RIASSUNTO
Abstract
Selective injection equipment (SIE), is used to control the volumes of injection fluid into each zone of a multi-zoned reservoir. It has traditionally been manufactured from a variety of different metal alloys, which usually makes SIE an expensive investment. This investment not only includes the initial cost of packers, sidepocket mandrels, and seating nipples, but after several years of operation, the equipment retrieval is expensive, and potentially impossible.
Drillable selective injection equipment has recently been developed for trial use in the Rangely Weber Sand Unit in Rangely, Colorado.
This new selective injection equipment used cup packers and sidepocket mandrels made primarily of fiberglass. These were almost entirely free of metal components, except for a stainless steel pocket in the mandrel, and a wire reinforcement in the packer cups.
Replacement of fiberglass SIE will result in substantial savings from the reduction of retrieval cost. The fiberglass SIE can easily be removed by drilling with a conventional rock bit and
circulating the cuttings from the well. The metal in the cups and mandrel could be removed with the bit, washed over, or pushed to the bottom of the hole. In any case, removal time is reduced from weeks or even months, to days.
Improvements in the next generation of drillable SIE will include even less metal in the sidepocket mandrels. An inflatable fiberglass packer will be developed to provide a stationary, as well as a drillable packer.
Introduction
The Rangely Weber Sand Unit is located in northwestern Colorado near Rangely, Colorado, and is operated by Chevron U.S.A. Inc. The unit is presently producing 35,000 BOPD with the help of alternating water and carbon dioxide injection. Production is from the Weber formation, which in Rangely has four to six distinct layers of sandstone separated by shale at an average depth of 5800 ft.
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