Experimental Investigation on Effectiveness of High Power EM Wave Usage for Decreasing Heavy Oil Viscosity

The paper explores the aspects negatively affecting the pipeline transportation of heavy oil and reviews the implementation possibility of cavitation processes as an alternative method of solving occurring problems. Based on the laboratory researches of abnormal oil from Azerbaijan fields, the parameters and technical upgrade of heavy oil in the system of hydrodynamic cavitation have been studied. Moreover, as a result of carried out experiments, the operation mechanism of cavitation process during reduction of heavy oil viscosity has been described and the implementation prospect of this technology in commercial scales analyzed as well.

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Rich-Gas Condensate Huff and Puff Process in High-Volume, Watered-Out, and Highly Viscous Heavy Oil Wells, Case Study in Iraq

10.2118/205742-ms ◽

2021 ◽

Author(s):

Xueqing Tang ◽

Ruifeng Wang ◽

Zhongliang Cheng ◽

Hui Lu

Keyword(s):

High Pressure ◽

Heavy Oil ◽

Oil Quality ◽

Oil Wells ◽

Gas Condensate ◽

Oil Viscosity ◽

Foamy Oil ◽

Artificial Lift ◽

Water Coning ◽

The Dead

Abstract Halfaya field in Iraq contains multiple vertically stacked oil and gas accumulations. The major oil horizons at depth of over 10,000 ft are under primary development. The main technical challenges include downdip heavy oil wells (as low as 14.56 °API) became watered-out and ceased flow due to depleted formation pressure. Heavy crude, with surface viscosities of above 10,000 cp, was too viscous to lift inefficiently. The operator applied high-pressure rich-gas/condensate to re-pressurize the dead wells and resumed production. The technical highlights are below: Laboratory studies confirmed that after condensate (45-52ºAPI) mixed with heavy oil, blended oil viscosity can cut by up to 90%; foamy oil formed to ease its flow to the surface during huff-n-puff process.In-situ gas/condensate injection and gas/condensate-lift can be applied in oil wells penetrating both upper high-pressure rich-gas/condensate zones and lower oil zones. High-pressure gas/condensate injected the oil zone, soaked, and then oil flowed from the annulus to allow large-volume well stream flow with minimal pressure drop. Gas/condensate from upper zones can lift the well stream, without additional artificial lift installation.Injection pressure and gas/condensate rate were optimized through optimal perforation interval and shot density to develop more condensate, e.g. initial condensate rate of 1,000 BOPD, for dilution of heavy oil.For multilateral wells, with several drain holes placed toward the bottom of producing interval, operating under gravity drainage or water coning, if longer injection and soaking process (e.g., 2 to 4 weeks), is adopted to broaden the diluted zone in heavy oil horizon, then additional recovery under better gravity-stabilized vertical (downward) drive and limited water coning can be achieved. Field data illustrate that this process can revive the dead wells, well production achieved approximately 3,000 BOPD under flowing wellhead pressure of 800 to 900 psig, with oil gain of over 3-fold compared with previous oil rate; water cut reduction from 30% to zero; better blended oil quality handled to medium crude; and saving artificial-lift cost. This process may be widely applied in the similar hydrocarbon reservoirs as a cost-effective technology in Middle East.

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Revisiting the Butler-Mokrys Model for the Vapor-Extraction Process

SPE Journal ◽

10.2118/194212-pa ◽

2019 ◽

Vol 24 (02) ◽

pp. 511-521

Author(s):

V.. Mohan ◽

P.. Neogi ◽

B.. Bai

Keyword(s):

Concentration Profile ◽

Heavy Oil ◽

Extraction Process ◽

Previous Model ◽

Oil Reservoir ◽

Vapor Extraction ◽

Oil Viscosity ◽

Solvent Vapor ◽

Vapor Interface ◽

Heavy Oil Reservoir

Summary The dynamics of a process in which a solvent in the form of a vapor or gas is introduced in a heavy-oil reservoir is considered. The process is called the solvent vapor-extraction process (VAPEX). When the vapor dissolves in the oil, it reduces its viscosity, allowing oil to flow under gravity and be collected at the bottom producer well. The conservation-of-species equation is analyzed to obtain a more-appropriate equation that differentiates between the velocity within the oil and the velocity at the interface, which can be solved to obtain a concentration profile of the solvent in oil. We diverge from an earlier model in which the concentration profile is assumed. However, the final result provides the rate at which oil is collected, which agrees with the previous model in that it is proportional to h, where h is the pay-zone height; in contrast, some of the later data show a dependence on h. Improved velocity profiles can capture this dependence. A dramatic increase in output is seen if the oil viscosity decreases in the presence of the solvent, although the penetration of the solvent into the oil is reduced because under such conditions the diffusivity decreases with decreased solvent. One other important feature we observe is that when the viscosity-reducing effect is very large, the recovered fluid is mainly solvent. Apparently, some optimum might exist in the solubility φo, where the ratio of oil recovered to solvent lost is the largest. Finally, the present approach also allows us to show how the oil/vapor interface evolves with time.

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