Modernization of pipe joints in machines and equipment of oil and gas fields

Introduction The problem of tight joint of pipelines and high pressure hoses (HPH) applied in various fields of human livelihood is considered. Special aspects of the high-pressure pipelines operation in the equipment of the oil and gas complex is as follows. At ambient temperatures below minus 50ºC, it is needed to transmit thousands of tons of stratum fluids heated up to 200-250ºC and containing aggressive media, abrasive and highly mineralized water. Materials and Methods. Various designs of metal seals applied in high pressure pipe connections are considered. Joints widely used for pipelines do not withstand pressures higher than 20-60 MPa. With that, in pipelines of the oil-industry equipment, pressure may exceed 100 MPa. A key feature of applying joints in question is to reduce their strength with increasing the diameter. These detriments confine the scope of use of the above-mentioned sealing schemes. It makes field repair of such joints, for example, during operation of oil and gas equipment, practically impossible. In this case, the use of quick connectors (Q/C) is required, for disassembling of which it is ample to have the keys. Research Results. For the solution to the specified problems, a principally new scheme of connection sealing for pipelines and HPH is developed and patented. The key element of the patented device is a stepped bushing which reliably seals the connection of pipelines and HPH. The stepped bushing (sealant) should be made of high-alloy steel by analogy with the joint in the flange couplings, and it can be hardened which will allow for increasing the strength of the connections in question and using them under low temperature conditions. Discussion and Conclusions. The comparative analysis of the sealing elements designs shows advantages of the proposed sealant. For its practical application, it is needed to optimize the shape and dimensions of the stepped bush in order to provide for leaktightness at given pressures, and, besides, to determine the required thread pull force to ensure safe performance of the unit

Sliding friction unit of connecting-rod end of high-lift plunger pump using self-lubricated bearing from powder antifriction material

Introduction. The powder antifriction materials applied in the oil and gas industry are considered. Special attention is given to the materials with the effect of self-lubricity. The use of such materials in a frictional unit of one of the most widespread types of the oil and gas well service equipment - a high-lift plunger pump - is offered. The pump construction diagram with the description of the modernized unit is provided; the problems arising under the production and exploitation of the connecting-rod pin bearing group are described. Materials and Methods. Upon the experience in applying bearing bushes from powder antifriction materials in mechanical engineering, the iron graphite porous material is selected. The design change considering the self-lubricating materials behavior and allowing the best usage of their properties is made. The bushing-to-shaft gap, one of the most important parameters of the plain bearer performance, is considered. The fit providing the fullest seating of the bushing to the shaft is selected. That improves the heat removal, promotes the even load distribution over the frictional area, and so enhances the operating capacity of the bearing unit. Research Results. A change option of the frictional unit design of a connecting-rod small power end with the use of the self-lubricated bearing from the powder antifriction iron-based material is offered. The proposed bearing meets the loading conditions of the considered unit. The design is developed due to the condition of self-lubricity that allows simplifying the production of a connecting rod obviating the manufacturing of oilholes in the connecting rod body. The analysis of the offered modernization is carried out with the application of 3D modeling. The constructed models permit to visually estimate the simplification of the entire connecting rod design, the production of its constituent parts, as well as its assembling. Discussion and Conclusions . The obtained models allow drawing a conclusion on the feasibility of the bearing design change for the sliding friction unit of the connecting-rod end of the high-lift plunger pump using the powder antifriction material to replace the existing one. The application of this bearing with the effect of self-lubricity will allow a substantial simplification of the pin bearing unit design