Research And Design Of Thread Compound Automatic Quantitative Spraying Device

With the increasing level of oil industry, China has become one of the three countries (United States, Canada and China) with the largest number of drilling wells. In the process of drilling and exploitation of oil and gas, the casings and tubings are the most important construction materials, whose service life determines the service life of the oil-gas wells.The oil casings are connected through the threads. When the oil casing pipes are connected, the gluing resistance, bonding strength and sealing performance of the thread should be confirmed. Thread compound can meet the lubricant and sealed requirements of thread connection. It can effectively extend the service life of oil spigot thread, and play an important role on avoiding the connection thread from tightly screwing. Therefore, the proper thread compound must be smeared to the surface of the screw thread as a lubricant and anti-wear agent between the threads before the connection of the oil casings. Currently, there is not existing a device used exclusively for spraying thread compound in the process of oil-gas well operation. For a long time, the coating work of thread compound inside the oil casing has been relied on hand-finishing manually, which caused a stably increasing construction repair rate as well as great economic loss. Therefore, the development of a device which can be used exclusively for spraying thread compound inside the oil casing in automatic and quantitative way is very important on cost reduction and efficient solution for thread sealing.Aiming at the thread compound coating requirements inside the oil casing, an automatic and quantitative thread compound spraying device has been developed to apply in coating work with different diameter sizes of casing and tubing.The main study contents are as follows:1. The rheological properties of thread compound were studied using Brookfield R/S Plus Series Rheometer of the United States. It includes:the affecting factors of the rheological properties of thread compound, the thread compound rheological model and its corresponding constitutive equation, the thixotropy analysis. These results provide a theoretical basis for the design and development of the automatic quantitative thread compound spraying device.2. For the thread size requirements and spraying process requirements inside the oil casing, three different coating designs have been presented and compared, then the air pressure spraying solution is finally adapted.3. An automatic quantitative spraying device platform of the thread compound has been established. With the mechanical system design using three-dimensional drawing software such as CATIA and Solid Works, the whole system framework, technology selection and implementation have been discussed in detail.4. The control performance and spray effects of the spraying equipment have been tested for verification. The corresponding spraying time and spraying pressure are determined depending on the size of the oil casing diameter.With an easy operation and qualified spraying effects, the developed thread compound automatic quantitative spraying device inside the oil casing can meet the design requirements. The device can effectively reduce the manual work intensity and improve efficiency and quality of the spraying.