Rotary Oil Research Articles

Control strategies for mitigating torsional and axial vibrations in rotary oilwell drilling systems

Abstract This paper examines a nonlinear dynamics model to explore the significant factors influencing the coupled torsional-axial vibrations of a drill string. The primary focus lies in effectively modeling, analyzing, and controlling both torsional and axial vibrations occurring in a rotary oil well drilling system. The model employed incorporates a wave equation with a damping term (PDE) connected to an ordinary differential equation (ODE) through a nonlinear function representing the interaction between the drill bit and the rock. We proceed to establish the well-posedness of the coupled PDE-ODE in an appropriate functional space. As a PDE-ODE coupled system, we specifically investigate the stability problem concerning the velocity at the bottom extremity, considering both the presence and absence of the damping term in the wave PDE. To address this, we propose a systematic method based on a Lyapunov approach for designing feedback controllers. These controllers ensure system stability and effectively suppress harmful vibrations.

Blocking of Gas–Liquid Coalescing Filters with Accumulated Oil during the On–Off Operation of a Filtration System

The study aims to eliminate the effect of coalescing filter blocking due to on–off operation by changing the wetting properties of the non-woven fiberglass filter media through their chemical modification with the use of a polydimethylsiloxane (PDMS) solution in hexane and a few commercial products that give the surface oleophobic properties. The best results—high separation efficiency, no redispersion of droplets at the outlet, and low flow resistance—were obtained for materials coated by immersion in a 0.2% PDMS solution, for which a reduction in oleophilicity was found, but the material was not oleophobic and still moderately wetted with the test liquid. The corresponding static contact angle with the VG-46 rotary compressor oil measured on the flat borosilicate glass wafer made of the same material as the fiberglass media was equal to 54° for the PDMS dip-coated surface. Moreover, the good stability of the applied polymer on the material surface was confirmed by the SEM imaging, the FTIR analysis, and maintaining a high performance in multiple tests run for a single coalescing element.

Design and Performance Analysis of Toothless Slip Type Magnetic Rotary Oil Well Pipe Tong

Although the current hydraulic power pipe tong can improve efficiency and reduce strength, there are still some deficiencies. Among them, the inevitable defects are a low degree of automation, high labor intensity, complex mechanical mechanisms, and high maintenance costs. In order to improve its performance, the principle of permanent magnet motor is applied to the processing of shackle of oil pipe tong, and a new type of magnetic rotary oil pipe tong is proposed. The design eliminates the complex planetary gear train transmission mechanism and hydraulic circuit in the traditional tightening device, simplifies the mechanism of the tightening device, reduces the size of the device, saves the manufacturing cost, improves the automation degree of the power tong and reduces the labor intensity of the workers. The triangular chuck is suitable for clamping pipe strings with different diameters. In addition, due to the use of toothless slips, the damage of the tightening device to the sleeve is reduced, the sleeve is protected and the service life of the sleeve is prolonged. Therefore, this new type of magnetic rotary tubing tong has a good application prospect in the up and down operation.

Gear Shift Coordinated Control Strategy Based on Motor Rotary Velocity Regulation for a Novel Hybrid Electric Vehicle

This paper proposes a novel hybrid power system to improve the shift quality of a hybrid electric vehicle (HEV). After selecting a typical shift scheme, the study focused on the motor rotary velocity control algorithm and coordinated control strategy for the motor and clutch. The effects of various control algorithms on different target rotary velocities were analyzed, and a proportional-integral-derivative (PID)–bang-bang–fuzzy compound intelligent algorithm for a motor rotary velocity control system was investigated. In addition, to address the problems of the long synchronizing time required for the rotary velocity and large sliding friction work, which affect the shift quality during the process of engaging the clutch, a coordinated control strategy for the motor rotary velocity and clutch oil pressure was investigated. The research results showed that, compared with a gear shift coordinated control strategy based on a PID control algorithm, the strategy based on the PID–bang-bang–fuzzy compound intelligent control algorithm proposed here reduced the shift time and clutch slipping friction work by 35.7% and 19.2%, respectively.

Research on Self-compensating Oil Sleeve for Hydraulic Chuck

Based on the oil supply principle of hydraulic chuck, analysis of the structural characteristics and failure reasons of the oil distribution sleeve showed that the main reason for the increase of the leakage of the oil sleeve is the increase of the value of the seal gap caused by the increase of the temperature and pressure of the hydraulic oil. The self-compensating oil sleeve for the rotary oil distribution of hydraulic chuck is designed by theoretical calculation, and the deformation of the self-compensating oil distribution sleeve and the common oil distribution sleeve are compared and analyzed by finite element software, and the sealing performance of the two kinds of oil sleeve is compared and analyzed by test. The results show that the sealing gap of the self-compensating oil sleeve has dynamic stability compared with that of the ordinary oil sleeve, and the leakage of the self-compensating oil sleeve is stable under the working condition, which can provide reference for the design innovation of the rotary oil distribution sleeve for the chuck of the full hydraulic drilling machine.

A nonsmooth approach for the modelling of a mechanical rotary drilling system with friction

<p style='text-indent:20px;'>In this paper, we show how the approach of nonsmooth dynamical systems can be used to develop a suitable method for the modelling of a rotary oil drilling system with friction. We study different kinds of frictions and analyse the mathematical properties of the involved dynamical systems. We show that using a general Stribeck model for the frictional contact, we can formulate the rotary drilling system as a well-posed evolution variational inequality. Several numerical simulations are also given to illustrate both the model and the theoretical results.

Adaptive output-feedback control of torsional vibration in off-shore rotary oil drilling systems

Motivated by an engineering application of torsional vibration suppression of off-shore oil drilling, we design an adaptive output-feedback controller for a one-dimensional wave partial differential equation (PDE) system, where an anti-damping term with an unknown coefficient and a general harmonic disturbance with unknown amplitudes exist in the bit, which is modeled as a second-order-in-time boundary. The control input anti-collocated with this boundary subject to uncertainty, is designed by using the adaptive control method and infinite-dimensional backstepping technique. The asymptotic convergence to zero of the uncontrolled boundary states, i.e., the oscillations of the angular displacement and velocity at the bit, and the boundedness of all states in the closed-loop system, are proved via Lyapunov analysis. The effectiveness of the proposed adaptive controller is verified via numerical simulation. The results also can be applied to other applications, such as vibration control of cable elevators with uncertain cage-guide friction and cage disturbances.

Oil Well Control Training and Safety Leadership Skills of Drilling Personnel

This research investigates the relationship between the most important rotary drilling oil well control training program and developing safety leadership skills among onshore and offshore drilling crews. The findings of this study indicate that this technical training program appears to improve safety leadership skills in well control situations. The results also suggest that these safety leadership skills could be transferred to other drilling and well operations, although there is some disagreement on the degree of possible transfer.

Oil Transport Cycle Model for Rotary Engine Oil Seals

Oil Transport Cycle Model for Rotary Engine Oil Seals

Flatness-based Control of Torsional-Axial Coupled Drilling Vibrations

The main purpose of this contribution is the control of both torsional and axial vibrations occurring along a rotary oil well drilling system. The considered model consists of a system of wave equations with non-linear coupled boundary conditions. We propose a flatness-based control approach to tackle the trajectory tracking problem guaranteeing the suppression of harmful dynamics. The closed loop control design ensures the stability of the error dynamics. Moreover, numerical simulations illustrate the efficiency of the established control laws.

The Improvement of Refrigerators Rotary Oil Pump

Screw refrigerators are widely used in subzero refrigeration and storage fields. The manufacturers always use rotor-type pumps as their lubricating oil pumps. This paper introduces the advantages of screw refrigerators, the usage of oil pumps and the working environments. It mainly studies the common faults of oil pump, proposes several design ideas for analysis and comparison and determines the final improvement schemes on the premise of comprehensively considering structure, performance and cost.

Numerical Simulation and Structural Model Shaking Table Test for Container Crane Equipped with Seismic-isolated Device

Modern large-gauge container cranes are often damaged or even collapse in earthquake. By researching into the damage forms of container cranes in Hyogo-ken Nanbu Earthquake, it is concluded that horizontal seismic force perpendicular to the rail is the main reason for the damage. Based on the theory of seismic isolation, a new type of seismic-isolated device, composed of dual eccentric rotary bearing, Belleville spring, oil damper and shear pin, was designed for container crane. A 3D-FEM system model was established to numerically analyze acceleration response, inspired by Iran seismic wave, etc., with the method of Newmark-. Furthermore, a seismic miniature model was designed according to similarity principle with dimensional analysis method. Then, taking acceleration and displacement as similar indicators, a shaking table test was carried out, and inspired by the same seismic wave. The results of numerical simulation and model test prove with each other, that the seismic-isolated device is a reasonable design and the effect of seismic isolation is significant.

A Study of an Arm-Type Damper with Two Links and Three Joints (Case in Which a Rotary Viscous Damper Is Used)

In this paper, a new type of arm-type damper consisting of two links, two joints (universal joints with friction) and a hinge (a rotary oil damper) has been developed. The damper is able to suppress six modes of vibration of a machine, three in translational modes and three in rotational modes. The trial damper was made and the resisting force characteristics in the three translational directions were discussed theoretically and experimentally. The seismic responses of a three-degree-of-freedom system and the frequency response of a one-degree-of-freedom system, which consist of a mass and four coil springs and supported by the damper, were measured using a two-dimensional electro-hydraulic type shaking table. The experimental results are compared with the calculated ones, and the effects of vibration suppression of the damper are discussed.

Laboratory simulation to select oil seal and surface treatment

Reliability of rotary oil seals depends on many parameters related to seal design and material, shaft material, hardness and surface texture, medium; operating conditions, etc. This presentation will describe the accelerated testing methodology development as well as the results of shaft surface roughness and hardness analyses to decrease wear in rotary oil seal lips. Seals went through 200 h of accelerated testing which not only reproduced operating conditions but duplicated field service mode or seal lip and shaft wear mechanisms during accelerated testing. Dana's new oil seal accelerated tester has many unique features: (1) reproduction of several extreme operating conditions including oil temperature cycling and superposition of reciprocal motion; (2) devices to easily change shaft-to-bore misalignment and shaft eccentricity, and (3) measurement equipment for torque evaluation and photo-optical oil leak detection. The methodology consists of establishing simple engineering parameters including the number of tested cycles before the leak, oil seal lip wear path, shaft surface groove depth under oil lip, varieties of shaft surface roughness, and friction forces between seal lip and shaft surface. An important part of this methodology is detailed metallurgical and metrological examination of the field and lab test usage of the oil seal lips and shaft surfaces including SEM and EDX analysis. The shaft surface hardness and roughness characteristics, including core roughness depth, reduced peak height and valley depth, their ratios, and their influence on seal lip wear will be presented.

Dynamic Behavior of a Drill-String: Experimental Investigation of Lateral Instabilities

This paper focuses on laboratory tests concerned with the lateral behavior of a rod representative of part of a drill-string in the area of rotary oil drilling. The original experimental set-up takes into account the curvature of the rod, mud, stabilizers and rotation speed. The lateral behavior of the drill-string subjected to the axial excitations of the bit is governed by time varying parameter equations due to torsion-lateral and longitudinal-lateral couplings. The experimental results highlight the different kinds of lateral instabilities and they are compared either with existing experimental, or theoretical results. The experimental investigation described in this paper is included in a wide ranging study which also involves theory and the development of a computer code, both briefly presented here.

Dynamic interaction between high-frequency rotary oil- and gas-transmission units and their foundations

Dynamic interaction between high-frequency rotary oil- and gas-transmission units and their foundations

INFLUENCE OF PRUNING METHOD, FERTILIZER AND TERBACIL ON THE GROWTH AND YIELD OF THE LOWBUSH BLUEBERRY

Lowbush blueberry (Vaccinium angustifolium Ait.) plants were pruned by rotary mowing or oil burning. Three rates of fertilizer and four rates of terbacil (3-tert-butyl-5-chloro-6-methyluracil) were applied. Burned plots produced twice as many blueberries as those mowed. High rates of fertilizer depressed yields of burned plants but not of mowed plants. Pruning method did not influence element concentrations in blueberry leaves. An increase in winter injury to flower primordia was associated with an increase in fertilizer rate. Terbacil applications increased blueberry yield only on plants pruned by burning. A system to prune plants closer to the soil surface needs to be developed.

6. The design of very cheap sorption pumps

The relative merits of sorption pumps and rotary oil pumps are compared. Despite their use being limited to ‘closed’ systems of small volume and the need for liquid nitrogen cooling, the advantages of sorption pumps, especially their freedom from contamination, lack of noise and vibration, and ability safely to handle toxic vapours are felt to make them suitable for wider applications in laboratory situations. Two types of sorption pump, fitted with effective venting valves (which are essential for safe operation) and designed for rapid pumping, are discussed in some detail. Results are presented for rate of pumping as a function of system size, type of molecular sieve used, storage time, sieve regeneration temperature, time of prechilling and pump configuration. A variety of physico-chemical applications for sorption pumps are discussed, including their use as the sole means of evacuating small quadrupole mass spectrometers. It is recommended that a ratio of 50 g of type 13X, 1/8 in. molecular sieve pellets to 1 dm3 of system volume be used. The sieve should be regenerated every 5 cycles for clean systems and every cycle for dirty systems, at a temperature of 250°C. The sieve can be stored for long periods in screw topped bottles. Prechilling is not recommended.

Quality Characteristics of Raw and Treated Effluents From Mississippi Poultry Processing Plants

Raw and treated wastewater samples were sampled bimonthly from 19 Mississippi poultry processing plants for a period of 8 months. Biochemical oxygen demand, chemical oxygen demand, oil and grease, total suspended solids and pH values of these samples were determined. Several wastewater treatment facilities were studied for their wasteload reducing efficiencies. These included rotary screens, oil and grease flotation units, lagoons and a clarifier. Readings for both raw and treated effluents varied greatly among the processing plants. Anaerobic lagoon digestion greatly reduced the effluent wasteloads. A simple oil and grease flotation pit, managed properly, reduced the oil and grease load substantially. The final effluent from processing plants with a clarifier or an anaerobic-facultative lagoon system was better in quality than final effluent of other plants.

Vacua: How they may be improved or impaired by vacuum pumps and traps

Increasing the size of a rotary mechanical or oil diffusion pump on a vacuum system may reduce the working pressure by raising the pumping speed for a given gas throughput but also enhance the rate at which oil products backstream into the vessel. It is the objective of good pump or trap design to enhance the ratio of pumping speed S to backstreaming rate Q b whilst not adversely affecting the pumping efficiency (or capture coefficient) as determined by the ratio of the molecules removed to those incident on the pump orifice. “Traps” have been reported which reduce both Q b and S by equal proportions and thus are not traps but merely restrictive components. A review is made of current studies in the writer's laboratory of rotary mechanical and oil diffusion pumps using an hf crystal microbalance and magnetic sector mass spectrometer adapted for determining the rate and composition of backstreaming products. Rotary and diffusion oil pumps release gas and fluid degradation products but the sources and backstreaming mechanisms are dependent on the mode of pumping. Mechanical friction, high temperature and gas and catalytic reactions can promote fluid degradation. Typical values of S/Q b are given for different types of pump. It is shown that backstreaming may occur by molecular flow or diffusion in a stationary or flowing gas depending on the pump and operating conditions. The effects on Q b are described of pipe conductance, gas flow rate and pressure, and trapping media. It is shown that gas flow at low pressure (⋍5×10 −2 torr) can be more effective than a high pressure (∼0.3 torr) stationary gas in limiting backstreaming from a rotary pump. Simple expressions are developed for diffusion and to explain the momentum exchange occuring with counter-gas flow. It is contended that “clean” vacuum systems can be designed providing the designer takes into account such factors as pump backstreaming rate and trap efficiency as well as pump speed and trap conductance.