METHOD FOR IMPROVING INJECTIVITY CONFORMANCE IN HETEROGENEOUS FORMATIONS

摘要

A method for improving injectivity conformance of a hydrocarbon bearing heterogeneous subterranean formation by reducing the variance in water saturation throughout the formation, as a means of improving recovery when steam injection is later applied. A solvent plunger is developed by incremental injections of solvent followed by periods of arrest to permit the solvent to mix with the oil in the areas of relatively high water saturation thereby creating a plunger to uniformly displace the water in the formation to achieve water injectivity conformance along the well.

主权项

1. A method for improving injectivity conformance of a hydrocarbon bearing heterogeneous subterranean formation, the formation having variable water injectivity due to water saturation variance throughout the formation, the method comprising:
(i) injecting a solvent into the formation, the solvent preferentially displacing into areas of relatively high water saturation; (ii) arresting injection of the solvent for a sufficient period of time to permit the solvent to mix with the oil in the areas of relatively high water saturation to create a homogenized oil and solvent mix, the homogenized oil and solvent mix having a viscosity that is higher than the viscosity of the solvent; (iii) resuming injection of the solvent into the formation, the solvent bypassing areas of the formation comprising the homogenized oil and solvent mix such that the solvent preferentially displaces into areas of relatively lesser water saturation than in step (i) to create the homogenized oil and solvent mix; and (iv) repeating steps (ii) and (iii) until the homogenized oil and solvent mix has uniformly displaced the water in the formation and water injectivity conformance is reached.