Noncondensable gas steam-assisted gravity drainage

SAGD(Steam Assisted Gravity Drainage) is commercially adopted as a main thermal recovery method for heavy oil reservoirs. How to improve the recovery effect and the heat efficiency of SAGD process draws the attention of all the heavy oil reservoir engineers, especially under low oil price circumstance. This paper aims to utilize gas as additives to reduce the steam demand of SAGD projects, hence to improve the recovery efficiency of this method.In this paper, study on improving recovery efficiency of steam injection process with gas additives in reservoir with great depth was carried out. Laboratory tests were carried out to quantify the properties of different gas additives with heavy oil. Also flooding experiment were carried out to compare the relative permeability curve before and after gas additives were included. Then simulation were done to evaluate the influence of gas additives on SAGD process. SAGD processes with different gas additives were compared and the influences of different gas additives on recovery process were analyzed in detail.The study reveals that the SAGD recovery process can be greatly influenced by gas additives. All of gas additives can sharply reduce the steam demand for SAGD process. It was shown that CO2 can improve the production effect of SAGD because of their great solubility and viscosity reduction effect. In the CO2 case the drainage threshold temperature was decreased by 17.1°C in comparison to the pure steam SAGD process with the help of viscosity reduction. Addition of CH4 will impair SAGD process because CH4 overrides faster than steam and hinders the development of steam chamber. N2 can accelerate the oil recovery rate but has no effect on improving recovery factor. On the contrary the viscosity reduction effect of CH4 and N2 is much less than CO2. With the results of this paper, the recovery factor of SAGD process can be improved by 8% and SOR can be improved by 14.7% when CO2 was co-injected with steam.The results of this paper are of great significance in that it combines the advantage of steam injection process and gas injection process. The heat assumption in SAGD process can be sharply decreased and the recovery factor can be enhanced with the help of soluble gas additives. Also the greenhouse gas emission can be lowered down.

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“…Also there are 9% decrease of the water cut from 82% [4]. Also there are similar pilot test in Cenovous [5], Nexen [6], and Jacos [7] company.…”

mentioning

confidence: 70%

Study On Thermal-GAS EOR Method in In-Depth Extra-Heavy Oil Reservoir in China

Guo

Jiang

Gao

et al. 2016

Day 2 Tue, March 22, 2016

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“…Equation (9) allows the calculation of the flow rate of gas being dragged by the falling films. Figure 5 shows the velocity profiles in a capillary tube obtained using equations (6) to (8).…”

Section: Capillary Tube Modelmentioning

confidence: 99%

“…The intentional addition of non condensable gases to SAGD has as well created some controversy in regard to the benefits or disadvantages this may cause in the bitumen recovery [2,7,9] .…”

Section: Introductionmentioning

confidence: 99%

Investigation of Gas Flow in SAGD

Canas¹,

Kantzas²,

Edmunds³

2009

Canadian International Petroleum Conference

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Non-condensable gases (CH 4 , CO 2 , and H 2 S) are present and play an important role in the thermal efficiency of SAGD. However, the role of these gases is not well understood and it is regarded by some people as beneficial, yet detrimental by others. The characterization of the gas flow in SAGD is crucial to predict its effect on the process performance.One mechanism involved in the flow of gas is the viscous drag due to the falling liquids in the SAGD chamber. In this work, the production of gas in SAGD was studied by deriving flow equations that describe the viscous drag in a gas-water-oil system. Two geometries have been studied; these are flow in a capillary tube and flow of a descending film on a plate.The three-phase flow analysis has been extended to a macroscopic level in order to predict the amount of gas produced due to the viscous drag of the falling phases. The assumption that the reservoir behaves as a bundle of capillaries with a pore size distribution was made.Results from this analytical model indicate that some of the gas in the steam chamber flows downwards and therefore could be produced by viscous drag of the falling liquids.

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“…1987; Metwally 1990; Canbolat et al 2004). Foam fluids often are used to inject with steam to solve the problems of steam channeling between wells (Zitha et al 2006;Li et al 2011;Pang et al 2012;Lu et al 2013).…”

Section: Introductionmentioning

confidence: 99%

The study on classification methods for low production wells of thermal recovery and its applications

Pang

Wang

Zhang

et al. 2018

J Petrol Explor Prod Technol

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During the later period of steam injection, the oil production largely decreases to be a state of low production or low oilsteam ratio. In this article, a classification method of low production wells was established and some measures of improving oil production were researched for the low production wells during thermal recovery. Three visualization experiments were implemented to analyze the sweep efficiency and to measure the oil recovery factor during injecting different flooding agents. Then a novel diagram was introduced to guide us how to precisely choose the appropriate measures for the low production wells during thermal recovery in heavy oil reservoirs. According to the statistical results, the low production wells can be categorized into three types involving high degree of oil recovery, thermal disturbance (even steam channeling) among wells and dual factors. The results of visualization experiments showed that the injection of chemical agents can effectively increase the displacement efficiency in swept zone after steam injection. Temperature-resistant gel or foams can be used to decrease thermal disturbance and even steam channeling among wells during steam injection in heavy oil reservoir. The values of a new parameter can be employed to confirm the boundary of different improvement measures. Finally, a diagram was established to help choosing appropriate measures involving nitrogen injection, foam injection, gel injection and invalid measure.

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Noncondensable gas steam-assisted gravity drainage

Cited by 40 publications

References 11 publications

Study On Thermal-GAS EOR Method in In-Depth Extra-Heavy Oil Reservoir in China

Study On Thermal-GAS EOR Method in In-Depth Extra-Heavy Oil Reservoir in China

Investigation of Gas Flow in SAGD

The study on classification methods for low production wells of thermal recovery and its applications

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