Development of Formation Pressure Simulation Gauging Nipple

The MWD tool for formation pressure is composed of mechanical, electronic and hydraulic components. The internal installation space is small, the structure is complex, and the integration is difficult. In order to reduce the research and development risk of the tool, the formation pressure simulation gauging nipple was developed firstly. The 3D visualization technology was used to establish the virtual digital prototype of the simulation gauging nipple. The hydraulic valve insertion technology was used to study the key modules such as the micro hydraulic system with an output pressure of 20 MPa. Meanwhile, a formation pressure simulation test apparatus was developed as a platform for indoor high-temperature and high-pressure test and test principle verification of simulation gauging nipple. Actual measurement shows that the simulation gauging nipple runs stably at 120 ℃ and 60 MPa. Cores with permeability of 1×10^-3 μm² and 320×10^-3 μm² were selected to investigate the gauging nipple test principle, obtaining the formation pressure test curve, with measurement accuracy reaching 96%. The laboratory test verified the correctness of the measurement principle of the simulation gauging nipple and the accuracy of the measurement data. The research results lay a solid foundation for the development of formation pressure MWD engineering prototype.