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Highlights • A efficient method is proposed to calculate the ambient radius and gas composition for sonoluminescing bubbles. • The method is based on diffusive equilibrium for each species inside the bubble. • On average, only ten acoustical cycles of dynamic simulation are needed. • The validation using existing experimental data shows the robustness of the method., A sound driven air bubble can be transformed into an argon bubble emitting light pulses stably. The very foundation to investigate the sonoluminescing bubble is to accurately determine the ambient radius and gas composition in the interior. The conventional approach is to model the air-to-argon transformation process through a large number of bubble dynamics simulations to obtain the physical parameters of the ultimate argon bubble. In this paper, we propose a highly efficient method to pinpoint this information in a phase diagram. The method is based on the diffusive equilibrium for each species inside the bubble and derives the ambient radius and composition inversely. To calculate the former parameter, the bisection algorithm is employed to consecutively narrow down the searching range until the equilibria is approached. Afterward, several cycles of full dynamics simulations are conducted to refine the composition. The method is validated using published experimental data. The calculated ambient radii deviate from the test results by less than 1 μm, which falls within the margin of measurement error. The advantages of this method over the semi-analytical approach reported by Hilgenfeldt et al. [J. Fluid Mech. 365 (1998)] are also discussed. Our study provides a standard procedure to calculate the ambient radius and composition and is beneficial for the numerical simulation of sonoluminescing bubbles.

A fracturing fluid is typically a water-based fluid that requires several chemical additives that may harm the environment. When the fracturing fluid enters a formation, it causes damage and reduces the oil and gas production. After the fracturing process, a part of the used fracturing fluid returns to the surface. This can contaminate the environment for a second time. To mitigate these problems, a waterless fracturing fluid is urgently needed. This chapter discusses three new fracturing fluids that have the potential to replace water-based fluids: supercritical carbon dioxide, liquid nitrogen, and thermal fluid.

In this part, the related hydraulic parameters, including the nozzle numbers, pressure drop, flow rate, pressure loss along the tubing, and the prediction of the surface pump pressure, are presented in detail. The main contents show how to calculate the aforementioned parameters using corresponding equations and methods. According to the calculated results, the operators can determine the bottom-hole assembly, possible maximum pump pressure, and the total fracturing fluid volume, etc. At the end of this chapter, through a practical field case, the calculation procedure and results are listed in a table. Then the operators can clearly know the working steps and the materials consumed in every step.

Water jet with high pressure can successfully cut rock, steel, and even reinforced concrete. However, at lower pressure, mixing a certain amount of abrasive particles in the water jet can also greatly improve the jet ability and effectively cut materials. High-pressure water jet blended with abrasives is known as an abrasive jet.

This chapter investigates the mechanisms of abrasive water jet (AWJ) perforation, and the results of laboratory experiments and field cases on abrasive AWJ perforation are presented. AWJ perforation is a two-stage process: the ductile casing erosion stage and the brittle rock penetration stage. Each stage follows different failure mechanisms. Experiments were conducted to reveal the effect of pressure, flow rate, abrasive material, particle size, abrasive concentration, ambient pressure, rock material, exposure time, etc., on penetration performance. The conclusions derived from the laboratory experiments were supported by field tests. Further simulation experiments of AWJ perforation are illustrated in the third section.

Understanding the characteristics of a flow field in a hydra-jet hole is crucial to explain why hydra-jets can realize pinpoint fracturing without using a mechanical packer. This chapter reports a numerical simulation and experimental study on flow fields in a hydra-jet hole, involving the modeling, experimental setup and scheme, and results. From laboratory experiments and numerical simulation data, five key factors—confining pressure, nozzle pressure drop, nozzle distance, inlet ratio, and perforation tunnel depth—were utilized to preliminarily calculate the law of pressure distribution of a perforation tunnel and the jetting boost pressure. The results indicated that the nozzle pressure drop and entry ratio significantly affect the pressure distribution of the perforation tunnel and the jetting boost pressure and that the nozzle pressure drop is linearly related to the jetting boost pressure.

The coiled tubing (CT) has many applications in the petroleum industry, which include drilling (CT drilling), cementing, wellbore cleanout, acidizing, and hydraulic fracturing. In contrast, the excessive friction pressure loss, due to the relatively small tubing diameter and tubing curvature (which is believed to cause secondary flow) of CT, often limits the maximum obtainable fluid injection rates. Therefore it is of practical importance to investigate the flow regularity and friction properties in CT. Professor Shah and his research team at the Well Construction Technology Center of the University of Oklahoma have conducted numerous theoretical and experimental studies regarding CT and have reported great achievements. This chapter primarily introduces the flow analysis of fluids in the helical segment of CT and friction calculations for Newtonian and non-Newtonian fluid flows.

Jetting hole geometry parameters definitely influence the fracture initiation and propagation in materials. This chapter introduces the numerical simulation and true triaxial fracturing experiments on hydra-jet fracture initiation and propagation. The Rock Fracturing Process Analysis software was used to calculate the fracture crack pressure and propagation. The investigated key parameters included perforation diameter, perforation depth, and the angle between perforation axis and the maximum horizontal stress. The results showed that the initiation pressure decreased as both perforation depth and diameter rose. The initiation pressure increased with increase in the angle. To quantify the complex fracture geometry, the fractal theory was employed and the fractal dimension was calculated.

As the critical components of this technology, the bottom-hole assembly, including its structure and the material, is very important to guarantee a successful hydra-jet multi-stage fracturing operation. This chapter presents the detailed structure and function of each part of the tool. First, the overall structure and the corresponding function are described in general. Then, the detailed structure of the jet sub and the slide sleeve inside is illustrated considering the possible risks in practical operations, like the pin's strength, sleeve's surface smoothness, and the jet sub or sleeve shoulder wear that results from proppant flowing, etc. Third, as the most important part of the technology, the nozzle inner structure and material are analyzed to get an effective jet for penetrating the casing and formation. A nozzle made of ceramics with a comparatively simple inner structure is adopted. Finally, the accessary parts, including the centralizer and one-way valve, guide, etc. are described briefly.