Hydraulic Expansion Research Articles

Hydraulic Expansion Techniques for Fracture-Cavity Carbonate Rock with Field Applications

Fracture-cavity carbonate reservoirs provide a large area, fracture development, high productivity, long stable production time, and other characteristics. However, after long-term exploitation, the lack of energy in the formation leads to a rapid decrease in production, and the water content in crude oil steadily increases, thereby disrupting normal production. To recover normal production, it is necessary to connect the cracks and pores that have not been affected during the original production, so as to allow the crude oil inside to enter the production cracks and replenish energy through methods such as hydraulic expansion of fracture-cavity carbonate rock. Accordingly, we propose hydraulic expansion techniques based on the following four processes for implementation: (1) applying high pressure to prevent a nearby fracture network from opening the seam, (2) connecting a distant fracture-cavity body, (3) breaking through the clay filling section of a natural fracture network, and (4) constructing an injection production well pattern for accelerating injection and producing diversion. Hydraulic fracturing involves closing or partially closing the original high-permeability channels, which usually produce a large amount of water, while opening previously unaffected areas through high pressure to increase crude oil production. We also introduce two composite techniques: (1) temporary plugging of the main deep fractures, followed by hydraulic expansion; and (2) capacity expansion and acidification/pressure processes. Hydraulic expansion allowed us to recover and supplement the formation energy and efficiently increase production. We tested various wells, achieving an effective hydraulic expansion rate of up to 85%. In addition, the productivity of conventional water injection and hydraulic expansion after on-site construction was compared for one well, clearly indicating the effectiveness of water injection and the remarkable crude oil increase after hydraulic expansion.

Mechanism of vertical displacement beneath shallow compression zone in coastal area

Previous studies showed that there is a discrepancy between total subsidence (measured on the ground surface) and shallow compression (measured within several hundred meters beneath the ground surface) in Taiwan. This difference is referred to as deep displacement in this study. The variations of deep displacement are opposite to those of ground surface displacement and groundwater level within the depth of several hundred meters. The mechanism is unknown and requires further investigation. This study adopts two kinds of geodetic observation data and separates land subsidence into shallow compression and deep displacement to investigate the mechanism of deep displacement. A tectonically active coastal area in Taiwan is selected as the study area. The assessment results show that the associated variations are likely due to cyclic hydraulic loading and unloading. The variations of deep displacement are opposite to those of ground surface displacement. This study proposes that these variations are due to hydraulic expansion and contraction. The mechanism is demonstrated using a hydromechanical model. The results of a cross-correlation analysis show that hydraulic expansion and contraction occur at certain depths. The study results provide important information on the mechanism of deep displacement that can be used in tectonophysical and land subsidence investigations.Graphical

Design and Research of Hydraulic Expansion Control System for Reducing Pipe

In the aerospace industry's part forming processes, there is a pursuit of structural integration and lightweighting to reduce material and energy waste. Consequently, hydraulic expansion (hydroforming) has been widely applied, commonly utilized during the manufacturing processes. This paper focuses on the production of stepped aluminum tubes using hydraulic expansion technology and mainly studies the control techniques of hydraulic expansion for stepped tubes.

Numerical simulation study on evolution law of three-dimensional fracture network in unconventional reservoirs

It has become a consensus that large-scale hydraulic fracturing is adopted to achieve the stimulation of unconventional oil and gas reservoir. The complex fracture network formed by fracturing is closely related to the effect of reservoir stimulation, which has extremely complicated evolution process. Therefore, it is necessary to study the evolution law of fracture network in large-scale hydraulic fracturing of unconventional reservoirs. In this article, the geological engineering parameters of horizontal well H in shale gas reservoir in southern Sichuan are taken as an example, a three-dimensional fracture network expansion model is established based on the boundary element method and finite volume method, and the simulation of the complex fracture network in a whole well section is carried out to analyze the evolution law of reservoir fracture network under different geological and engineering parameters. The results show that the horizontal stress field distribution has a significant effect on fracture geometric form. Hydraulic fractures in reservoirs with larger horizontal stress difference have stronger directivity, while the horizontal wellbore tends to obtain better reservoir stimulation results when it is parallel to the minimum horizontal principal stress setting. The conjugated natural fracture developed in the reservoir inhibits the hydraulic expansion fractures in both directions. Although it increases the complexity of the fractures, it is not necessarily conducive to improving the reservoir stimulation effectiveness. The lower the strength of natural fracture is, the more complex the fracture geometric form becomes, and the smaller the stimulated reservoir volume is. Correspondingly, the higher the strength of natural fracture is, the simpler the fracture geometric form becomes, and the larger the stimulated reservoir volume is. Suitable fracturing construction displacement can not only contribute to form a more complex fracture distribution, but also help to obtain a larger stimulated reservoir volume. The optimal construction displacement ranges from 10 to 14 m3/min. Low viscosity fracturing fluids are suitable for the formation of long-narrow fractures and able to connect with the remote reservoir and form complex fracture networks. Lower viscosity fluids can be used to achieve better reservoir stimulation effectiveness when sand-carrying capacity is met.

Mechanical and Impermeability Properties of Polymer Grouting Materials for Hydraulic Expansion Joints

Mechanical and Impermeability Properties of Polymer Grouting Materials for Hydraulic Expansion Joints

Hydraulic Expansion Joint Contact State of Heat Exchanger Based on New Contact Area Measurement Method

The contact state of a seamless internal threaded copper tube and an aluminium foil fin not only affects the heat transfer efficiency of a tube–fin heat exchanger but also seriously affects its service life. In this study, hydraulic expansion technology was used to connect the copper tube with an internal thread with a 7 mm diameter to the fin of the heat exchanger. The influence of the expansion pressure and pressure holding time on the contact state was analysed through experiments and finite element simulation, and the variation law of the two on the contact state was obtained. The contact state was characterised by the contact gap and contact area. In order to obtain the specific contact area value, a new method of measuring the contact area was developed to reveal the variation in contact area between the copper tube and the fin after expansion. The results show that the contact gap decreases with an increase in expansion pressure, while the pressure holding time remains the same. The contact area increases with an increase in expansion pressure, and the rate of increase slows. When the expansion pressure is 18 MPa, the average contact gap is approximately 0.018 mm. When the expansion pressure reaches 16 MPa, the contact area ratio is 91.0%. When the expansion pressure increases to 18 MPa, the contact area ratio only increases by approximately 0.6%. Compared with the influence of the expansion pressure on the increase in contact area, the influence of the pressure holding time on the contact area is lower.

Residual contact pressure for mechanically lined pipe hydroforming with carrier pipe plastification

Mechanically Lined Pipe (MLP) is a rigid carbon steel pipe internally lined with a flimsy Corrosion Resistance Alloy (CRA). This bi-metal composite structure has become an economic and flexible solution to offshore Oil & Gas (O&G) transportation of highly caustic hydrocarbon fluids. The residual contact pressure that arises from the hydraulic expansion fabrication process may prevent wrinkling and interlayer detachment when the pipe is bent or axially compressed during installation and operation. Increasing the residual contact pressure thus becomes a relevant topic for maintaining MLP integrity. The traditional MLP manufacturing process retains the carrier pipe entirely elastic. Yet, a light degree of plastification of carrier pipe will enhance the mechanical adhesion. Mathematical formulations including linear and Ludwik Power Law (LPL) hardening models are here developed to describe the stress-strain behavior of partially plastified carrier pipe. The stress state analysis is performed throughout the whole fabrication process based on the Tresca criterion. Results for residual contact pressure and residual stress state are obtained analytically and numerically. It suggests that an appropriate plastification of carrier pipe favors the mechanical adhesion.

Forming Performance of Multi-way Tubes in Hydroforming

The tube hydroforming technology is a rapid-forming technique in multi-way tube integrated and lightweight manufacturing. The forming performance of the multi-way tube under this technology was comprehensively analyzed and summarized in this paper. Firstly, the influencing factors, such as axial feed loading path and internal pressure, forming friction, and die transition fillet, in the process of multi-way tube forming were analyzed and summarized. Secondly, the optimization method of the multi-way tube forming performance in hydroforming was analyzed. Finally, the reduction of hydraulic expansion costs and the development of new hydroforming technologies were expounded.

Optimization of High Pressure Forming Parameters in Conical Tubes Based on Response Surface Method

The appearance of conical muffler improves the aerodynamic performance and acoustic performance of expansion chamber muffler. The inner surface of this type of pipe has variable section and continuous smoothness. The improvement of the manufacturing efficiency of such tubes is a key issue that needs to be addressed urgently today. To this end, a method of producing conical muffler tubes using a hydraulic expansion process is proposed, using which the weight of the conical muffler tubes can be reduced while the aerodynamic impact of the weld on the muffler tubes is eliminated thereby enhancing the fuel economy of the vehicle. The effect of internal pressure, taper ratio and friction coefficient on the forming results was investigated by using finite element simulation combined with response surface optimization for the hydraulic expansion process method.

Failure analysis on unexpected fracture of the hydraulic expansion mandrel for tube to tubesheet expanding in the steam generator of nuclear power plant

Hydraulic expansion is commonly adopted for the tube to tubesheet expansion in the steam generator of nuclear power plants, and its quality greatly influences the stable and reliable operation of the steam generator. In this paper, an unexpected fracture of the hydraulic expansion mandrel occurred during the hydraulic expansion process, which caused the internal bulge defect (IBD) in the expanding area of the heat exchange tube. The corrosion test results showed that the IBD area had higher susceptibility to stress corrosion cracking (SCC) than the original tubes, which might lead to premature failure of the heat exchange tube in practical operation. To find out the root causes of this failure, the fracture morphologies of the hydraulic expansion mandrel were observed under the optical microscope (OM) and the scanning electron microscope (SEM), and the stress distribution during service were analyzed by mechanical calculation, The results indicated that the hydraulic expansion mandrel was repeatedly loaded by high-pressure medium during service, thus its weakest point was fractured due to high strain level and low cyclic number inelastic strain fatigue. Based on the results, the underlying mechanisms were discussed, and the countermeasures were proposed. The achievements of this paper provide theoretical and practical support for preventing similar failure and ensuring the expansion quality of the steam generator tubes for nuclear power plants.

Evaluation of Expansion Process to Improve Corrosion Resistance of Copper Tubes with High Residual Carbon on the Inner Surface

Residual carbon on the inner surface of copper tubes is known to be a cause of pitting corrosion. We showed previously that the rapid filling test was useful to evaluate the pitting corrosion resistance of copper tubes. Immersion tests using the rapid evaluation test solution showed that corrosion occurs on the entire surface of copper tubes with low residual carbon amounts, while those with high residual carbon amounts show pitting corrosion. Therefore, it is necessary to improve the corrosion resistance of copper tubes with high residual carbon amount, which are expected to undergo pitting corrosion. As pitting corrosion occurs when anodes are locally concentrated on part of the metal surface, it has been suggested that anodes be dispersed over the entire surface by the processing of the metal surface. Metal processing methods have various purposes, including changing the shape and properties of metals, and in this case, leading to desirable surface properties (such as expansion and drawing processes). Here, we focused on the expansion process and its effects on corrosion resistance of copper tubes. The results showed that hydraulic expansion has a significant effect on the inner copper surface by improving corrosion resistance as the anode area increases.

Correlation analysis of mechanical properties of dilated packer cylinder

The expanding packer is a commonly used packer, which is widely used in the process of oil and gas production. Taking the most commonly used K344 hydraulic expansion packer as the research object, using SolidWorks and ANSYS Workbench software to establish a two-dimensional finite element model of the K344 packer rubber cylinder, carry out stress analysis on the packer rubber cylinder, and obtain the packer rubber cylinder Von Mises stress and contact stress nephograms. The research results show that when the packer is in the working state of internal pressure of 20.0 MPa, the stress level of the upper and lower rubber cylinder seats is the highest, and the maximum Mises stress is 54.86 MPa; the stress level at both ends of the rubber cylinder is the highest, up to 43.465 MPa, and the strain energy density on both sides is the largest; when the packer is in the working state, the shoulder deformation is the largest, with the increase of the pressure, the deformation trend slows down, and the strain energy density has a linear relationship with the working pressure. The obtained results can provide a theoretical basis for the structural design of the expandable packer.

Theoretical Study on Thermal Hydraulic Expansion Process of Stainless Steel Lined Clad Pipe

Abstract The stainless steel lined clad pipe (SSLCP) can be widely used in different fields. Industrial SSLCP are generally manufactured by the cold hydraulic expansion (CHE) method which requires high hydraulic pressure and good sealing property. The interlayer bonding force is difficult to obtain by the CHE when there is little difference between the yield strengths of inner and outer pipes. Furthermore, the hydraulic expansion process nearly cannot be achieved when the yield strength of inner pipe is higher than that of outer pipe. The thermal hydraulic expansion (THE) method can overcome these difficulties. In this paper, the graph method was adopted to analyze the THE principles for “inner strong and outer weak (ISOW)” and “outer strong and inner weak (OSIW)” pipes. The effective hydraulic expansion criterion conditions of SSLCPs were proposed and can be used as basis of clad pipe material matching and forming process selection. Through the stress and strain analysis of inner and outer pipes during THE process, the deformation coordination conditions of elastic deformation and thermal deformation of the inner and outer pipe were established. The correlation between the residual contact pressure p*c, the hydraulic expansion pressure pi, and the effective temperature difference ΔTe were derived. The calculation formula of the maximum expansion pressure pimax and the minimum expansion pressure pimin was obtained. The maximum heating temperature of outer pipe was also derived. Furthermore, the finite element analysis (FEA) method was adopted and simulated results verify the feasibility and applicability of the theory study.

Buckling of dented bi-material pipe under bending Part I: Experiments and simulation

As a cost-effective solution for transporting corrosive hydrocarbons, mechanically lined pipe has been used in many offshore and onshore projects. The bonding between the carbon steel carrier and the non-corrosive liner is commonly achieved by mechanical expansion. As typical pipeline damage, the local dent brings deformation to the bimetallic composite, which is expected to undermine the structural integrity. This work investigates the influence of a local dent on the plastic responses and stability of a lined pipe system during bending. Part I presents the results of the experiments and numerical analysis involving a set of small-scale lined tubes. The lined tubes, made of carbon steel Grade GB45 (AISI 1045) and copper Grade T2, are manufactured using a custom hydraulic expansion facility. The products have finished diameters of 50 mm and an overall D/t of 16.5, with 1.0 mm thickness for the liner. A minor transverse dent is introduced to the specimen using a cylindrical indenter. The dented tube is subsequently bent to collapse in a four-point bending facility. It is found that the local dent tends to induce early collapse of both the outer tube and the liner, resulting in a noteworthy reduction of the bending capacity of the composite. Initially, the local dent grows stably instead of collapsing right away. With increasing bending, the liner develops a major buckle and several satellite dimples around it. Subsequently, the manufacture, indentation, and the succeeding bending to collapse are simulated using a custom numerical framework, and the experimental results are reproduced reasonably well. Part II will use the validated numerical model to conduct an extensive parametric study of the important variables of the problem for full-scale lined pipes.

Experimental Investigations of Expansion Strength of Hydraulic Expansion Joints Interconnecting Tube and Fins Heat Exchanger

As a high expansion strength corresponds to a high heat transfer efficiency, this study investigated the expansion strength of an air-conditioning heat exchanger jointed by hydraulic expansion. A device that would be reliable and adaptable to different types of tubes and fins was designed and developed for testing hydraulic expansion. The device was used to perform a non-pulsating hydraulic expansion experiment on samples comprising tubes and fins to determine the hydraulic pressure range. The expansion strength was tested by performing tensile tests to evaluate the pull-out force at different bulging zones of the same sample with the selected hydraulic pressure. A series of pulsating hydraulic expansion experiments were performed on the joints of tubes and fins with different pulsating amplitudes and frequencies. Tensile tests were performed on the pulsating hydraulic expansion samples to study the influence of the pulsation parameters on the pull-out force. When the amplitude was fixed, an increase in frequency led to uniform expansion in the exchanger. This indicates that joint expansion in tubes and fins results in a more reliable heat exchanger performance.

Development of Expanded Steel Pipe Pile to Enhance Bearing Capacity

An expanded steel pipe pile increases the cross-sectional area of conventional micropile by expanding the steel pipe to exhibit a higher bearing capacity owing to increased frictional resistance. However, construction cases of the expanded steel pipe pile are insufficient due to the absence of equipment for expanding steel pipes inside the ground. In this study, hydraulic expansion equipment was developed to verify the reinforcing impact on the bearing capacity and field applicability of the expanded steel pipe pile. A series of laboratory and test bed experiments was conducted to measure the expansion time and deformation of carbon steel pipes by using the developed equipment. The results of these experiments demonstrated that the developed equipment has sufficient ability and constructability to be used in the field for constructing expanded steel pipe piles. Then, field load tests were performed by constructing expanded and conventional steel pipe piles to confirm the improved bearing capacity of the expanded steel pipe pile compared to that of the conventional micropile. As a result, the expanded steel pipe pile exhibited a 20.88% increase in bearing capacity compared to that of the conventional steel pipe pile.

Experimental Study on Crack Extension Rules of Hydraulic Fracturing Based on Simulated Coal Seam Roof and Floor

Hydraulic fracturing can increase the fracture of coal seams, improve the permeability in the coal seam, and reduce the risk of coal and gas outburst. Most of the existing experimental specimens are homogeneous, and the influence of the roof and floor on hydraulic fracture expansion is not considered. Therefore, the hydraulic fracturing test of the simulated combination of the coal seam and the roof and floor under different stress conditions was carried out using the self-developed true triaxial coal mine dynamic disaster large-scale simulation test rig. The results show that (1) under the condition of triaxial unequal pressure, the hydraulic fractures are vertical in the coal seam, and the extension direction of hydraulic fractures in the coal seam will be deflected, with the increase of the ratio of the horizontal maximum principal stress to the horizontal minimum principal stress. The angle between the extension direction of the hydraulic fracture and the horizontal maximum principal stress decreases. (2) Under the condition of triaxial equal confining pressure, the extension of hydraulic fractures in the coal seam are random, and the hydraulic fracture will expand along the dominant fracture surface and form a unilateral expansion fracture when a crack is formed. (3) When the pressure in one direction is unloaded under the condition of the triaxial unequal pressure, the hydraulic fractures in the coal seam will reorientate, and the cracks will expand in the direction of the decreased confining pressure, forming almost mutually perpendicular turning cracks.

Deformations and Stresses of Thick-Walled Heat Exchange Pipes during Hydraulic Expansion

Deformations and Stresses of Thick-Walled Heat Exchange Pipes during Hydraulic Expansion

Detection methods for springback of assembled camshaft under hydraulic expansion

The assembled camshaft under hydraulic expansion has the advantages of low cost, lightweight and high performance, which is an advanced technology with great development potential. By applying the tube hydroforming to the fabrication of assembled camshaft, the expansion principle is due to the different degrees of resilience of the cam and the shaft. Therefore, the effective detection method of elastic recovery of camshaft is of great significance to research how to improve the connection strength of the assembled camshaft. This paper introduces several springback detection methods for assembled camshaft under hydraulic expansion, namely resistance strain detection method, gap dynamic detection method and finite element simulation.

Hydraulic expansion facilitates remodeling of arteriovenous fistulas without increasing venous intimal hyperplasia in rabbits.

An arteriovenous fistula (AVF) is considered essential for chronic hemodialysis. To determine the effects of hydraulic expansion on the intimal hyperplasia of an AVF. We divided 12 healthy male New Zealand white rabbits into a control group (vein without special handling and direct anastomosis with an artery, n = 6) and a hydraulic expansion group (vein dilated by hydraulic pressure before anastomosis, n = 6). Histopathomorphology was examined with hematoxylin and eosin staining and immunohistochemistry. Analysis of covariance (ANCOVA) was used to compare the data between the groups. Immediately and 1 day after surgery, the diameter of the fistula vein in rabbits in the hydraulic expansion group was significantly larger than it was in the control group (P = 0.02 and 0.03 respectively), but not on subsequent days. After hydraulic expansion and before construction of the fistula, the wall of vein was noticeably thinner on macroscopic observation, and the anterior and posterior walls were indistinguishable. At 3 weeks after surgery in the hydraulic expansion group, cells in the vein wall were disordered, there were fewer elastic fibers, tissues from the endothelium to tunica externa were less dense, and there was less extracellular matrix than in the control group. Expression of connective tissue growth factor in the hydraulic expansion group was significantly less than that in the control group (P = 0.01). No differences were found in intimal thickness or immunohistochemistry scores for transforming growth factor-β1 between the groups. Hydraulic expansion did not increase intimal hyperplasia of an AVF, but facilitates remodeling of AVFs in rabbits.