An apparatus and method of drilling a wellbore using a drill string and a smart downhole system that comprises one or more downhole controllers and one or more downhole sensors. The method includes storing, in the downhole controller(s), a target efficiency parameter; drilling the wellbore using the drill string; and measuring, by the downhole sensor(s), a parameter. The method also includes, using the downhole controller(s) to: calculate an efficiency parameter based on the measured parameter; calculate a difference between the calculated efficiency parameter and the target efficiency parameter; generate first instructions to reduce the difference; and send to a surface controller, the first instructions. The method also includes generating, by the surface controller, second instructions based on the first instructions; and implementing, by the surface controller, the second instructions to reduce the difference between the measured efficiency parameter and the target efficiency parameter.

A variety of methods, systems, and apparatus are disclosed, including, in one embodiment a method of steering a drilling bit including: determining at least one control command to a drilling system, wherein the control command includes a combination of one or more nominal control commands output from a feedforward controller and one or more control command error values output from a feedback controller operating in an error space; and directing the drill bit of the drilling system in the wellbore based on at least the control command to extend the wellbore towards a planned depth-based wellbore trajectory.

Systems and methods for visualizing data from radially-oriented look-ahead sensors coupled to a drill bit are disclosed herein. A system comprises a processor, a memory, and a data analysis module. The data analysis module is operable to receive formation information from each of a plurality of formation sensors coupled to a downhole drilling system, the formation information being associated with one or more properties of a formation at a depth in front of the downhole drilling system, receive angular information from one or more orientation sensors coupled to the downhole drilling system, the angular information being associated with the formation information, compile sensor data based on the formation information and the angular information, and generate a visualization based on the sensor data.

A method for controlling drilling fluid properties, in some embodiments, comprises determining a predictive model for a fluid circulation system that routes drilling fluid downhole to a drill bit to remove debris from said drill bit; determining a cost function associated with the fluid circulation system; using the predictive model and the cost function to determine a set of input values for the predictive model; operating a controlled device according to at least some of the set of input values, said controlled device changes properties of the drilling fluid in the fluid circulation system; and obtaining measurements of the properties.

In some aspects, the present invention comprises a system and method for optimizing the control scheme used for drilling operations based on the complex and large data sets available in realtime during operation of a wellsite and based on existing model data available at the wellsite for past similar drilling operations. Such optimizations typically require downtime to quantify how the realtime values will factor into the control model, but the present invention allows for such optimization in realtime in a closed-loop system that will reduce the non-productive time associated with reservoir operations.

In a logging tool, a plurality of detectors (such as, e.g., a plurality of scintillation detector assemblies each including a scintillation crystal and associated photomultiplier tube) may be individually pressure-encased and arranged about a longitudinal axis of the tool, leaving a flow space between the detectors for the flow of drilling mud or other fluid through the tool. In some embodiments, this arrangement allows increasing the volume of detector material (e.g., scintillation crystal) without compromising the total cross-sectional area of the flow space (or increasing the total cross-section area without reducing the volume of detector material), compared, e.g., with tool configurations in which a single pressure case encloses the detectors. Additional apparatus, systems, and methods are disclosed.

A method for logging in a cased well is disclosed. The method includes receiving well data comprising an orientation of the cased well, selecting a logging while levitating (LWL) assembly type based on the well data, running the LWL assembly into the well to a start depth, and activating the LWL assembly based on a downhole condition so that the LWL assembly levitates in a center of the cased well, wherein the activated LWL assembly moves downhole in the cased well while levitating. The method further includes determining whether the LWL assembly has reached a target depth and performing logging in the cased well while the LWL assembly is levitating in the cased well when the target depth is reached.

A downhole rotational rate control apparatus, adapted for coupling to the lower end of a drill string, includes a progressive cavity pump or motor, a mud flow control valve, and an electronics section. Drilling mud flowing downward through the drill string is partially diverted to flow through the pump or motor, with the mud flow rate and, in turn, the pump or motor speed being controlled by the mud flow control valve. The control valve is actuated by a control motor in response to inputs from a sensor assembly in the electronics section. By varying the rotational rate of the pump or motor relative to the rotational rate of the drill string, the tool face orientation or non-zero rotational speed of the controlled device in either direction can be varied in a controlled manner.

Embodiments herein relate to apparatus for selecting between direct manipulations of a downhole tool and shifting of the operational mode of a downhole tool, and more particularly to a mode selector tool coupled with a J-Slot mechanism for the downhole tool, the selector enabling either an unimpeded shifting of, or a locking, of the J-Slot mechanism and connected downhole tool.

In accordance with some embodiments of the present disclosure, systems and methods for a nonlinear toolface control system for a rotary steerable drilling tool is disclosed. The method includes determining a desired toolface of a drilling tool, calculating a toolface error by determining a difference between a current toolface and the desired toolface, generating a model to describe the dynamics of the drilling tool, modify the model, based on at least one intermediate variable, to create a modified model, calculating a correction to reduce the toolface error, the correction based on the modified model, transmitting a signal to the drilling tool such that the signal adjusts the current toolface based on the correction, and drilling a wellbore with a drill bit oriented at the desired toolface.