In a well that opens into an unconsolidated reservoir formation through a perforated portion of grouted casing, the effective permeability is increased by flowing acid through the perforation tunnels to form channels between the grouting material and the reservoir formation and, while maintaining a fluid flow rate that keeps the channels free of solid particles inflowing a sand consolidating fluid that converts the walls of the channels to structures that are integral and permeable.
In a process for completing and operating a well, which process involves passing carbon dioxide through a case, cemented and perforated well, carbon dioxide-induced damage of the cement is avoided by coating the cement tunnel walls so that the carbon dioxide is passed through perforation tunnels which have been internally coated by epoxy resin.
A method of stimulating a subterranean well permits each desired location within a portion of a well to be isolated from other portions of the well during stimulation operations therein, but does not require lining a portion of the well with casing and cement, and does not require the use of sealing devices, such as inflatable packers, in the well portion. In a preferred embodiment, a stimulation method includes the steps of depositing a barrier fluid in a portion of a well, forming a radially extending opening through the fluid, and flowing stimulation fluids through the opening and into a formation surrounding the portion of the well.
A method for gravel packing perforations in a wellbore where an acid is directed into the perforations so as to dissolve formation fines in channels contained in said perforations. The acid is of a strength sufficient to dissolve said fines. After the fines are dissolved, a sand consolidation agent is introduced into the perforations before the channels can be filled with formation fines. The consolidation agent remains in the perforations for a time sufficient to form a cement in situ which cement has permeability retentive characteristics. The cement forms pores of a size sufficient to exclude formation fines from the wellbore. Thereafter, a substantially fines free hydrocarbonaceous fluid is produced from the wellbore.
The formation is consolidated by means of a silicon halide compound that reacts with water present on the walls of the formation pore space thereby forming silicon dioxide that bonds the formation grains together. The bonding strength is increased by a pretreatment of the formation grains with an acid in liquid or gaseous form.
A process for metal plating the perforation tunnels in the cement sheath between casing and wellbore in a subterranean well to protect the cement from CO.sub.2 attack.
