Constricting flow diverter

In one aspect of the present invention, a downhole assembly has a downhole tool string component with a bore adapted to accommodate drilling mud having a central passage and at least one periphery passage. At least two movable segments are peripherally positioned around a bore wall adapted to constrict a diameter of the central passage and are adapted to divert drilling mud into the at least one periphery passage. At least one opening mechanism is adapted to move a portion of the at least two movable segments toward the bore wall.

BACKGROUND OF THE INVENTION

This invention relates to downhole drilling assemblies, specifically downhole drilling assemblies for use in oil, gas, geothermal, and horizontal drilling. The ability to efficiently provide a power source downhole is desirable to electronically and mechanically power downhole instrumentation.

U.S. Pat. No. 5,626,200 to Gilbert et al., which is herein incorporated by reference for all that it contains discloses a logging-while-drilling tool for use in a wellbore in which a well fluid is circulated into the wellbore through the hollow drill string. In addition to measurement electronics, the tool includes an alternator for providing power to the electronics, and a turbine for driving the alternator. The turbine blades are driven by the well fluid introduced into the hollow drill string. The tool also includes a deflector to deflect a portion of the well fluid away from the turbine blades.

U.S. Pat. No. 5,839,508 to Tubel et al., which is herein incorporated by reference for all that it contains, discloses an electrical generating apparatus which connects to the production tubing. In a preferred embodiment, this apparatus includes a housing having a primary flow passageway in communication with the production tubing. The housing also includes a laterally displaced side passageway communicating with the primary flow passageway such that production fluid passes upwardly towards the surface through the primary and side passageways. A flow diverter may be positioned in the housing to divert a variable amount of the production fluid from the production tubing and into the side passageway. In accordance with an important feature of this invention, an electrical generator is located at least partially in or along the side passageway. The electrical generator generates electricity through the interaction of the flowing production fluid.

U.S. Pat. No. 4,211,291 to Kellner, which is herein incorporated by reference for all it contains, discloses a drill fluid powered hydraulic system used for driving a shaft connected to a drill bit is disclosed. The apparatus includes a hydraulic fluid powered motor actuated and controlled by hydraulic fluid. The hydraulic fluid is supplied to the hydraulic fluid powered motor through an intermediate drive system actuated by drill fluid. The intermediate drive system is provided with two rotary valves and two double sided accumulators. One of the rotary valves routes the hydraulic fluid to and from the accumulators from the drill fluid supply and from the accumulators to the drill bit. The rotary valves are indexed by a gear system and Geneva drive connected to the motor or drill shaft. A heat exchanger is provided to cool the hydraulic fluid. The heat exchanger has one side of the exchange piped between the drill fluid inlet and the drill fluid rotary valve and the other side of the exchange piped between the hydraulic fluid side of the accumulators and the hydraulic fluid rotary valve.

U.S. Pat. No. 4,462,469 to Brown, which is herein incorporated by reference for all that it contains, discloses a motor for driving a rotary drilling bit within a well through which mud is circulated during a drilling operation, with the motor being driven by a secondary fluid which is isolated from the circulating mud but derives energy therefrom to power the motor. A pressure drop in the circulating mud across a choke in the drill string is utilized to cause motion of the secondary fluid through the motor. An instrument which is within the well and develops data to be transmitted to the surface of the earth controls the actuation of the motor between different operation conditions in correspondence with data signals produced by the instrument, and the resulting variations in torque in the drill string and/or the variations in torque in the drill string and/or the variations in circulating fluid pressure are sensed at the surface of the earth to control and produce a readout representative of the down hole data.

U.S. Pat. No. 5,098,258 to Barnetche-Gonzalez, which is herein incorporated by reference for all that it contains, discloses a multistage drag turbine assembly is provided for use in a downhole motor, the drag turbine assembly comprising an outer sleeve and a central shaft positioned within the outer sleeve, the central shaft having a hollow center and a divider means extending longitudinally in the hollow center for forming first and second longitudinal channels therein. A stator is mounted on the shaft. The stator has a hub surrounding the shaft and a seal member fixed to the hub wherein the hub and the shaft each have first and second slot openings therein. A rotor comprising a rotor rim and a plurality of turbine blades mounted on the rotor rim is positioned within the outer sleeve for rotation therewith respect to the stator such that a flow channel is formed in the outer sleeve between the turbine blades and the stator. A flow path is formed in the turbine assembly such that fluid flows though the turbine assembly flows through the first longitudinal channel in the central shaft, through the first slot openings in the shaft and the stator hub, through the flow channel wherein the fluid contacts the edges of the turbine blades for causing a drag force thereon, and then through the second slot openings in the stator hub and the shaft into the second channel.

BRIEF SUMMARY OF THE INVENTION

In one aspect of the present invention, a downhole assembly has a downhole tool string component with a bore adapted to accommodate drilling mud having a central passage and at least one periphery passage. At least two movable segments are peripherally positioned around a bore wall adapted to constrict a diameter of the central passage and are adapted to divert drilling mud into the at least one periphery passage. At least one opening mechanism is adapted to move a portion of the at least two movable segments toward the bore wall.

The at least one periphery passage may direct drilling mud to a turbine. The turbine may be in communication with an electrical generator. The at least one periphery passage may direct drilling mud to a downhole hammer, a downhole steering tool, sensors, or combinations thereof.

The at least one opening mechanism may comprises a motor, a spring, a pin, a hydraulic actuator, or combinations thereof. The at least two movable segments may be interlocked. Springs may connect the at least two movable segments together. The at least two movable segments may be foils. The at least two movable segments may have a forward tapered face. The at least two movable segments may have a rearward tapered face. An edge of the at least two movable segments may taper from a bottom end of the at least two movable segments to a top end of the at least two movable segments.

The at least two movable segments may be adapted to pivot on the opening mechanism. The at least two movable segments may be adapted to pivot on a stator disposed within the bore. The at least two movable segments may be adapted to pivot on a wall of the at least one periphery passage. A turbine body disposed within the bore and the at least two movable segments may form a barrier separating the central passage and the at least one periphery passage. The bore may have an expanded diameter region. The downhole assembly may be in communication with a telemetry system.

FIG. 1is an embodiment of a drill string100suspended by a derrick101. A downhole assembly102is located at the bottom of a bore hole103and comprises a drill bit104. As the drill bit104rotates downhole the drill string100advances farther into the earth. The drill string100may penetrate soft or hard subterranean formations105. The downhole assembly102and/or downhole components may comprise data acquisition devices which may gather data. The data may be sent to the surface via a transmission system to a data swivel106. The data swivel106may send the data to the surface equipment. Further, the surface equipment may send data and/or power to downhole tools and/or the downhole assembly102.

Referring now toFIGS. 2 through 3b, the downhole assembly102comprises a downhole tool string component200comprising a bore201adapted to accommodate drilling mud202. The bore201comprises a central passage203and at least one periphery passage204. The at least one periphery passage204may direct drilling mud202to a turbine210. At least two movable segments205are disposed within the bore201and are peripherally positioned around a bore wall206. The at least two movable segments205are adapted to constrict a diameter207of the central passage203and are adapted to divert drilling mud202into the at least one periphery passage204. In the embodiment ofFIGS. 3athrough3bthe at least two movable segments205may be adapted to pivot on a wall208of the at least one periphery passage204. An edge250of the at least two movable segments205may taper from a bottom end251of the at least two movable segments205to a top end252of the at least two movable segments205. The at least two movable segments205may be foils205. It is believed that as drilling mud202flows through the bore a pressure drop may develop and the top ends252of the at least two movable segments205will move towards the center of the bore201. It is anticipated that as the top ends252of the at least two movable segments205move towards the center of the bore201, the tapered edges250of the at least two movable segments205may abut one with another preventing the top ends252of the at least two movable segments205from advancing further towards the center of the bore201. The downhole tool string component200is considered to be in a closed position when the top ends252of the at least two movable segments205can no longer advance further towards the center of the bore201. When the downhole tool string component200is in the closed position the at least two movable segments205constrict the diameter207of the central passage203and divert drilling mud202into the at least one periphery passage204.

The downhole tool string component200comprises at least one opening mechanism260adapted to move a portion of the at least two movable segments205toward the bore wall206. In the embodiment ofFIGS. 3athrough3b, the at least one opening mechanism260may comprise at least one pin261with a first end262and a second end263. The first end262may be connected to the bore wall206and adapted to pivot. A spring264may be used to apply a force on the pin261pushing the pin towards the bore wall206. As the spring264pushes the pin261in the direction of the bore wall206the second end263of the pin261may contact one of the at least two movable segments205and move the top end252of the contacted movable segment205toward the bore wall206. The downhole tool string component200is considered to be in an opened position when the top ends252of the at least two movable segments205are positioned proximate the bore wall206the diameter207of the central passage203is not constricted. The spring264may exert a force strong enough to keep the at least two movable segments205in the opened position when drilling mud202is not flowing through the bore201and weak enough to allow the at least two movable segments205to move to the closed position when drilling mud202is flowing through the bore201. The embodiment ofFIGS. 3athrough3bmay comprise as many pins261and springs264as there are movable segments205and may comprise as few as one pin261and one spring264. The at least two movable segments205may be interlocked such that if one of the at least movable segments205is moved towards the bore wall206the rest of the at least two segments205are also moved towards the bore wall206. It is believed that the interlocked movable segments205may be beneficial when instruments from the surface are passed down the center of the drill string100and as the instruments approach the at least two movable segments205the instruments will contact at least one of the pins261forcing all of the at least two movable segments205to the opened position if they are not already in the opened position. The at least two movable segments205may close the at least one periphery passage204when in the opened position preventing drilling mud202from entering the at least one periphery passage204.

In the embodiment ofFIGS. 3aand3b, a turbine body211and the at least two movable segments205may form a barrier209separating the central passage203and the at least one periphery passage204. Turbine blades212may be connected to the turbine body211and disposed within the at least one periphery passage204. The turbine210may be in communication with an electrical generator220. The turbine210may transfer mechanical energy to the electrical generator220via a connecting rod221disposed intermediate the turbine210and the electrical generator220. The bore201may comprise an expanded diameter region270adapted to accommodate the turbine210, the electrical generator220, the at least two movable segments205, and the at least one periphery passage204.

FIGS. 4athrough4bdisclose an embodiment wherein the at least one opening mechanism260may comprise an actuator301. In some embodiments, the actuator may be a hydraulic actuator. The actuator301may comprise a piston302disposed in a piston housing303located within the bore wall206. A distal end306of the piston302is in communication with the at least two movable segments205. A pump304may be in communication with the piston housing303and may direct hydraulic fluid307from a fluid reservoir305to the piston housing303and the pump304may direct hydraulic fluid307from the piston housing303to the fluid reservoir305. As hydraulic fluid307is directed to the piston housing303the piston302may move the at least two movable segments205into the closed position. As hydraulic fluid307is directed from the piston housing303to the fluid reservoir305the piston302may move the at least two movable segments205into the opened position. A telemetry system308may be in communication with the downhole assembly102and may be used to control the opening mechanism260. In the embodiment ofFIGS. 4athrough4b, the telemetry system308may be used to control the pump304.

Referring now toFIGS. 5athrough5b, the at least two movable segments205are adapted to pivot on the opening mechanism260. The distal end306of the piston302may comprise a spherical geometry401adapted to fit within a recess402formed in the at least two movable segments205. The spherical geometry401of the distal end306and the recess402in the at least two movable segments205may form a ball-and-socket joint403wherein the at least two movable segments205may pivot on the distal end306of the piston302.

Referring now to the embodiment ofFIGS. 6athrough6b, springs501may connect the at least two movable segments205together. The springs501may be used to move the at least two movable segments205apart from each other into the opened position. The springs501may exert a force strong enough to keep the at least two movable segments205in the opened position when drilling mud202is not flowing through the bore201and weak enough to allow the at least two movable segments205to move to the closed position when drilling mud202is flowing through the bore201. The springs501may be used to move the at least two movable segments205together into the closed position. The at least two movable segments205may comprise a forward tapered face502. It is believed that the forward tapered face502may be beneficial when instruments from the surface are passed down the center of the drill string100and as the instruments approach the at least two movable segments205the instruments will contact the forward tapered face502of the at least two movable segments205which will direct the instruments towards the central passage203. The at least two movable segments205may comprise a rearward tapered face503. It is believed that the rearward tapered face502may be beneficial when instruments from the surface that have been passed down the center of the drill string100and the downhole component200are being raised back up to the surface and as the instruments approach the at least two movable segments205the instruments will contact the reward tapered face503of the at least two movable segments205which will direct the instruments towards the central passage203and may assist the instruments in moving the at least two movable segments205to the opened position if the at least two movable segments205are in the closed position.

Referring now toFIGS. 7athrough7b, a stator601, the turbine body211and the at least two movable segments205may form the barrier209separating the central passage203and the at least one periphery passage204. The stator601may be disposed intermediate the turbine body211and the at least two movable segments205and at least two movable segments205may be adapted to pivot on the stator601. Bearings602may be disposed intermediate the turbine body211and the stator601. Bearings602may also be disposed intermediate the turbine body211and the bore wall206.

The at least one periphery passage204may direct drilling mud to a downhole hammer, a downhole steering tool, sensors, or combinations thereof. Referring now toFIG. 8, the at least one periphery passage204may direct drilling mud to a downhole hammer701. The downhole hammer701may comprise a loading spring702, fluid chamber703, entry valves704, exit valves705, and a hammer head706. The at least one periphery passage204may direct drilling mud202to the entry valves704and into the fluid chamber703. As the fluid chamber703fills, pressure in the fluid chamber703compresses the loading spring702. After the loading spring702is compressed, the exit valves705are opened allowing the drilling mud202to exit the fluid chamber703and the loading spring702pushes the hammer head706against the formation105. The central passage203may direct drilling mud202to a nozzle707.