Early gas kick detection in vertical wells via transient multiphase flow modelling: A review

Steam injection and thermal recovery of oil from the reservoir are increasing day by day. However, the recovery of the heat remained stored in the steam-flooded oil reservoir is nor in practice nei...

The numerical simulation and wellbore modelling of steam injection and stored heat recovery from light oil reservoir

Two-phase flow-based numerical investigation of the temperature maps of sodium-cooled exhaust valves in a turbocharged engine

Multiphase throttling characteristic analysis and structure optimization design of throttling valve in managed pressure drilling

In order to evaluate the behavior of a high power pulsed underwater electrical discharge, and especially characterize the pressure generated by such a discharge, we implemented several optical diagnostics. We first observed directly the expansion of the plasma produced by the dielectric breakdown of the water between the electrodes and the resulting gaseous pulsating bubble. This observation led to an estimate of the pressure inside the bubble with respect to time. We then visualized the propagation of the pressure wave generated by the discharge with shadowgraph and Schlieren setup. The obtained velocity was then used to evaluate the theoretical maximum pressure at the pressure front. Finally, we measured the velocity induced by the pressure wave on a thin aluminum disk with a heterodyne velocimeter and used numerical simulation to obtain a temporal form of pressure. These methods and results can be used to develop and assess performances of processes using underwater electrical discharges to generate pressure waves such as electrohydraulic forming.

/pdf/optical-diagnostics-for-high-power-pulsed-underwater-4onqei3x7v.pdf

Optical diagnostics for high power pulsed underwater electrical discharge characterization

Temperature prediction of two phase flow in wellbore using modified heat transfer model: An experimental analysis

Similarity evaluation of stratum anti-drilling ability and a new method of drill bit selection

Shale oil and gas reservoirs, as well as compact oil and gas reservoirs, are important oil exploration resources. However, their tight lithology and extremely low permeability and porosity hinder extraction. Production stimulation measures, such as reservoir fracturing transformation, are needed to increase production by low-permeability oil and gas reservoirs. This study explored a new type of fracturing technology, namely, pulsed-plasma rock fracturing, to increase rock fracturing efficiency and recovery. First, a model of stress distribution on the sidewalls of open holes was established. Then, a fracturing experiment was conducted on polymethyl methacrylate (PMMA). Morphological features were analyzed on the basis of the visual characteristics of PMMA, and the influential factors of fracture breakdown were summarized. Meanwhile, the stress-changing rule was analyzed by simulating pulsed-plasma shock-wave rock fracturing with LS-DYNA. Results show that pulsed-plasma fracturing can generate valid cracks with actiniform and wave-form features. High discharge voltages and loads on rocks associate with long crack lengths. In the simulation, applies load strengths form 9 MPa to 30 MPa, and the crack lengths increase from 16 mm to 67.5 mm. At the same time, the width and number of fractures show an increasing trend, and radioactivity and multi-branched cracks inside the rocks become increasingly complex. This study provides a practical and reliable reference for the technology of pulsed-plasma rock fracturing.

/pdf/visualization-experiment-and-numerical-simulation-of-cracks-5frz3ukyvt.pdf

Visualization Experiment and Numerical Simulation of Cracks Caused by Pulsed- Plasma Rock Fracturing

Gas bubble formation behavior in the wellbore has influence on wellbore temperature and pressure by varying bubble movement characteristics. For now, most researches on gas bubble migration...

Research on gas bubble formation using CFD during gas kick

Cuttings are likely to accumulate and eventually form a cuttings bed in the highly-deviated section, which usually lead to high friction and torque, slower rate of penetration, pipe stuck and other...

Zhaokai Hou

Papers

Temperature prediction of two phase flow in wellbore using modified heat transfer model: An experimental analysis

Similarity evaluation of stratum anti-drilling ability and a new method of drill bit selection

Visualization Experiment and Numerical Simulation of Cracks Caused by Pulsed- Plasma Rock Fracturing

Research on gas bubble formation using CFD during gas kick

Prediction of Cuttings Transport Behavior under Drill String Rotation Conditions in High-Inclination Section