Patent Application
20190003284
The field of the invention is inflow control devices for borehole use and more particularly devices that are mechanically adjustable when downhole to balance flow from or into a formation.
Various types of flow devices are used in the production of hydrocarbons. One common surface mounted device is a choke which is a multi-position valve operated manually or with a motor at a surface location to control flow to the surface from a formation. Another type of flow control for boreholes is a system of flow balancing using a plurality of spaced inlets that feature a tortuous flow path with the devices closest to the surface configured before running in to have more resistance to flow than devices on the same string further from the surface. While incremental resistance in the tubular string for a given flow rate is reliably calculated in advance there are other variables such as formation pressures and porosities that make flow balancing with non-adjustable inflow control devices ahead of time much more difficult. Flow balancing is also important in operations such as gravel packing for uniform gravel distribution around a series of spaced apart screens.
Inflow control devices (ICD) commonly feature a tortuous path from an annulus inlet to a tubing side outlet to direct flow from the formation to the surface. Injection service reverses the flow direction but the objective remains the same, balancing flow. In some designs a spiral path for the fluid is induced with stationary vanes with the idea that if the properties of the produced fluid change primarily in viscosity a different flow regime will ensue without moving any parts. A design of this type is shown in U.S. Pat. No. 8,376,047. Other designs feature multiple fluid inlets with each configured with variable diodes where the paths are defined within an outer shroud as described in US 2015/0337622. This design would entail delivered or stored electric power which can add expense and operational issues. Another design involves stackable rings with passages that have flow resistors that can be stacked in advance of running in to quickly get the degree of flow resistance desired at each location. This is described in US 2013/0206245.
References have suggested restriction variability downhole using stepper or other types of motors to change flow resistance. One example is U.S. Pat. No. 8,204,693 item 81 and another using a motor driven selector plate is U.S. Pat. No. 8,267,180 items 12 and 14. Regulation of gas lift flow is taught in U.S. Pat. No. 5,937,945 using a helical surface advanced toward and away from a similarly shaped seat to change resistance to flow while the devices are mounted in the borehole. U.S. Pat. No. 7,789,145 teaches a shifting tool to engage the ICD and axially shift a sleeve with collet fingers from one profile groove to another to change the resistance to flow. This reference mentions multiple stop positions between least and most resistance to flow. Such a tool is expensive to manufacture and may not give sufficient feedback that it has shifted sufficiently or worse still it may skip the desired collet locating groove to an adjacent groove in which case the resistance to flow may change more than desired in either direction.
Using variable ICDs that require electric power creates difficulties in the space that power devices take up or the need to deliver power from a remote source. Operational reliability issues can spring up. What is offered is mechanically adjustable designs that vary the resistance to flow. One way is by using a thread mounted sleeve whose rotation covers or uncovers a labyrinth passage so as to short circuit some of the labyrinth by uncovering it when the sleeve is retracted and to increase the flow resistance if the sleeve moves in an opposite direction. In another variation the labyrinth path can be spiral with part of the path on a stationary outer sleeve and the remainder of the path on a movable sleeve. Axial movement of the movable sleeve can lengthen or shorten the number of overlapping spiral paths so as to change the resistance to a given flow rate. The inner member can be advanced with rotation about a threaded connection. The spiral paths in the two members have a clearance in between. Thus as more spirals overlap there is more resistance to flow and vice versa. These and other aspects of the present invention will be more readily apparent to those skilled in the art from a review of the description of the preferred embodiment and the associated drawings while understanding that the full scope of the invention is to be determined from the appended claims.
An adjustable inflow control device features a mechanically rotatable sleeve that advances or retreats axially when rotated in opposed directions to cover or uncover a labyrinth flow path from an inlet to an outlet. When used for inflow the outlet is into a tubular string to a surface location. The more the sleeve is retracted away from the labyrinth path the less resistance to flow is offered and vice versa. Another way to mechanically alter the flow resistance is to have an outer housing with a spiral groove and an axially movable inner mandrel with another spiral groove. The mandrel can be axially advanced with rotation when connected with a thread. Advancing the mandrel so that there is more overlap between the spiral patterns increases resistance to a give flow rate and vice versa. A gap between the mandrel and housing allows the mandrel to rotate and translate.
The axial movement of the sleeve 22 is accomplished by engaging tabs or profiles 40 with a schematically illustrated tool T that can impart a rotational force to the tabs or profiles 40 to advance sleeve 22 axially as it rotates by using engaged threads 24 and 26. Although a thread is illustrated, the shifting tool T can also move the sleeve 22 using a j-slot pattern with progressively longer slots so that the resistance to flow can be incrementally changed mechanically with a series of opposed axial movements to balance flow among locations followed by removal of the tool without there being restrictions to flow in the string 10 that could impede production. As previously described one or more ICDs 12 can be completely shut off or they can all be shut off to stop production of undesired fluids from a part or an entirety of a given formation or to allow operation of tools with pressurizing string 10. Each ICD 12 can have a signal transmitter 44 to communicate with tool T to allow surface personnel to know that tool T has reached a specific ICD 12. Keeping the actuation system for the sleeve 22 mechanical keeps it simple and reliable. Using a thread to induce axial movement of sleeve 22 allows more reliable incremental axial movements to be imparted to the sleeve 22 and it further resists forces from high velocity produced fluid passing through string 10 that could change the position of the sleeve 22 were it only retained by a collet in a groove as in U.S. Pat. No. 7,789,145.
The adjustment mechanism for the ICD that is illustrated relies on rotation with a tool T that can optionally send information to the surface to indicate the number of turns applied or the position of sleeve 22 or mandrel 66 with respect to end travel stops representing maximum flow resistance and minimum flow resistance. The use of rotation whether with a thread form or with a j-slot and a rotating sleeve having slots at different lengths also helps to fixate the sleeve 22 or the mandrel 66 against flow induced forces during production of injection. Mandrel 66 is hollow to allow flow from other regions to continue from or to the surface depending on the application. Using rotation to vary the resistance allows for infinite adjustments between closed and the least resistance position. The sleeve 22 or mandrel 66 stays put in service as opposed to collets in a profile that can be prone to displacement which would upset the flow balance among multiple ICDs. Disassembly after use is facilitated as the simplicity of the design allows component replacement with merely undoing a thread.
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:
