High-pressure Oil Research Articles

A macro-microscopic investigation of high-pressure sprays injected by a common rail system

The main purpose of this research is to investigate high-pressure diesel oil sprays generated by a common-rail system through small nozzle holes. High-speed photography, phase Doppler particle analyzer (PDPA), and a combination of data obtained with high-speed photography and PDPA, based on the light extinction principle within sprays are used to deal with the objective. The sprays are characterised in an environment, which simulates in-cylinder air density of the actual diesel engine when the injection starts. However, it must be pointed out that isothermal condition at room temperature is considered and no-evaporation of drops occurs. A wide parametric study has generated evidence needed to quantify the influence of the common-rail pressure, nozzle hole diameter and environment gas density on the macroscopic evolution of sprays (spray tip penetration, and spray cone angle) as well as microscopic behaviour (spatial and temporal evolution of drop size, drop velocity and drop concentration distributions).

The Influence of Injection Pockets on the Performance of Tilting-Pad Thrust Bearings—Part II: Comparison Between Theory and Experiment

This is Part II of a two-part series of papers describing the effects of high-pressure injection pockets on the operating conditions of tilting-pad thrust bearings. The paper has two main objectives. One is an experimental investigation of the influence of an oil injection pocket on the pressure distribution and oil film thickness. Two situations are analyzed: (i) when the high-pressure oil injection is turned off and (ii) when the high-pressure injection is turned on. The other objective is to validate a numerical model with respect to its ability to predict the influence of such a pocket (with and without oil injection) on the pressure distribution and oil film thickness. Measurements of the distribution of pressure and oil film thickness are presented for tilting-pad thrust bearing pads of ∼100cm2 surface area. Two pads are measured in a laboratory test rig at loads of ∼1.5MPa and ∼4.0MPa and velocities of up to 33m∕s. One pad has a plain surface. The other pad has a conical injection pocket at the pivot point and a leading-edge taper. The measurements are compared to theoretical values obtained using a three-dimensional thermoelastohydrodynamic (TEHD) numerical model. At the low load, the theoretical pressure distribution corresponds well with the measured values for both pads, although the influence of the pocket is slightly underestimated. At the high load, large discrepancies exist for the pad with an injection pocket. It is argued that the discrepancies are due mainly to geometric inaccuracies of the collar surface, although they may to some extent be due to the simplifications employed in a Reynolds equation description of the pocket flow. The measured and theoretical values of oil film thickness compare well at low loads and velocities. At high loads and velocities, discrepancies grow to up to 25%. This is due to the accuracy of the measurements. When using hydrostatic jacking the model predicts the start-up behavior well.

The Influence of Injection Pockets on the Performance of Tilting-Pad Thrust Bearings—Part I: Theory

This is Part I of a two-part series of papers describing the effects of high-pressure injection pockets on the operating conditions of tilting-pad thrust bearings. In Part I a numerical model based on the Reynolds equation is developed extending the three-dimensional thermoelastohydrodynamic (TEHD) analysis of tilting-pad thrust bearings to include the effects of high-pressure injection and recesses in the bearing pads. The model is applied to the analysis of an existing bearing of large dimensions and the influence of the pocket is analyzed. In the analysis, the high-pressure oil injection used for hydrostatic jacking is turned off (i.e., only the effect of the pocket is studied). It is shown that a shallow pocket positively influences the performance of the bearing because it has characteristics similar to those of a Rayleigh-step bearing. In Part II of the paper (Heinrichson, N., Fuerst, A., and Santos, I. F., 2007, ASME J. Tribol., 129(4), pp. 904–912) measurements of pressure profiles and oil film thickness for a test-pad are compared to theoretical results. The analysis of Part II deals both with flow situations, where the high-pressure injection is turned off, as well as with situations where it is turned on for hydrostatic jacking.

Surface Modification of Steel Using Liquid Jet Peening (Fatigue Performance)

Oil jet peening is a surface modification process developed for the introduction of compressive residual stresses. In this process, a high-pressure oil jet impinges on the surface to be peened. Specimens made of AISI 1040 steel were peened at oil pressure of 50 MPa. Residual stresses induced on the oil jet peened specimen was in the order of -200 MPa. Standoff distance influenced the residual stress induced and also the erosion and surface roughness. Fully reversed cantilever bending tests conducted on the peened and unpeened conditions revealed the improved performance of the oil jet peened specimens.

Key techniques in R&D of out-size extrusion press with oil-driven double action

A modern design method,in which traditional design formulas are conjoined with numerical simulation and optimization,is successfully used to design the out-size extrusion frame precisely so that the press cost can be saved. A new technology used for decompressing by a multi-steps dynamical mode is put forward,which makes it possible to decompress the large flow-volume high-pressure oil in the main cylinders. In addition,a method for realizing the fixed mandrel process by hydraulic support is proposed and its control equation is established. Pre-tightening frame tests are carried out by over-operating pressure on 100 MN aluminium extrusion press with oil-driven double action,which is developed based on the above key techniques and is the largest press so far in the world,and the results show that the frame structure designed is reasonable and reliable,and the modern design method used is an useful tool for designing large and out-size heavy plastic forming machinery. The results of decompressing curve in main cylinder and noise inspection indicate that multi-steps dynamical mode for decompressing the large flow-volume high pressure oil is valid and reliable. Meanwhile,the fixed mandrel process is well realized based on the control equation. These key techniques have been used in the development of 125 MN aluminium extrusion press with oil-driven double action.

弾性流体潤滑下における転がり軸受しゅう動部の応力状態

The high stress into the rolling bearing are locally generated because of the high oil pressure concentrating on a small area under EHL condition. As the result, the failure of rolling bearing might happen if the generated stress is beyond the strength of the material. Therefore it is important to take the stress distribution of rolling bearing into consideration for the efficient design of rolling bearing. Furthermore, it is also important to estimate the oil film thickness as well as stress as the metal-metal contact between the sliding pairs is directly related to the failure of the rolling bearing. In this paper, stress distribution of rolling bearing and oil film thickness are numerically analyzed in a point contact under EHL condition, and the optimum design for rolling bearing was obtained from the result. As a result, it is preferable to give the smaller value of equivalent radius of curvature and the larger value of rotating speed of ball.

Poly-$alpha$Olefin Synthetic Oil: A New Paradigm in Repetitive High-Pressure Oil Switches

A high-pressure oil switch for high-energy systems has been developed and tested to repetition rates up to 100 pps in burst mode and test voltages to -300 kV. The switch utilizes high-pressure flowing synthetic oil and advanced mechanical designs to achieve high-performance operation at pressures to 17.24 MPa (2500 psi). Experimental data is presented for both single-shot performance as well as continuous repetition rate performance to 20 pps. Electrode lifetime is evaluated for stainless steel and Elkonite to demonstrate electrode lifetime. Evidence is presented in support of the dependence of switching performance on the geometry of the switch

Surface Modification and Fatigue Behavior of High-Pressure Oil Jet-Peened Medium Carbon Steel, AISI 1040

Introduction of compressive residual stresses on the fatigue-loaded components is one of the techniques followed to improve the fatigue life of industrial components. Oil jet peening is a surface modification process for the introduction of compressive residual stresses. A high-pressure oil jet is made to impinge on the surface to be peened. Preliminary studies were carried out on the medium carbon steel at the oil pressure of 50MPa. The compressive residual stress induced on the surface of unpeened and oil jet-peened AISI 1040 steel was 21MPa and 200MPa, respectively. Fully reversed cantilever bending fatigue behaviors of medium carbon steel in both under peened and unpeened conditions were evaluated at room temperature. Oil jet-peened specimens exhibited superior fatigue performance compared to the unpeened specimens. Fractographical analyses were carried out for specimens broken at several tested stress levels using optical microscope.

A novel surface modification technique for the introduction of compressive residual stress and preliminary studies on Al alloy AA6063

A new peening process for introducing compressive residual stresses with less erosion and good surface finish using a high pressure oil jet was developed. Aluminium alloy, AA 6063 was peened with an oil pressure of 50 MPa at different stand-off-distances. Residual stresses measured using X-ray diffraction indicated the induction of about 50 MPa (compressive) residual stresses on the surface. The depth of compressive residual stress developed was about 250 μm. The surface roughness of the oil jet peened surface depends on the stand-off-distance. Significant work hardening was observed at low stand-off-distances. The temperature rise during the process was marginal and doesn't contribute to stress relaxation. Erosion during the process was also reported based on the mass loss rate measured.

Surface modification by oil jet peening in Al alloys, AA6063-T6 and AA6061-T4: Residual stress and hardness

The life of structural members that experience cyclic loading is improved by the introduction of surface compressive residual stresses. A high-pressure oil jet is used for the introduction of surface compressive residual stresses in aluminum alloys, AA6063-T6 and AA6061-T4. The peening machine designed and developed in the laboratory is capable of generating high pressures using hydraulic oil. The magnitude of residual stress developed depends upon the stand-off distance and yield strength of the material. A hardened layer up to a depth of about 350μm was developed in the materials investigated. The residual stresses and surface hardening induced are comparable to that produced by other peening processes. An analytical model is proposed to predict the impact pressure.

An overview of marine renewables in the UK: a synopsis of Michael Hay's presentation

An overview of marine renewables in the UK: a synopsis of Michael Hay's presentation

ベトナム・ランドン油田フラクチャー型貯留層モデル構築

The Rang Dong oil field is located in the Cuu Long basin, offshore Vietnam. The field was discovered by Japan Vietnam Petroleum Company Ltd. in 1994. The field has naturally fractured basement reservoir, which is producing with 14 producers and 7 injectors as of now. One of the production bottlenecks of the Rang Dong field is gas and water break through. High bubble point pressure oil provides secondary gas cap drive system to the reservoir. But control of the liberated gas production by coning is difficult. Deeper completions to avoid gas break through often result in water break through, although there is no significant pressure support from aquifer. Currently, water injection is applied to the field to control reservoir energy and gas cap development. With this situation, development of reliable model to predict field performance is a key technical requirement to manage the field. This paper describes evolution of the reservoir modeling. Generally, characterization of fractured crystalline rock reservoir is more difficult than sedimentary rock reservoir. After some lessons learnt, new approaches such as 3D seismic reprocessing, highly deviated-horizontal wells, extended well testing were applied to fully evaluate the reservoir. These new approaches made a lot of improvement to understanding of the fracture system and resulting simulation models. Integration of different disciplinary data introduced key concepts such as discrete fractures, productive network and dynamic data matching. The fracture data gathered so far were re-evaluated in the view of connectivity to the productive network. The simulation model consists of discrete mega-fracture framework and associated relatively continuous lower order fractures. The model is calibrated with both static and dynamic data, using such data as seismic, log and well test. This model describes pore space distributions and their connectivity in single porosity system and can re-produce the history of break through and predict the reservoir performances with some practical accuracy in natural depletion condition.

Development of Multi-type Fatigue Testing Machine in Axial Loading and Verification of Its Fundamental Performance

Fatigue behavior of metallic materials in very high cycle regime has become an impotant subject to guarantee the safety of mechanical structures during the long term service. In order to perform fatigue tests in very high cycle regime of N=109, a long period such as 230 days is required at the testing fiequency of 50 Hz. The multi-type fatigue testing machine which can give cyclic loadings to a number of specimens simultaneously is valuable to obtain fatigue test data within the specified period. From this point of view, a multi-type fatigue testing machine for axial loading was developed by using a special hydraulic system with a rotary valve to distribute high pressure oil into the respective actuators. By means of this testing machine, fatigue tests for four different specimens can be perfermed simultaneously at the frequency of 80 Hz. The loading capacity for each specimen is ±10kN and the applied load can be given independently to the individual specimen. Thus. one can perform the fatigue tests in the long life regime for many specimens within the specified period even in the usual frequency where the temperature rise does not take place on the specimens. The fundamental structure and its performance are presented here together with the fundamental experimental results on the bearing steel of SUJ 2.

New generation of multifunctional mobile high-pressure oil and gas field pumping units

Technical data and description of basic versions of UNB type of mobile pumping units designed for operation with almost any abrasive-containing, fast-hardening, corrosive, and other fluid media having densities of up to 2.4 g/cm3 are given. The equipment of the units is mounted on truck chassis fit for long-distance traveling.

A web-enabled collaborative quality management system

To cope with increasingly rapid globalization, more outsourcing, and reduced product development cycle time, various kinds of new approaches and tools have been introduced and applied. This paper proposes the concept of collaborative quality management as an extension of currently available quality management techniques. The concept provides an effective approach to collaboratively carry out quality management activities throughout the entire product life cycle. The conceptual model, process model, and multi-agent system technology for the collaboration mechanism in quality management are presented. A prototype system has been developed and tested with the Web for life cycle collaborative quality management. The function models for the system have been examined and configured. In addition, the issues of system architecture, relevant key technologies, and system integration are discussed in detail. Finally, an example study with a high-pressure oil pump from a Ford Motor Co. automobile illustrates the benefit of the system.

A new series of unitized mobile high-pressure oil and gas pumping units

Technical characteristics of several versions of a unitized series of pumping units differing essentially in hydraulic blocks, materials of domestic elements of the delivery lines, and high-pressure safety devices are given. Designs of blocks of the pumping unit are described.

A Combined Optical-Ultrasonic Method of Establishing the Compressibility of High-Pressure Oil and Grease Films Entrapped in a Ball on Flat Contact

The paper describes an experimental technique combining optical interferometry and ultrasonic attenuation to measure the bulk modulus (compressibility) and film thickness profiles of oil and grease films entrapped between a stationary steel ball and a sapphire plate. Results are presented for lithium- and urea-based greases, and their base oils alone, at contact pressures up to and around 3 GPa, and are compared with some models and results from other studies, extrapolated to the higher pressures achieved here. Results show that the bulk modulus of a particular grease and its base oil are found to be similar, at a given pressure, and largely dependent on the base-oil properties, which is demonstrated to be what is expected with the concentration levels of fillers and solid lubricants present. However, the film shapes measured for the grease and its base oil can be quite different. This is seemingly due to the manner in which the lubricant samples “solidify”, due to the high pressures, and also to the way in which the edges of the squeeze-film entrapped fluid are sealed. This latter sealing effect seems to be assisted by secondary phases, particularly with greases where fillers and solid lubricants are present, creating a very effective sealed contact where the entrapped lubricant samples could be observed to remain stable for several hours.

Subsea HIPPS: A Way To Develop High-Pressure Subsea Fields

Summary One of the challenges for the development of high-pressure oil and gas prospects in ultradeep water is the high capital-expenditure (CAPEX) cost of subsea flowlines and risers. Installing a high integrity pressure protection system (HIPPS) in the subsea system allows the flowline to be designed to just above well flowing pressure instead of well shut-in pressure. On the basis of flow simulations, pipeline design, and economic analysis, this paper demonstrates that installing subsea HIPPS results in the following: Lower installed cost of flowlines and risers. Early payback with incrementally higher flow of oil and gas. Secondary benefits including higher flowing wellhead and flowline temperatures. Another important benefit of using subsea HIPPS is that the weight of the risers hanging off at the host facility can be reduced substantially. Otherwise, heavy-walled risers may restrict the tie-in of the deepwater prospect to host facilities. With pressure decline over time, the thick-walled flowlines become overkill and tend to restrict the well flow rate. With subsea HIPPS, the larger flow area in the subsea flowlines will allow the field to be abandoned at a lower reservoir pressure. This means that that the total recoverable reserves from the field can be increased. The major finding of this paper is that for high-pressure reservoirs in ultradeep water, installing HIPPS subsea accelerates cash flow and increases the project net present value. These benefits will be illustrated on the basis of the analysis of a deepwater field-development design case.

Numerical analysis of a cross-flow compact heat exchanger for vehicle applications

A numerical thermo-fluid–dynamic study of a compact crossed flows heat exchanger (HX), used to cool the high-pressure oil used in hydraulic circuits of earth-movement industrial vehicles, was performed. The numerical analysis was carried out to verify the influence of the hydrodynamic regimes of the fluids involved in the heat transfer process, induced by fins in the channels, on the performances of the whole HX. The analysis was developed through three steps of increasing complexity. After a simple model built to evaluate the consistent boundary conditions of temperature, a small scale analysis of the fluid–dynamic phenomena inside the HX was carried out, taking into account geometrical periodical units at oil (OS) and at air side (AS). With the results obtained in this way, the HX performances were evaluated on an overall scale, extrapolating the data up to the real dimensions in terms of heat transfer and pressure loss. With the “small scale” approach at the OS the local heat flux and the pressure losses were quantified, using a laminar scheme and a high detail in the geometry description of the turbulence generators. With the “full scale” approach, then, simulations were performed considering a porous media with characteristics set up on the previous analysis. The global heat transfer coefficient and the pressure losses were so accounted for. At the AS, the schematization was limited to two periodic portions of the flow and results allowed to evaluate both local and overall heat transfer coefficients. Results were again extrapolated to the real dimensions of the channels. The results come out from the AS detailed analysis were, then, related to the output of the ones at OS. This was done to obtain crossed confirmations of the overall results in terms of thermo-fluid–dynamic performances of the HX at design conditions.

Measurement and corresponding states modeling of asphaltene precipitation in Jilin reservoir oils

The asphaltene precipitation of two reservoir oil samples collected from Jinlin oil field has been studied under pressure and with/without CO 2-injection conditions. No asphaltene precipitation was detected during the pressure depletion processes without CO 2 injection. For the CO 2-injected oil systems, the effects of operating pressure, injected CO 2 concentration, and multiple-contact on the onset and amount of asphaltene precipitation were studied under the reservoir temperature. No asphaltene precipitation was observed when the operating pressure is remote from the minimum miscibility pressure (MMP). However, appreciable asphaltene precipitation was detected when the operating pressure approached or exceeded the MMP. The amount of asphaltene precipitation increased with the concentration of injected CO 2. A generalized corresponding states principle (CSP) for prediction of asphaltene precipitation data is produced and reported here. The proposed CSP theory complements the scaling equation for asphaltene precipitation under the influence of n-alkane precipitants. Based on literature data and the data measured in this work, the parameters and exponents of a corresponding states equation capable of describing the asphaltene precipitation behavior in the studied high-pressure CO 2-injected crude oil systems are reported.