Abstract: A multiphase flow meter comprising two Venturis separated by a choke. The choke may be varied to adjust the properties of the multiphase fluid flow being measured. The two Venturis may be identical and may be arranged horizontally with respect to the multiphase fluid flow. The choke may be a choke in a return line of a managed pressure drilling system.

Abstract: Injection of gas into a managed pressure drilling system to provide for operation of the drilling system in a downhole pressure window defined by the pore pressure of a formation being drilled and a fracture pressure of the formation. Gas injection being controlled so as to produce the desired downhole pressure without causing large oscillations in borehole pressure.

Abstract: An expandable reamer for a borehole has a plurality of support elements (202) distributed around a central axis of the tool with cutters (234, 236) and stabilising pads (250) on the support elements, arranged such that at least one of the support elements comprises at least one region comprising cutters and at least one support element comprises a stabilising pad having a front surface positioned to face the wall of the borehole. The reamer includes drive mechanism for expanding the support elements (202) radially outwardly from the central axis. The support elements differ in the presence or axial positions of stabilising pads (250) thereon such that at least one support element differs from at least one other support element in the presence or axial position of at least one stabilising pad. This arrangement allows the stabilising pads to be positioned at or close to full gauge, thereby reducing vibration.

Abstract: The operation of rotary equipment carried on elongate structure such as coiled tubing extending into a borehole from the Earth's surface is carried out by providing at least one optical fibre extending downhole to the rotary equipment from the surface, using optical time domain reflectometry to operating the optical fibre as a distributed vibration sensor while the rotary equipment is in operation, and thereby observing vibration created by the rotary equipment.

Abstract: A method for determining hydraulic compliance of a wellbore during a managed pressure drilling procedure. Measurements are made of the pressure of a drilling fluid being circulated in the wellbore during the procedure at the top of a drilling annulus, the flow rate qin of the drilling fluid into the wellbore and the flow rate qout of the fluid out of the wellbore. These three measurements are used to determine the difference of the flow rates and a discrete time derivative (Pt?Pt-?t)/?t of the pressure, where t is time and ?t is a time interval. The differences in flow rates and the time derivatives are then processed by applying a low pass filter to determine the hydraulic compliance of the wellbore.

Abstract: Injection of gas into a managed pressure drilling system to provide for operation of the drilling system in a pressure window defined by the pore pressure of a formation being drilled and a fracture pressure of the formation. The gas is injected through gas injection ports and drilling fluids are allowed to flow between the drilling annulus and the gas injection system though a plurality of flow ports that are disposed vertically below the gas injection ports in the borehole being drilled. The gas injection ports and the flow ports are configured so that when gas is flowing through the gas injection ports, the flow ports are sealed.

Abstract: Wear sensors are provided on a drill bit or other rotary cutting tool which is for operation in a subterranean borehole and has a plurality of separate cutters protruding from a support structure towards the material to be cut by the tool. The electrically operated sensing means are located at or coupled to a sensing point within a protrusion from the support structure. This sensing point is located within a protrusion such that attrition of at least one cutter to a partially worn state brings the protrusion into abrasive contact with the material being cut and attrition of the protrusion then exposes the sensing point to the material which is being cut by the tool and thereby brings about a detectable change, which may include damage to the sensor at the sensing point, indicative of wear. The tool includes means to communicate data from the sensing means to the surface.

Abstract: Method for controlling bottomhole pressure in a borehole during managed pressure drilling. In the drilling procedure fluid is circulated down a drillstring and to surface through an annulus between the drillstring and an inner-wall of the borehole. A compressor/pump is used to inject gas into the returning drilling fluid at a gas injection point. The method comprises receiving a target bottomhole pressure; determining actual bottomhole pressure during the procedure; and adjusting a variable as directed by a feedback controller, which operates to reduce the difference between the target pressure and the measured pressure. The manipulated variable may be one or any combination of: (1) pressure of drilling fluid at the entry of the fluid into the drillstring, (2) the flow rate of drilling fluid out of the drillstring into the annulus, (3) pressure of the gas exiting from the compressor, and (4) the injection rate of the gas.

Abstract: An apparatus for drilling a wellbore (10) is disclosed, the apparatus comprising a lowermost pilot drill bit (16) having a diameter less than that of the diameter of wellbore (12) drilled by the apparatus, above which is a reamer, having an adjustable drill diameter from a first diameter less than that of the pilot drill to a second diameter greater than that of the pilot drill, above which is a body portion (24) having a lower diameter less than that of the pilot drill and an upper diameter greater than that of the pilot' drill but less than the second diameter of the reamer.

Abstract: A method is provided for determining a discharge coefficient of a managed pressure drilling choke/valve as a function of valve opening position. The method comprises: a flow of air/gas through the choke/valve; measuring a velocity of the air/gas flow at an inlet of the choke/valve; and measuring a pressure drop of the air/gas flow across the choke/valve.

Abstract: Milling systems, tools, and methods include using a mill with a barrier to promote re-circulation of debris and cuttings to the face of the mill. The face of the mill may include cutting elements. A barrier may obstruct the flow of cuttings and debris away from the face to re-circulate the cutting and debris to promote re-milling of the cuttings and debris by the cutting elements of the face of the mill. The barrier may include a hydraulic barrier formed by fluid expelled from nozzles in or above the mill. A secondary attrition system uphole of the mill may also be used to stage conditioning and re-sizing of cuttings and debris. After debris and cuttings pass through the barrier, the secondary attrition system may re-mill the cuttings and debris to a finer size before allowing the cuttings and debris to pass into the wellbore annulus for transport to the surface.

Abstract: A method for controlling a managed pressure drilling system including a drillstring located in a borehole, a pump that delivers drilling fluid, and a choke that controls the flow of the drilling fluid from an annulus formed between the drillstring and the wall of the borehole. During drilling, the drilling fluid flows downwardly through the drillstring from the pump and through a drill bit, and returns through the annulus to the choke. The method includes determining a correction ?Vcorr in the volume of the fluid in the annulus to achieve a target pressure in the fluid; calculating a choke flow rate correction term ?qcorr by dividing ?Vcorr by a factor related to the acoustic travel time to of a pressure wave in the fluid travelling the length of the annulus; and determining a flow demand from the choke on the basis of the flow rate correction term ?qcorr.

Abstract: A method is provided for controlling a managed pressure drilling system. The method comprises providing a fast system interpretation model for the operation of the managed pressure drilling system, obtaining real-time measurements from one or more sensors regarding the operation of the managed pressure drilling system, using the measurements to calibrate the fast system interpretation model for the managed pressure drilling system in real-time and using a predictive controller to run the calibrated fast system interpretation model to a time horizon in the future.

Abstract: Managing operation of a sealing element is described. In some aspects, failure of the sealing element of a pressure drilling system may be predicted. Deformation of the sealing element as a tool joint is pulled through the sealing element may be detected and tracked to determine if a deformation pattern of sealing element changes. Responses of sealing element due to one or more of stress, strain, temperature, mechanical load, and pressure using a network of sensors around sealing element can be detected. Responses may be tracked over time. Detected responses are compared to tracked responses to identify changes in the symmetry of responses over time or changes in magnitude of responses over time. Changes are associated with fractures occurring within sealing element. A remaining life of sealing element is predicted based on the changes and replacement may be scheduled based at least in part on the predicted remaining life.

Abstract: Systems and methods are provided for aligning pressure drilling system equipment. According to such methods, a longitudinal axis of a shaft of the pressure drilling system is determined. An offset between the axis of the shaft and a longitudinal axis of a blowout preventer is determined. A first adjustment component is coupled with the blowout preventer. A second adjustment component is aligned relative to the first adjustment component based on the measured offset. The second adjustment component is coupled with the first adjustment component. A rotating control device is coupled with the second adjustment component such that an axis of the rotating control device corresponds with the axis of the shaft to account for the measured offset.

Abstract: A method for automating a downhole milling process includes receiving an input stream from at least one sensor within a downhole milling system, and segmenting the input stream. A safe operating envelope is identified based on segments of the input stream and models for the segments. At least one parameter of the milling system is then automatically changed along a path of optimal rate of penetration while remaining within the safe operating envelope. In some embodiments, an input stream may include surface pressure and the safe operating envelope may include swarf transport conditions.

Abstract: Injection of gas into a managed pressure drilling system to provide for operation of the drilling system in a downhole pressure window defined by the pore pressure of a formation being drilled and a fracture pressure of the formation. Gas injection being controlled so as to produce the desired downhole pressure without causing large oscillations in borehole pressure.

Abstract: A drilling procedure is operated such that a formation around the wellbore being drilled is fractured and then reservoir fluids from a hydrocarbon reservoir contained in the formation are flowed into the wellbore where the flow of the reservoir fluids is tested. Production predictions for the wellbore are processed from the measurements made on the flow of reservoir fluids and decisions regarding further drilling operations are made based upon the reservoir fluid measurements. By testing reservoir fluids prior to completing the wellbore, drilling operations such as, for example, continuing to drill the wellbore may be made without tripping the drillstring from the wellbore.

Abstract: The present specification describes a drill bit for drilling a cavity. The drill bit may include a chassis, a plurality of gauge pad sets, and at least one gauge pad structure. The chassis may be configured to rotate about an axis. The plurality of gauge pad sets may each include at least one gauge pad. The at least one gauge pad structure may moveably couple at least one of the gauge pads of at least one of the plurality of gauge pad sets with the chassis.

Abstract: A drill bit system for a drilling assembly is disclosed. The drill bit system may include a chassis, a head, and one or more compliantly coupled gauge pads. The head may include a first plurality of cutters coupled with an end of the head, and the head may be coupled with chassis. The one or more gauge pads may include a second plurality of cutters, and the one or more gauge pads may be movably coupled with the chassis.