Abstract

The Cold Lake project, in Alberta, Canada, is one of the world's largest heavy oil in-situ thermal developments with oil production of about 24,000 m3/d (150 kB/d) from more than 4000 wells. The world class Cold Lake hydrocarbon resource is a bitumen deposit, featuring in-situ viscosities in excess of 100,000 cP. The high viscosity of Cold Lake bitumen severely limits steam injectivity below fracture pressure, necessitating the development throughout the 1970s and 1980s of a modified cyclic steam stimulation (CSS) recovery process.

Imperial Oil and ExxonMobil are pursuing a research program to develop the next-generation of bitumen recovery processes that use hydrocarbon solvents as a mobilizing agent, reducing greenhouse gas (GHG) emissions relative to the current commercial recovery processes. Imperial and ExxonMobil are pursuing three processes: a solvent-only process known as Cyclic Solvent Process (CSP), a solvent assisted SAGD process and a solvent assisted CSS process known as Liquid Addition to Steam for Enhancing Recovery (LASER). LASER has the potential to increase oil recovery by more than 5% and reduce direct GHG emissions intensity by approximately 25%.

This paper describes the first commercial application of LASER. The Cold Lake H trunk LASER project is to date the world's largest implementation of a thermal solvent recovery process, with injection of 297 km3 (1.87 million barrels) of solvent into the 240 well project. This paper describes the successful operation of this thermal solvent project over a six year period; including reservoir numerical simulation work to develop bitumen and solvent production forecasts, development of field solvent production measurement methods, and the recovery process learnings from the first cycle of LASER operations. Completion of the first commercial LASER cycle has demonstrated on a large scale the success of solvent addition as a means to increase thermal efficiency and oil production in a heavy oil thermal recovery operation.

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