A packer is an expandable plug configured to isolate sections of a conduit, such as a well casing, a borehole or a pipe. Packers can be used for performing various operations in the isolated sections of the conduit. For example, in a well casing or a bore hole, packers can be used to isolate different sections (i.e., zones) for hydrofracturing, grouting, sampling and monitoring. Packers can also be used to isolate different sections of a well casing or borehole for pumping fluids out of, or injecting fluids into the isolated sections.
One type of packer is known as an inflatable packer. Inflatable packers have been used in the oil and gas industry since the 1940's. Until recently, however, their use was restricted by prohibitive cost and limited availability. Now, several disciplines (e.g., ground water development, contamination studies, dewatering, geothermal, mining, coal bed methane, and geotechnical studies) use a wide selection of reasonably priced inflatable packers. The inflatable packer has significant advantages compared to other packer designs. These include a high expansion ratio, a minimal outside diameter combined with a large interior diameter opening, a long sealing section, which conforms to uneven sides in a conduit, and a high pressure rating.
The inflatable packer includes a mandrel made of tubing or pipe, having an inflatable element attached at one or both ends to an outside diameter thereof. Typically, the mandrel has threaded connections (e.g., NPT, API casing threads) at both ends. An inflation port allows gas, water or a solidifying liquid to be injected between the mandrel and the inflatable element. This expands the inflatable element against the inside diameter of the well or borehole to prevent fluids from flowing along the outside of the packer. However, since the mandrel also has an inside diameter, fluid can pass through the mandrel. Similarly, tubes, wire or other elements can be passed through the mandrel.
Recently, inflatable packers have been used to control fluid flow and pressure in a well or borehole. For example, U.S. Pat. No. 5,316,081 to Baski et al. and U.S. Pat. No. 6,273,195 to Hauck et al. disclose inflatable packers configured as flow and pressure control valves for wells.
One application for this type of inflatable packer is in aquifer and storage recovery (ASR). With aquifer and storage recovery (ASR) large volumes of treated water are injected and stored in aquifers during periods of the year when water and treatment facility capacity are available (e.g., winter). During periods of the year when water is in high demand (e.g., summer), water is pumped out of the aquifers. Both injection of water into an aquifer, and pumping of water out of the aquifer require flow and pressure regulation over a wide range of flow rates. In addition, it is advantageous for a flow control packer to provide flow control during both injection of water into the aquifer, and during pumping of water out of the aquifer.
Various embodiments of the flow control packer (FCP) to be further described can be used to control the flow and pressure of a fluid in either direction in a conduit, such as a well casing, a borehole, or a pipe. In addition, the flow control packer (FCP) can be used over a wide range of flow rates, pressures, and conduit sizes. Further, the flow control packer (FCP) can be used to construct various systems including aquifer and storage recovery (ASR) systems, and can be constructed to control flow rates for either injection into an aquifer or for pumping out of the aquifer.
However, the foregoing examples of the related art and limitations related therewith, are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the drawings.
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