 publications

(4 citation statements)

References 30 publications

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“…Water production decreases the recovery by reduction of the life of the reservoir [17][18][19], limits productivity and efficiency of wells, and elevates safety risks in gas production. Water production can cease the well from production by water loading or make the production economically deficient.…”

Section: Introductionmentioning

confidence: 99%

Water Production Problem in Gas Reservoirs: Concepts, Challenges, and Practical Solutions

Roozshenas

Hematpur²,

Abdollahi³

et al. 2021

Mathematical Problems in Engineering

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Gas resources play a key role in nowadays energy supply and provide 24% of the diverse energy portfolio. Water encroachment is one of the main trapping mechanisms in gas reservoirs. It decreases recovery by reduction of reservoir life, limits productivity and efficiency of wells, and elevates safety risks in gas production. The lack of a comprehensive study about water production problems is the primary motivation for this study. Contrary to the serious concern over the standalone investigation of an actual water production case study, less concern is put to deal with the problem comprehensively through an investigation of all potential sources and mechanisms, required methods, and available techniques. This study presents the potential sources of the problem, methods to identify it, and approaches to address it. Firstly, possible sources are described. Secondly, the diagnostic techniques are expressed. Then, practical solutions used in actual cases to overcome problems are elaborated. The solutions include both well- and reservoir-oriented approaches. Finally, all proper strategies are summarized to tackle the water problems in gas fields. The current study comprehensively presents the available methods for water control problems in parallel with conceptual and qualitative comparison. The finding of this study can be very constructive for better understanding of water sources, available diagnostic tools, and solutions for controlling water production in gas reservoirs and, consequently, taking the best decision in real case studies before attempting many water shut-off approaches.

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Section: Introductionmentioning

confidence: 99%

Water Production Problem in Gas Reservoirs: Concepts, Challenges, and Practical Solutions

Roozshenas

Hematpur²,

Abdollahi³

et al. 2021

Mathematical Problems in Engineering

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show abstract

“…Wei et al developed a transient flow model considering the water influx/waterflood. Subsequently, the functions of the production decline-type curves for a vertical well with a water influx/waterflood are derived based on the material balance equation [10]. Liu and Cheng's research shows that the farther the barriers and interlayers from the OWC, the better the horizontal well development effect [11].…”

Section: Introductionmentioning

confidence: 99%

The Effect of Interlayer on Water Cut Rise in a Bottom Water Reservoir

Hu¹,

Wei

Cheng

et al. 2021

Geofluids

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A bottom water reservoir is universal in all reservoirs in the world. In the exploitation process of the bottom water reservoir, because the reservoir is in complete contact with bottom water, the natural energy supply of the bottom water reservoir is sufficient. At the same time, in the production process, the pressure drop generated by the formation is mainly concentrated near the wellbore, which leads to a short period of waterless oil production, fast water breakthrough, and fast water cut rise, which seriously affects the overall recovery factor and increases the risk of oil filed exploitation. Since the distribution of an interlayer enhances the heterogeneity of the reservoir, it has a prominent impact on the flow of oil and water in the bottom water reservoir. However, people know little about the impact of the interlayer on the bottom water reservoir. In this paper, the mathematical model of two-phase flow in the bottom water reservoir with the interlayer is proposed, and the numerical solution of the model is obtained by a finite element method. The influence of the distribution of the interlayer on the water cut rising law of the bottom water reservoir is analyzed. The results show that the bottom water is blocked by the interlayer and its own gravity and the rising height of the bottom water is limited, so that the interlayer has a significant inhibitory effect on the coning of the bottom water. The closer the interlayer is to the oil-water interface, the faster the water cut will rise; the narrower the interlayer is, the faster the bottom water ridge will advance; when the width of the interlayer is the same as that of the reservoir, the water cone will not appear; the higher the permeability of the interlayer is, the faster the upper body of the water cut will be; when the permeability of the reservoir and the interlayer is over 1000, the influence of the interlayer on the water cut rise is not obvious; the thickness of the interlayer on the water cut rise law has little effect. Finally, through the case analysis, it is proposed that the new horizontal wells should be arranged in the position where the interlayer develops. The findings of this study can help for the better understanding of control laws of the interlayer on the bottom water and providing a crucial theoretical basis for the development of the bottom water reservoir.

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“…Waterflooding is by far the most widely applied method in improving oil recovery. − However, large-scale and long-term water injection will cause reservoirs to enter the high water-cut stage, even the extra-high water-cut stage, and the yield will seriously drop in the meantime. − For decades, the oilfield development industry in China has gradually formed a technology series featuring water injection technology . Meanwhile, most oilfields in China have entered the stage of high water-cut and high oil recovery.…”

Section: Introductionmentioning

confidence: 99%

Novel Method for Inverted Five-Spot Reservoir Simulation at High Water-Cut Stage Based on Time-Varying Relative Permeability Curves

et al. 2020

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After large-scale and long-term waterflooding, reservoir physical properties such as the pore throat structure and rock wettability may change. In this paper, the relative permeability curves under different water injection volumes through core-flood experiments were used to characterize the comprehensive changes of various reservoir physical properties at high water-cut stage. The novel concept of "water cross-surface flux" was proposed to characterize the cumulative flushing effect on the reservoir by injected water, and a novel method for inverted five-spot reservoir simulation at high water-cut stage based on time-varying relative permeability curves was established. From the relative permeability curves measured through two cores from the X oilfield under different water injection volumes (100, 500, 1000, 1500, and 2000 PV), it is found that with the increase of injected water volume, the two-phase co-flow zone becomes wider, the water permeability under residual oil saturation increases, and the residual oil saturation decreases. A waterflooding core model was established, simulated, and verified by the method proposed in this paper. It is found that using time-varying permeability curves for simulation, the highest oil recovery factor (61.58%) can be obtained with injected water volume up to 2000 PV, and the purpose of improved oil recovery (IOR) can be achieved by high water injection volume, but the increment is only approximately 10%. Besides, a waterflooding model of an inverted five-spot reservoir unit based on the X oilfield was also established, simulated, and analyzed. Simulation results have shown that no matter which set of core permeability curves measured from 100 to 2000 PV is directly used alone, the oil recovery factor will be simulated inaccurately. The findings of this study can help in better understanding the quantitative description of the oil recovery changes with time-varying reservoir physical properties in high water-cut reservoirs during waterflooding.

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Production Decline Behavior Analysis of a Vertical Well with a Natural Water Influx/Waterflood

Cited by 8 publications

References 30 publications

Water Production Problem in Gas Reservoirs: Concepts, Challenges, and Practical Solutions

Water Production Problem in Gas Reservoirs: Concepts, Challenges, and Practical Solutions

The Effect of Interlayer on Water Cut Rise in a Bottom Water Reservoir

Novel Method for Inverted Five-Spot Reservoir Simulation at High Water-Cut Stage Based on Time-Varying Relative Permeability Curves

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