Waterflood Behavior of High Viscosity Crudes in Preserved Soft and Unconsolidated Cores

Jennings, Harley Y.

doi:10.2118/1202-pa

Cited by 26 publications

(14 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In heavy oil applications, even though this is not the case, practitioners often still attempt to apply the same theoretical understanding to their fields. There has been only limited documented experience for waterfloods in heavy oil reservoirs (22)(23)(24)(25) , but in general, the mechanism of viscous oil recovery by waterflooding has not been explored. Waterflood recoveries are known to be low for high viscosity heavy oil, but in many heavy oil fields, waterflooding is still commonly applied since it is relatively inexpensive and field operators have years of experience designing and controlling waterfloods.…”

Section: Waterflooding After Primary Recoverymentioning

confidence: 99%

Insights Into Non-Thermal Recovery of Heavy Oil

Mai

Bryan

Goodarzi

et al. 2009

Journal of Canadian Petroleum Technology

106

View full text Add to dashboard Cite

Many heavy oil reservoirs contain oil that has some limited mobility under reservoir conditions. In these reservoirs, a small fraction of the oil-in-place can be recovered using the internal reservoir energy through heavy oil solution gas drive (primary production). An integral part of this process is the so-called 'foamy oil mechanism', whereby oil is produced as a gas-in-oil dispersion. At the end of primary production, the bulk of the oil is still in place, while the natural energy of the reservoir has been depleted. This remaining oil is still mostly continuous and presents a valuable target for further recovery. Many of these reservoirs are relatively small or thin, or may be contacted by overlying gas or underlying water. As such, they are poor candidates for thermal oil recovery methods, so any additional oil recovery after primary production must be non-thermal. In this work, we present experimental results of foamy oil depletion at two different length scales and varying depletion rates. Tests were conducted in the absence of sand production, and the results from the depletion experiments are interpreted in terms of viscous forces. At the conclusion of primary recovery, the potential for further non-thermal exploitation of these reservoirs is explored. Results for waterflooding and chemical flooding are presented, demonstrating the viability of these techniques for heavy oil EOR. Several displacement mechanisms are identified through the secondary and tertiary processes that contribute to significant (although potentially slow) incremental recovery of heavy oil. Introduction Many countries have heavy oil reservoirs. Canada and Venezuela in particular contain some of the largest heavy oil and bitumen resources in the world. Rising energy demands, coupled with a decline in conventional oil reserves, has led to increased interest in heavy oil recovery in recent years. The size of these heavy oil deposits is considerable, and with volatile crude oil prices making it difficult to produce from some higher viscosity bitumen reservoirs, production of heavy oil could potentially be very important in years to come. Understanding the mechanisms by which heavy oil can be displaced in reservoirs is crucial to the successful recovery of this resource base. Heavy oil can be defined as a class of oils with viscosity ranging from 50 mPa.s up to around 50,000 mPa.s. This oil has limited mobility under reservoir temperature and pressure, and Darcy's Law predicts that the oil can flow slowly under high applied pressure gradients. However, it has been observed that in these reservoirs, solution gas drive leads to significantly higher rates and recoveries than what was expected by conventional understanding of gas-oil relative permeability behaviour(1). This behaviour, first reported in Canadian heavy oil, has since been observed in many other reservoirs around the world including South America, China and Albania. Investigations into the causes of this abnormal, but fortuitous, primary production response have been the focus of many publications in the past 25 years. The recovery from primary production in heavy oil reservoirs may be as high as 20%(2), but is usually lower.

show abstract

Section: Waterflooding After Primary Recoverymentioning

confidence: 99%

Insights Into Non-Thermal Recovery of Heavy Oil

Mai

Bryan

Goodarzi

et al. 2009

Journal of Canadian Petroleum Technology

106

View full text Add to dashboard Cite

show abstract

“…There has been some limited experience documented for waterfloods in heavy oil reservoirs (4)(5)(6)(7) but, in general, the mechanism of viscous oil recovery by waterflooding has not been explored. Waterflood recoveries are known to be low for high viscosity oil due to the adverse mobility ratio between oil and injected water.…”

Section: Theorymentioning

confidence: 99%

Heavy Oil Waterflooding: Effects of Flow Rate and Oil Viscosity

Mai

Kantzas

2009

Journal of Canadian Petroleum Technology

104

View full text Add to dashboard Cite

Many countries in the world contain significant heavy oil deposits. In reservoirs with viscosity over several hundred mPa's, waterflooding is not expected to be successful due to the extremely high oil viscosity. However, in many smaller, thinner reservoirs, or reservoirs at the conclusion of cold production, thermal enhanced oil recovery methods will not be economic. Waterfloods are relatively inexpensive and easy to control; therefore, they will still often be employed in high viscosity heavy oil fields. This paper presents experimental findings of waterflooding in laboratory sandpacks for two high viscosity heavy oils of 4,650 mPa.s and 11,500 mPa.s at varying water injection rates. The results of this work show that capillary forces, which are often neglected due to the high oil viscosity, are important even in heavy oil systems. At low injection rates, water imbibition can be used to stabilize the waterflood and improve oil recovery. Waterflooding can therefore be a viable non-thermal enhanced oil recovery technology, even in fields with very high oil viscosity. Introduction Although conventional oil reserves are declining in many countries, the global energy demand is still increasing. As a result, the industry focus is now shifting towards unconventional oil resources, such as the oil sands in countries like Canada and Venezuela. The size of this resource base is immense, but the production of high viscosity crude oil carries its own unique challenges. Heavy oil is a special class of this unconventional oil, and has viscosities ranging from 50 to 50,000 mPa.s. Heavy oil reservoirs are often found in highly porous, highly permeable, unconsolidated sand deposits. At reservoir conditions, the oil may contain dissolved solution gas; thus, some oil can be initially recovered using the energy from heavy oil solution gas drive. At the end of primary production, however, a significant amount of oil still exists for potential secondary recovery. Many of these reservoirs are small and thin or were disturbed during primary production, making them poor candidates for expensive thermal enhanced oil recovery strategies. In times of uncertain commodity pricing, it is beneficial to examine the potential for relatively inexpensive, non-thermal oil recovery techniques. Waterflooding is often employed, at least initially, in heavy oil reservoirs, both along with or after primary recovery in order to re-pressurize the reservoir and displace oil to producing wells. In these applications, it is very important to understand the forces that are present in the reservoir and how they can be used to properly design the waterflood. Specifically, proper design and maintenance of waterfloods requires comprehension of how viscous oil can be displaced by water, and how oil recovery can be optimized. This work presents the results for water injection into laboratory sandpacks containing gas-free heavy oil of varying viscosity. The responses for different waterfloods are compared in order to investigate the mechanisms by which heavy oil can be recovered by water injection. Theory Waterflooding of oil reservoirs is a well-recognized technique for oil recovery after primary production. In conventional oil, waterflooding theory has been well documented(1).

show abstract

“…There has been some limited experience documented for waterfloods in heavy oil reservoirs [4][5][6][7] , but in general the mechanism of viscous oil recovery by waterflooding has not been explored. Waterflood recoveries are known to be low for high viscosity heavy oil, due to the adverse mobility ratio between oil and injected water.…”

Section: Theorymentioning

confidence: 99%

Heavy Oil Waterflooding: Effects of Flow Rate and Oil Viscosity

Mai¹,

Kantzas²

2007

Canadian International Petroleum Conference

View full text Add to dashboard Cite

Many countries in the world contain significant heavy oil deposits. In reservoirs with viscosity over several hundred mPa⋅s, waterflooding is not expected to be successful due to the extremely high oil viscosity.In many smaller, thinner reservoirs or reservoirs at the conclusion of cold production, however, thermal enhanced oil recovery methods will not be economic. Waterfloods are relatively inexpensive and easy to control; therefore they will still often be employed even in high viscosity heavy oil fields. This paper presents experimental findings of waterflooding in laboratory sand packs for two high viscosity heavy oils: 4650 mPa⋅s and 11500 mPa⋅s, at varying water injection rates. The results of this work show that capillary forces, which are often neglected due to the high oil viscosity, are in fact important even in heavy oil systems. At low injection rates, water imbibition can be used to stabilize the waterflood and improve oil recovery. Waterflooding can therefore be a viable non-thermal enhanced oil recovery technology even in fields with very high oil viscosity.

show abstract

Waterflood Behavior of High Viscosity Crudes in Preserved Soft and Unconsolidated Cores

Cited by 26 publications

References 0 publications

Insights Into Non-Thermal Recovery of Heavy Oil

Insights Into Non-Thermal Recovery of Heavy Oil

Heavy Oil Waterflooding: Effects of Flow Rate and Oil Viscosity

Heavy Oil Waterflooding: Effects of Flow Rate and Oil Viscosity

Contact Info

Product

Resources

About