Abstract: Well servicing agents and processes for use with fluids circulated into wells penetrating subterranean formations in the earth's crust. Circulation losses of well servicing fluids including drilling muds, workover and completion fluids, and the like, are alleviated by incorporating a particulate material into the servicing liquid. The particulate material is formed of a thermoplastic polymer in a flexible, elongated laminar form in which its length is substantially greater than its width and its width substantially greater than its thickness. A second particulate material in a rigid granular form may be employed an admixture with the laminar particulate material. A particular lost circulation agent is a blend of a particulate thermoplastic polymer in a flexible, elongated form and a particulate thermoset polymer in a rigid granular form with the ratio of the laminar material to the granular material being at least 1:6.

Abstract: A method for controlling or terminating the flow of gas, oil or other fluids from an uncontrolled well penetrating a subterranean formation which comprises introducing into the active string metallic balls which melt at a temperature below that of the formation at the bottom end of the active casing or tubing string. Alternatively, liquid alloy is introduced into the active string which will cool and solidify in the well to form a plug of solid alloy in the string to stop the flow of fluid.

Abstract: An arrangement for drilling deviated wellbores, such as in extended reach drilling, which is particularly designed to reduce the chance of pressure-differential sticking of the drill string by removing the drilling cuttings from the wellbore bottom by reverse circulation of the drilling fluid using a pump powered by the cones of the rotary bit. The drill string is turned by a rotary, and as the drill string turns, the cones turn as they are rolled on the bottom of the hole. A power drive is taken off the bit cones, and powers a pump which pumps mud from the annulus, around and through the bit, and up the drill pipe. In this way, troublesome cuttings are kept out of the annulus, and the cuttings are more effectively removed by pumping up and out the drill pipe.

Abstract: A method of cementing a well drilled into the earth is disclosed wherein there is formed a pumpable thixotropic cement slurry having essentially zero water separation at downhole conditions and being formed of Portland cement, bentonite and water. This cement slurry is injected into a well and allowed to set.

Abstract: A method of preparing and using a cement slurry having water swellable clays therein as extenders for the cement is described, which method enhances the effectiveness of the water swellable clays by preshearing aqueous suspensions thereof prior to mixing these suspensions with cement to form a pumpable cement slurry. Also described is a particular technique for using bentonite as a cement extender in a cement slurry formed with salt water.

Abstract: This specification discloses a technique of providing a wellbore that extends from a surface location to a subsurface location in a mineral bearing formation which subsurface location is spaced a great lateral distance from the surface location. The wellbore is provided to have a first portion that extends essentially vertically from the surface location into the earth's crust and into a formation having good drilling characteristics, a second portion that extends for a great distance within and essentially parallel to the bedding plane of the formation having good drilling characteristics, and a third portion that extends essentially vertically from the farthest extension of the second portion to the subsurface location in the mineral bearing formation.

Abstract: This specification discloses a method and system for cementing a casing string with returns to the seafloor in an offshore wellbore. The hydrostatic pressure at a preselected point within the annulus formed intermediate the casing string and the wellbore wall is monitored during a cementing operation to determine when cement returns in the annulus reach the seafloor and thereafter the cementing operation is terminated.

Abstract: This specification discloses a method of controlling the loss of drilling fluid into a lost circulation zone of a subterranean earth formation penetrated by a well. A nonaqueous slurry of a hydratable material and an oleophilic clay is introduced into the well and mixed in the vicinity of the lost circulation zone with an aqueous liquid to form a soft plug.

Abstract: This specification discloses a method of cementing pipe in a well and discloses the use of a designed oil-wetting liquid and cement slurry for cementing pipe against evaporite sections penetrated by the well. The cement slurry is formulated from hydraulic cement, silica flour, ionization control agent, sodium chloride, weighting agent, dispersing and retarding agent, and water, and has a density within the range of about 15.8 to 21.0 pounds per gallon.

Abstract: This specification discloses a method of treating a well drilled into the earth. In carrying out this method there is formed a lightweight thixotropic cement slurry that is comprised of a low density calcined shale cement, attapulgite and water, in ratios to provide a pumpable slurry that has zero water separation. This lightweight thixotropic cement slurry having zero water separation is placed in a well and allowed to set.

Abstract: This specification discloses a method of cementing pipe in a well and discloses a cement slurry which may be used for cementing pipe against evaporite sections penetrated by the well. The cement slurry is formulated from hydraulic cement, silica flour, attapulgite, sodium chloride, weighting agent, dispersing and retarding agent, and water, and has a density within the range of about 13.0 to 21.0 pounds per gallon.

Abstract: This specification discloses a method of controlling an active zone that is penetrated in the drilling of a well. In accordance with the method there is formed a mixture of inert particulate material and an oil-wetting dispersing agent in a light oil and the mixture is circulated to a lower portion of the well and maintained there to allow the inert particulate material to separate from the light oil and form a plug in the well to control the active zone.

Abstract: this specification discloses a well completion method for deviated boreholes and in particular a schedule for placing wipers and centralizers along a casing string to be cemented in a deviated borehole to facilitate the reciprocation and cementing thereof in the borehole. A plurality of wipers spaced a first selected distance one from the other are positioned on a portion of the casing string to be located adjacent a zone of interest in the deviated portion of the borehole. A first plurality of centralizers are also positioned on the casing string on the portion to be located adjacent the zone of interest and a second plurality and a third plurality of centralizers are positioned on the casing string, respectively, below and above the zone of interest. The centralizers of the first, second and third pluralities are all spaced a second selected distance, one from the other.