Radial Jet Research Articles

Sandstone breaking performances and mechanisms of swirling abrasive waterjet during radial jet drilling process

Radial jet drilling (RJD) is one of the emerging hydrocarbon drilling technologies. And, the swirling abrasive waterjet (SAWJ) is expected to drill larger diameter laterals during RJD. Here, the performances and mechanisms of SAWJ breaking sandstone were studied by laboratory experiments. Results showed that the SAWJ could drill a smooth (surface roughness was 0.043 mm) & large (diameter was in 52.0–73.0 mm) circular hole on sandstone. The hole depth/volume increased as the jetting pressure, abrasive mass concentration and exposure time increased. Conversely, they decreased as the standoff distance increased. The optimal parameter combination under our experimental conditions was 30 MPa, 0 mm, 12% and 1 min. The SAWJ sandstone breaking mechanism were the erosion of cements, the integrally peeled off and broken of crystal grain. Failure mode of sandstone was mainly the tensile fracture. The key findings will provide guidance for the application of SAWJ in RJD technology.

Optimization of Radial Jet drilling for hard formations present in deep geothermal wells

Creating controllable fractures in geothermal wells with deep crystal structures is challenging due to rock strength. Radial Jet Drilling (RJD), which creates micro holes through rock, could stimulate these wells. However, it is challenging to implement RJD when drilling hard magmatic formations that are difficult to jet. Several factors influence RJD's effectiveness, including the jetting bit design, fluid properties, circulation rate, injection pressure, stress state in the formation, borehole pressure, and temperature. These factors determine RJD's performance parameters, such as jet stagnation pressure, jet hydraulic power, and maximum lateral hole length. This study aims to develop a generalized model for optimizing RJD's application in geothermal wells with hard formations. A unique feature of the study is the coupling of a hydraulic model with jetting criteria (threshold conditions) developed for evaluating jet-rock interactions under high-pressure conditions.This study introduces an advanced hydraulic model for RJD application, distinct from classical models that rely on field measurements and typically analyze only horizontally oriented nozzles. Our model encompasses a broader scope of operational and design parameters, facilitating the optimization of RJD in challenging geothermal environments without necessitating direct field data. Key performance metrics such as jet stagnation pressure, jet hydraulic power, and maximum lateral hole length are evaluated, emphasizing the critical role of each in overcoming the inherent challenges of hard rock formations, which require stagnation pressure of more than 100 MPa and jet hydraulic power of more than 5.2 KW. The findings reveal that achieving these conditions requires carefully balancing injection pressure, fluid flow rate, and equipment capabilities. Notably, the model underscores the necessity for robust equipment capable of high-pressure operations, including flexible tubing, compact downhole pressure intensifiers, and more advanced inclination and azimuth detection systems for lateral hole trajectory measurement and control.According to the new model, the RJD technique can be optimized by varying the densities of flexible tubes, the inclination angles of the lateral hole, and the number of back-jetting (BJ) nozzles. Results demonstrate that using an aluminum tube or adjusting the lateral hole to an inclination of 74° can enhance the maximum lateral hole length (MHL) by up to four times for the baseline case. Furthermore, increasing BJ nozzles from four to six can lead to an eightfold improvement in the MHL for the baseline scenario. Overall, the study enhances our understanding of RJD's potential in geothermal well stimulation. It offers a comprehensive framework for effectively implementing it in hard rock settings, creating a scenario for more efficient and economically viable geothermal energy production.

Numerical Simulation of Vertical Well Depressurization with Different Deployments of Radial Laterals in Class 1-Type Hydrate Reservoir

Gas production efficiency is a key indicator in the commercial development of natural gas hydrates (NGHs). Based on the data from the first natural gas hydrate field test production in the Shenhu Sea area of China, the gas production capability of Class 1-type hydrate reservoirs was numerically evaluated by vertical well depressurization with different deployment schemes for radial laterals. The results showed that the radial laterals can effectively improve production efficiency and that the radial laterals deployed at the three-phase layer (TPL) have the best production performance. Compared with the single vertical well production, the completion length of the radial laterals is 150 m with a radius of 0.05 m, and the production pressure difference is set to 6 MPa. The cumulative gas production Vg reaches up to 594.10 × 104 ST m3, increased by about 208.53% after 360 days of production, which provides a reference for the development of natural gas hydrates with radial jet drilling (RJD) technology.

Flow characteristics in a semi-confined circular-pipe impinging jet

The impinging jet is a complex heat and mass transfer technique that involves several process variables, such as the jet Reynolds number, impingement distance, and jet configuration. In this study, the flow characteristics of a semi-confined circular-pipe impinging jet over different Reynolds numbers and impingement distances were experimentally investigated using a two-dimensional particle image velocimetry technique. The confinement was achieved by positioning a plate parallel to the impinging plate at the nozzle exit. The time-averaged velocity field exhibited a recirculation structure that gradually shifted downstream with increasing Reynolds numbers or impingement distances. Notably, at H/d = 2, this downstream shift of the structure was accompanied by an increase in the vortex intensity. Moreover, the confined plate induced alterations in the overall flow pattern within the confined region, significantly reducing the wall jet decay rate compared with both unconfined and confined radial wall jets for H/d ≥ 3. Conversely, the confinement did not affect the expansion of the wall jet. Unlike the free (unconfined) impinging jets, the semi-confined circular-pipe impinging jet did not exhibit self-similar behavior in the conventional outer-scaled coordinates, particularly concerning the turbulence intensity and Reynolds shear stress. Finally, self-similarity in the time-averaged velocity and various turbulence parameters was achieved using the parameter scale proposed in this study, thereby obtaining the corresponding scaling laws in the wall jet region. Our study results can deepen the current understanding of the flow characteristics of semi-confined circular-pipe impinging jets and are significant for optimizing the performance and efficiency of compact electronic packaging equipment.

Experimental Study of Different Radial Jet Drilling Parameters and Operation Regimes for Effective Well Stimulation

Experimental Study of Different Radial Jet Drilling Parameters and Operation Regimes for Effective Well Stimulation

LES study of the precessing vortex core mitigation by radial injection in a Francis turbine air model

This work is devoted to a numerical study of the precessing vortex core (PVC) mitigation in a Francis turbine air model. The approach utilized to suppress the PVC, injection of radial jets, was based on influencing flow zones that are most susceptible to control. The analysis of the time-averaged velocity fields revealed extending of a recirculation zone. The time-averaged pressure pulsations in the flow decreased significantly, that indicates a mitigation of the PVC dynamics. Spectra of the azimuthally decomposed pressure pulsations signal demonstrated a suppression of the m = 1 mode by 25% and m = 2 by 40%, however, it does not coincide with the control efficiency in experimental work of I. Litvinov et al. In further investigations it is planned to vary the spatial orientation of the injection jets in order to achieve more effective PVC suppression.

Active Control of the Vortex Induced Pressure Fluctuations in a Hydro Turbine Model via Axial and Radial Jets at the Crown Tip

Active Control of the Vortex Induced Pressure Fluctuations in a Hydro Turbine Model via Axial and Radial Jets at the Crown Tip

The Structure and Stability of Premixed CH4, H2, and NH3/H2 Flames in an Axially Staged Can Combustor

Abstract An experimental investigation of flame structure, stability, and emissions performance was conducted in a two-stage lab-scale generic combustor design operated with CH4, H2, and NH3/H2 fuel blends. The main flame zone features a premixed bluff body stabilized flame, with a secondary flame zone initiated downstream by injecting premixed air and fuel using two opposing radial jets. The total power and air flowrate are kept constant between the different fueling cases, while the air split between stages and equivalence ratios are varied to explore conditions relevant to gas turbine operation. Given the relative novelty of the configuration, special emphasis is given to analyzing the structure of the opposing jet flames in the secondary stage. In contrast to previous literature on reacting jets in cross flow, these interact significantly due to their proximity, leading to a merged flame zone at the impingement location in the center of the combustion chamber, and some flame propagation upstream of the jet location. As the jet-to-crossflow momentum ratio increases, the merged flame zone changes shape, reaching close to the walls for the methane cases but remaining very compact when operating with almost pure hydrogen. For the hydrogen flames, diverting more air to the second stage allows higher total thermal power conditions to be reached, while avoiding flashback, and eliminates thermoacoustic instabilities. For ammonia-hydrogen flames, air is diverted to the second stage, while a constant fuel flow is sent to the primary stage, resulting in some locally rich conditions in the primary flame. A local minima in terms of NOX occurs when the primary flame is operated at an equivalence ratio of 1.15. Analysis of the flame structure suggests that this state corresponds to almost complete combustion or pyrolysis of NH3 in the main flame, with the remaining hydrogen burned in an inverse diffusion flame in the secondary zone.

Experimental study of the Reynolds stress distribution and its self-similarity in a semi-confined impinging jet

This paper investigates the Reynolds stress distribution and its self-similarity of a semi-confined impinging jet using the two-dimensional particle image velocimetry (2D-PIV) technology. The confinement is achieved by placing a plate parallel to the impinging plate at the nozzle exit. Nine sets of measurements are conducted at three impingement distances (4, 5, and 6 times the nozzle diameter) and three Reynolds numbers (5084, 8179, and 13,926). The spatial distribution and the self-similarity of Reynolds stresses are obtained. The results indicate that high turbulence occurs mainly in the free jet shear layer and the wall jet shear layer. The variation of Reynolds stresses with impingement distances and Reynolds numbers are determined. The Reynolds stresses in the radial wall jet region do not exhibit self-similarity in the outer-scaled coordinates. Scaling parameters based on Reynolds stresses are proposed, and the Reynolds stress velocity scales decay by a power-law function in the self-similar region, while the Reynolds stress length scales increase linearly. The Reynolds stresses in the radial wall jet region show extremely strong self-similarity using the Reynolds stress scaling parameters normalization. Finally, the corresponding scaling laws for Reynolds stresses are obtained.

Proof of Concept in a Full-Scale Field Test for the Novel Micro-Turbine Drilling Technology from a Cased Borehole in Granite Rock

Summary Exploration risks of geothermal projects are high, as required economic production rates are often not achieved. Stimulation methods from the oil and gas industry, such as radial jet drilling (RJD), which can be used to cost-effectively create flow paths around a main borehole, are usually not applicable in geothermal applications due to especially hard reservoir formations. Because of that, a novel technology called micro-turbine drilling (MTD®) has been developed, which allows for the drilling of micro-sidetracks from cased boreholes even into very hard reservoir rock. The approach is based on the principles of the RJD operation. However, instead of a jetting nozzle, a microdrilling turbine is used to drive a bit that mechanically drills rock. This study presents the results of the proof of concept for MTD, which was conducted in the BedrettoLab in Switzerland at a depth of up to 1,053 ft (321 m) in granite rock.

A numerical simulation of high-Reynolds-number opposed impinging wall water jets in a limited field

In the impinging region of opposing jets, strong mixing and significant energy dissipation are observed, but the mixing parameters invariably change with the opposed impinging strength (OIS). In this paper, the ratio of the turbulent kinetic energy (TKE) intensity at the theoretical impinging point to the nozzle exit is defined as the opposed impinging strength. To examine the mixing properties of opposed impinging jets (OIJs) in a limited field under various OIS, a renormalization group k-ε turbulence model is employed to calculate three-dimensional OIJs under various OIS. The nozzle exit diameter is set to 0.6 m, and the inlet velocity is between 0.08 and 8 m/s, so the simulations are performed at Re between 4.8 × 104 and 4.8 × 106. This work focuses on the radial and vertical jets produced after impinging as well as the distribution of the TKE, flow field, and vortices. A thorough investigation reveals that although the OIS of the jets is primarily determined by the degree of jet development, it increases with the Reynolds number. A low OIS results in less mixing in the surrounding water and relatively unconstrained jet generation; however, it also results in limited energy extraction from the fluid. Once the OIS is high, there is more mixing in the surrounding water, and more energy is also lost during impinging. The distribution of vortices in the vortex field is not only influenced by the OIS but is also very closely related to the scale of the limited mixing field.

Particle Image Velocimetry (PIV) measurements of USP Apparatus 1 hydrodynamics with 500 mL fill volume

Changes to hydrodynamics arising from changes within dissolution testing systems, such as the fill volume level, can potentially cause variability in dissolution results. However, the literature on hydrodynamics in Apparatus 1 is quite limited and little information is available for vessels with different liquid volumes. Here, velocities in a USP Apparatus 1 vessel with a liquid fill volume of 500 mL, a common alternative to 900 mL, were experimentally measured using 2D-2C Particle Image Velocimetry (PIV) for different basket rotational speeds. Tangential velocities dominated the flow field, while axial and radial velocities were much lower and varied with location. The velocities distribution increased proportionately with the basket rotational speed almost everywhere in the vessel excepting for underneath the basket. A nearly horizontal radial liquid jet was found to originate close to the basket upper edge. Comparison of these results with those previously reported with 900-mL liquid volume (Sirasitthichoke et al., Intern. J. Pharmaceutics:X; 3 (2021) 100078) showed that the flow rate through the baskets was similar in both systems, implying that, at least initially, the amount of drug in solution would increase linearly with time. In other words, the flow rate through the baskets would be independent of the liquid volume. Velocity profiles were also found to be similar, except in the region above the basket, which was affected by the radial jet with an orientation significantly different between the 500-mL and the 900-mL systems.

An innovative experimental apparatus for the analysis of natural gas hydrate cavitation erosion process using laser-induced cavitation.

Natural gas hydrates (NGHs) are an emerging source of clean energy distributed in the pores of soil sediments in deep seabed and permafrost zones with abundant reserves. Cavitation contains enormous energy, thus allowing radial cavitation jets to improve drilling and production rates of NGHs. This paper presents an experimental apparatus that was developed to synthesize NGHs and generate cavitation bubbles by laser for the analysis of the erosion rules of NGHs by cavitation in a reservoir environment. The apparatus consists of a working fluid injection and pressure control system, a temperature control and circulation system, a laser-induced cavitation system, a visual reaction vessel, and a data acquisition and measurement system. The laser-induced cavitation erosion on NGHs and multi-bubble interaction experiments can be conducted over temperatures and pressures in the range of 0-20 °C and 0-12 MPa, respectively, in a visualized reaction vessel. Hydrophones and high-speed photography were utilized for monitoring and analyzing the erosion process within the visualized reaction vessel. In addition, bubble groups of different components in various environments can also be tested in this apparatus to obtain the interaction characteristics under different conditions. This paper discusses the basic structure and principle of the apparatus and conducts a series of experiments to verify the effect of cavitation erosion on hydrate and the feasibility of using cavitation to increase production in hydrate exploitation.

Radial Jet Reattachment impingement drying of corn tortillas

This study evaluates the heat and mass transfer behavior of innovative Radial Jet Reattachment (RJR) nozzles to analyze the texture and color characteristics of crispy tostadas. A new experimental method for measuring steady-state evaporation is proposed and validated to determine the averaged coefficients of convective heat and mass transfer for different drying conditions and geometrical parameters of RJR nozzles. The experiment is designed using a 24 factorial design approach. The factors that are considered include nozzle exit angle (10° and 45°), tortillas thicknesses (1.03 mm and 1.66 mm), air drying temperature (200 °C and 250 °C) and air mass flow rate (17.0 m3/h and 27.2 m3/h). The findings indicate that for the impingement drying of tortillas, it is crucial to consider convection and diffusion as the primary factors in selecting the appropriate operating conditions. Moreover, the study concludes that the RJR nozzle with a 45° exit angle exhibits a higher drying rate than the RJR nozzle with a 10° exit angle. The study found that neither the type of nozzle nor the air drying conditions had a significant impact (α ≤ 0.05) on the texture and color of the final product. The utilization of RJR nozzles for impinging drying of tortillas is a promising and robust process that enables the production of crispy tostadas without negatively impacting the quality characteristics of the final product.

Complexity analysis of multiscale flow field of dynamic impinging stream based on chaos theory and Stockwell transform

The complexity analysis of the flow field is of great significance for studying the flow mechanism and strengthening the mixing. The multiscale flow field of dynamic impinging stream reactors is studied by experimental and theoretical methods. The chaotic characteristic parameters (correlation dimension, K entropy, the largest Lyapunov exponent) are investigated under different nozzle spacing L, different outlet velocity difference vd, and different outlet average velocity vp. The flow mechanism of dynamic impinging stream mesoscale flow field is revealed. The results show that the flow field of dynamic impinging stream reactor presents chaotic characteristics, and the chaotic characteristic parameters firstly increases and then decreases with the increase of nozzle spacing L. With the increase of outlet velocity difference and average outlet velocity, the chaotic characteristic parameters show an increasing trend. The time-frequency analysis of the microscale flow field in the dynamic impinging stream reactor is carried by Stockwell transform to obtain the energy evolution, the flow mechanism is further revealed. With the increase of outlet velocity difference and average outlet velocity, the energy of flow field gradually accumulates to the low frequency region, and the flow field energy enlarges. The radial flow field of dynamic impinging stream impact center is divided into radial jet region and radial vortex region by the energy characteristic. According to the analysis of chaotic characteristics and energy evolution of dynamic impinging stream, the optimal working condition is that nozzle spacing L=4d, outlet velocity difference is 1m/s, and outlet average velocity is 1.7m/s.

Flow Pattern and Mixing Performance of a Dynamic Impinging Stream Reactor

AbstractThe mixing process of a dynamic impinging stream reactor was measured by planar laser induced fluorescence. The fluid flow pattern and mixing characteristics were studied under different conditions. The flow field was divided into the following regions by flow pattern: free jet region, impingement region, radial jet region, and radial vortex region. The mixing characteristics were analyzed under different operational conditions. The mixing time first decreased and then increased with increasing nozzle spacing. The mixing time decreased with increasing outlet velocity difference and outlet average velocity, and the optimal working conditions were nozzle spacing L = 4d, where d is nozzle diameter, outlet velocity difference vd = 1 m s−1, and outlet average velocity vp = 1.7 m s−1.

A New Modeling Method for Spray Angle Prediction of Liquid–Liquid Pintle Injector

Accurate predictions of the spray angle play a significant role in the design and operation of the pintle injectors. However, existing prediction models are often based on idealized assumptions and expressed as the functions of the jet-to-film momentum ratio corrected by different coefficients, which result in the weak generalization abilities of these models. In the present study, a prediction model for the spray angle of the liquid–liquid pintle injector was established and verified. The initial interactions between the radial jet column and the axial jet film were considered, and the deflected trajectory of the transverse jet column was derived theoretically; then, the spray angle of the pintle injector was thus obtained. Specially designed experiments were carried out, and the spray angles were extracted by using high-speed photography. The comparisons between the experimental and the predicted results clearly exhibit the limitations of the traditional models that are based on the momentum ratio only, and they prove the accuracy of our new model.

Study on Stimulation Mechanism and Parameter Optimization of Radial Water Jet Drilling Technique in Low Physical Property Sections of Petroleum Reservoirs

Radial drilling-fracturing is an innovative fracturing technology that achieves superior stimulation effects. In order to study the permeability-increasing effect and main influencing factors of radial water jet drilling in the low physical section, this paper uses a fracking electrical simulation experiment, based on the principle of hydropower similarity, to simulate the reservoir conditions and well pattern in the low physical section and, at the same time, establishes the radial fracturing model of the low physical section reservoir, simulates the saturation field, pressure field, and production-change law under different drilling parameters, and studies different influencing factors. The experimental results show that when the number of drilling holes exceeds two, the effect of increasing production gradually becomes less significant as the number of drilling holes increases; Within the range of the angle between the two boreholes, the forward distance of the oil–water displacement front is the farthest and the sweep is relatively uniform. On both sides of the included angle, the forward distance of the oil–water displacement front edge is smaller than the forward distance of the displacement within the included angle range and it is clearly inclined towards the radial drilling with uneven spread. Radial drilling has an impact on the seepage field, causing changes in its streamline. The pressure inside the borehole is lower than the surrounding formation pressure and most of the flow lines change direction near the borehole location, causing deflection. As the borehole length increases, the oil-well production also increases. The optimal effect is for the borehole length to be 100 m. This study provides a reference for the on-site application of radial fracturing in low physical properties sections.

Cavitation damage inducing the improvement of jet breaking efficiency during hydrate drilling

Natural gas hydrate (NGH) is an environment-friendly energy source with great development potential. Cavitation jet is a promising technology to improve drilling rate for both the solid fluidization method and integrated method of radial jet drilling and completion. This work aims at the improvement of jet breaking efficiency and thereby the NGH production. Firstly, gas hydrate-bearing sediments (GHBS) samples are synthesized in laboratory, and the erosion tests are conducted with the conical jet (CJ) and convergent-divergent cavitation jet (CDCJ). Then, the distribution characteristics of velocity, cavitation and pressure are simulated in CJ and CDCJ flows. Finally, the collapse behaviours of a single cavitation bubble near a hydrate surface are investigated to preliminarily identify the responsible cavitation damage mechanisms. Results indicate that the CDCJ shows stronger reaming effect and performance of hole depth extension. Under the present hydraulic conditions, the CDCJ increases the erosion pit volume by 30% and saves the specific energy by 23%. The cavitation damage along the hydrate wall can be produced by the combination of impulse pressure and thermal damage. This study reveals the effect of cavitation damage on GHBS and presents preliminary insights into the potential application of cavitation jets in NGH production.

Study on Energy Conversion Efficiency and Structure Optimization of the Multorifices Nozzle for Radial Jet Drilling

Underground gas storage (UGS) is a crucial method for mitigating seasonal fluctuations in natural gas consumption. However, in China, UGS is primarily achieved through the conversion of abandoned gas reservoirs with limited storage capacity. Radial jet drilling (RJD) is an effective technology for the secondary development of depleted reservoirs. The multiorifice nozzle is a critical component that can efficiently break rock and create radial holes to increase gas production. In this study, we investigate the impact of nozzle structure on energy conversion efficiency through numerical simulations and experiments. Additionally, we design a swirling multiorifice nozzle and verify its effectiveness in field applications. Our findings indicate that the nozzle pressure drop and vorticity are primarily generated at the acute angle of the orifices. The number of forward orifices is directly proportional to energy loss, while the discharge coefficient and hydraulic performance initially increase and then decrease. Swirling multiorifice nozzle have fewer backward orifices, so they have less energy loss and a larger discharge coefficient. It has achieved better rock-breaking results in field applications. In conclusion, this study provides theoretical guidance and technical support for the secondary development of gas storage.