Abstract: A safety valve having a mono spring closure mechanism. The closure mechanism may be free of any spiral wound spring. The closure mechanism may include a spring having a beam which bends along its length to apply a biasing force to the closure member at its fully closed position and at its fully open position. The closure mechanism may include only a single spring, with the spring having at least two legs, the legs being joined to each other at an end of each leg, and each leg including at least one beam.

Abstract: A fracturing/gravel packing tool with variable direction and exposure exit ports. A system for delivering an erosive flow into a subterranean well includes a port displacing in the well while the erosive flow passes through the port. Various displacement devices may be used in the system to displace the port.

Abstract: A system for variably resisting flow of a fluid composition can include a flow passage and a set of one or more branch passages which intersect the flow passage, whereby a proportion of the fluid composition diverted from the passage to the set of branch passages varies based on at least one of a) viscosity of the fluid composition, and b) velocity of the fluid composition in the flow passage. Another variable flow resistance system can include a flow path selection device that selects which of multiple flow paths a majority of fluid flows through from the device, based on a ratio of desired fluid to undesired fluid in the fluid composition. Yet another variable flow resistance system can include a flow chamber, with a majority of the fluid composition entering the chamber in a direction which changes based on a ratio of desired fluid to undesired fluid in the fluid composition.

Abstract: A slurry discharge device for use in a subterranean well can include a slurry flow passage extending longitudinally in the device. The slurry flow passage has flow passage sections. One flow passage section is positioned downstream of, and is laterally offset relative to, another flow passage section. Another slurry discharge device can include the slurry flow passage having multiple flow areas. One flow area is positioned in a downstream direction from, and is greater than, another flow area. A method of delivering a slurry into a subterranean well can include discharging the slurry from a tubular string through a first sidewall section of a slurry discharge device; and flowing only a returned fluid portion of the slurry through a second sidewall section of the slurry discharge device. The second sidewall section has a lateral thickness greater than a lateral thickness of the first sidewall section.

Abstract: A method of constructing a vehicle suspension system includes forming a suspension arm having a pivot connection at an end thereof, and a brake mounting integrally formed with the suspension arm; and then securing the suspension arm to an axle. A suspension system includes an axle and a suspension arm having a pivot connection which pivotably connects the axle to a vehicle frame, whereby the axle is vertically displaceable relative to the frame. At least one brake shoe is pivotably mounted to the suspension arm. Another suspension system includes a suspension arm having a pivot connection at an end thereof, and a brake spider integrally formed with the suspension arm. The brake spider includes at least one opening which receives a brake shoe pivot therein.

Abstract: A method of selectively actuating well tools includes the steps of: selecting a well tool for actuation by current flow in one direction through a set of conductors; and selecting another well tool for actuation by opposite current flow through the set of conductors. A system includes multiple control devices that control which well tool is selected for actuation in response to current flow in at least one conductor set. A current direction in the conductors selects a certain well tool for actuation. A method of using n conductors to selectively actuate n*(n?1) well tools includes the steps of: arranging the conductors into n*(n?1)/2 sets; connecting the conductor sets to respective groups of the well tools; and controlling direction of current flow through at least one of the sets of conductors, thereby selecting at least one well tool in the respective group of the well tools for actuation.

Abstract: A method for removing at least a portion of an object in an annulus formed between an external surface of a tubular element and a wall surface. A method for removing an annulus packer, of the swellable type or the foam type, from an annulus in a wellbore comprises the placement of a jetting tool inside the tubular element and effecting a high-pressure fluid flow from the jetting tool to the object, whereby the object is removed.

Abstract: A fully stabilized excavator tooth attachment. An excavator tooth includes a nose-receiving pocket bounded by an inner end, upper and lower, and opposing side walls, the end wall having a nose-engaging interface surface formed orthogonal to a longitudinal axis of the tooth, at least one of the side walls having a fastener opening formed therethrough, and each of the upper and lower walls having two spaced apart nose-engaging interface surfaces formed thereon substantially parallel to each other. Another excavator tooth includes side walls having generally planar nose-engaging interface surfaces formed therein, one surface resisting rotation of the tooth about the longitudinal axis in one direction, and another interface surface resisting rotation of the tooth in an opposite direction. An attachment system includes a fastener configured for releasably securing the tooth on the nose, the fastener having a thread which is eccentric relative to a body of the fastener.

Abstract: A fastening method and adapter configuration for mounting an excavation tooth to an excavation implement lip. A fastening system for the adapter can include a retainer which is receivable in an opening formed through the implement lip. The retainer cannot be removed from the opening while the adapter remains fully engaged with the lip. A method of fastening an adapter to an excavation implement lip can include: installing a retainer in an opening formed through the lip; then engaging the adapter with the retainer and the lip; and then securing the adapter to the lip by biasing the retainer forward. Another fastening system can include a retainer which is receivable in an opening formed through an excavation implement lip, with the retainer including one or more movable teeth and one or more stationary serrations. A wedge biases the retainer forward when the retainer teeth displace relative to the retainer serrations.

Abstract: Construction of well screens utilizing pre-formed annular-shaped elements. A well screen includes a filter layer configured to filter fluid flowing through the well screen and a drainage layer which radially supports the filter layer, the drainage layer including multiple individual annular-shaped elements. Another well screen includes a drainage layer configured to support the filter layer, with the drainage layer including at least one cavity molded therein. Another well screen includes a base pipe and a layer made up of multiple individual annular-shaped elements stacked coaxially on the base pipe. A cavity is formed in at least one of the elements.

Abstract: A system which attaches at least one line to a tubular string can include at least one clip pivotably secured on one side of a recess. At least one structure is positioned on an opposite side of the recess. Rotation of the clip into engagement with the structure secures the line in the recess. A method of attaching at least one line to a tubular string can include securing the line to a support on the tubular string as the tubular string is being conveyed into a wellbore. The securing step further includes rotating at least one clip into engagement with at least one structure, thereby preventing removal of the line from a recess formed in the support.

Abstract: A method of maintaining a desired downhole pressure during a drilling operation can include measuring a parameter with a sensor, communicating actual parameter values from the sensor to a predictive device, training the predictive device to output predicted parameter values in response to input of the actual parameter values, and outputting the predicted parameter values from the predictive device when the predictive device ceases receiving the actual parameter values. A well drilling system can include a predictive device which outputs predicted parameter values in response to input of actual parameter values to the predictive device. The predictive device continues to output the predicted parameter values, even when the predictive device fails to receive valid actual parameter values. Another well drilling system includes a data validator which communicates valid actual parameter values to the predictive device, but does not communicate invalid actual parameter values to the predictive device.

Abstract: A well drilling system for use with a drilling fluid pump includes a flow control device regulating flow from the pump to a drill string interior; and another flow control device regulating flow through a line in communication with an annulus. Flow is simultaneously permitted through the flow control devices. A method of maintaining a desired bottom hole pressure includes dividing drilling fluid flow between a line in communication with a drill string interior and a line in communication with an annulus; the flow dividing step including permitting flow through a flow control device interconnected between a pump and the drill string interior; and the flow dividing step including permitting flow through another flow control device interconnected between the pump and the annulus, while flow is permitted through the first flow control device.

Abstract: A variable flow resistance system for use in a subterranean well can include a flow chamber having an outlet and at least one structure which resists a change in a direction of flow of a fluid composition toward the outlet. The fluid composition may enter the chamber in the direction of flow which changes based on a ratio of desired fluid to undesired fluid in the fluid composition. Another variable flow resistance system can include a flow chamber through which a fluid composition flows, the chamber having an inlet, an outlet, and a structure which impedes a change from circular flow about the outlet to radial flow toward the outlet.

Abstract: Downhole orientation sensing with a nuclear spin gyroscope. A downhole orientation sensing system for use in conjunction with a subterranean well can include a downhole instrument assembly positioned in the well, the instrument assembly including an atomic comagnetometer, and at least one optical waveguide which transmits light between the atomic comagnetometer and a remote location. A method of sensing orientation of an instrument assembly in a subterranean well can include incorporating an atomic comagnetometer into the instrument assembly, and installing the instrument assembly in the well.

Abstract: A method of controlling pressure in a wellbore can include placing a barrier substance in the wellbore while a fluid is present in the wellbore, and flowing another fluid into the wellbore while the first fluid and the barrier substance are in the wellbore. The first and second fluids may have different densities. Another method can include circulating a fluid through a tubular string and an annulus formed between the tubular string and the wellbore, then partially withdrawing the tubular string from the wellbore, then placing a barrier substance in the wellbore, then partially withdrawing the tubular string from the wellbore and then flowing another fluid into the wellbore. A well system can include at least two fluids in a wellbore, the fluids having different densities, and a barrier substance separating the fluids.

Abstract: An alignment system can include at least one alignment device positioned between two flanges, the alignment device having a greater thickness on one side of the alignment device than on an opposite side of the alignment device. A method of producing a relative angular offset between a first flange and a second flange can include positioning at least one alignment device between the first and second flanges, and securing the alignment device between the first and second flanges, thereby producing the angular offset. A method of aligning an axis of a blowout preventer stack with a rig floor can include positioning at least one alignment device between a first flange, and a second flange of the blowout preventer stack; and securing the alignment device between the first and second flanges, thereby producing an angular offset of the second flange relative to the first flange.

Abstract: A variable flow resistance system can include a flow chamber through which a fluid composition flows in a well, the chamber having an inlet and an outlet. The fluid composition enters via the inlet in a direction which changes based on a ratio of desired to undesired fluid in the fluid composition. A well system can include a variable flow resistance system through which a fluid composition flows between a tubular string and a formation, the flow resistance system including a flow chamber through which the fluid composition flows, with only one chamber inlet. The fluid composition flows more directly from the inlet to an outlet as a ratio of desired to undesired fluid in the fluid composition increases. Another flow resistance system can include at least one structure which influences portions of the fluid composition which flow circuitously between the inlet and the outlet to maintain such circuitous flow.

Abstract: An excavator implement attachment system can include a tooth having a pocket formed therein, an insert received in a recess formed in an adaptor nose and a threaded fastener which releasably secures the tooth on the nose, the fastener having a helical thread formed thereon which is eccentric relative to a fastener body. A tooth can include a pocket with at least one side wall which has an insert-receiving recess and generally planar insert-engaging interface surfaces formed therein, with one interface surface resisting rotation of the tooth about a longitudinal axis in one direction, and another interface surface resisting rotation of the tooth about the longitudinal axis in an opposite direction. An excavator tooth can include a pocket bounded by opposing side walls, with at least one of the side walls having an insert-receiving recess internally formed thereon, whereby the recess receives an insert installed in an adaptor nose.

Abstract: A method of controlling pressure in a wellbore can include determining a real time wellbore pressure PwbRT1 at a pressure sensor in the wellbore, calculating hydrostatic pressure Ph1 at the pressure sensor, determining a real time annulus pressure PaRT, calculating friction pressure Pf due at least to circulation of the fluid through the wellbore and depth in the wellbore, calculating a friction pressure correction factor CFPf1 equal to (PwbRT1?Ph1?PaRT)/Pf, and controlling operation of a pressure control device, based on the friction pressure correction factor CFPf1. The method can further include determining a desired wellbore pressure PwbD1 at the pressure sensor, calculating an annulus pressure setpoint PaSP1 equal to PwbD1?Ph1?(Pf*CFPf1), and adjusting the pressure control device as needed to maintain PaRT equal to PaSP1.