An improved method of fracturing an underground fluid bearing formation penetrated by a well bore for the production of fluids therefrom by injecting a composition comprising cement, sand and oil, capable of forming a fluid permeable barrier in said formation at a pressure sufficient to form fissures therein extending from said well bore, and thereafter maintaining pressure on the composition for a predetermined period to permit the composition to set and form a fluid permeable barrier in the formed fissures.
A method of propping fractures in a subterranean formation whereby a high viscosity fluid is introduced into the formation to open and extend the fractures, the high viscosity fluid containing slugs of a hardenable liquid which are carried into and held in spaced relationship in the fractures and permitted to harden therein whereby the fractures are propped in the open position.
A method for preventing annular fluid flow following primary cementing of oil and gas well casings is disclosed. Pursuant to said method the casing is vibrated so as to maintain the hydrostatic pressure of the cement column surrounding the casing at or above the pressure of the fluids in the various formations penetrated by the well until the cement has acquired its initial set. The vibration may be either continuous or intermittent. Preferably, the vibration has a low frequency. The method may include the additional step of applying pressure to the surface of the cemented annulus while the cement is curing. The vibration may be induced in several ways. For example, the casing may be vibrated by simultaneous or sequential explosions of a slow-burning black powder. Alternatively, hydraulic jars may be used to strike blows on the casing causing the casing to vibrate.
A method for cementing a wellbore wherein a slurry comprising at least five percent by weight of particles having a particle size greater than about 0.04 inches is placed in the wellbore. The slurry has a density which exceeds the hydraulic fracture gradient of the formation but the slurry is not lost to fractures because the larger particles enable the solids in the slurry to bridge and prevent excessive slurry loss. The cement slurry of the present invention is preferably placed in the wellbore by a direct placement method such as a coil tubing placement to minimize the pressure placed on the formation by any particular cement slurry.
A method of stimulating a subterranean formation using a foamed cement composition. When hardened, the cement composition has a permeability of at least about 0.3 darcies. The inventive formation stimulation method comprises the steps of: (a) injecting the foamed cement composition into the formation at a pressure sufficient to fracture the formation and (b) allowing the cement composition to harden in the formation.
The current invention provides an improved permeable cement composition for formation of downhole sand screens. The improved composition includes an effective amount of a surfactant. Addition of the surfactant to the permeable cement composition yields at least a pumpable slurry with a minimal amount of water or brine solution.
