Abstract: An improved well cementing plug assembly adapted to be connected to a string of drill pipe or a circulation tool for use in a pipe during the cementing of the pipe in a well bore is provided. The top and bottom plugs are selectively releasable by activating balls dropped into the plug assembly. Different sizes of plugs can be used utilizing the same inner tubes and other assembly parts, and the top plug slides on its inner tube when a pressure differential is exerted on it thereby insuring a seal between the top and bottom plugs when the plugs are landed on a float shoe or the like.

Abstract: The present invention relates to tools and methods for stabilizing incompetent or otherwise unstable subterranean zones or formations penetrated by a well bore during drilling. The methods basically comprise drilling the well bore through an unstable subterranean zone or formation when it is encountered, pumping a fluid through a well stabilization tool while moving the tool through the portion of the well bore in the unstable zone or formation whereby fluid jets formed by the well stabilization tool enlarge the diameter of the well bore by fluid jet erosion, pumping a hardenable cementitious material through the well stabilization tool while moving the tool through the enlarged portion of the well bore whereby the enlarged portion is filled with the hardenable cementitious material, allowing the cementitious material to harden and then drilling the well bore through the hardened cementitious material.

Abstract: The present invention provides cementitious well drilling fluids and methods of drilling subterranean well bores. The drilling fluids are basically comprised of water, a water viscosity increasing material and a cementitious material which when deposited on the walls of the well bore as a part of the filter cake thereon consolidates the filter cake into a stable mass that readily bonds to a cementitious material slurry subsequently placed in the well bore. The methods of drilling a subterranean well bore are basically comprised of the steps of preparing a drilling fluid of the invention and drilling a subterranean well bore using the drilling fluid.

Abstract: Improved methods of cementing in a well are provided whereby stress failures in the resulting set cement are prevented or reduced. The methods basically comprise the steps of placing a foamed cement composition in a zone in the well to be cemented which when set has sufficient elastic properties to resist stress failure comprised of hydraulic cement, water, a gas present in an amount in the range of from about 5% to about 75% by volume of the cement composition and a foaming agent, and then allowing the cement composition to set across the zone.

Abstract: The present invention provides resilient cement compositions and methods which are particularly useful in the construction and repair of oil and gas wells. The cement compositions have improved mechanical properties including elasticity and ductility and are basically comprised of cementitious material, an aqueous rubber latex and a latex stabilizer.

Abstract: Methods and compositions for controlling iron in aqueous well fracturing fluids are disclosed. In accordance with the methods, ferric iron contained in a fracturing fluid is prevented from precipitating or otherwise disadvantageously reacting by adding a thioalkyl acid or derivative thereof to the fracturing fluid. The thioalkyl acid or derivative reduces ferric ion to ferrous ion which remains in solution at pH levels below about 7.5.

Abstract: Improved well casing fill apparatus and methods for filling a casing string with well bore fluid while running the string into a well bore and then cementing the casing in the well bore are provided. A well casing fill apparatus of this invention is basically comprised of a tubular housing having a well bore fluid fill port extending through a wall thereof and a closing sleeve slidably disposed in the tubular housing between an upper open position whereby the fill port is uncovered to a lower closed position whereby the closing sleeve covers the fill port. The closing sleeve includes a cementing plug landing seat thereon for receiving a cementing plug and slidably moving the closing sleeve to the closed position.

Abstract: A well pipe string joint locator for attachment to the end of a length of coiled tubing and moved within the pipe string as the coiled tubing is lowered or raised therein is provided as well as methods of using the joint locator. The joint locator is comprised of an elongated tubular housing having a longitudinal fluid flow passageway therethrough and having at least one lateral port extending through a side thereof. Electronic means are disposed within the housing for detecting the increased mass of a pipe joint as said locator is moved through the joint and generating a momentary electric output signal in response thereto. Valve means are disposed within the housing responsive to the electric signal for momentarily opening or closing the lateral port of the housing to thereby create a surface detectible pressure drop or rise.

Abstract: The present invention provides lightweight, fast setting cement compositions and methods which can be utilized in performing a variety of well cementing operations. The cement compositions are basically comprised of slag cement, water sufficient to form a pumpable slurry, a gas sufficient to foam the slurry and a foaming agent.

Abstract: Hydrocarbon base drilling fluids which are selectively convertible to cementitious compositions that set into hard substantially impermeable masses and methods of using such drilling fluids are provided. The drilling fluids are basically comprised of a hydrocarbon liquid having particulate hydraulic cement suspended therein. The drilling fluids are converted to cementitious compositions by admixing water and a surfactant therewith.

Abstract: The present invention provides well cementing methods and compositions for use in cold environments which are particularly suitable for cementing conductor strings in deep water offshore wells. The cement compositions are basically comprised of a relatively coarse particulate hydraulic cement mixed with an ultra fine particulate hydraulic cement, sufficient water to form a pumpable slurry and a fluid loss control additive.

Abstract: Methods are provided for detecting the surface and/or subterranean locations of well treating fluids after the treating fluids have been introduced into wells and used for performing treatments therein. The methods of determining the subterranean locations of treating fluids basically comprise introducing a treating fluid into a well having a non-hazardous thermal neutron absorbing material combined therewith and performing a treatment in the well with the fluid. Fast neutrons from a source thereof are emitted in the well after the treatment whereby they interact with elements in the well and are thermalized. The thermal neutrons backscattered in the well are detected, and a count representing the detected thermal neutrons is generated. The subterranean locations of the treating fluid are determined by comparing the thermal neutron counts in the well before and after placement of the thermal neutron absorbing treating fluid therein.

Abstract: The present invention provides improved cementitious compositions which can include drilling fluid as a component thereof and methods of cementing wells utilizing such compositions. The compositions are basically comprised of a cementitious material, water, a hardenable resinous material and optionally, drilling fluid in an amount up to about 70% by volume of the cementitious material in the composition.

Abstract: Early evaluation testing of a subsurface formation is provided by monitoring pressure fall-off in the formation. This is accomplished by providing a column of fluid in the well having an overbalanced, hydrostatic pressure at the subsurface formation greater than a natural formation pressure of the subsurface formation. A testing string is run into the well, and the testing string includes a packer, a pressure monitor and a closure tool arranged to close a bore of the testing string. The formation is shut in by setting the packer and closing the bore of the testing string with the closure tool and thereby initially trapping the overbalanced hydrostatic pressure of the column of fluid in the well below the packer. Then the pressure in the well below the packer is monitored as it falls off toward the natural formation pressure. This data can be extrapolated to estimate the natural formation pressure based upon a relatively short actual test interval on the order of ten to fifteen minutes.

Abstract: Methods of completing poorly consolidated, weak, or otherwise unstable subterranean formations bounded by one or more consolidated formations to prevent well bore stability problems and/or sand production from the poorly consolidated or unstable formations are provided. The methods basically comprise the steps of drilling a well bore into the consolidated boundary formation adjacent to the poorly consolidated or unstable formation, creating at least one flow channel communicating with the well bore in the consolidated boundary formation which extends into the poorly consolidated or unstable formation and producing fluids from the poorly consolidated or unstable formation into the well bore by way of the flow channel.

Abstract: A number of improvements are provided in early evaluation systems which can be utilized to test and/or treat a subsurface formation intersected by an open uncased borehole. An outer tubing string is run into the well and has a packer which is set in the open, uncased borehole above the subsurface formation of interest. An inflation passage is provided and preferably has an inflation valve associated therewith which is operated by manipulation of the tubing string. A communication passage communicates the interior of the outer tubing string with the borehole below the packer. An inner well tool is run into the outer tubing string and engaged therewith, whereupon it is placed in fluid communication with the subsurface formation to either sample the formation or treat the formation. Preferably, a circulating valve is provided above the packer to allow fluid circulation in the well annulus during the testing procedure to prevent differential sticking of the outer tubing string.

Abstract: The present invention provides set retarding additives, set retarded hydraulic cement compositions including such additives and methods of using the cement compositions for cementing zones in wells. The set retarding additives are copolymers or terpolymers containing monomer units formed from one of maleic acid, itaconic acid, fumaric acid, citraconic acid and mesaconic acid along with other monomer units.

Abstract: A high pressure well cementing plug assembly for use in a pipe during the cementing of the pipe in a well bore is provided by the present invention. The assembly basically comprises top and bottom cementing plugs which include high strength inner tubes for supporting high differential pressures exerted on the plugs. The bottom end of the inner tube of the bottom plug is adapted to supportingly engage a float shoe or the like upon landing. Also, the bottom end of the inner tube of the top plug and the top end of the inner tube of the bottom plug are adapted to supportingly engage each other when the top plug lands on the bottom plug. The high strength inner tubes support high pressure differentials exerted on the plugs and prevent the plugs from collapsing or otherwise being damaged.

Abstract: Methods of combating production problems in wells containing defective gravel packs are provided. The methods basically comprise forming at least one perforation in the well bore extending from the well bore through the defective gravel pack and into the producing formation, forming at least one fracture containing proppant material in the formation communicating with the perforation and consolidating the proppant material in the fracture.

Abstract: Methods and compositions for removing gelled and dehydrated drilling fluid and filter cake from the walls of wellbores are provided. The methods basically include contacting the drilling fluid and filter cake with a removal composition comprised of an aqueous sugar solution for a period of time sufficient to cause the disintegration of the drilling fluid and filter cake. The composition, having the disintegrated drilling fluid and filter cake dispersed therein, is then displaced from the wellbore.