In one aspect, embodiments disclosed herein relate to an oil-based wellbore fluid. The oil-based wellbore fluid may include an oleaginous liquid and a surface-modified precipitated silica, wherein the surface-modified precipitated silica comprises a lipophilic coating. In another aspect, embodiments disclosed herein relate to a method of drilling or servicing a well. The method may include circulating a wellbore fluid, such as that described in the paragraph above, into a wellbore, and recovering at least a portion of the wellbore fluid from the wellbore.

One implementation of the disclosure provides a computer implemented method for underbalanced drilling. The implementation may include determining an initial 2D UBD operation envelope based on a set of initial operating points for a selected TVD or time, displaying the initial 2D UBD operation envelope on a computer display, providing at least one data point representing actual data from a well, determining at least one actual UBD operation point using the at least one data point and displaying it on the computer display along with the 2D UBD operation envelope, selecting an optimization parameter, determining a set of optimized operating points based on the optimization parameter, and displaying the set of optimized operating points on the computer display along with the 2D UBD operation envelope.

A method of increasing a stimulated reservoir volume in a hydrocarbon-bearing formation in fluid communication with a wellbore, the method including drilling a plurality of lateral extensions at varying depths in the formation extending from a vertical wellbore using underbalanced coiled tubing drilling; and injecting an exothermic reaction component into the plurality of lateral extensions to create a plurality of fractures extending outwardly from and between the plurality of lateral extensions to create a multilateral fracture network.

The present invention relates to a downhole string (1) for drilling through a low pressure zone (Zlow) in a formation (45) in a well (3), comprising a drawdown casing (2) having a first end (4) closest to a top (5) of the well and a second end (6), and an operational tool (8) connected to the second end of the drawdown casing, wherein the downhole string further comprises an annular barrier (10) having an expandable metal sleeve (11) surrounding the drawdown casing, each end of the expandable metal sleeve being connected with the drawdown casing, the expandable metal sleeve being adapted to contact a wall (16) of a borehole (17) or another casing so that the drawdown casing can rotate and slide in relation to the annular barrier after expansion of the expandable sleeve. Furthermore, the present invention relates to a downhole system and to a downhole method.

A method of drilling a wellbore includes drilling the wellbore through a formation by injecting drilling fluid through a drill string and rotating a drill bit. The drill string includes a shifting tool, a receiver in communication with the shifting tool, and the drill bit. The method further includes retrieving the drill string from the wellbore through a casing string until the shifting tool reaches an actuator. The casing string includes an isolation valve in an open position and the actuator. The method further includes sending a wireless instruction signal to the receiver. The shifting tool engages the actuator in response to the receiver receiving the instruction signal. The method further includes operating the actuator using the engaged shifting tool, thereby closing the isolation valve and isolating the formation from an upper portion of the wellbore.

A depth range manager provide users with a way to run and retain multiple depth range analyzes for a drill string operation, including the operational parameters for each analysis. This allows users easily to view and compare the analyzes at the different drilling depth ranges. In some embodiments, instead of drilling depth ranges, users may also urn and retain multiple different models and analyzes using multiple different drilling times. The operational parameters for the multiple different models and analyzes may be defined and stored using a flexible one-to-many database structure that accommodates the different sets of operational parameters as well as any existing single-analysis parameters associated with legacy analyzes. A graphical interface allows users easily to define and store the operational parameters in the flexible one-to-many database structure.

A shifting tool for use in a wellbore includes a tubular housing having a bore formed therethrough; a tubular mandrel disposed in the housing and longitudinally movable relative thereto; and an engagement member moveable relative to the housing between an extended position, a released position, and a retracted position, wherein: the engagement member is movable from the retracted position to the extended position in response to movement of the mandrel relative to the housing, and the engagement member is further movable from the extended position to the released position in response to movement of the mandrel relative to the housing.

An assembly is used with a remote source of hydraulic power to control flow of wellbore fluid in a drilling system. At least one choke is operable to control the flow of the fluid to other portions of the system. At least one hydraulic actuator disposed with the choke actuates operation of the choke in response to the hydraulic power. At least one control valve disposed with the choke controls supply of the hydraulic power to and controls return of the hydraulic power from the actuator. An accumulator can be disposed with the choke and coupled to the supply upstream of the control valve. The control valve can couple to the actuator with a pair of pilot-operated check valves disposed in fluid communication between the control valve and the actuator. A stage tank and stage pump can be disposed with the choke. The tank receives the return from the control valve, and the stage pump can pump the return from the stage tank to the source.

A system and methods for petro-steering methodologies are provided. An exemplary method obtains rock fabric data, and integrate rock fabric data with dynamic productivity data to identify patterns between the rock fabric data and dynamic productivity data. Gas rates and steering values are predicted across UBCT wells based on the patterns.

The disclosed embodiments include a method, apparatus, and computer program product for monitoring underbalanced drilling operations. For example, one disclosed embodiment is a system that includes at least one processor and at least one memory coupled to the at least one processor and storing instructions that when executed by the at least one processor performs operations for generating a three dimensional tunnel view of an operating envelope of a well as the well is being drilled.