Drilling and grinding tubular column structure of two-stage shunting screw drill

Abstract

The invention discloses a drilling and grinding tubular column structure of a two-stage shunting screw drill, which comprises an oil pipe string and a drill and also comprises a firsts-stage shunt, a first-stage connecting oil pipe, a second-stage connecting oil pipe and a second-stage shunt, wherein one end of the second-stage shunt is connected with the oil pipe string, while the other end is connected with the second-stage connecting oil pipe; the other end of the second connecting oil pipe is connected with one end of the first-stage connecting oil pipe, the other end of the first-stage connecting oil pipe is connected with the first-stage shunt and the other end of the first-stage shunt is connected with the drill; and tap holes are formed on both the first-stage shunt and the second-stage shunt. The tap holes in the invention have special requirements; the two-stage shunting is realized by adopting the shunts with specific tap holes; the liquid amount of the downward axial flow can be reduced by shunting, and thus the aims of reducing the pressure of workover fluid on the screw-drill, guaranteeing that the screw-drill works at an optimal flow and protecting the screw-drill are fulfilled.

Description

Technical field [0001] The invention relates to a workover tool in petroleum development, in particular to a two-stage split screw drilling tool drilling and grinding pipe string structure. Background technique [0002] At present, the screw drilling tool is a commonly used workover tool for downhole workover operations and is widely used in drilling and grinding operations. However, screw drilling tools are used for drilling and grinding operations in small-sized liners. It will be restricted by the size of the wellbore. The reason is: due to the small size of the wellbore in the lower part of the production well, the size of the screw drilling tool used is also small, and the rated flow rate of the small screw drilling tool is lower, in order to meet the well flushing The large-size liner or casing cleaning in the upper part of the production well requires a larger displacement, and the small-size screw drilling tool that can be used for the small hole in the lower part of the ...

AI Technical Summary

Problems solved by technology

[0002] At present, the screw drilling tool is a commonly used workover tool for downhole workover operations, and is widely used in drilling and grinding operations. However, when the workover operation is performed in a small-sized liner, the screw drilling tool is used for drilling and grinding operations. Due to the small borehole, It will be limited by the size of the wellbore. The reason is: due to the small size of the wellbore in the downhole of the production well, the size of the screw drilling tool used is also small, and the rated flow rate of the small-sized screw drilling tool is low. The large-sized liner or casing flushing in the upper part of the production well requires a larger displacement, and the rated flow rate of the small-sized screw drilling tool that can be used for the small hole in the lower part of the production well is lower than that of the upper large-sized screw drilling tool. The liner or casing requires a large amount of displacement for well washing and carrying sand. If the cuttings generated during the drilling and grinding process cannot be carried to the surface in time, they will sink downward, which is prone to complex downhole situations such as pipe sticking. Therefore, it cannot Meet the requirements of the drilling and grinding process; for example, in the slim hole with the casing structure of 139.7mm and the liner of 101.6mm, the drilling and grinding operation in the liner is carried out. The commonly used drilling and grinding strings for workover are as follows from bottom to top: Drilling and grinding tools, 73 screw drilling tools, 60.3mm tubing and 73mm tubing, and 139.7mm casings generally require a well flushing displacement of not less than 8L / s. However, the rated flow rate of the currently used 73 screw drilling tools is only 2~ 4L / s, (rated flow rate motor pressure drop 2.4MPa, rated speed 125 ~ 270RPM,) is far lower than the displacement required for well washing, another example: the well body structure is 244.5mm casing, 177mm tailpipe, 127mm tailpipe Drilling and grinding operations are carried out in the slim hole of the pipe, and the commonly used drilling and grinding strings for workover are from bottom to top: drilling and grinding tools, 89 screw drilling tools or 95 screw drilling tools, tubing (73mm tubing for 127mm liner, 244.5mm Casing and 177mm tailpipe use 73mm tubing, or 89mm tubing), the required well flushing displacement in the 244.5mm casing is generally not less than 24L / s, and the required well flushing displacement in the 177mm tailpipe is generally not less than 14L / s, however, the current constant flow rate of 89 screw drilling tools is only 3~8L / s, (rated motor pressure drop 2.4MPa, rated speed 95~200RPM), the rated flow rate of 95 screw drilling tools generally does not exceed 13L / s, Therefore, it cannot meet the requirements of the drilling and grinding process; due to size constraints, the rotor is difficult to manufacture as a hollow (rotor), and the small-sized screw drilling tool cannot be manufactured as a hollow split-type screw drilling tool, so it enters the workover of the screw drilling tool All the liquid passes through the motor. However, even if the small-sized screw drilling tool works at the maximum rated flow rate, it cannot meet the requirements of the drilling and grinding process. In order to meet the requirements of the drilling and grinding process, the displacement can only be increased to overload the screw drilling tool. As a result, the rotor of the screw drilling tool rotates at an overspeed, the pressure drop of the motor increases, and the wear is accelerated, which leads to the short service life of the screw drilling tool, which is prone to damage, breakage, and drill sticking.

[0003] In order to solve the problem that small-sized screw drilling tools have a small rated flow rate and cannot meet the drilling and grinding process, the usual practice in the prior art is: ① make the screw drilling tool work at a rate exceeding the rated flow rate, ② adjust the performance of the workover fluid to increase its ability to carry cuttings, ③ Use abrasive drilling and grinding tools to reduce the outer diameter of cuttings particles produced by drilling and grinding, and reduce the sinking speed of cuttings; Circulation off the bottom hole to remove cuttings

Although the above-mentioned method can solve some problems, the above-mentioned method is not only low in efficiency and high in cost, but also cannot solve the existing problems fundamentally because it does not solve the problem that the small-sized screw drilling tool has a small rated flow rate and limits the drilling and grinding process.

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