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 method of operating an isolation valve can include continuously transmitting a signal to a detector section, and a control system operating an actuator in response to the detector section detecting cessation of the signal transmission. A well system can include an isolation valve which selectively permits and prevents fluid communication between sections of a wellbore, a remotely positioned signal transmitter, and the isolation valve including a control system which operates an actuator in response to detection of a signal by a detector section. Another well system can include an isolation valve interconnected in a tubular string, and the tubular string being cemented in a wellbore, with cement being disposed in an annulus formed radially between the isolation valve and the wellbore.

Abstract: A fiber optic splice housing and integral dry mate connector system. In a described embodiment, a fiber optic connection system includes optical fiber sections in respective conduit sections. Each of the conduit sections is received in the housing assembly. An optical connection between the optical fiber sections is positioned within the housing assembly.

Abstract: A fiber optic splice housing and integral dry mate connector system. In a described embodiment, a fiber optic connection system includes optical fiber sections in respective conduit sections. Each of the conduit sections is received in the housing assembly. An optical connection between the optical fiber sections is positioned within the housing assembly.

Abstract: A fiber optic splice housing and integral dry mate connector system. In a described embodiment, a fiber optic connection system includes optical fiber sections in respective conduit sections. Each of the conduit sections is received in the housing assembly. An optical connection between the optical fiber sections is positioned within the housing assembly.

Abstract: A fiber optic splice housing and integral dry mate connector system. In a described embodiment, a fiber optic connection system includes optical fiber sections in respective conduit sections. Each of the conduit sections is received in the housing assembly. An optical connection between the optical fiber sections is positioned within the housing assembly.

Abstract: A fiber optic splice housing and integral dry mate connector system. In a described embodiment, a fiber optic connection system includes optical fiber sections in respective conduit sections. Each of the conduit sections is received in the housing assembly. An optical connection between the optical fiber sections is positioned within the housing assembly.

Abstract: A fiber optic splice housing and integral dry mate connector system. In a described embodiment, a fiber optic connection system includes optical fiber sections in respective conduit sections. Each of the conduit sections is received in the housing assembly. An optical connection between the optical fiber sections is positioned within the housing assembly.

Abstract: Methods and apparatus for determining at least one property of fluids related to oilfield operations may include an optical calculation device for measuring light having interacted with the fluid (e.g., flowing fluids and flames). The flame may be fueled, at least in part, by the stream of fluid from the subsurface well. Methods may include directing interacted light that comprises light having passed through a fluid relating to an oilfield operation to an iris; performing a regression calculation on the interacted light with an optical calculation device responsive to the interacted light incident thereon to produce at least one output light signal; and determining at least one property of the fluid from the at least one output light signal.

Abstract: A rotating control device can include a housing assembly, a body and a clamp device which releasably secures the housing assembly to the body. The clamp device can include a piston which radially displaces a clamp section. A well system can include a rotating control device which includes at least one seal which seals off an annulus between a body of the rotating control device and a tubular string which extends longitudinally through the rotating control device. The rotating control device can also include a piston which displaces longitudinally and selectively clamps and unclamps a housing assembly to the body.

Abstract: An RCD can include a housing assembly containing a bearing assembly and a rotating seal which seals an annulus between a tubular string and a body of the RCD, and a remotely operable clamp device which selectively permits and prevents displacement of the housing assembly relative to the body. A method of remotely operating a clamp device can include rotating a threaded member which is secured relative to an RCD body, and displacing a clamp section in response to the threaded member rotation, thereby selectively securing and releasing a bearing assembly and an annular seal relative to the body. Another RCD can include a rotating seal which seals an annulus between a tubular string and a body of the RCD, and a remotely operable clamp device which selectively permits and prevents access to an interior of the body, the clamp device including a motor which rotates a threaded member.

Abstract: Purging of fiber optic conduits in subterranean wells. A downhole optical sensing system includes an optical line, at least two tubular conduits, one conduit being positioned within the other conduit, and the optical line being positioned within at least one of the conduits, and a purging medium flowed in one direction through one conduit, and flowed in an opposite direction between the conduits. A method of purging a downhole optical sensing system includes the steps of: installing at least two conduits and an optical line in a well as part of the sensing system, one conduit being positioned within the other conduit, and the optical line being positioned within at least one of the conduits; and flowing a purging medium through the conduits in the well, so that the purging medium flows in one direction through one conduit and in an opposite direction between the conduits.

Abstract: Purging of fiber optic conduits in subterranean wells. A downhole optical sensing system includes an optical line, at least two tubular conduits, one conduit being positioned within the other conduit, and the optical line being positioned within at least one of the conduits, and a purging medium flowed in one direction through one conduit, and flowed in an opposite direction between the conduits. A method of purging a downhole optical sensing system includes the steps of: installing at least two conduits and an optical line in a well as part of the sensing system, one conduit being positioned within the other conduit, and the optical line being positioned within at least one of the conduits; and flowing a purging medium through the conduits in the well, so that the purging medium flows in one direction through one conduit and in an opposite direction between the conduits.

Abstract: A method of operating an isolation valve can include transmitting a signal to a detector section of the isolation valve, and a control system of the isolation valve operating an actuator of the isolation valve in response to detection of the signal by the detector section. An isolation valve can include a detector section which detects a presence of an object in the isolation valve, and a control system which operates an actuator of the isolation valve in response to an object presence indication received from the detector section. A well system can include an isolation valve which selectively permits and prevents fluid communication between sections of a wellbore, the isolation valve including a detector section which detects a signal, and the isolation valve further including a control system which operates an actuator of the isolation valve in response to detection of the signal by the detector section.

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 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 system and method of drilling and/or perforating uses a laser beam to remove material, such as to perforate the casing, cement and formation or drill a well bore. The system and method can further or alternately encompass material analysis that can be performed without removing the material from the well bore. The analysis can be performed apart from or in connection with drilling operations and/or perforating the casing, cement and formation. The analysis can be used in a feed back loop to adjust material removal, adjust material analysis, determine the location of future material removal, and for other uses.

Abstract: Methods, systems, and devices related to downhole wellbore operations such as drilling and completing wells in an earth formation include a laser device.

Abstract: A fiber optic splice housing and integral dry mate connector system. In a described embodiment, a fiber optic connection system includes optical fiber sections in respective conduit sections. Each of the conduit sections is received in the housing assembly. An optical connection between the optical fiber sections is positioned within the housing assembly.