Abstract: Wellbore fluids are disclosed which comprise liquid dispersions of particulate mixed divalent metal carbonates having a generally platy crystal form. Mixed alkaline earth metal carbonates are preferred. The invention further relates to a method of well construction, well remediation, or stimulation utilizing such wellbore fluids.

Abstract: The invention, in one embodiment, relates to a fluid loss control additive or composition comprising a granular starch composition and fine particulate mica, in specified proportions. The invention further comprises a fracturing fluid containing a starch composition and mica, in a specified ratio. In yet a third embodiment, the invention comprises a method of fracturing a subterranean formation penetrated by a borehole, comprising injecting into the borehole and into contact with the formation, at a rate and pressure sufficient to fracture the formation, a fracturing fluid containing starch and mica, in specified ratios, and in an amount sufficient to provide fluid loss control.

Abstract: The invention concerns wellbore fluids suitable for use in the oil and gas exploration and production industries and embraces fluids used for drilling, completion, workover or packing of wellbores. The invention is especially concerned with biodegradable wellbore fluids the liquid phase of which consists of an oil, or of water-in-oil "invert" emulsions, where the oil phase comprises n-alkanes.

Abstract: Products and methods relating to composite materials and their use in coiled tubing is disclosed. The composite tubing is a pressurized structure for conveying fluids downhole in a wellbore. It has a multilayered laminate that resists buckling within the wellbore and is fabricated into a hollow tube. The fibers are oriented in angular relationship to the longitudinal direction of the coiled tubing such as to provide appropriate strength and buckling characteristics to the coiled tubing. Further, the coiled tubing layered laminate may transmit signals representing data from downhole to the surface. In some embodiments, a composite disconnecting structure having a blend of fibers of different types or orientations is shown. The disconnecting structure shows a failure load range corresponding to the failure characteristics of the fiber blend, the fiber blend having a predetermined failure limit.

Abstract: The present invention is directed to an aqueous foamed Drilling Fluid for drilling well bores into a subterranean formation, comprising water, at least one clay and at least one foaming agent. According to the invention, it further comprises at least one metal hydroxide. The invention further relates to a method for preparing said foamed drilling fluid.

Abstract: A downhole activated circulating sub is adapted to be interconnected between various tools installed on coiled tubing and placed into a wellbore; for example, between a coiled tubing/measurement while drilling tool and a downhole motor/drill bit for drilling a wellbore. The circulating sub can be repeatedly set and reset while the circulating sub is disposed in the wellbore. As a result, it is not necessary to retrieve the circulating sub to the wellbore surface for the purpose of resetting the sub. The circulating sub includes a latch mechanism which locks and latches the sub in either a set condition or a reset condition when a fluid is pumped through the circulating sub. When fluid flow through the circulating sub stops, the latch mechanism is unlocked and the circulating sub can change between the set condition and the reset condition.

Abstract: In the horizontal parts of deviated wells arranged within a producing formation, good communication between the formation and the wellbore liner is required, and this may be achieved by using a slotted or perforated liner in the horizontal section without any cementing to bond the liner to the wellbore. However, problems can arise if it is desired to work selectively in a zone in the horizontal section, since with a perforate liner there is no way of isolating the zone from the remainder of the well by using internal packers. This problem can be overcome by providing packers around the outside of the liner, this then allows packers inside the liner to be used to isolate a portion of the well. However, these external casing packers must be sealed against the wellbore, they must be positioned in advance, and they substantially increase the cost of the completion.

Abstract: A latch is adapted to be connected to a tubing string and will snap into a packer disposed in a wellbore. A predetermined first number of pounds is required to snap the latch into the packer and a predetermined second number of pounds, greater than the first number, is required to pull the latch out of the packer in the wellbore. In order to maintain constant the first and second number of pounds, the latch has the following special characteristics. The latch has a plurality of flanges separated, respectively, by a plurality of gaps, that snap into the packer, each flange having external threads disposed around its periphery, each thread including an engaging surface and a disengaging surface, an angle between the surface of each disengaging thread relative to a vertical being in a range from 20 to 28 degrees. An elastomeric barrier occupies the gap between adjacent ones of the flanges.

Abstract: A drilling tool, adapted to drill a wellbore in an earth formation, comprises a weight on bit equalizer shock sub. The weight on bit equalizer shock sub includes a precharged nitrogen chamber and additional chambers, the nitrogen in the nitrogen chamber adapted to telescopically open the equalizer shock sub during the drilling of the wellbore thereby maintaining a constant weight or force on the drill bit during the drilling operation. A force resultant from the pressurized nitrogen exists in the nitrogen chamber and additional forces resultant from a pressurized wellbore fluid exist in the additional chambers. The shock sub is specially designed in a particular manner to cause the sum of the force of the nitrogen in the nitrogen chamber and the additional forces of the wellbore fluid in the additional chambers to be equal solely to the force of the nitrogen in the nitrogen chamber.

Abstract: A slat-type inflatable packer includes a plurality of longitudinal metal slats on the exterior thereof which are partially overlapping to allow expansion of the packer element while providing a barrier against extrusion. In one embodiment each slat has narrow end portions and a wide central portion to provide greatly increased lateral stiffness as well as improved extrusion barrier and slat deployment characteristics, particularly in high expansion ratio packers, and in another embodiment such characteristics are further improved by upper and lower intermediate sections which are wider than such central portion.

Abstract: The present process permits the use of more efficient, low viscosity fluids to efficiently perforate and fracture a subterranean formation in an overbalanced condition in the wellbore.

Abstract: A cable is injected into a length of coiled tubing disposed on a reel by an apparatus and method which includes attaching a small diameter pipe to the end of the coiled tubing, feeding the cable into the opposite end of the pipe through a seal and pumping a liquid into the annular space defined by the cable and the pipe at sufficient pressure and flow rate so that fluid drag on the cable overcomes the frictional force of the cable passing through the seal to inject the cable through the entire length of the coiled tubing. This method avoids the prior expensive practice of deploying coiled tubing in a straight line, either horizontally or vertically in order to feed cable through the tubing.

Abstract: Viscoelastic surfactant based aqueous fluid systems are described that are useful in fracturing subterranean formations penetrated by a wellbore. The preferred thickening agents are quaternary ammonium halide salts derived from certain waxes, fats and oils. The thickening agent is used in conjunction with an inorganic water soluble salt such as ammonium chloride or potassium chloride, and an organic stabilizing additive selected from the group of organic salts such as sodium salicylate. The resulting fluids are stable to a fluid temperature of about 225.degree. F.

Abstract: A low-temperature, low-rheology synthetic cement comprises an epoxy resin, catalyst and hardener and further including an aromatic solvent have the formula ##STR1## wherein R and R' are independently selected from hydrogen and C1 to C4 hydrocarbons.

Abstract: The invention relates to iron control in an acid medium for forestalling the formation of precipitates known as "sludges" (asphaltic products) in contact with certain crude oils.Use is made of compounds comprising a mercaptan function non miscible in water and, in combination, a selection of catalysts.Application to acid treatments for oil, gas, water, geothermal and analogous wells, as well as to industrial cleaning.

Abstract: The particulate phase of fluids according to the present invention comprises particles which have specifically adapted size ranges or granulometries. All the essential properties of fluids and their cost are very clearly improved. The technique may be applied to all well operations in oil wells or the like, such as in matrix treatment and the like.

Abstract: The invention relates to the cementing of high temperature wells. The retarder consists of a methylene phosphonic acid derivative and of a boric acid or a borate at least as acid as borax in an aqueous solution, in particular, Na pentaborate, in a preferred ratio of 0.08 to 0.92 parts by weight. A long setting time and a very swift compressive strength development are obtained at the same time.

Abstract: The invention relates to the cementing of high temperature wells. A cement retarder comprises a phosphonic acid derivative combined with borax in a weight ratio of phosphonic acid derivative to borax of about 0.025 to about 0.2. A long pumping time is realized with rapid compressive strength development following placement.

Abstract: The addition of fibrous mixtures in intimate mixtures with particulates for fracturing and gravel packing decreases or eliminates the undesirable flowback of proppant or formation fines while stabilizing the sand pack and lowering the demand for high polymer loadings in the placement fluids. Fibers are useful for forming a porous pack in the subterranean formation. In some cases, channels or fingers of void spaces with reduced concentrations of proppant may be introduced into the proppant pack.

Abstract: A deflecting tool or whipstock is oriented and anchored in a well casing during a single trip of a running string so that a window can be formed in the wall of the casing at a selected azimuth. The angular orientation of the deflecting tool is measured, and signals representative thereof are transmitted to the surface. When the desired orientation is obtained, the anchor is actuated to prevent movement of the deflecting tool, and the orientation adjusting and measurement and transmission tools are released from the whipstock and removed from the casing by withdrawing the running string which preferably is coiled tubing. Then a downhole motor and milling bit are run into the casing on coiled tubing and operated to form a window through the wall thereof opposite the deflection surface of the whipstock so that a new borehole can be drilled outside the casing.