A method for inhibiting the longitudinal protruding of sagd steam chamber

Abstract

The invention provides a method for suppressing longitudinal protrusion of an SAGD steam chamber. The method comprises the steps that normal temperature water is injected into a well point of the longitudinally protrusion of the steam chamber of an SAGD mining reservoir to reduce the temperature of a protruding cavity at the top of the steam chamber, and the water is stopped from being injected when the temperature drops to 150-180 DEG C; nitrogen gas is injected, a heat insulation strip is formed at the top of the steam chamber and at the bottom of the protruding cavity, heat transfer from the steam chamber to the top protruding cavity is controlled, the temperature in the protruding cavity is reduced, and the rising speed of the steam chamber at the well point is suppressed; repeated injection of the normal temperature water and nitrogen gas is performed for a plurality of times, and the longitudinal protrusion of the SAGD steam chamber is suppressed. The method for suppressing the longitudinal protrusion of the SAGD steam chamber adopts the method of alternately injecting the water and the nitrogen gas, the protrusion of the steam chamber can be suppressed and the stable expansion of the steam chamber can be ensured, and the production effect of the SAGD can be effectively improved.

Description

technical field [0001] The invention relates to a method for suppressing the longitudinal advance of a SAGD steam chamber, which belongs to the technical field of petroleum exploitation. Background technique [0002] Steam Assisted Gravity Drainage (SAGD) uses steam as a heat source to recover heavy oil by gravity of bitumen and condensate. Under the original conditions of the formation, the crude oil has high viscosity and no flow ability. To be exploited, the thermal connection between the injection and production wells must first be realized (that is, the temperature of the oil layer reaches the flowable temperature of crude oil); after the thermal connection is formed, the steam injection well Continuously inject high-dryness steam into the oil layer to form a steam cavity in the formation, move upward and sideways through the steam cavity, and exchange heat with the crude oil in the oil layer, and the heated crude oil and steam condensate flow to the Produced in the lo...

AI Technical Summary

Problems solved by technology

However, in the existing SAGD production process, especially for super-heavy oil reservoirs with top water, due to the influence of reservoir heterogeneity, steam overlay and other factors, there will be local intrusion phenomenon in the longitudinal direction of the steam chamber, which is very likely to occur. It is easy to soften the asphalt shell in the upper part of the oil layer, and the pressure difference between the top and the bottom will cause the top water to leak down, which seriously affects the SAGD production effect

Aiming at the problem of steam cavity intrusion, in the prior art, the method of shutting down the steam injection well is generally used to slow down the inrush, but the long-term shutdown of the steam injection well will cause the steam cavity to shrink, the temperature will drop, and the oil production will decrease. SAGD development The effect becomes worse

Images