Application of bypass valve

application
Application of bypass valves. The current situation is that the bypass valve structure of the screw drilling tool has been using the past technology, and the current advanced concept has not been applied to it. It is basically a backward method, which includes the design of the valve body, valve The installation of the core and the material selection of the valve sleeve and the sealing ring are all important parts that affect the construction process. Therefore, the construction cost of the drilling process must be increased, the old parts must be replaced, and advanced technology must be used to ensure the reliability of the screw drilling tool. normal operation.

Working principle and structural composition

It is composed of four parts: valve body, valve core, valve sleeve and spring. The installation position of each of them affects the next installation. For example, the key part of the screw drilling bypass valve is the valve body. It connects the rod of the drilling tool and the motor, and is the connecting rod in the middle. For the valve core and valve sleeve, it mainly exists in the hollow valve body inside, and finally the spring assembly is installed on the valve core and valve sleeve. The basic working principle is that when drilling downhole, the pressure capacity of the top and bottom of the spool is equal, and the valve body is affected by the spring so that the spool is at the upper end. When the bypass valve is in the open state, the column The inner space will be merged with the annular space of the cylinder, so that the liquid generated in the drilling can flow into the drill pipe through the bypass valve. During the drilling process, affected by the hydraulic pressure, the spring around the valve core will move around. In this process, the flow of fluid in the drilling can form a circulation mode and become the driving force of the motor. When drilling starts, the influence of hydraulic pressure will be eliminated and the spring will return to its original state. , the spool moves upward, and the bypass valve is reopened, so that the liquid in the drill pipe can flow smoothly into the annular passage on the well wall.
Failure Analysis
(1) Pollutants entering the passage of the bypass valve. At the beginning of drilling, the main function of the screw drilling tool bypass valve is to connect the drill string and the annular space of the wellbore, so that the mud in it can pass through the pipeline of the bypass valve and enter the annular space of the wellbore smoothly during the drilling process. In order to prevent pollutants from reaching the well platform. For the drilling process, the surrounding hydraulic pressure will disappear, allowing the spring to return to its original state, displacing the valve core, causing the valve to open, so that the column and the wellbore form a channeling connection, and the internal mud is discharged. Due to the shape of these pollutants Different, it is extremely easy to form accumulation, resulting in the failure of the spring to function normally, resulting in the abnormal use of the screw drilling tool, resulting in process failure and loss of a lot of money.
(2) The operation performance of the bypass valve is not sensitive. During the initial production of the bypass valve, due to the unclear data on the opening of the flow rate, it is difficult to determine the contraction coefficient that the spring needs to bear, which will cause the spring to shrink tightly, resulting in operational errors. However, for the screw drilling tool bypass valve with small flow rate, because the pressure resistance between the two ends of the valve core is poor, it cannot resist the contraction of the spring, resulting in the loss of energy, so low-speed and small-flow drilling work cannot be performed. Therefore, when designing the screw drilling tool bypass valve, it is necessary to combine various factors to make a reasonable idea to ensure the contact between the upper and lower springs, and then solve the problem of insensitive operation performance.
Structural optimization
First, in the way of fixing the valve sleeve, replace the past hole with a circlip with a new type of positioning pin. After the installation of the basic equipment of the bypass valve is completed, four positioning pins are distributed on it respectively, and keep The spacing position is the same, and the bottom of the pin needs to be flattened to increase the contact range between it and the valve sleeve, so as to strengthen the pressure resistance and increase the stability of the screw drilling bypass valve; secondly, when installing the middle hole , It is necessary to install a filter-type bypass wire to prevent pollutants from flowing into the bypass valve, making it difficult for the spring to function. The filter-type bypass wire needs to be fixed in the hole in the channel, and ensure that each one has the same size and position, so that the liquid generated by drilling can flow out smoothly, and the residue existing in it can be filtered out to avoid bypass valve failure. Thereby shortening the service life.