Drilling system and method for improving drilling efficiency in permafrost

A permafrost and high-efficiency technology, applied in drilling equipment and methods, drilling equipment, ice drilling, etc., can solve problems such as environmental pollution and downhole complexity, and achieve simplified operation procedures, improved rock breaking efficiency, and well maintenance The effect of wall stabilization

CN106401463BInactive Publication Date: 2018-07-06SOUTHWEST PETROLEUM UNIV
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2018-07-06
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention discloses a drilling system and method for improving tundra drilling efficiency. The drilling method comprises the following steps of: adopting a downward drilling pipe column, starting a nitrogen gas compressor and a high-pressure pump unit; pumping liquid nitrogen into a shaft from a continuous oil pump, providing power to an underground motor, cutting shaft-bottom rocks by a PDC drill bit, and starting drilling operation; spraying out the liquid nitrogen through a spray nozzle of the drill bit to form liquid nitrogen jet flow which is matched with cutting of the PDC drill bit; upwards returning and circulating nitrogen gas along with rock debris to ground along an annular space, and recycling through a sand remover, a back pressure valve and a gas purifier; and drilling to a target layer, thereby completing drilling operation. Liquid-nitrogen fracturing effect is beneficial for expanding cracks generated inside rocks, so that rock breaking efficiency is effectively improved; the temperature of liquid nitrogen is extremely low, and liquid nitrogen is vaporized to absorb heat in an upward return process, so that decomposition of natural gas hydrates is effectively restrained, a well wall is kept stable, and underground complexity is prevented; and in an operation process, liquid nitrogen is recycled, so that the process is simple, is economical and is good in field applicability.
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Description

technical field

[0001] The invention belongs to the technical field of permafrost drilling for energy exploitation, and in particular relates to a drilling system and method for improving drilling efficiency in permafrost. Background technique

[0002] Gas hydrates are ice-like crystalline substances formed by natural gas and water under high-pressure and low-temperature conditions, and are widely distributed in deep-sea sediments or land permafrost. Natural gas hydrate has become a hot spot in the development of the contemporary energy industry due to its large reserves, wide distribution, high energy density, clean and pollution-free. Especially in recent years, the energy shortage has been increasing day by day, which has made countries pay more attention to it, and have increased their efforts in exploration and development research.

[0003] In recent years, my country has also successfully drilled natural gas hydrates in the Shenhu area of ​​the South China Sea, the p...

Examples

Embodiment Construction

[0043] In order to make the object, technical solution and advantages of the present invention more clear, the present invention will be further described in detail below in conjunction with the examples. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

[0044] The application principle of the present invention will be further described below in conjunction with the accompanying drawings.

[0045] Such as figure 1 As shown, the method for improving drilling efficiency in the permafrost layer provided by the embodiments of the present invention includes:

[0046] S101: run into the drilling string, turn on the nitrogen compressor and high-pressure pump set; pump liquid nitrogen from the coiled tubing into the wellbore to provide power for the downhole motor, the PDC bit cuts the bottom rock, and starts drilling;

[0047] S102: Liquid nitrogen is sprayed out through the noz...