A while drilling mud loss treatment method includes providing a drilling tool main body with a through bore connected to an above arranged wired drill pipe string with a communication line to a topsides monitoring and control system, the drilling tool main body connected to a below arranged one or more drill collar sections with a lower of said drill collar sections connected to a drill bit, and drilling in a well. The main body is provided with an annular tank with a swellable sealant and the annular tank has a valve to an outlet to the through bore. A control system in the main body receives MWD sensor signals from an MWD sensor system and controls the valve having a valve actuator. The control system is, during drilling, running a monitoring and control algorithm using the signals as input for detecting an undesired mud loss state during drilling, and, if a mud loss state is detected, to command said valve actuator to open said valve upon detecting an undesired mud loss state, so as for ejecting said swellable sealant to said through bore.

Embodiments of a downhole drilling assembly generally include a rotatable lower drilling assembly, a rotatable upper drilling assembly, and a drill bit, wherein the upper drilling assembly contains a mud motor adapted for clockwise rotation of its stator and counter-clockwise rotation of its rotor, whereby the lower drilling assembly is rotatable in the opposite direction of the upper drilling assembly or maintainable in a non-rotating state. The apparatus further includes sensors adapted to continuously measure physical properties and/or drilling parameters and a mechanism for continuously transmitting information relating thereto to the surface.

Embodiments of a method for operating a downhole drilling assembly generally include continuously measuring physical properties and/or drilling parameters proximate the drill bit, continuously transmitting information relating thereto to the surface, and controlling rotation of a lower drilling assembly in a non-rotating state or in the opposite direction of an upper drilling assembly by varying drill string rotation.

A wellbore lining system that puts liners into place immediately behind the drill head tool is used in drilling and for preparing natural gas hydrate (NGH) deposits for production of its natural gas. The system overcomes the requirement of setting casing from the wellhead, which controls well bore diameter with depth and allows for flexibility in well bore size at any depth. Wellbore liners stabilize the well walls by being very tightly fitting against bounding rocks and sediments, which overcomes the requirement for cementing, which commonly accompanies conventional well casing. In addition, liners can be emplaced with designed impermeability, permeability, and complex flow-through patterns so that production processes, such as sand flow, can be put in place as part of a liner section.

A boring tool is movable through the ground. A transmitter supported by the boring tool transmits an electromagnetic homing signal. A portable device monitors the electromagnetic homing signal and receives the electromagnetic homing signal in a homing mode for guiding the boring tool to a target position. A processor generates steering commands for guiding the boring tool based on a bore plan in a steering mode such that at least some positional error is introduced without using the electromagnetic homing signal. Switching from the steering mode to the homing mode is based on monitoring of the electromagnetic homing signal as the boring tool approaches the portable device to then guide the boring tool to the target position location in compensation for the positional error. Intermediate target positions are described as well as guiding the boring tool based on the homing signal so long as the portable device receives the signal.

A method includes providing a Bottom Hole Assembly (BHA) in a wellbore. The BHA includes a rotary steerable system and a downhole attitude correction and control system. The downhole correction and control system includes a first sensor set, the sensors of the first sensor set positioned near ferromagnetic components of a drill string and a second sensor set, the sensors of the second sensor set positioned further from the ferromagnetic components of the drill string than the sensors of the first sensor set. Corrupted data from the first sensor set and reference data from the second sensor set is obtained, the corrupted data including cross-axis magnetometer and accelerometer measurements. The method additionally includes correcting the corrupted sensor data to form corrected sensor measurements and calculating an estimated azimuth from the corrected sensor measurements. The method further includes steering the rotary steerable system based on the estimated azimuth.

A drilling system includes a drill string, a plurality of sensors, and a computing system. The drill string includes a downhole motor. The sensors are coupled to the drill string. The computing system is coupled to the sensors. The computing system is configured to compute, based on measurements provided by the sensors, a motor stall index, and to determine, by comparing the motor stall index to a motor stall threshold, whether the downhole motor has stalled. The computing system is also configured to, responsive to a determination that the downhole motor has stalled, adjust operation of the drill string to restart the downhole motor.

A method and system of adjusting near-bit weight on a drill bit in a drill string having a bottom hole assembly located at an end of a drill pipe, an anti-stall device near the bottom hole assembly, surface sensing and control equipment and a downhole-to-surface communication system, the anti-stall device measuring downhole performance criteria and evaluation of the measured downhole performance criteria, comprising the steps of measuring at least one downhole performance criteria by the anti-stall device; evaluating the measured downhole performance criteria in substantially real time by the anti-stall device; adjusting weight on the drill bit by the anti-stall device based on the evaluation by the anti-stall device; and communicating the adjustment to weight on the drill bit to the surface sensing and control equipment by the downhole-to-surface communication system for further adjustment of weight on the drill bit.

A downhole communication system includes a mud pulse generator that generates a set of pressure pulses in a pattern, the pattern including encoded data. A roll stabilized platform includes a turbine that is rotatable in response to the pressure pulses. The rotational rate of the turbine is correlated with a pressure value. A processor on the roll stabilized platform demodulates the pressure pulse pattern, and then decodes the encoded data.

Aspects of the subject technology relate to systems and methods for improving mud motor trajectory controls. Systems and methods are provided for receiving control data from a mud motor trajectory controller, predefining a plurality of control modes based on the control data from the mud motor trajectory controller, achieving desired slide rotate ratios and toolface angles by solving an established objective function that mathematically represents operational preferences and system constraints for a selected control mode of the plurality of control modes, generating a modulation procedure that converts the slide-rotate ratios to a binary slide and rotate control sequence, and applying the modulation procedure to generate the binary slide and rotate control sequence.

A method of determining a drilling activity includes receiving a set of measurements at different times. The set of measurements includes a depth of a wellbore, a depth of a drill bit, and a position of a travelling block. The method also includes identifying a connection by determining when the position of the travelling block changes but the depth of the drill bit does not change. The method also includes determining when the depth of the wellbore does not increase between two different connections. The method also includes determining a direction that the drill bit moves between the two connections.