Thermal-prestressed fusion casing for heavy-oil thermal recovery process, and using method thereof

Abstract

The invention provides a thermal-prestressed fusion casing for heavy-oil thermal recovery process, and a using method thereof. A plurality of slits (2) penetrating through the wall of an oil casing are evenly distributed on the surface periphery of seal grooves at two ends of the oil casing (1); the interval between every two slits is 60 millimeters; the slits (2) are at an equidirectional-dislocation angle of 60 degrees, are evenly distributed on the peripheral surface of the oil casing (1), and are filled with filler material; a structure surplus gap is arranged reserved between the oil casing (1) and a steel sheath (3); and a wound pipe (4) is arranged outside the steel sheath (3). When the thermal-prestressed fusion casing is arranged at the lower end of a thermal packer (13) of an oil pipe (11), the axial and radial thermal stress of the oil pipe (11) can be fully digested and absorbed, so the interface integrity of the casing can be effectively protected; steam leap and water leap caused by cracked or crushed of cement sheaths are avoided; and the casing can also be prevented from integrally leaping up to destroy wellhead equipment and collar connection. The thermal-prestressed fusion casing has the characteristics of simple structure, practicability and good effects.

Description

1. Technical field [0001] The invention relates to a casing damage prevention device in the field of oil production engineering, in particular to a heat-prestress fusion casing used in heavy oil thermal recovery technology and a method for using the same. 2. Background technology [0002] With the increasing shortage of energy and the advancement of thermal oil recovery technology, heavy oil recovery has been paid more and more attention. At present, shallow heavy oil reservoirs in Blocks 6 and 9 of Karamay Oilfield are an important part of heavy oil in Xinjiang; heavy oil is also distributed in Liaohe and Shengli Oilfields, with an annual production capacity of more than 4.5 million tons, mainly relying on steam injection thermal extraction method, that is, steam Huff and steam drive. [0003] Due to the special requirements of heavy oil thermal oil recovery, the casing of heavy oil thermal recovery wells is seriously damaged. It has become an important topic in the curre...

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Problems solved by technology

[0008] In the Chinese patent with the notification number CN2849162, a thermal expansion device for gas injection wells is proposed. With this expansion device, the expansion joint used when running the casing can eliminate the axial thermal stress to the greatest extent. Due to the existence of hoops, the thermal elongation of the casing after cementing is greatly restricted by the cement sheath, making this technology unable to exert its own technical advantages

In addition, the radial load of the casing is not considered

Therefore, the use effect of the patent will be affected

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