Flow Loop System Research Articles

Mitigating Liquid Loading in Gas Wells Using Thermochemical Fluid Injection: An Experimental and Simulation Study.

Liquid loading significantly hinders gas production in unconventional shale wells, restricting flow and causing productivity decline. This study presents a novel approach to address this challenge, utilizing thermochemical fluids to generate in situ pressure and heat and effectively mitigating liquid loading issues. Laboratory experiments were conducted using a specially designed flow loop system to evaluate the performance of thermochemical fluids in alleviating liquid loading. The key treatment parameters such as thermochemical volumes, injection rate, number of cycles, and optimum injection time were optimized to improve the removal efficiency. In addition, PIPESIM software (pipe simulation program) was used to validate the effectiveness of the thermochemical approach for removing the liquid loading issue. Both laboratory results and PIPESIM outcomes confirmed the efficiency of thermochemical fluids in handling liquid loading. Removal efficiency of more than 90% can be achieved using thermochemical injection. The liquid removal efficiency increases with the number of cycles due to the generation of more pressure and heat at later injection cycles. Increasing injection cycles from 1 to 3 resulted in liquid removal efficiency rising from 17 to 95%. Also, PIPESIM results indicated that the gas production rate can be improved by around 74% after applying thermochemical treatment. Overall, this study introduces an effective treatment for liquid loading mitigation with significant potential to enhance gas production. The proposed method offers several advantages, including ease of application and extended well life.

Evaluation of Lost Circulation Material Sealing for Geothermal Drilling

Lost circulation is a pervasive problem in geothermal wells that can create prohibitive costs during drilling. The main issue with treatment is that the mechanism of plug formation is poorly understood. Here we applied two experimental approaches to characterize the clogging effectiveness of different materials. Fracture flow tests with different geometries were conducted with various individual materials and mixtures at relevant conditions. A high-temperature flow loop system was also developed to inject single- and mixed-material plugs into a gravel pack with a non-uniform geometry to compare with the fracture tests. The fracture tests revealed that single materials tended to form no plug or an unstable plug, while mixtures of materials were uniformly better at sealing fractures. Gravel pack tests at high temperatures show most of the materials are intact but degraded. The fibrous materials can create partial or unstable plugs in the gravel pack, but mixed-material plugs are far more effective at clogging. Both test types suggest that (1) mixed materials are more effective at blocking fluid flow and (2) fibrous materials seal fracture openings better, while granular materials seal inside fractures or pore throats better. Further research is needed to study the long-term stability of different plug configurations.

Probing pipe flow impact corrosion monitoring effectiveness under corrosion monitor coupons conditions

To reduce the corrosion failure frequency of oil and gas pipelines, corrosion monitoring coupons are often used to evaluate the internal corrosion status of pipelines. However, the local flow field varies after the installation of the coupons, so the monitoring corrosion rate is different from that of the pipe wall. To evaluate the effectiveness of corrosion coupons monitoring, a lab-scale flow loop system was used to carry out flow corrosion experiments to obtain the local corrosion rates of corrosion monitoring coupons and pipe wall, respectively. Combined with the characterization of corrosion products and multiphase flow, a mechanism model of corrosion monitoring effectiveness was established. It was clear that the deviation of corrosion monitoring rate was related to the flow rate, shear force and turbulent kinetic energy. The accumulation of corrosion media and the detachment of corrosion product films resulted in variation in the morphology and the monitoring effectiveness.

P37: Development of a Large Diameter In Vitro Flow Loop Thrombogenicity Test System

Purpose: To accommodate a wide range of medical device sizes for in vitro thrombogenicity testing, a larger flow loop system using 9.5 mm inner diameter (ID) tubing was developed and evaluated based on the 6.4 mm ID system that we previously used. Methods: Four cardiopulmonary bypass roller pumps were used concurrently to drive four different flow loops constructed with 9.5 mm ID polyvinyl chloride (PVC) tubing. To ensure that the four pumps produced a consistent blood flow rate (around 530 mL/min), a simplified dynamic roller-occlusion method was developed and applied. ACDA-anticoagulated bovine blood from live donors was obtained commercially, shipped overnight, and used within 24-36 hours of the blood draw. Immediately before starting each flow loop test, the blood was recalcified and heparinized to a donor-specific concentration (0.5 – 0.8 U/mL). The donor-specific heparin level was selected based on an established static pre-test and verified by an initial flow loop test with the following acceptance criteria: thrombus surface coverages of ≤10% on the negative control (PTFE) and ≥50% on the positive control (latex) materials, and platelet (PLT) reduction of ≤30% for the negative control and ≥90% for the positive control. For the dynamic testing, the heparinized blood was recirculated at 20 rpm for 1 hour at room temperature through each PVC tubing loop containing a test material. Six materials (3.2 mm OD, 12 cm long) with different thrombogenic potentials were assessed: negative control polytetrafluoroethylene (PTFE), positive control latex, BUNA rubber, silicone, abraded PTFE, and 3D printed nylon. Thrombogenicity potentials of the test materials were evaluated after the recirculation by measuring the thrombus surface coverage on test materials and platelet count reduction in the blood samples. Results: The in vitro flow loop test system effectively differentiated the known thrombogenic materials (latex, BUNA) from the historically thromboresistant PTFE (p<0.05 for PLT count reduction and thrombus surface coverage, Figure 1). Additionally, the 3D printed nylon and silicone test samples were shown to have an intermediate thrombogenicity level with significantly less thrombus surface coverage and PLT count reduction than latex and BUNA, but significantly more thrombus surface coverage than the PTFE (p<0.05). While the average PLT count reductions for the 3D printed nylon and silicone were also greater than that of PTFE, the differences were not statistically significant. Conclusion: The preliminary data suggest that the 9.5 mm ID test system is capable of differentiating materials of varying thrombogenicity potentials, and the different pumps can produce consistent results when appropriate occlusion settings are used. This system will be further investigated in an ASTM interlaboratory study to develop standardized best practices for performing in vitro dynamic thrombogenicity testing of medical devices and materials.Figure 1. A) Platelet count reduction, and B) Thrombus surface coverage on test material after 1 hour blood recirculation at room temperature. Data are shown as a mean ± standard error. n=4 for all materials, except BUNA and silicone (n=3). *p<0.05.

Experimental study on visualization of TBAB hydrate formation in confined small channels

Hydrate crystals' microscopic characteristics and agglomerating morphologies play an important role in the hydrate reaction equipment's flow assurance and heat transfer. In order to study the formation process of hydrate, experimental quartz tubes with small diameters were selected, and a fully visualized flow loop system was established. The study investigated the effects of supercooling, solution concentration, tube diameter, and flow rate on hydrate blockage time and agglomeration morphology. The results show that under the same supercooling conditions, the density of single crystal hydrate formed in 10 wt%-20 wt% TBAB (Tetra-n-butylammonium bromide) hydrate solution is low, and the crystal front appears needle-like or sword-like, which is conducive to mass and heat transfer. High concentration TBAB solution(30 wt%-40 wt%) can form dense hydrate crystals, and the tip effect was significantly weakened. For low concentration TBAB solution, the increased flow rate can accelerate the formation of new nuclei and inhibit the growth of large crystals. Grout solutions with different particle sizes can be obtained by adjusting the flow rate. It was found that the initial morphology of TBAB hydrate crystals included spherical and cylindrical shapes, and the morphological evolution process of a single hydrate crystal was similar. Finally, a microscopic physical model of the TBAB hydrate growth and aggregation process was established.

Effect of Temperature on Thrombogenicity Testing of Biomaterials in an In Vitro Dynamic Flow Loop System.

To develop and standardize a reliable in vitro dynamic thrombogenicity test protocol, the key test parameters that could impact thrombus formation need to be investigated and understood. In this study, we evaluated the effect of temperature on the thrombogenic responses (thrombus surface coverage, thrombus weight, and platelet count reduction) of various materials using an in vitro blood flow loop test system. Whole blood from live sheep and cow donors was used to assess four materials with varying thrombogenic potentials: negative-control polytetrafluoroethylene (PTFE), positive-control latex, silicone, and high-density polyethylene (HDPE). Blood, heparinized to a donor-specific concentration, was recirculated through a polyvinyl chloride tubing loop containing the test material at room temperature (22-24°C) for 1 hour, or at 37°C for 1 or 2 hours. The flow loop system could effectively differentiate a thrombogenic material (latex) from the other materials for both test temperatures and blood species ( p < 0.05). However, compared with 37°C, testing at room temperature appeared to have slightly better sensitivity in differentiating silicone (intermediate thrombogenic potential) from the relatively thromboresistant materials (PTFE and HDPE, p < 0.05). These data suggest that testing at room temperature may be a viable option for dynamic thrombogenicity assessment of biomaterials and medical devices.

Effect of fin density and fin height on flow-induced vibration behavior of finned tube arrays subjected to water cross flow

PurposeThe prediction of critical velocity at instability threshold for shell and tube heat exchangers is important to avoid failure of tubes as a result of flow-induced vibrations due to water cross flow. The flow-induced vibration in finned tube heat exchangers is affected by various parameters such as fin height, fin pitch, fin material, tube array, pitch ratio, fin type, fluid velocity etc. In this paper, an experimental investigation of fluid elastic instability in shell and tube heat exchangers is carried out by subjecting normal square finned tube arrays of pitch ratio 1.79 to water cross flow.Design/methodology/approachThe five tube arrays, namely plain array, two finned tube arrays with 3 fpi and 9 fpi fin density, and two finned tube arrays with 3 mm and 6 mm fin height are tested in the experimental test setup with water flow loop and vibration measurement system. The research objective is to evaluate the effect of fin density and fin height on the instability threshold. The critical velocity at instability threshold is determined to characterize the fluid elastic instability behavior of different tube arrays. The vortex shedding behavior of the tube arrays is also studied by determining Strouhal number corresponding to the small peaks before fluid elastic instability.FindingsThe fluid elastic instability behavior of the tube arrays was found to be the function of fin tube parameters. The experimental results indicate that an increase in fin density and fin height results in delaying the instability threshold for finned tube arrays. It is also observed that critical velocity at instability is increased for finned tube arrays compared to plain tube arrays of the same pitch ratio. The design modifications in the outer box have resulted in further reduction in the natural frequency. This enabled to reach clear instability for all the five-tube arrays.Originality/valueThe research data add the value to the present body of knowledge by knowing the effect of fin height and fin density on the fluid elastic instability threshold of normal square finned tube arrays subjected to water cross flow.

Real-time control and monitoring of drilling fluids density by fuzzy-based control system

The drilling fluids play a significant role in the oil drilling process, being its physicochemical properties the focus of the operation control. Nowadays, the control methods are usually based on manual dosing of additives by the specialized operators, where the recipes are obtained by pilot or bench tests, demanding a greater amount of raw material, increasing the operation time and costs. Control strategies of drilling fluids properties based on fuzzy logic may contribute to a high reliability and safety for human resources in drilling operations, a higher process efficiency and the mitigation of environmental impacts. This research aimed to propose and develop an automated flow loop system for fluid preparation with real-time monitoring, control, and self-correction of the drilling fluid density. The control strategy was based on fuzzy logic and used the Mamdani-type inference rules as the basis for developing a Fuzzy-PI controller. The performance of the proposed Fuzzy-PI controller was compared to a classic PI controller in disturbance-rejection and setpoint-tracking control problems. Beyond efficient control, the Fuzzy-PI controller enabled a reduction in raw material consumption of 63% for barite and 38% for water, in the disturbance-rejection control scenario; and 21% for barite and 47% for water, in the setpoint-tracking control scenario.

Experimental and numerical investigation of an innovative non-combustion impulse gas turbine for micro-scale electricity generation

Fulfilling electricity demand in a remote platform has been a great challenge for oil and gas industry. With only pressurized gas line available, the choice of technology that can be implemented is limited; one of it is impulse gas turbine. At the moment, no studies investigating the performance of a compact impulse gas turbine which utilizes pressurized gas line has been reported, hindering the wide adoption of this technology. This study is therefore conducted with the main objective to investigate the performance of small scale impulse gas turbine for electricity generation by using computational fluid dynamics (CFD) approach in tandem with experimental validation. Three-dimensional computational model for the turbine is developed. Concurrently, an experimental set-up, consisting of micro impulse gas turbine, electric generator, flow loop and control system, is prepared to validate the model prediction. The effect of several key parameters, such as working fluid, rotational speed, mass flow rate and input pressure are evaluated to obtain operating envelope of the turbine. Overall, good agreement is achieved between numerical model prediction and experimental measured value. On the effect of working fluid, the results indicate that the impulse gas turbine driven by natural gas at 69 bar produce maximum power output of 1743.81 W at lower speed of 4500 RPM while maximum power of 1084.04 W can be achieved when driven by compressed air at 19 bar at rotational speed of 7000 RPM. In addition, a complete operating envelope for the turbine operating with either compressed air or natural gas has been developed. Furthermore, the effect of distance between nozzle outlet and turbine blade has been evaluated for which the optimum distance within studied range is obtained: 49.62 mm for one with compressed air and 54.62 mm for one with natural gas. The result from this study is expected to serve as a guideline in designing micro impulse gas turbine for electricity generation especially for remote offshore platform.

An experimental and theoretical approach on real-time control and monitoring of the apparent viscosity by fuzzy-based control

This paper aimed to develop a real-time monitoring and Fuzzy-based control system for non-Newtonian fluids properties as apparent viscosity. Fuzzy logic was chosen as the control paradigm due to its low implementation complexity compared to other advanced control techniques and its outstanding feature of simplifying the transfer of knowledge from the operator/expert to the control system. To validate the proposed fuzzy control strategy, the authors developed a flow loop system for real-time monitoring and controlling the viscosity of carboxymethylcellulose's aqueous solutions. For apparent viscosity monitoring, a tubular viscometer was developed based on volumetric fluid flow and pressure drop in a defined tube length. The control strategy used in this work was based on Fuzzy Logic, with the Mamdani inference method, which was based on the possibility of transferring the linguistic information from the expert process operator's knowledge to the machine domain language, thus establishing the knowledge basis of the fuzzy controller. The proposed control strategy was validated by experimental tests in a flow loop system, regulator, and servo problems for apparent viscosity. Results showed the Fuzzy controller's satisfactory performance, which proved to be a great potential tool for online monitoring, preparation, and control of the apparent viscosity of drilling fluids.

Comparison of animal and human blood for in vitro dynamic thrombogenicity testing of biomaterials.

To determine suitable alternatives to human blood for in vitro dynamic thrombogenicity testing of biomaterials, four different animal blood sources (ovine, bovine, and porcine blood from live donors, and abattoir porcine blood) were compared to fresh human blood. To account for blood coagulability differences between individual donors and species, each blood pool was heparinized to a donor-specific concentration immediately before testing in a dynamic flow loop system. The target heparin level was established using a static thrombosis pre-test. For dynamic testing, whole blood was recirculated at room temperature for 1h at 200 ml/min through a flow loop containing a single test material. Four materials with varying thrombotic potentials were investigated: latex (positive control), polytetrafluoroethylene (PTFE) (negative control), silicone (intermediate thrombotic potential), and high-density polyethylene (HDPE) (historically thromboresistant). Thrombus weight and surface area coverage on the test materials were quantified, along with platelet count reduction in the blood. While donor-specific heparin levels varied substantially from 0.6U/ml to 7.0U/ml among the different blood sources, each source was able to differentiate between the thrombogenic latex and the thromboresistant PTFE and HDPE materials (p < 0.05). However, only donor ovine and bovine blood were sensitive enough to differentiate an increased response for the intermediate thrombotic silicone material compared to PTFE and HDPE. These results demonstrated that multiple animal blood sources (particularly donor ovine and bovine blood) may be suitable alternatives to fresh human blood for dynamic thrombogenicity testing when appropriate control materials and donor-specific anticoagulation levels are used.

Acute Stent Thrombogenicity in the Transition From DAPT to SAPT in an Ex Vivo Pig Blood Flow Loop System

Acute Stent Thrombogenicity in the Transition From DAPT to SAPT in an Ex Vivo Pig Blood Flow Loop System

Modelling of cohesive expandable LCMs for fractures with large apertures

The problem of loss circulation in geothermal wells is inherently challenging due to high temperatures, brittle rocks, and presence of abundant fractures. Because of the inherent challenges in geothermal environments, there are limitations in selecting proper lost circulation materials (LCMs). Traditional LCMs such as calcium carbonates that are commonly used in the oil and gas drilling may be softened and prone to failure during geothermal drilling. Moreover, evaluating the performance of different LCMs for geothermal drilling requires unique testing setups, which is expensive, and complicated to run due to harsh environmental conditions of geothermal systems. Herein, we present a numerical approach to simulate LCM transport and bridging through fractures in downhole conditions. By discrete element methods, each individual particle trajectory, and their interactions with the fluid and surrounding particles are incorporated into the analysis. To validate the model, we used experimental results acquired from a high-temperature flow loop system built specifically for this purpose. We took a further step in this work and considered LCM particles that are made from a shape memory polymer (SMP). These particles start expanding and adhering to each other in downhole conditions. The use of SMP is shown to be advantageous in sealing large fractures (3 mm aperture). We demonstrated how numerical modelling may supplement laboratory tests to show initiation of the bridging process, fracture plugging or even its failure. Using the proposed methodology may significantly reduce the number of experiments needed to find an effective LCM recipe, hence drillers can save time and costs by assessing different LCM systems numerically.

3D numerical and experimental modelling of multiphase flow through an annular geometry applied for cuttings transport

Accurate estimation of volume fraction and pressure gradient is considered indicating parameters of efficient cuttings transportation. It is vital, in this regard, to consider all parameters that can affect cuttings volume fraction and pressure drop during enrollment of the drilling process. The analysis was conducted based on the turbulent flow of a power-law fluid through an annular domain by employing the Finite Volume Method. In addition, dimensional relationships were developed with the Buckingham-π theorem. Before carrying out simulations, the numerical schemes were validated using actual measurements made with the flow loop system available in Texas A&M University at Qatar. The simulation results demonstrated the followings: (i) using a power-law type drilling fluid with a shear-thinning character would reduce energy consumption for an inclination greater than 45°; (ii) inclination angles from 45° to 60° would be least desirable for an effective cuttings transportation with a turbulent Ostwald-de Waele fluid.

CRT-100.51 Acute Stent Thrombogenicity in the Transition From DAPT to SAPT in an Ex Vivo Pig Blood Flow Loop System

CRT-100.51 Acute Stent Thrombogenicity in the Transition From DAPT to SAPT in an Ex Vivo Pig Blood Flow Loop System

A flow loop study on the effect of Ca2+ ions on the CO2 corrosion of 1Cr carbon steel in a CaCO3-saturated solution

ABSTRACT This paper investigates the effect of calcium on the CO2 corrosion behaviour of 1Cr carbon steel under the effect of flow. The experiments were performed in a flow loop system in 1 wt-% NaCl solution at 80°C, pH = 6.34 with initial S CaCO3 = 2 and pCO2 = 0.53 bar. The flow velocity was kept at 3 m s−1 and the system was pressurised to 3 bar. The corrosion process was monitored with linear polarisation resistance and electrochemical impedance spectroscopy (EIS). Phase analysis of the corrosion products was obtained using X-ray powder diffraction and surface morphology was characterised with scanning electron microscopy. Results show that the flow delayed the precipitation of substitutional solid solution of Fe0.31Ca0.69CO3, deferring the pseudo-passivation stage. The flow did not cause Mesa attack or localised corrosion. The protectiveness of this film was not affected by the presence of calcium and was comparable to the one of pure FeCO3.

Compliant vascular models 3D printed with the Stratasys J750: a direct characterization of model distensibility using intravascular ultrasound

PurposeThe purpose of this study is to evaluate biomechanical accuracy of 3D printed anatomical vessels using a material jetting printer (J750, Stratasys, Rehovot, Israel) by measuring distensibility via intravascular ultrasound.Materials and methodsThe test samples are 3D printed tubes to simulate arterial vessels (aorta, carotid artery, and coronary artery). Each vessel type is defined by design geometry of the vessel inner diameter and wall thickness. Vessel inner diameters are aorta = 30mm, carotid = 7mm, and coronary = 3mm. Vessel wall thickness are aorta = 3mm, carotid = 1.5mm, and coronary = 1mm. Each vessel type was printed in 3 different material options. Material options are user-selected from the J750 printer software graphical user interface as blood vessel wall anatomy elements in ‘compliant’, ‘slightly compliant’, and ‘rigid’ options. Three replicates of each vessel type were printed in each of the three selected material options, for a total of 27 models. The vessels were connected to a flow loop system where pressure was monitored via a pressure wire and cross-sectional area was measured with intravascular ultrasound (IVUS). Distensibility was calculated by comparing the % difference in cross-sectional area vs. pulse pressure to clinical literature values. Target clinical ranges for normal and diseased population distensibility are 10.3-44 % for the aorta, 5.1-10.1 % for carotid artery, and 0.5-6 % for coronary artery.ResultsAorta test vessels had the most clinically representative distensibility when printed in user-selected ‘compliant’ and ‘slightly compliant’ material. All aorta test vessels of ‘compliant’ material (n = 3) and 2 of 3 ‘slightly compliant’ vessels evaluated were within target range. Carotid vessels were most clinically represented in distensibility when printed in ‘compliant’ and ‘slightly compliant’ material. For carotid test vessels, 2 of 3 ‘compliant’ material samples and 1 of 3 ‘slightly compliant’ material samples were within target range. Coronary arteries were most clinically represented in distensibility when printed in ‘slightly compliant’ and ‘rigid’ material. For coronary test vessels, 1 of 3 ‘slightly compliant’ materials and 3 of 3 ‘rigid’ material samples fell within target range.ConclusionsThis study suggests that advancements in materials and 3D printing technology introduced with the J750 Digital Anatomy 3D Printer can enable anatomical models with clinically relevant distensibility.

Drag reduction assessment of some new copolymers of 1-hexene and maleic anhydride in light crude oil

Poly(1-hexene-co-maleic anhydride) derivatives containing various lengths of linear alkyl side chains (C11–C22) were experimentally evaluated as drag reduction agents in the turbulent flow of Iraqi crude oil using a circulating flow loop system. Good drag reduction performances were obtained. The results showed that the drag reduction has been influenced by the flow rate, concentration, chemical structure, molecular weight, and temperature. Their mechanical stabilities were also investigated using a cylindrical rotator device, and a good relationship was obtained between copolymers' drag reduction efficiency and branch length, in which longer branches significantly enhance copolymer mechanical stability.

A New Investigation on Asphaltene Removal from Crude Oil: Experimental Study in Flow–Loop System Using Maghemite Nanoparticles

Asphaltene is the heaviest organic compound in crude oils that its precipitation and deposition cause many negative effects on oil production such as an overall decrease in production rate and an increase in operating costs. Nanoparticle technology is a rapidly growing field that may supply an alternative and novel technique for heavy oil upgrading and recovery. As asphaltene depletion by nanoparticles in a system close to reality has not been studied yet, in this work the adsorption process was investigated in a flow–loop system to resemble a real process. To this end, the co-precipitation of ferric and ferrous ions method was applied to synthesis maghemite (γ-Fe2O3) nanoparticles. The synthesized maghemite nanoparticles (MNPs) were applied for the adsorption and removal of asphaltene from crude oil samples in the flow–loop system. The influence of different factors such as contact time, the dose of the nanoparticles, and flow velocity on the adsorption process was investigated. The results of the flow–loop mode experiment indicated that the rate of asphaltene adsorption onto MNPs increases with increasing oil velocity, contact time, and the dose of MNPs. Kinetic experiments were also showed that asphaltene adsorption onto MNPs follows the nonlinear Thomas model and the equilibrium could be achieved in less than 4 h.

Experimental investigation of model-based IMC control of severe slugging

Severe slugging formation has been investigated experimentally in a two-phase flow-loop composed of a downwardly inclined pipe and a vertical riser. In this study, a bifurcation diagram was made to more clearly identify which flow the current system has at each valve opening. A model was made by inputting the dimensions of the flow loop using OLGA, a multiphase flow simulation program, to compare the experimental results. The model-based control logic was constructed by estimating the transfer function utilizing the OLGA model. The estimated transfer function is used to tune the gain of the PI controller, using the method called the Internal Model Control (IMC). Through this method, PI gain can be easily obtained through only one tuning parameter. When the PI controller gain is obtained through the transfer function of the flow loop system, mitigation of severe slugging was achieved while increasing the flow rate than the case with manual choking.