Oil Pools Research Articles

Flame expansion behavior induced by a water droplet impacting on burning and stratified oil-water pool

The dynamic process of a water droplet impacting stratified oil-water and the phenomena of instantaneous flame expansion were recorded using a high-speed digital camera. The flame expansion scales (flame height and flame volume) were calculated under various conditions. Moreover, the effects of the water droplet diameter and impact height on the flame expansion scales and flame expansion duration were quantitatively analyzed. For a water droplet impacting the burning oil pool, the flame expansion is mainly caused by the steam explosion. But for the water droplet impacting the stratified oil-water, many small daughter oil droplets splash to increase the contact area between the fuel and air, which is probably the main reason for the instantaneous expansion of the flame. The flame expansion duration, height, and volume increase with the water droplet diameter and the impact height. The frequency of flame pulsation decreases gradually with the increase of the impact height. For the burning diesel oil pool, the flame volume expands about 50–135 times, while for the burning diesel layer on the water surface, the flame volume expands only 6 to 16 times.

Fire plume characteristics of annular pool fire with different cylindrical obstacles in a ship engine room

A numerical study of oil pool fire with different cylindrical obstacles in a ship engine room was carried out. The characteristics of flame height, maximal temperature rise, and centerline axial velocity of fire plume were investigated and analyzed. The results showed that the flame height of the merged flame decreases with the increased radius ratio and obstacle height, while the plume maximal temperature rise and axial velocity decreases with a larger radius ratio. Under the broken flames, the flame height only decreases with a larger radius ratio, while the plume temperature rise and axial velocity decreases with the increase of both radius ratio and obstacle height. When the obstacle is smaller, the annular flames merge above the obstacle, while the annular broken flames surround the cylindrical obstacle when the obstacle is larger. And there is a competition between flame height enhancement effect and weakening impact when the flame could merge above obstacle. The empirical models of flame height, centerline temperature rise and axial velocity of annular pool fire with different cylindrical obstacles are obtained and validated by experimental test data. These results can offer an essential reference for fire prevention design and fire science research in the ship engine room.

A facies- and sequence stratigraphy-based reservoir model for a carbonate reef complex: South Swan Hills oil pool, Alberta

We present a reservoir model for the South Swan Hills oilfield, Alberta, Canada, developed in a Devonian atoll reef, based on facies analysis and sequence stratigraphy. The analysis illustrates the complex reservoir geometries in such a reef, caused by facies variation from reef margin to reef interior and fluctuations in relative sea level. The latter resulted in cyclic deposition of facies and formation of field-scale sequence boundaries. The model is built on lithofacies analysis from high-resolution core descriptions that recorded lithologies, bioclast type and characteristics, and sedimentary structures. Core descriptions were correlated to well logs, enabling lithofacies to be mapped across the field. Lithofacies distributions permit definition of three distinct reef environments: a reef interior, a reef margin and a terminal shoal. Vertical variability is characterized using sequence stratigraphic interpretations. Two 3rd order and four 4th order sequence boundaries were identified and correlated across the reef. The analysis illustrates the complex reef geometries linked to facies variation from reef margin to reef interior and fluctuations in relative sea level. The latter resulted in cyclic deposition of facies and formation of field-scale unconformities. These and the intervening deposits represent the response to fluctuating sea level.The geological analysis was transformed into a 3-D geocellular model using a sequential indicator simulator. The simulator models lithofacies and, in turn, porosity and permeability distributions based on strong relationships between lithofacies and petrophysical properties for the three representative regions; the interior, margin and terminal shoal. The interior deposits formed forms the bulk of non-reservoir material in the centre of the reef build-up. The margin surrounded surrounds the interior and formed forms a continuous 1–2 km band of reservoir around it. Reservoir thickness is 20–30 m and primarily composed of reef flat deposits. The terminal shoal forms a reservoir body that caps the reef complex, but is disconnected from the bulk of the underlying reef by a thick layer of impermeable clay associated with a sequence boundary. The high-resolution realization displays the geometry and continuity of the reservoir and exposes demonstrates the compartmentalized and variable producibility of the atoll.

Experimental study on continuous spill fire of liquid fuel on porous bed

ABSTRACT As a traditional fossil fuel, petroleum fuel is prone to spills and fire accidents during storage, transportation, and use, which poses a great threat to the safe utilization of energy. This work aims to study the effect of porous media on the combustion characteristics of continuous spill fires. The transformer oil spill fire experiment is carried out on a porous bed with a length of 120 cm, a width of 15 cm, and a depth of 5 cm. The effects of sand diameter (0.75 mm, 1.5 mm, 3 mm, and 6 mm) and discharge rates (25 ml/min, 50 ml/min, and 75 ml/min) on the development of spill fires are analyzed. The results show that the spill fire fuel transport mechanism mainly includes gas phase diffusion caused by fuel consumption on the surface of a porous bed and liquid phase convection caused by capillary flow. Thus, three zones are formed from top to bottom: (i) the top vapor zone; (ii) the middle gas–liquid two-phase zone; and (iii) the bottom liquid phase zone. The presence of sand reduces the efficiency of the heat and mass. And it makes the spill fire stable combustion area increase compared with the smooth substrate. The stable combustion area has a positive correlation with the mass discharge rate and a negative correlation with the sand size. The stable combustion area of 1.5 mm, 3 mm, and 6 mm sand is 87.1%, 81.9%, and 77.5% of that of the 0.75 mm sand. In contrast to transformer oil pool fires and spill fires on smooth substrates, the burning rate is negatively related to the equivalent burning diameter. Meanwhile, the burning rate of spill fire on porous beds is significantly reduced compared with the first two. Based on the analysis of heat and mass transfer, a model for the burning rate of spill fire in porous media is formed and its correctness is verified. The experimental results are of great significance to the safe utilization of liquid energy.

Multiphase dolomitization mechanisms of the Cambrian upper Changping Formation, North China Platform, China

The Cambrian dolomite reservoirs of the North China Platform offer good exploration prospects, but their occurrence and the impacts of dolomitization on reservoir quality are not yet clearly understood. The study herein assesses outcrop samples in the Cambrian upper Changping Formation, Dingjiatan area, and highlights the important role of multiphase dolomitization in the formation of paleo-reservoirs of acceptable porosity, where oil pools and fields may be discovered. A combination of petrology, fluid inclusion microthermometry, isotopes, and trace element compositions has been used to explain multiphase dolomitization mechanisms and their impacts on dolomite reservoirs. Five types of dolomites are identified through outcrop observation, thin section identification via transmitted light, and cathodoluminescence. The following geochemical analyses reveal various dolomitization mechanisms. In the (pene) contemporaneous stage, microbial dolomite is commonly related to microbial metabolic activities with significant carbon isotopic depletion compared to the Cambrian seawater values. With the influence of microbial dolomitization, dolomicrite corresponds to the sabkha dolomitization mode in a low-salinity seawater environment and early-stage dolomitization. The structureless dolomite (ssD) in the early highstand systems tract (EHST), characterized by elevated 87Sr/88Sr ratios and low oxygen isotopic values, forms from stratum brine water in the shallow-middle burial stage rather than in the (pene) contemporaneous stage. In contrast, ssD in the late highstand systems tract (LHST) undergoes (pene) contemporaneous dolomitization at salinities between 6% and 28% before later pore water transformation, with the participation of atmospheric freshwater through faults and unconformities exhibiting the lowest inclusion temperature and salinity values. The medium to coarse crystalline dolomite (MCD) in the LHST and the saddle dolomite (SD) in the EHST with low REE values are atypical hydrothermal dolomites caused by a combined superposition of middle-deep burial hydrothermal fluids at temperatures >150°C and stratigraphic brines. The MCD is also influenced by terrigenous water characterized by relatively low Eu anomaly values. Finally, the mechanisms of porosity increase are investigated, and it is concluded that the pore increase caused by the (pene) contemporaneous reflux interaction and the later pore retention both lead to better ssD reservoirs in the LHST than in the EHST.

Review of Oil Pool Fire Research

Oil has a very important place in modern industry. However, the safe application of petroleum products is very important for the safety of human life and environmental safety. Therefore, many researchers have conducted extensive research on the combustion properties of petroleum products and the performance of fire extinguishing agents. This paper first describes the progress of several different influencing factors in terms of their impact on the development pattern of oil pool fires, including ambient wind, pressure, tunnel environment, and obstructions. In addition, the progress of research on risk assessment models for oil pool fires is summarized. Finally, the research progress in some new fire extinguishing materials, such as protein foam, two-fluid water mist and modified ultra-fine dry powder, is presented.

Study on fire extinguishing performance of different foam extinguishing agents in diesel pool fire

The physical properties and fire extinguishing performance in diesel fire of aqueous film-forming foam (AFFF) and protein foam (PF) were studied, and the fire extinguishing mechanism of different foams were also analyzed. The results show that 6%AFFF and 6%PF have better performance than that of 3%AFFF and 3%PF, respectively, and AFFF possess higher expansion ratio, 25% drainage time and surface tension than PF at the same concentration. The fire extinguishing test show that the extinguishing performance of foam enhanced with the increase of gas-liquid ratio firstly, and decreased subsequently. The best fire extinguishing performance were achieved when gas-liquid ratio of 6%AFFF and 6%PF were 17 and 20, and the extinguishing agent dosage were 229 ml and 260 ml, respectively. Compared with PF, the fire extinguishing time and agent dosage of AFFF are reduced by 10% and 6.15% respectively at gas-liquid ratio of 20. Besides, AFFF can form more dense, stable and high-multiple foam cover layer, endow it with better fire extinguishing performance than PF. However, PF can reduce the temperature around the oil pool more quickly, showing better cooling effect than AFFF.

Effect of Transducer Position on Droplet Coalescence

The increasing demands for fossil fuels and the current geopolitical context have driven petroleum producers to optimize production processes and reduce their carbon footprint. This study investigates the effects of ultrasounds on droplet coalescence. Using COMSOL Multiphysics, simulations were conducted to explore the influence of transducer position on droplet coalescence. The effects of ultrasounds on water droplets coalescing in oil under different flow regimes were examined, considering a 2D computational domain divided into three parts representing the transducer, oil pool, and water droplets. The results demonstrate that switching the transducer from the side to the bottom or top significantly reduces coalescence time, with the top position yielding the shortest time. Droplets exhibit motion and deformation when the transducer is placed on the bottom or top, while no noticeable motion is observed when placed on the side. This motion induces relative deformation of the resulting droplet. Moreover, as the continuous oil phase moves with a certain velocity, whether in laminar or turbulent flow, more significant deformation occurs. Overall, placing the transducer on the top consistently yields the lowest coalescence time.

Numerical model of oil, water and gas flow in oil pools

During the oil well usage its flow rate inevitably lessens. As a result the oil production enterprises must solve the most important problem of the oil extraction intensification. When solving filtration problems (there is a great set of problems; here we will deal with one of them including physical processes, difficulties and problem setting-up) ordinarily use well-known problems. However, in many cases, for example, when describing thermogas-chemica modification (TGCM) there capacity is insufficient. For example, one needs describing of more than two phases, taking into account chemical reactions and so on. We produced a program which clears this trouble. This program can model main features of the TGCM case: many-phase and non-isothermal process, non-one-dimensional flow. As a result we can better tune calculation programs for specific deposits by taking into consideration of geologic peculiarities and near-well zone defects occurred as a result of previous usage.

Wind action on whirling flame characteristics

The behavior of whirling flame above a pool fire under cross wind was studied using a small wind tunnel. Whirling flames with different heat release rates were generated by an experimental rig. Effect of different wind speeds on the whirling flame was studied by an oil pool of two different diameters. Lateral images of the whirling flame collected were analyzed. Results show that under cross flow, the whirling flame was deflected along the direction of incoming flow. With the increase in wind speed, the deflection angle increased gradually. The angle also increased with the increase in pool diameter. When the cross flow increased to a certain value, the flame stopped swirling, and changed to an irregular shape. The maximum cross wind speed of the flame that did not stop flame rotation decreased with diameter. Crosswind with lower speed would raise the temperature of the whirling flame. When the wind speed was higher than a critical value, the temperature was reduced because burning rate decreased.

Delineation of horizons and suites based on quantitative indicators of oil-field geophysical parameters

The limits of horizons IX and X and a parting suit in the productive strata are adjusted using the methods of electrical resistivity of clay and the maximal potential of sandy rocks as a case-study of Gunsehli and Bahar fields in the South-Caspian Basin. It is known that in oil-field geophysics, delineation of oil and gas bearing suites and horizons by the existing methodology uses the curves of standard electric logging. However, despite that the standard electric logging reflects apparent resistivities of all rocks across the section, it disalllows evaluating stratigraphic characteristics of rocks. Differentiation ability of the electric logging curves depends on many factors, including variation of borehole diameter, thickness and resistivity of surrounding layers, drilling mud resistivity, equipment parameters, etc. All these have their negative impact while outlining the oil and gas bearing suites and horizons using the standard electric logging. In this respect, in distinction from the existing methodology, this article suggests to correlate borehole logs using not the apparent resistivity curves but the curve of the true resistivity variation in clays with depth and the change in maximal self-potential in sandy layers. It is shown that adjsutment of outlines of lithostratigraphic units, including horizons and suites, and correlation of well sections based on the new approach applied jointly with other data for identification of oil and gas pools opens up new opportunities, which, in turn, can enhance geological efficiency of well logging.

Heat Transfer Performance of Gel Foam Layer with Nanoparticles Doping under a Radiative Heat Flux.

The risk of fire in the chemical industry's production process is fatal. Gel foam has been widely employed in petroleum storage tanks, oil pools, and other petrochemical equipment for fire extinguishing and thermal protection. Recently, nanoparticles have been doped into gel foam to enhance thermal stability and insulation. However, heat transfer behaviors of the gel foam layer containing nanoparticles are still missing. In this study, a numerical heat transfer model of a gel foam layer containing silica nanoparticles under a radiative heat flux was established. Through simulation, the changes in foam thickness and temperature distribution were analyzed. The effects of the maximum heating temperature, initial gas content, nanoparticle size, and concentration on the thermal insulation behavior of the gel foam layer were systematically studied. The results showed that the thermal stability and insulation performance of the three-phase gel foam layer decreased with the increase in the initial gas content and particle size. Increasing the nanoparticle concentration could enhance the foam's thermal stability and insulation performance. The results provide guidance for a designing gel foam with high thermal protection performance.

Fluorosilane-Modified Antireflash Sodium Bicarbonate Fire Extinguishing Agent with Advanced Hydrophobic and Oleophobic Properties

The poor antireflash performance of NaHCO3 dry powder fire extinguishing agent in class B fire is the key problem that restricts its application in large oil fires. In this work, the NaHCO3 was surface modified by sol–gel method to introduce functional fluorosilane structure (named FSi-NaHCO3) and enhance the hydrophobic and oleophobic properties. The water contact angle (WCA) and oil contact angle (OCA) of FSi-NaHCO35 are 147.0° and 144.2°, respectively, which means that FSi-NaHCO35 has advanced hydrophobic and oleophobic properties. The hydrophobic and oleophobic ratio of FSi-NaHCO35 are 92.35% and 91.59%, respectively. Furthermore, FSi-NaHCO35 dry powder fire extinguishing agent can extinguish aviation kerosene and n-heptane oil pool fires in 0.15 and 0.18 s, respectively, which is shorter than that of NaHCO3 dry powder fire extinguishing agent. After the secondary ignition, using FSi-NaHCO35 as dry powder fire extinguishing agent, the fire temperature of the aviation kerosene oil is significantly lower, and the full reburning time of the aviation kerosene oil fire is significantly longer than that of NaHCO3 dry powder fire extinguishing agent, which means FSi-NaHCO35 obviously has antireflash performance in an aviation kerosene oil pool fire.

Using monazite U-Pb geochronology of Precambrian shales to constrain fluid flow and hydrocarbon accumulation events of a petroliferous basin

Obtaining precise ages of the Phanerozoic fluid flow events of petroliferous basins is essential for understanding the tectonothermal histories, petroleum- and ore-forming processes. Conventional isotopic dating methods are often compromised by inheritance from detrital constituents and/or subsequent thermal resetting. Monazite is a trace mineral widely present in low-grade metasedimentary rocks, and as an excellent U–Th–Pb geochronometer it has great potential in dating fluid flow activities related to basin evolution. We present results of an in-situ monazite U-Th-Pb geochronology study on shale samples from the Neoproterozoic (651 Ma) Datangpo Formation intersected by a drill-hole in the Sichuan Basin, a typical petroliferous basin in western South China. We recognized two fluid flow events at ca. 450 Ma and ca. 263 Ma, and relate the former to the far-field effect of the Proto-Pacific Ocean subduction and the latter to emplacement of the Emeishan large igneous province. We infer that the ca. 450 Ma fluid flow event induced the first stage of oil charging in the paleo oil pools in the Sichuan Basin, as also recorded by the bitumen samples from the Anyue gas field which yielded re-Os isotopic ages of 458–492 Ma, whereas the ca. 263 Ma event triggered the gas generation of the Paleozoic marine strata in the Sichuan Basin. The results and findings of this study have important implications to reconstructing the complex histories of fluid flow, oil charging and gas generation events of petroliferous basins.

Experimental investigation on RP‐3 aviation kerosene large‐scale pool fires at high altitude

AbstractRP‐3 aviation kerosene is a standard fuel that is used in civil aircraft and is a substitute for Jet‐A fuel. This paper investigates the combustion behaviour of RP‐3 aviation kerosene in an open space in the low‐pressure environment of a plateau. A series of large‐scale pools with diameters ranging from 0.4 m to 2.82 m combustion experiments are performed. Typical combustion characteristic parameters, including combustion rate, flame height and axial plume temperature distribution is measured. Results show that a low‐pressure environment significantly affects pool fires. With combustion rate, there is a linear variation law between oil pool size and combustion rate. The experimental data are fitted as a means of obtaining the large‐scale combustion rate relationship equation at low pressure. Experimental flame height data is compared using classical prediction models. Prediction model coefficients at low pressure are determined. The axial plume temperature distribution is greater than in the literature findings due to flames becoming longer in a low‐pressure environment. The three regimes in McCaffery's model are redefined and correlate well with the vertical temperature profile of the pool centreline. The results of the experimental investigation will help research fire hazards in low‐pressure environments while also contributing to the provision of basic data for the development of firefighting operation strategies.

Marangoni convection in shallow annular pools of silicone oil heated from above

A numerical study in a two-dimensional, axisymmetric cylindrical geometry is performed to evaluate the effect of Marangoni convection in shallow liquid layers of silicone oil. The study aims to understand Marangoni convection for a range of temperature gradients (9.0 K, 11.5 K, and 14.0 K), layer depths (4.0 mm, 4.5 mm, and 5.0 mm) under earth gravity (1.0 g), and microgravity (0.5 × 10 −3 g) conditions. The finite element method is used to solve the present problem using COMSOL V5.6 commercial tool. The microgravity studies ensure Marangoni convection dominates natural convection. In the present simulation, it is found that Marangoni convection is influenced more by temperature difference than layer depths as the change in temperature gradient gives a higher velocity deviation than a change in layer depths. In the presence of fluid meniscus, the thermo-capillary force is observed to be less significant in driving the flow as the peak velocity magnitude is observed to get reduced by 60%. From the microgravity study, it is clear that for velocity magnitude at z = 2.5 mm the Marangoni convection contributes to almost 90% of the total convection.

The investigation of the water mist suppression pool fire process's flame expansion characteristics

Flame expansion is a typical fire suppression phenomenon that happens during the water mist suppression of liquid fuel fires, particularly heavy oil fires, and poses a risk to process safety. A series of transformer oil fire expansion experiments were carried out to study the mechanism of flame expansion in the process of water mist suppression pool fires. A theoretical model of the interaction of water mist with flame and hot fuel was developed after a quantitative investigation of flame structure changes during expansion. According to the results of the study, the presence of a fuel-rich vapor layer on the oil pool's surface is a prerequisite for flame intensification, and the thickness of this layer is proportional to the height of the transformer oil flame, Lc=0.195Lf. Furthermore, the impact of water mist on the fuel-rich vapor layer is found to be the principal cause of flame expansion, and the transformer oil flame expansion rate is determined using a combination of theoretical and experimental methods, φv=13.9−41.8. Finally, one of the factors that aggravates flame expansion is the overpressure on the fuel surface caused by the water-oil mixture. Droplet size reduces as water mist pressure rises, and flame expansion shifts from the parallel effect of jet impact and water-oil mixing to the serial effect, lowering the flame expansion rate. As a result, reducing droplet size causes flame expansion to weaken.

Simulation of interfacial deformations for 2D axisymmetric multi-material flows

A numerical method is developed to model the deformation of interfaces between various materials in a multi-material system. The method involves a new and straightforward interface reconstruction scheme integrated with the volume-of-fluid (VOF) technique capable of addressing triple-point configurations. The developed method can track various interfacial structures between liquids in liquid-liquid-gas systems. First, a few standard test cases are used to demonstrate the capabilities of the numerical scheme and examine its performance. Next, the impact of a water drop onto a pool of silicone oil is simulated. Experiments were also performed to obtain time-resolved images of this phenomenon for comparison and validation purposes. Computer simulations well agree with those of the experiments.

Fire-extinguishing performance and gas-phase pollution characteristics of different foam agents in extinguishing transformer oil pool fire

In this study, aqueous film-forming foam, fluoroprotein foam, and synthetic foam were applied to extinguish the transformer oil pool fires. The fire-extinguishing performance and burn-back resistance were investigated using a laboratory fire-extinguishing system. Moreover, the emission products were analyzed to evaluate the gas-phase pollution characteristics. Results show that aqueous film-forming foam presents the highest fire-extinguishing efficiency, while fluoroprotein foam has the best burn-back performance. Flue gas and gas chromatography–mass spectrometer analyses demonstrate that the use of fluoroprotein foam results in much higher CO emissions than other foams, and the pollutants are mainly from various hydrocarbons produced by incomplete combustion of transformer oil. Synthetic foam and aqueous film-forming foam lead to higher SO2 and NO emissions, and pollutants are mainly dominated by alcohols and ethers. Noteworthily, when using aqueous film-forming foam to extinguish oil pool fire, a persistent organic pollutant, perfluorooctanoic acid, is detected in the gas phase.

Structural and geodynamic control of abnormal thermobaric conditions and physical properties of oil reservoirs in the Chezhen sag of the Jiyang depression, East China

Geologically, the rift system of East China has a complex block structure influenced by large-scale and differently directed tectonic movements which took place in the Earth’s crust many times in the geological history of East China. The neotectonic movements greatly complicated the geological structure and, naturally influenced formation of the modern fluid dynamical system. Exploration for oil within the Chezhen block of the Shengli field involves certain difficulties associated with the complex block geological structure, small size of most oil pools and varying thermobaric conditions within a pool (even in the range of two neighbor wells). This article describes the studies aimed at enhanced efficiency of exploration for oil, including shale oil which is a new petroleum source in East China. The physical properties of oil and the thermobaric conditions of oil occurrence in the Paleozoic and Paleogene deposits in the Chezhen sag are described. Well information is analyzed in package with geological and geodynamic data. It is for the first time found that in the Chezhen sag: the local areas of increased thermobaric conditions in the oil pools and the better quality oil (lower density and viscosity) occur at the faults of the younger age; the actual deviations from the classical geological and physical correlations (direct reservoir pressure–temperature–depth dependence, direct oil viscosity–temperature/depth dependence) are governed by the migrational geodynamics; the borderline between the notions of a reservoir and a non-reservoir (cap) is quite tentative. The authors propose two mechanisms of origination of the abnormally high reservoir-pressure zones in pools of oil, including shale oil, associated with the migrational geodynamics and with the formation and accumulation of hydrocarbons.