method for improving steam usage in a sag-assisted gravitational drainage process for crude oil recovery

摘要

Methods for making efficient use of steam in a steam assisted gravitational drainage (sagd) process to recover heavy oils from bituminous sands and similar oil deposits are disclosed. The methods utilize a surfactant to generate steam foam in ways that maximize the efficient use of steam. In some aspects, steam foam is used in gas layers or layers of water residing above steam chambers to prevent vapor loss from the steam chamber. The predominant use of relatively dry steam in sagd processes makes it difficult to find ways to introduce surfactants and generate steam foam. however, decreasing steam mobility by converting at least an amount of it to foam allows the wellbore and steam chambers above the injection site to be more fully developed, provide more effective heat transfer to heavy oil and stones, improve production and allow recovery of heavy oil with a minimum amount of steam usage.