Patent Application
20090000787
1. Field of the Invention
The present invention relates to an inflow control device for use in regulating the flow of fluid in a horizontal subterranean wellbore.
2. Description of the Prior Art
In long horizontal wellbores, water or gas coning has a tendency to develop near the heel of the wellbore, because of the buildup of frictional pressure loss towards the toe in the base pipe. The total oil recovery from the well may be significantly reduced as coning results in a much lower oil production rate, which, if allowed to continue, eventually makes the well unprofitable.
Inflow control devices are used to regulate the amount of fluid flowing into the base pipe to avoid coning and to achieve a preferential production of profile. One type of input control device may be deployed via the sand screen assembly. A sand screen joint is usually between 35 and 40 feet long and one inflow control device may be fabricated as part of that joint. Typically, the inflow control device comprises a nozzle through which production fluid may pass. On the upstream side of the nozzle, a plurality of openings are formed in the base pipe, and the number and size of the openings dictate the level of flow of production fluid through that joint.
The anticipated pressure profile for the well is used in designing the sand screen/inflow control device joints in a production string, with the number and size of the openings in the base pipe being greater at a joint near the toe than at a joint near the heel of the production tubing. The number and configuration of sand screen/inflow control device combinations in a given wellbore are thus different from one another and are the result of a unique design effort for each wellbore. Sand screen/inflow control device combinations have typically been designed and manufactured at one location and shipped to the wellbore site where they are assembled. The joints must then be assembled in a particular order at the well site in accordance with the design criteria. The drawbacks from using this technique are that errors in assembly may occur at the well site and substantial time and money are required to design and fabricate a production string unique to each wellbore.
In accordance with the present invention, an inflow control device is provided for use in controlling the flow of fluid into a production tubing in a subterranean wellbore. The input control device comprises a body with two ends comprising inner and outer concentric tubular members with an annulus between the members, where the annulus is closed at one end of the body and open at the other end of the body. An opening is formed in the inner tubular member proximate the end of the body which is closed, and a wall is disposed in the annulus between the first and second ends of the body. An orifice is disposed in the wall in the annulus to permit communication of fluid from one of the body to other.
In accordance with the present invention, the orifice has an opening which is variable in size. Thus, a given production tubing may be implemented using an inflow control device whose flow control characteristics may be adjusted in the field. In one embodiment of the present invention, the orifice comprises a variable pressure control valve while in another embodiment of the invention, the orifice comprises a variable relief valve. In yet a further embodiment of the invention, the adjustable orifice comprises an opening formed in the wall between the first and second ends of the body and the plate for adjusting the size of the opening through which fluid may flow when the inflow control device is part of the production tubing.
In accordance with the present invention, apparatus is provided for controlling the flow of fluid from the subterranean wellbore into a production tubing in that subterranean wellbore. The apparatus comprises a plurality of sand screen assemblies which are connected together in tandem. An uninterrupted path exists through the sand screen assemblies for fluid to flow.
An inflow control device is coupled to the upstream end of the plurality of sand screen assemblies for controlling the flow of fluid into the production tubing.
In one embodiment of the present invention, the aforesaid apparatus includes an inflow control device as described above.
In the accompanying drawings:
It will be appreciated that the present invention may take many forms and embodiments. In the following description, some embodiments of the invention are described and numerous details are set forth to provide an understanding of the present invention. Those skilled in the art will appreciate, however, that the present invention may be practiced without those details and that numerous variations and modifications from the described embodiments may be possible. The following description is thus intended to illustrate and not to limit the present invention.
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Wall 105 is disposed in the annulus 106 between ends 101a and 101b of inflow control device 101, and an orifice, 108 is established in the wall 105 to permit the communication of fluid from one side of the body of inflow control 101 to other. A significant aspect of an input control device in accordance with the present invention is that the size of the opening in orifice 108 is adjustable.
In one embodiment of the present invention, the adjustable orifice 108 comprises a variable pressure control valve, while in another embodiment of the invention, the adjustable orifice comprises a variable relief valve. In yet another embodiment of the invention, the adjustable orifice comprises an opening formed in wall 105 and a movable plate for covering a portion of that opening to regulate the flow of fluid through the opening.
In operation, the opening in adjustable orifice 108 may be adjusted appropriately based on the position of the inflow control device 101 in the production tubing string. Such adjustment may, for example, be made when the production string is being assembled at the well site. Inflow control device 101 may then be operatively connected to the upstream end of sand screen assembly 115 and to the downstream end of sand screen assembly 116. Such connections may, for example, be effected by using threaded connections.
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Further, while the foregoing description has focused on use of the present invention in connection with flow from the wellbore into the production string, those skilled in the art will appreciate that the present invention may also be utilized when injecting fluids into the wellbore. The appended claims are intended to cover all such uses.
Several advantages are realized with an inflow control device 101 according to the present invention. First, the openings 107 may be a uniform size for all inflow control devices in the production string, with the flow through a given inflow control device being regulated by the setting of adjustable orifice 108. Having a uniform size for openings 107 reduces the complexity and cost of production. Second, inflow control devices 101 according to the present invention may be mass produced, which also results in less expensive devices. Third, by having the inflow control device be manufactured separately from the sand screens, the sand screens may also be mass produced with an attendant reduction in cost over the cost of prior art devices. Fourth, the operator has the ability to tailor the production from the wellbore at the well site by using the present invention.
