Chen Chen

The University of Manchester · School of Materials

Depressurization combined with heat (mainly hot water) injection is an important technique for exploiting natural gas hydrate (NGH). To overcome the problems of pore water intrusion and hot water energy loss in the technique, this paper employs a method of setting sealing boundaries in permeable overburden and underburden to exploit NGH. The influe...

The fracture network’s stimulation of China’s second hydrate trial production area was investigated. First, the stimulation potential of the fracture network and the influence of well arrangement on hydrate development were explored. Second, the fracture distributions’ influence on development behavior was investigated. Results showed that the frac...

Natural gas hydrates, as a clean and green energy source, are widely distributed in extreme environments near the seabed. They release relatively low concentrations of carbon dioxide gas dissolved in water. Therefore, precise detection of changes in the concentration of dissolved carbon dioxide gas in water is an effective means to accurately chara...

This paper proposes a model for determining deformation in the upper 50% of an ice borehole. Based on this model, the borehole deformation of DK-1 at Dome A was studied. Furthermore, the effects of surface temperature, temperature gradient, surface snow density, and drilling fluid density on borehole deformation were investigated. The results showe...

Fine-grained natural gas hydrate (NGH) reservoirs are widely distributed across the world and bear more than 90% of global NGH. However, it is difficult to exploit this kind of NGH reservoir economically and environmentally using conventional methods. Water-jet cutting is an efficient and environmentally friendly technique for mining such hydrate r...

Methane, as an important component of oil-gas, provides valuable data reference for determining the origin of oil-gas through its concentration variations, which is essential for identifying new oil-gas reservoirs. However, the concentration of methane undergoes continuous changes during drilling processes, with a range of variation reaching up to...

The exploitation of challenging oceanic gas hydrate reservoirs with low permeability and permeable boundary layers faces the challenges of methane leakage and low production. Considering this aspect, a novel five-spot injection–production system combined with hydraulic fracturing was proposed. In particular, the potential of this development mode,...

Gas recovery from hydrate-bearing sediments attracts worldwide interest due to the huge reserves of methane there, recognized as a promising future energy resource. However, the mechanical behavior of hydrate-bearing sediment is rarely studied. In this study, the drained shear test on hydrate-bearing sand with different hydrate saturation was simul...

Hydraulic fracturing is considered a promising stimulation technology for low-permeability hydrate reservoirs. To date, only a few studies have focused on hydraulic fracturing in hydrate-bearing sediments. However, the numerous factors that affect fracture initiation and propagation are not clearly understood, and the fracability of non-diagenetic...

In this study, the influence of acidification and the compound effect of acid and pressure on the multi-scale pore structure distribution characteristics of oil shale were investigated. The pore morphology and elemental distribution characteristics of the oil shale were obtained by scanning electron microscopy–energy-dispersive spectroscopy, and th...

The exploitation of challenging hydrate (CH)¹ reservoirs without impermeable boundaries (CH–B)² faces a series of challenges such as poor production, gas escape to the boundary layers, and possible ocean and air pollution. This paper presents a new methodology for the exploitation of CH–B with a five-spot diamond horizontal well system (FSD)³. In p...

In this study, the productivity of depressurisation combined with thermal stimulation using the injection-production mode (D + Ti) in a CH-Bk reservoir (a natural gas hydrate reservoir exhibiting a low permeability and lack of impermeable boundaries) was explored. By exploring the influence of production parameters and well patterns on hydrate deve...

Branching structure is often used as a supporting structure of the grid shell due to its geometrical and force-transferring features, and the rationality of its shape is very important. The “physical” and “numerical” hanging models can be used for the joint form-finding of the branching structure and free-form grid shell. However, slack elements ma...

In this study, the stimulation effect of the fracture network on hydrate development by depressurization combined with hot water injection (D + Tiw) utilizing injection-production well patterns was explored and the key fracture properties’ influences on stimulation effect were investigated. The results showed that D + Tiw significantly improved hyd...

Acidification as an effective means of reservoir modification, it is necessary to investigate the influence of acid on the mechanical properties and fracture initiation and extension of oil shale. We conducted acidification test using hydrochloric acid, and performed numerical simulation and multi-factor analysis for hydraulic fracturing. Results s...

The stimulation of hydraulic fracturing on a combination of depressurization with thermal stimulation for natural gas hydrate (NGH) exploitation from challenging ocean hydrate reservoirs is investigated in this study. The influence of fracture permeability, well spacing on hydrate exploitation, and the enhancement effect of hydraulic fracturing on...

In natural gas hydrates’ (NGHs) exploration, the carbon dioxide isotope abundance of dissolved gas in seawater should be accurately measured. However, in practical application, many challenges, such as the interference by organic compounds or the influence of the scatter distribution of NGHs, should be solved. In this study, a prototype of a midinf...

System-level integration of a mid-infrared carbon dioxide (CO2) sensor system based on tunable laser absorption spectroscopy (TLAS) was realized for the analysis of dissolved CO2 in seawater employing an interband cascade laser (ICL) centered at 4319 nm and a multi-pass cell (MPC) with an optical path length of 29.8 m. At low measurement pressure o...

For deep-sea natural gas hydrate (NGH) exploration, the highly sensitive detection of dissolved gas in seawater near the seabed is important. A prototype of a midinfrared (MIR) carbon dioxide (CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) sensing system based on a wavelength modulation s...

For deep-sea natural gas hydrate exploration, highly sensitive detection of the dissolved gas in seawater near the seabed is significant because it requires the sensor system to be small in size, low in power consumption, and high in sensitivity. A mid-infrared sensor system was developed to detect dissolved carbon dioxide (CO2) in sea-water, while...

CuAlO 2 thin films were prepared on sapphire substrate by sol-gel method. The influences of annealing temperature, heating rates and annealing time on composition, morphology and photoelectric performance of film were investigated. The results of X-ray power diffraction, scanning electron microscope, transmissivity, and hall parameter tests showed...

The detection of dissolved gas (e.g. carbon dioxide (CO2), methane (CH4)) in seawater is important for deep-sea natural gas hydrates exploration, which requires that the sensor especially the optical structure should be of compact size and capable of operation under deep-sea environment. A compact optical structure with simple beam alignment and tr...

In order to provide the experiences and references to the researchers who are working on infrared(IR) mixed gas detection field. The proposed manuscript reviews two sections of the aforementioned field, including optical multiplexing structure and detection method. At present, the coherent light sources whose representative are quantum cascade lase...

Electrostatic actuators are being widely investigated to convert electrical energy into mechanical deformation in a broad variety of microrobotic applications. Both electrostatic gap closing and comb drive actuators require high excitation voltages for high performance operation. In the majority of applications, external bulky and heavy power suppl...

Presented in the present paper is a compact instrument developed for rapid, sensitive and continuous monitoring of trace gases in air, with results shown for carbon monoxide concentration. This instrument takes advantage of recent technology in mid-infrared quantum cascaded laser (QCL) operating at 4.8 μm and mercury cadmium telluride (HgCdTe) mid-...

A portable near-infrared (NIR) CH4 detection sensor based on a distributed feedback (DFB) laser modulated at 1.654 μm is experimentally demonstrated. Intelligent temperature controller with an accuracy of -0.07 to +0.09 °C as well as a scan and modulation module generating saw-wave and cosine-wave signals are developed to drive the DFB laser, and a...

Presented is a compact instrument developed for in situ high-stable and sensitive continuous measurement of trace gases in air, with results shown for ambient methane (CH4) concentration. This instrument takes advantage of recent technology in thermoelectrically cooled pulsed Fabry–Perot (FP) quantum cascaded (QC) laser driving in a pulse mode oper...

Design of on-board chargers for plug-in electric vehicles (PEVs) is a challenging issue due to size and weight of high-power switching converters, as charging power can be up to 19.2kW in level-2 charging scheme. This paper proposes a reduced-part single stage on-board charger topology, which is integrated to the dc/dc converter used for adjusting...

Dielectric elastomers are being used as actuators to convert electrical energy to mechanical deformation in a wide variety of potential microrobotic applications. Majority of these actuators are being excited using external bulky power supplies, which limit the functionality of the actuator. One of the major challenges towards enabling operation of...

Flapping-wing robotic insects are novel micro air vehicles (MAVs) inspired from biological insects in order to achieve a small size, high manoeuvrability and super remote ability. Such MAVs are centimetre scale flying robots with a number of applications, including exploration, environmental monitoring, rescue and reconnaissance. Due to the strict...

Presented is a compact instrument developed for in situ high-stable and sensitive continuous measurement of trace gases in air, with results shown for ambient methane (CH4) concentration accurate, real-time and in-situ. This instrument takes advantage of recent technology in thermoelectrically cooling (TEC) pulsed Fabry-Perot (FP) quantum cascaded...

Titanium doped indium oxide (TIO) thin films were deposited on glass substrate by DC sputtering with different O2/Ar gas ratios at 330 °C. The effects of sputtering on the structural, morphologic, optical and electrical characteristics of TIO thin films were investigated by XRD, Hall measurement and optical transmission spectroscopy. The deposited...

In this paper, titanium doped (2 wt. %) indium oxide (TIO) thin films deposited on quartz substrates by DC sputtering were presented. Dealt with different temperatures from 420°C to 620°C of post-annealing in vacuum for 40 minuets, the samples display different optical and electric properties. The deposited films exhibited polycrystalline in the pr...

To eliminate the great influence of temperature variation on the high-power semiconductor laser, we propose an approach using digital temperature sensor to control the temperature of the laser. Compared to the traditional analog temperature sensor RTDS, the digital temperature sensor has an advantage of high sensitivity, linearity, fast response an...

In order to meet the requirements of mid-infrared gas detection, a high-precision DSP lock-in amplifier is designed with MATLAB/Simulink and DSP. By using Target for TI C2000 toolbox which integrates Simulink with TMS320F2812, the automatic generation of C code can be achieved and the programming time can be saved enormously. An AD correction modul...

A high-precision self-adaptive proportion integral derivative (PID )control system for semiconductor laser is introduced. Output wavelength of the semiconductor laser can be drifted with the temperature changing. It affects the wavelength accuracy and the characteristics of semiconductor laser. In order to enable the semiconductor laser works stead...

In the first, show the important factors that influence the working condition and service life of the laser diode. Then, aim at the stability and reliability of the current, brought forward a dual feedback constant current driving plan based on deeply negative feedback theory and PID algorithm. Utilizing deeply negative feedback theory to strengthe...

This paper presents a microsecond, high current pulse generator to drive quantum cascade lasesrs. The driver systems consist of pulse generator; power amplifier; fast switches and constant current supply circuits. The pulse width and pulse repetition rate are varied from 1μs to 100μs and 1 kHz to 2 kHz, respectively. Pulsed peak current could achie...