National Oilwell Varco Norway As

National Oilwell Norway As

National Oilwell, Inc.

National Oilwell Vareo Norway As

National Oilwell Varco, L.p.

Åge Kyllingstad

Magne Mathias Moe

Karl Erik Thoresen

Pål Jacob Nessjøen

Geir K Skaugen

Pål Jacob Nessjoen

Pål Jakob NESSJØEN

A method for drilling a borehole includes selecting a lower pressure limit and an upper pressure limit for a drilling fluid at a drilling location in the borehole. In addition, the method includes activating a pump to circulate the drilling fluid down a drill string and up an annulus disposed about the drill string. Further, the method includes operating the pump to maintain the drilling fluid at the drilling location at a pressure between the upper and the lower pressure limits. Still further, the method includes deactivating the pump to stop circulating the drilling fluid up the annulus. The method also includes sealing the drilling fluid in the annulus at a selected time after deactivating the pump and maintaining the pressure of the drilling fluid at the drilling location between the lower and the upper pressure limits.

Systems and methods for managing fluid pressure in a borehole during drilling operations

Disclosed is a method and system for tuning a hydraulic model to be used for estimating down hole dynamic pressure as a function of flow rate includes:

System and method for calibration of hydraulic models by surface string weight

A method for estimating downhole speed and force variables at an arbitrary location of a moving drill string based on surface measurements of the same variables. The method includes a) using properties of said drill string to calculate transfer functions describing frequency-dependent amplitude and phase relations between cross combinations of said speed and force variables at the surface and downhole; b) selecting a base time period; c) measuring surface speed and force variables, conditioning the measured data by applying anti-aliasing and/or decimation filters, and storing the conditioned data, and d) calculating the downhole variables in the frequency domain by applying an integral transform, such as Fourier transform, of the surface variables, multiplying the results with said transfer functions, applying the inverse integral transform to sums of coherent terms and picking points in said base time periods to get time-delayed estimates of the dynamic speed and force variables.

Method and device for estimating downhole string variables

There are described methods for controlling the direction of a wellbore trajectory during directional sliding drilling by means of a drill string having a drill bit rotatable, by means of a mud motor, around a drill bit rotation axis at its lower end, the direction of the drill bit rotation axis defining a tool face, wherein one of the methods comprises the following steps: There are also described systems for executing the methods as well as computer program products comprising instructions for causing a processor to perform the methods as described herein.

Methods and systems for control of wellbore trajectories

A method for detecting and localizing a valve leak in a piston machine having a shaft includes: attaching one or more vibration sensor to a valve block of the piston machine; measuring the vibrations from at least one of the vibration sensors; attaching a sensor to the piston machine where the sensor is designed to produce, directly or indirectly, an angular shaft position signal for the shaft; determining, directly or indirectly, an angular shaft position signal for the shaft; transforming vibration signals from the one or more vibration sensors into one envelope signal representing an instant vibration level; using the angular position signal for constructing window functions that pick the envelope signal in selected angular shaft sectors; using the window functions to find sector based averages of the vibration level; and comparing said averages with a critical ambient vibration level to detect and localize leaks in one or two valves.

Method and system for detection and localization of a fluid related to a piston machine

A method for reducing cogging torque effects of an electrical permanent magnet machine includes running an 'a' test and a 'b' test with different cogging compensation signals. A first value is calculated by multiplying a complex cogging amplitude of the compensation signal applied for the &#x201c;a&#x201d; test with a complex amplitude of a vibration signal resulting from cogging torque of the &#x201c;b&#x201d; test. A second value is calculated by multiplying a complex cogging amplitude of the compensation signal applied for the &#x201c;b&#x201d; test with a complex amplitude of the vibration signal resulting from cogging torque of the &#x201c;a&#x201d; test. A desired complex cogging compensation amplitude is calculated by dividing the difference between the first and second values by a difference between the complex amplitudes of the vibration signals resulting from the &#x201c;b&#x201d; test and the &#x201c;a&#x201d; test. A cogging compensation torque is applied to the machine based on the desired complex cogging compensation amplitude.

Method for reducing cogging torque effects of an electrical permanent magnet machine

A method of filtering out pressure noise generated by one or more piston pumps, where each pump is connected to a common downstream piping system, and where the discharge pressure is measured by a pressure sensitive gauge, wherein the instantaneous angular position(s) of the pump(s)' crankshaft or actuating cam is/are measured simultaneously with the discharge pressure and used as fundamental variables in an adaptive mathematical noise model.

Method of filtering pump noise

A valve arrangement for reciprocating machine, where the arrangement () comprises an in-valve () and an out-valve (), each valve (), () being a springloaded one-way valve designed to open for flow when the pressure differential in the direction of flow provides a force that exceeds the spring tension, wherein the valves () are mounted in a casing () that forms or is connected to the cylinder head of the reciprocating engine (). The in-valve () and the out-valve () are mounted in a sleeve () designed to be fitted in a bore () in the casing (), and where fluid may flow to the sleeve () from an inlet () in the casing () and into the sleeve () via the in-valve (), and where the sleeve () is provided with at least one perforated area where fluid may flow radially out of or into the sleeve () via holes (), thereby flowing to or from a passage () that forms a perpendicular or near perpendicular connection with the bore ().

Valve arrangement for reciprocating machinery such as a pump and an compressor

An apparatus and method for protecting against the problems associated with heave of a floating drilling rig are disclosed. The disclosed invention is a unique inline compensator in which a plurality of cylinders housed within a tubular housing and a plurality of low pressure and high pressure accumulators function together to provide a system for compensating for heave in the event a primary heave compensation system fails or becomes inoperative. The typical inline compensator of the present invention utilizes a plurality of hydraulic cylinders that act in opposite directions and that have different piston areas such that the piston rods of the cylinders are extended or retracted at different pressure levels to account for heave. The typical inline compensator of the present invention is self-contained and compact enough to fit in the limited space available on a floating drilling structure. Further, a pair of inline compensators of the present invention can be utilized with coiled tubing operations. In such a case, the inline compensators will not interfere with the tooling necessary to conduct the coiled tubing operations.

Inline compensator for a floating drill rig

A method of and device for detecting a leak in reciprocating machinery, comprising at least two pistons, by the volume flow at least out of the reciprocating machinery being monitored and analysed, e.g. by means of Fourier analysis, in order to make it possible to detect a flow component, where the flow component has a frequency that differs from the fundamental frequency of the reciprocating machinery, the fundamental frequency of the reciprocating machinery being constituted by the rotational frequency of the reciprocating machinery multiplied by the number of pistons in the reciprocating machinery.

Method and device for detecting leaks in reciprocating machinery

A piston engine in the form of a piston pump or a piston engine (motor) comprises two or more piston cylinders (), preferably positioned with the same angular distances of 180 degrees for two cylinders, 120 degrees for three cylinders etc. with regards to an axis, and each comprising a reciprocating piston with a projecting piston rod (). Via the piston rods (), each piston is given a controlled displacement matched to the controlled, given displacement of another or other pistons. The control means is rotatable and influences the projecting outer end portions of the piston rods or parts fitted to these, for instance rotatable rollers (). By a piston pump of this type, the pistons are to contribute to impelling a fluid flow, while a piston engine of this type shall be designed to be driven by a fluid flow. Operating conditions are aimed at which give a more even volume flow, i.e. without any significant fluctuations. For this purpose, said rotatable control means is designed with an encircling cam surface () which the piston rod ends abut via the peripheral surface of said rotatable rollers (). According to a feature of a method associated with the application of such a piston engine, each piston may with advantage be driven at a constant speed through part of its power stroke.

Growing community of inventors

Ålgård, Norway

Åge Kyllingstad