Near-bit composite torsion-reducing rock-breaking device

Abstract

The invention relates to a near-bit composite torsion-reducing rock-breaking device in the fields of petroleum and natural gas drilling, geological prospecting, mine drilling and coalbed methane development equipment. The near-bit composite torsion-reducing rock-breaking device is mainly composed of an outer shell, a mushroom head, a by-pass hole, a center shaft, a center hole, pressing covers, bolts, bases, bearings, knife wings, a sliding groove, a positioning pin and a spring. The near-bit composite torsion-reducing rock-breaking device is mounted between a bottom hole assembly and a bit, the drilling fluid pressure is utilized to control the knife wings to stretch out or be retracted and locked tightly, and the knife wings rotate simultaneously along with the pilot bit to cut the well wall. The distance between the near-bit composite torsion-reducing rock-breaking device and the pilot bit is shorter, the rock-breaking load is small, operating efficiency is high, the reaming process requirements of a deep well, an ultra deep well and a complex structure well can be met, and further improvement of the development effect of deep oil and gas reservoirs is facilitated. Meanwhile, the near-bit composite torsion-reducing rock-breaking device further has the advantages of being simple in structure, convenient to operate, convenient to mount, safe and reliable, and batch manufacturing and large wide application and popularization are facilitated.

Description

Technical field [0001] The invention relates to the fields of oil and natural gas drilling, geological prospecting, mine drilling, and coalbed methane development, in particular to a near-bit composite rock-breaking device with twisting and lowering. Background technique [0002] With the depletion of shallow oil and gas reservoirs, the number of deep wells and ultra-deep wells has increased year by year. During the drilling process, there are more and more formations that must be sealed, such as lost circulation, wellbore instability, high pressure, and low pressure. However, due to the lack of standard drill bit series and casing series in China relative to foreign countries, non-standard drill bits and casing need to be customized, with long production cycles and high prices, which makes the design of deep well and ultra-deep well wellbore very complicated, and the lower wellbore size is very large. It not only seriously affects the improvement of drilling efficiency of deep a...

AI Technical Summary

Problems solved by technology

[0002] With the development of shallow oil and gas reservoirs exhausted, the number of deep wells and ultra-deep wells is increasing year by year, and there are more and more formations that must be isolated during drilling, such as lost circulation zones, wellbore instability zones, high-pressure zones, and low-pressure zones. However, due to the lack of standard drill bit series and casing series in China compared with foreign countries, non-standard drill bits and casings need to be customized, the production cycle is long and the price is high, making the wellbore structure design of deep and ultra-deep wells very complicated, and the size of the lower wellbore is very large. It not only seriously affects the improvement of drilling efficiency of deep wells and ultra-deep wells, but also the quality of cementing is very low, which increases the development cost of deep oil and gas reservoirs; in addition, the window opening point of sidetracking directional wells for deep wells and ultra-deep wells is located at a depth of 5,500 meters Below, the wellbore size of the conventional sidetracking process is small. If the open hole completion method is used, the development effect will be poor. If the casing completion method is used, due to the small hole size and the small annular space between the casing and the borehole wall, the solid The well quality is very low, and the development effect cannot be ensured

The reaming-while-drilling technology is one of the key technologies to effectively solve the above problems. It not only overcomes the shortage of optional standard drill bit series and casing series, but also does not need to customize and process non-standard drill bits and casing. Large-size standard casing and requirements for improving cementing quality, but the existing reaming device while drilling has the following problems: (1) The reaming device is far away from the pilot bit and can only be used for wells with a well deviation of less than 40 degrees; ( 2) The torque load of reaming and rock breaking is large and the efficiency is low; (3) The structure of reaming device is complex and the overall cost is high

It can be seen that the current reaming-while-drilling devices at home and abroad still cannot effectively meet the requirements of deep well and ultra-deep well drilling technology. The drill bit is relatively close to meet the reaming-while-drilling technical requirements of various types of wells such as vertical wells and sidetracking wells. At the same time, it is also necessary to have a compound torsion-reducing rock-breaking device near the drill bit with simple structure, reliable performance, and convenient maintenance and operation. The level of drilling technology for the efficient development of oil and gas reservoirs, and the enhancement of international competitiveness have important economic and social values

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