Exxonmobil Upstream Research Company

Imperial Oil Resources

Mori Y Kwan

Thomas J Boone

J Pierre Lebel

Robert D Kaminsky

Robert Chick Wattenbarger

Matthew A Dawson

Tapantosh Chakrabarty

Rahman Khaledi

Owen J Hehmeyer

James A Dunn

Brian C Speirs

Git Lim

Jean-Pierre Lebel

P Richard Kry

Brad C Harker

Mark S Beckman

Olusola B Adeyinka

Thomas James Boone

Jeffrey A Yerian

Xiaomeng Yang

Ivan J Kosik

Described are methods of distributing a viscosity reducing solvent to a set of wells terminating in an underground oil reservoir where the variation in the net solvent injection rate is minimized. The net solvent injection rate is the difference between the total solvent injection rate and the total solvent production rate from the set of wells, for example on an instantaneous or daily rate basis. Minimizing this variation can reduce costs associated with surface solvent storage, subsurface solvent storage, and solvent supply, since solvent supply often is least expensive when supplied at near a fixed rate. One option is to operate well pairs and to inject solvent into one well of the pair while producing oil and solvent from the other well of the pair. These methods are particularly useful in solvent-dominated, cyclic or non-cyclic, viscous oil recovery processes.

Method of distributing a viscosity reducing solvent to a set of wells

Certain viscous oil reservoirs are too deep to be commercially mined but lack an adequate top seal to employ in situ recovery methods such as SAGD. Without an adequate top seal, gases from the reservoir can rise into overlying aquifers and potentially to the surface. While ice-like hydrates would not normally form above the oil reservoir during in situ recovery, an additive can be added to promote hydrate formation. In this way, a hydrate barrier can be formed to act as a top seal to contain these gases.

Creation of a hydrate barrier during in situ hydrocarbon recovery

The present invention relates generally to in situ hydrate control during hydrocarbon production when applying a recovery method utilizing cyclic injection of light hydrocarbon solvents. Hydrate formation is limited by creating an energy reserve within a hydrocarbon reservoir adjacent to the wellbore. A heated solvent is injected during an injection phase of a cyclic solvent dominated recovery process to form a heated region adjacent to the wellbore at the end of an injection cycle. The energy reserve is used to act against the evaporative cooling effect caused by subsequent production and associated depressurization to maintain reservoir conditions outside of hydrate formation conditions. In situ conditions are estimated and injected energy amounts are controlled.

Hydrate control in a cyclic solvent-dominated hydrocarbon recovery process

A process is disclosed for using heavy petroleum fraction as a drive fluid in the recovery of hydrocarbons from a subterranean formation. The hydrocarbons may be in the form of bitumen or heavy oil. The heavy petroleum fraction may be injected into at least one injection well and hydrocarbons produced out of at least one distinct production well. The heavy petroleum fraction may be co-injected together with steam and/or hot water and/or solvent. The heavy petroleum fraction may be a heavy fraction of a process used to upgrade crude oil, such as a heavy asphaltene fraction produced from solvent deasphalting crude oil produced by this recovery process.

Use of a heavy petroleum fraction as a drive fluid in the recovery of hydrocarbons from a subterranean formation

A process for recovery of hydrocarbons in a production fluid from an underground reservoir of said hydrocarbons, the process comprising of: (a) injecting a viscosity reducing solvent of a fraction of said hydrocarbons into said reservoir at a pressure in the reservoir of above a liquid/vapor phase change pressure of a fraction of said solvent; said pressure in said reservoir also being sufficient to cause geomechanical formation dilation or pore fluid compression, and then, (b) allowing said solvent to mix with said hydrocarbons under pore dilation conditions, and then, (c) reducing the pressure in said reservoir to below said liquid/vapor phase change pressure of at least said fraction of said solvent thereby evincing solvent gas drive of said fraction of said hydrocarbons from said reservoir; and then, (d) repeating steps (a) to (c) as required.

Cyclic solvent process for in-situ bitumen and heavy oil production

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Calgary, Canada

Mori Y Kwan