Solvent and gas injection recovery process

A process for the recovery of hydrocarbons from a hydrocarbon bearing formation in which are situated an upper injection well and a lower production well, the method comprising the steps:

• circulating solvent through at least part of both of the wells until hydraulic communication between both wells is achieved;
• injecting one or more hydrocarbon solvents into the upper injection well, thereby:
• (i) creating a solvent chamber,
• (ii) mixing of the formation hydrocarbons and the solvent at the boundary of the solvent chamber so formed, and
• (iii) causing a mixture of the hydrocarbon and solvent to drain downwards by gravity and sideways by pressure gradient towards the lower production well;
• and
• producing the mixture to the surface through the lower production well;
• wherein the injecting step further comprises:
• injecting a non-condensable gas and the solvent into the solvent chamber during respective alternating periods in a cyclic phase, and
• establishing a growing blanket of non-condensable gas from the upper parts of the solvent chamber that over time fills the entire solvent chamber,
• wherein the last injection period is with non-condensable gas which displaces the remaining solvent vapour to the lower production well.

A process for the recovery of hydrocarbons from a hydrocarbon bearing formation in which are situated an upper injection well and a lower production well, the method comprising the steps:

• circulating solvent through at least part of both of the wells until hydraulic communication between both wells is achieved;
• injecting one or more hydrocarbon solvents into the upper injection well, thereby:
• (i)creating a solvent chamber consisting of solvent vapour and liquid,
• (ii) mixing of the formation hydrocarbons and the solvent at the boundary of the solvent chamber so formed, and
• (iii) causing a mixture of the hydrocarbon and solvent to drain downwards by gravity and sideways by pressure gradient towards the lower production well;
• and
• producing the mixture to the surface through the lower production well;
• wherein the injecting step further comprises:
• injecting a non-condensable gas and the solvent into the solvent chamber during respective alternating periods in a cyclic phase to make the solvent chamber lower and wider, and
• establishing a growing blanket of non-condensable gas from the upper parts of the solvent chamber that over time fills the entire solvent chamber and enhance hydrocarbon recovery,
• wherein the last injection period is with non-condensable gas which displaces the remaining solvent vapour to the lower production well.

A process for the recovery of hydrocarbons from a hydrocarbon bearing formation in which are situated an upper injection well and a lower production well, the method comprising the steps:

• circulating solvent through at least part of both of the wells until hydraulic communication between both wells is achieved;
• injecting one or more hydrocarbon solvents into the upper injection well, thereby:
• (i)creating a solvent chamber,
• (ii) mixing of the formation hydrocarbons and the solvent at the boundary of the solvent chamber so formed, and
• (iii) causing a mixture of the hydrocarbon and solvent to drain downwards by gravity and sideways by pressure gradient towards the lower production well;
• and
• producing the mixture to the surface through the lower production well;
• wherein the injecting step further comprises:
• injecting a non-condensable gas and the solvent into the solvent chamber during respective alternating periods in a cyclic phase to make the solvent chamber lower and wider, and
• establishing a growing blanket of non-condensable gas from the upper parts of the solvent chamber that over time fills the entire solvent chamber and enhance hydrocarbon recovery,
• wherein the last injection period is with non-condensable gas which displaces the remaining solvent vapour to the lower production well.