Abstract: A wellbore completion system utilizes casing conveyed devices to establish a fluid communication path between a downhole formation and the casing string. Extendible pistons are mounted in the wall of the casing pipe string and are extended toward contact with the downhole formation after the casing is set. An explosive device is mounted in the pistons and includes a detonator and a shaped charge. The detonator is housed in a plug threaded into one end of the piston. The shaped charge is housed in a canister conveniently inserted into the other end of the piston. The explosives included in the system may thus be conveniently assembled at the well site. Explosive in the pistons are activated by a separately conveyed activation system which produces a pressure wave to detonate the explosives and establish fluid communication between the casing and formation.

Abstract: Powdered and liquid fluid loss additives are disclosed for use in cementing wellbores, particularly oil and gas wellbores. Excellent fluid loss control is achieved over a wide range of conditions using various cements systems. The invention utilizes polyvinyl acetate polymers as a fluid loss additive. The polyvinyl acetate polymer is used in conjunction with a dispersing sulfonated polymer and surfactant. This highly effective combination is then adjusted to individual well conditions with chelating agent, cross-linking agent, biocides, antifoams, or combinations of these. The dispersants are novel dispersing agent polymers such as melamine sulfonate polymer, vinyl sulfonate polymer and styrene sulfonate polymer and mixtures of these. These dispersant materials are usually prepared at low pH and can be used in the acid form, or neutralized to form salts of the polymers, wherein the salt can be a Group I or Group II metal salt, or ammonium salts (common salts).

Abstract: Powdered and liquid fluid loss additives are disclosed for use in cementing wellbores, particularly oil and gas wellbores. Excellent fluid loss control is achieved over a wide range of conditions using various cements systems. The invention utilizes polyvinyl acetate polymers as a fluid loss additive. The polyvinyl acetate polymer is used in conjunction with a dispersing sulfonated polymer and surfactant. This highly effective combination is then adjusted to individual well conditions with chelating agent, cross-linking agent, biocides, antifoams, or combinations of these. The dispersants are novel dispersing agent polymers such as melamine sulfonate polymer, vinyl sulfonate polymer and styrene sulfonate polymer and mixtures of these. These dispersant materials are usually prepared at low pH and can be used in the acid form, or neutralized to form salts of the polymers, wherein the salt can be a Group I or Group II metal salt, or ammonium salts (common salts).

Abstract: The present invention provides a single trip system for placing perforating apparatus and sand control equipment in a wellbore. This system includes a casing string equipped with extendible pistons and a pumpable activator plug for extending the pistons. Additionally, this system utilizes a single gravel-pack and completion tool string. Further, this system includes a means for opening the extendible pistons to fluid flow.

Abstract: A system for centralizing casing pipe in a wellbore includes lateral pistons in the side wall of the casing string which are movable by force applied to their inner end, from a retracted position within the maximum exterior profile of the casing pipe string to a predetermined extended position which will move the casing pipe string toward a central position in the borehole. Various well operations can be performed using the pistons in addition to the centralizing function. When a predetermined deploying force is applied to the pistons, they are released from their retracted position for movement to a fixed extended position. The deploying force is accurately determined by a simple retaining mechanism involving a snap ring and groove on the pistons.

Abstract: A system for centralizing casing pipe in a wellbore includes lateral pistons in the side wall of the casing string which are movable by forces applied to their inner end, from a retracted position within the maximum exterior profile of the casing pipe string to a predetermined extended position which will move the casing pipe string toward a central position in the borehole. Various well operations can be performed using the pistons in addition to the centralizing function.

Abstract: This invention relates to a downhole activated centralizer for centralizing pipes in a wellbore for the exploration and production of hydrocarbons. The downhole activated centralizers are carried within either the pipe casing or the collars or both and remain generally within the maximum outward profile of the pipe string so as not to interfere with the movement and placement of the pipe string in the wellbore. The pipe string may be rotated, reciprocated and circulated which enhances the ability of the installer to place the pipe string in a deviated or long reach wellbore. Once the pipe string is in place, the centralizers may be deployed by one of several methods such that pistons mounted in openings in the peripheral wall of the pipe string move outwardly with sufficient force to move the pipe string way from the walls of the wellbore sufficient to form a complete annulus for cementing.

Abstract: A fluid loss additive for addition to a cement slurry used in cementing a casing string in a wellbore. The additive reduces loss of water from the slurry into the formation, resulting in a better cement job. The additive is comprised of partially hydrolyzed polyvinyl acetate polymer, calcium sulfate, a crosslinker for the polymer, and optionally a defoamer.

Abstract: A method for servicing an offshore well having a subsea blowout preventer. A sealing nipple having a wireline extending therethrough and connected to a servicing tool is lowered into the well and sealed by sealing rams of the blowout preventer. After the sealing rams are closed about the sealing nipple, the well can be pressurized through a fluid line extending to a work area. The method is particularly useful for pressurizing a cased well to eliminate any microannulus between the well casing and cement surrounding the casing prior to running a cement evaluation logging tool through the well.

Abstract: A composition comprising water, a water soluble alkali metal silicate, and a water soluble metal compound capable of releasing a multivalent metal cation to react with the soluble silicate to form a pumpable gel is employed as a spacer for displacing a drilling mud from a borehole, particularly immediately preceding injection of a fluid, such as a cement slurry, containing compounds capable of detrimentally reacting with the mud. Optionally, the composition may contain one or more of: a water dispersible cellulose compound and an inert particulate which cooperate to provide fluid loss control; a chelating agent for polyvalent metal cations; a weighting material; a material to minimize lost circulation, and a salt to stabilize fresh water sensitive sandstones and shales.