Drillable grading hoop
A grading hoop, a part of the technology, used in earth-moving drilling, wellbore/well components, sealing/packing, etc., can solve the difficulty of opening the sliding sleeve, the liquid cannot be discharged from the closed space, and the sliding sleeve cannot be lowered into place and effectively sealed. And other issues
Active Publication Date: 2019-05-14
青岛鑫源晟石油科技有限公司
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Problems solved by technology
In the cementing process of the existing drillable grading collars, the following situations may occur that cause the cement slurry circulation hole to be unable to be effectively opened and closed: (1) During the process of opening the cement slurry circulation hole, the gravity plug and the lower part of the sliding sleeve are filled with In the closed space of incompressible liquid, the opening sliding sleeve that closes the hole needs to descend to expose the cement slurry circulation hole. When the opening sliding sleeve is separated from the body and descends, the liquid in the lower closed space of the opening sliding sleeve cannot be discharged. It is difficult to open the sliding sleeve to go down, so the down distance of the sliding sleeve cannot fully expose the cement slurry circulation hole and affect the grouting; When the casing is descended by external force and starts to block the cement slurry circulation hole, the cement slurry in the grading hoop has no leakage channel, which makes it impossible for the closing sliding sleeve to go down in place and effectively seal the cement slurry circulation hole. The pressure display mistakenly thinks that the cement slurry circulation hole is completely closed, remove the pressure and wait for the cement to solidify
However, this is likely to cause some serious problems, such as cement slurry at a height of about 1500-2000 meters in the annulus, water at a height of 1500-2000 meters in the grading hoop and casing, and the density of the water is less than that of the cement slurry. A maximum pressure difference of about 8MPA is formed at the cement slurry circulation hole. Under the action of the pressure difference, the cement slurry returns to the inside of the grading hoop through the incompletely closed cement slurry circulation hole, and the rubber plug matched with the closing sliding sleeve back flows into the casing , sometimes even back up to tens of meters until the pressure between the inside and outside of the casing is balanced, which leads to cementing failure
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[0032] Exemplary aspects of the drillable graded hoop according to the present invention will now be described in detail with reference to the accompanying drawings. The drawings are provided to illustrate various embodiments of the invention, but the drawings are not necessarily to scale of particular embodiments and certain features may be exaggerated, removed, or partially sectioned to better illustrate and explain aspects of the invention. public content. Some components in the drawings can be adjusted according to actual needs without affecting the technical effect. Appearances of the phrase "in the drawings" or similar terms in the specification do not necessarily refer to all drawings or examples.
[0033] Certain directional terms used hereinafter to describe the drawings, such as "inner," "outer," "upper," "lower," and other directional terms are to be understood to have their normal meaning and refer to the drawings as viewed normally those directions involved. Un...
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The invention relates to the technical field of oil well sealing, in particular to a drillable grading hoop for grading well cementation, comprising: a body configured to be approximately cylindricaland provided with a circulating hole in the side wall, a first sliding sleeve arranged in the body, blocking the circulating hole and provided with a first sealing plug so as to seal the upper space and the lower space of the first sliding sleeve, a one-way valve pin connected with the body and the first sliding sleeve, constructed and arranged to regularly break into two parts after bearing a force enough to break the one-way valve pin, wherein one part is accommodated in the first sliding sleeve and moves in the body along with the first sliding sleeve until the circulating hole is opened, and the other part is configured to allow a mixed liquid in the body to flow to an annulus and prevent the mixed liquid in the annulus from returning to the body.
Description
technical field [0001] The invention relates to the technical field of oil well sealing, in particular to a drillable grading hoop for grading cementing. Background technique [0002] In the cementing process, the casing is generally lowered to the designed well depth, and cement slurry is injected into the casing and the wellbore annulus, and the annulus is sealed by the solidification of the cement slurry to prevent leakage between layer fluids, thereby protecting the production layer. , Strengthen the well wall, support the casing while preventing the layer fluid from corroding the casing, and establish safe drilling channels and oil and gas production channels. Cementing is an important link in the construction process of oil and gas wells. [0003] However, the existing cementing device and technology often have cementing failures during the cementing operation. Since the drillable grading hoop is operated at a position about 1500 meters downhole, and the operation of...
Claims
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IPC IPC(8): E21B33/13
Inventor 韩治花
Owner 青岛鑫源晟石油科技有限公司