Research on Novel Multi-Way Hydraulic Quick Connector for Underwater Production System

The underwater hydraulic connector is one of the most important components of an underwater oil production system. The equipment is mainly used to transport oil, chemical reagents, and other high-pressure fluids. We developed a novel underwater hydraulic multi-way quick connector system (MQCS) that is able to realize simultaneous, rapid, and precise plugging and unplugging of 10 underwater pipelines. It can be widely used for connection between subsea oil production equipment. The MQCS consists of a fixed plate assembly that is fixed to the oil production equipment and a free plate assembly that is connected to the pipelines on the drilling platform. This study describes the structure and working principle of the MQCS in detail. In addition, the process of the elastic collet clamping the mandrel was studied. Based on the finite element analysis software Abaqus, we investigated how the key geometric parameters of the elastic collet influence the axial force that needs to be provided by the underwater robot. A prototype was built based on the simulation results. To verify the performance of MQCS, a high-pressure chamber test was conducted. The results show that MQCS can accurately connect 10 high-pressure lines (about 69 MPa) in a high-pressure chamber and there is no pressure drop for 3 h after docking.

Design and Experimental Verification of Pressurized Cylinders in Hydraulic Rubber Hose Pressure Washers

Hydraulic rubber hoses are subject to great hydraulic impact during the actual working process, which causes a great potential safety hazard. Therefore, it is necessary to carry out pressure tests on hose assemblies to ensure its quality, so providing a high pressure for the hydraulic hose has become the key technology of this problem. Aiming at solving the problem of detection of pressure resistance in hydraulic rubber hose cleaning machines, this paper analyzed the pressurization mechanism of the hydraulic pressurized cylinder and proposed a method of continuous pressurization. This paper also theoretically analyzed the pressure expansion of the rubber hose, and the conclusion is that for the maximum hose capacity (hose size is Φ25 mm × 6 m), the volume of water required to provide water in the hose from 10 MPa to 100 MPa is 0.59 L. The pressurized cylinder was designed and checked theoretically and analyzed by the finite element method. It is concluded that the maximum stress of the pressurized cylinder is concentrated at the bottom of the high-pressure chamber, and the outlet hole at the bottom of the cylinder barrel of the high-pressure chamber is the weakest part of the pressurized cylinder. The performance of the supercharging cylinder is verified by experiments, which proves the feasibility, rapidity and stability of the supercharging cylinder.

INVESTIGATION OF PROCESSES IN THE HIGH-PRESSURE CHAMBER OF SHOCK TUBE

There are several installations with shock tubes in the world, in which a shock wave in air propagates at a speed close to the second cosmic one. Such velocities are achieved by supplying of high energy (~ 1 MJ) to the pushing gas in the high-pressure chamber.

Laboratory study of hydraulic refracturing possibility

<p>The results of laboratory experiments will be considered, that are carried out in a laboratory setup that differs from the standard ones in the shape and size of the test samples. The setup consists from two disks and wide ring between them, which form a high-pressure chamber, and it is capable to produce true 3D stresses in the samples. Laboratory experiments are performed on saturated artificial porous samples created according to similarity criteria using gypsum with Portland cement added as a model material. The samples are created directly in the high-pressure chamber and have the forms of disks with diameters of 430 mm and heights of 70 mm. This sample is saturated with water gypsum solution and loaded with vertical and two horizontal stresses using special chambers. In the upper, lower and lateral parts of the installation there are pressure sensors, ultrasonic transducers and generators. The first fracture was created by viscous fluid (mineral oil) injection through a cased borehole preliminary created in the center of the sample. After the first fracturing, the principal maximal and minimal stress axis orientations were changed, and refracturing was carried out. We failed to create two fractures oriented along the borehole, but we succeeded in creation one fracture perpendicular to the borehole and the second fracture along the borehole. Comparison of the ultrasonic wave amplitude changes during the fracturing with the fracturing pressure variations allowed us to distinct the fracture propagation and the fracture fill-up by the fracturing fluid. It was also found that for an adequate calculation of the minimum compressive stresses from the characteristic parameters ​​of the pressure change in the well, it is necessary to take into account the plastic properties of the rock, the diffusion of the fluid pore pressure in the vicinity of the well and the hydraulic fracture, the lag of the filling of the fracture with the fluid.</p>

Study of Transfer Characteristics of a Molecular Electronic Sensor for Borehole Surveys at High Temperatures and Pressures

The paper considers the development and experimental study of the characteristics of a high-temperature motion parameter sensor based on molecular-electronic technology (MET) operating at elevated pressures. Studies were conducted in an extended temperature range (25–125 °C) with a static external pressure of up to 10 atm. A pilot plant based on a high-pressure chamber with the ability to output an electrical signal was specially designed and commissioned. A family of amplitude-frequency characteristics of a ME sensor in an extended temperature range was obtained for the first time. A theoretical model was constructed and verified to describe the transfer function of the sensor at high temperatures and pressures. The activation energies of active carriers were calculated, and a prediction was made about the possibility of using the developed devices for the needs of the oil and gas mining industries.

Observation of Supersonic Jet Using Small Volume High-Pressure Shock Tube

The unsteady supersonic jet and the shock wave injected by the small volume shock tube are experimentally studied in this paper. The experimental was performed by the background oriented schlieren method. The main parameters for the jet are the pressure ratio by the high pressure chamber/ a back pressure 10.9-53.0 and the length of high pressure chamber/diameter ratio 1 and 10. The velocity of the shock wave and supersonic jet were estimated by using the principle of the background oriented schlieren method. The results showed that the influence of the length of the high pressure chamber on the velocity of the jet.