Whipstock valve with nozzle bypass feature

Abstract

A valve for subterranean whipstock service has a side port and a through passage with a biased movable sleeve to shift between circulation mode into the annulus and flow through mode for setting an anchor and then feeding window mill nozzles. The valve is run in when in circulation mode to allow operation of a measurement while drilling device. When the whipstock is properly oriented the pressure is increased to break a shear pin to allow a spring to bias the sleeve to the flow through position. The shifting of the sleeve opens a bypass passage around the restriction orifice that was first used to build pressure to break the shear pins that let the sleeve move under spring bias. As a result the spring can hold the sleeve in position despite high flow rates needed to remove cuttings from the mill as the window is opened.

Claims

1. A method of window milling with an assembly comprising a measurement while drilling (MWD) assembly, a valve assembly, at least one window mill, a whipstock, and an anchor for said whipstock, comprising: running in with said valve assembly in a circulation configuration for operation of said MWD assembly; orienting said whipstock with said MWD assembly; reconfiguring said valve assembly for flow through configuration to set said anchor and direct flow to said window mill; accomplishing said reconfiguring in part with increasing flow through an orifice in a valve member to shift said valve member to close at least one circulation port while opening a flow through passage to said mill and a bypass for said orifice.

2. The method of claim 1, comprising: retaining said valve member in said flow through configuration exclusively with a bias force.

3. The method of claim 1, comprising: releasably securing said valve member in said circulation configuration; releasing said securing with flow through said orifice; biasing said valve member toward said flow through configuration after said releasing.

4. The method of claim 3, comprising: providing at least one spring or compressed gas for said biasing.

5. A method of window milling with an assembly comprising a measurement while drilling (MWD) assembly, a valve assembly, at least one window mill, a whipstock, and an anchor for said whipstock, comprising: running in with said valve assembly in a circulation configuration for operation of said MWD assembly; orienting said whipstock with said MWD assembly; reconfiguring said valve assembly for flow through configuration to set said anchor and direct flow to said window mill; accomplishing said reconfiguring in part with increasing flow through an orifice in a valve member to shift said valve member to close at least one circulation port while opening a flow through passage to said mill and a bypass for said orifice; aligning at least one port on said valve member with a lateral port on a housing of said valve assembly for said circulation configuration; moving said valve member port into misalignment and sealing isolation from said lateral port on said housing and into position to serve as a flow bypass for said orifice in said flow through configuration.

6. A method of window milling with an assembly comprising a measurement while drilling (MWD) assembly, a valve assembly, at least one window mill, a whipstock, and an anchor for said whipstock, comprising: running in with said valve assembly in a circulation configuration for operation of said MWD assembly; orienting said whipstock with said MWD assembly; reconfiguring said valve assembly for flow through configuration to set said anchor and direct flow to said window mill; accomplishing said reconfiguring in part with increasing flow through an orifice in a valve member to shift said valve member to close at least one circulation port while opening a flow through passage to said mill and a bypass for said orifice; providing initially isolated flow paths around a block in said valve member when closing a lower end of said passage in said circulation configuration; moving said block opposite a recess in said passage to allow flow to said lower end of said passage through said flow paths in said flow through configuration.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is an enlarged section view of the prior art valve in the circulating position;

(2) FIG. 2 is the view of FIG. 1 showing the entire valve on both sides of what is shown in FIG. 1;

(3) FIG. 3 is the view of FIG. 2 after the valve is shifted to a flow through position;

(4) FIG. 4 is a section view of the valve of the present invention showing it in the circulation mode;

(5) FIG. 5 is the view of FIG. 4 showing the shear pin sheared with pressure still applied;

(6) FIG. 6 shows the shifted position of the sleeve when the pressure is turned off and the valve in the flow through position with the restriction orifice bypassed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

(7) Referring to FIG. 4 a housing 70 has a through passage 72 having an upper end 74 and a lower end 76. Threads 78 and 80 connect the housing 70 to a tubular string that is not shown. In the preferred embodiment a measurement while drilling module would be connected above the housing 70 and a window milling assembly, whipstock and anchor would be connected below to thread 80. A plurality of circumferentially spaced lateral ports 82 are in communication with passage 72 in FIG. 4 through a restriction orifice 84. Seals 86 and 88 prevent fluid entering at the top end 74 of the passage 72 from bypassing the orifice 84. Seal 90 is against inner wall 32 of passage 72 preventing any flow into slanted passages 50. Recess 36 allows bypassing of seal 90 when sleeve 38 is made to shift. Initially sleeve 38 is shear pinned by pins 40. A spring 42 pushes against sleeve 38 when the sleeve 38 is in the FIG. 4 position and restrained by pins 40. Spring 42 is supported by shoulder 44 on housing 70.

(8) Arrow 46 represents initial circulation flow that exits ports 82 to establish circulation for the operation of the measurement while drilling device. This is done to properly orient the whipstock that is not shown before the anchor below it can be set with built up pressure. Once the proper whipstock depth and orientation are established, the circulation rate is increased through the orifice 84 which causes the force on sleeve 38 to be increased. At some point the higher force on the sleeve 38 results in the shear pins 40 shearing but with the flow being maintained the seal 90 is still against inner wall 32 and the ports 82 are still open. This means that the passage 72 is still closed to its lower end 76 and still open to lateral ports 82.

(9) When the pumps are turned off at the well surface, as shown in FIG. 6 the spring 42 is able to push sleeve 38 toward the upper end 74 of the passage 72 so that seal 90 moves off surface 32 and due to the positioning of recess 36 allows passages 34 communicate with passages 50 so that flow is directed through the passage 72 from end 74 to end 76. At the same time the movement of sleeve 38 positions seals 52 and 58 on opposed sides of ports 82 to close them off. However, ports 56 in sleeve 38 have now shifted enough toward upper end 74 of the passage 72 such that flow into passage 72 now can travel around the orifice 84 and through ports 56 and into passages 34 followed by recess 36 and then to passages 50 and through the spring 42 to lower end 76 of the passage 72. Sleeve 38 has been pushed until it shoulders on radial surface 48 and the force of the spring 42 is sufficient to hold the sleeve 38 in the FIG. 6 position. The reason is that very little flow will pass through the orifice 84 in the FIG. 6 position as the open area of ports 56 is more than 6 times the area of the orifice 84. While flow through the orifice 84 will put some downhole oriented force on the sleeve 38 the spring force from spring 42 can readily overcome that force so that locking sleeve 38 in its shifted position will no longer be needed as in the prior design shown in FIGS. 1-3.

(10) Those skilled in the art will appreciate that the new design with the bypassing of the orifice due to the shifting of ports 56 from alignment with ports 82 for running in to an open position in to passage 72 near its top end 74 with ports 82 closed off and the lower end 76 of passage 72 opened up allows the spring itself to fixate the sleeve 38 without snap rings or other fasteners. The design becomes more reliable and cheaper to manufacture as well. When milling the pressure buildup seen at the surface is fully reflective of the flow at the milling nozzles because the orifice 84 is essentially bypassed even though some minimal flow may go through it. This makes the milling operation more reliable as there is direct data at the surface as to the condition of the milling nozzles and the pressure drop through them. Erosion damage to the orifice 84 is also minimized. While a coil spring is shown other springs such as a stack of Belleville washers or a piston under gas pressure can be used to bias the sleeve 38.

(11) The above description is illustrative of the preferred embodiment and many modifications may be made by those skilled in the art without departing from the invention whose scope is to be determined from the literal and equivalent scope of the claims below: