| 摘要 |
Apparatus for use in injecting treatment solutions through the annulus between two concentric conduits, such as tubing and casing, and then circulating it upwards with produced hydrocarbons. The apparatus comprises an integral valve and seal, including a mandrel, a packoff valve and a casing bore receptacle. The mandrel is incorporated in the tubing, and the casing bore receptacle is incorporated in the casing. The packoff member is releasably carriable on the mandrel and comprises an integral check valve and a radially expandable latch which is cammed outward by the relatively movable mandrel. The annular packoff member has seals on the interior and exterior surfaces for providing sealing integrity between the mandrel and the casing bore receptacle. The integral check valve permits fluids injected from above to flow radially across the packoff member between longitudinally annular flow paths defined by the packoff member and the casing, and by the packoff member and the mandrel. Net pressure in the annulus below the packoff member urges the check valve to the closed position.
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