High Water Content Conditions Research Articles

Impact of water content on minimum miscibility pressure during CO2 flooding in high water-cut reservoirs

This study focused on the X block stratum oil, specifically addressing the application of CO2 displacement technology in enhancing oil recovery under high water content conditions. It systematically investigates the variation of the minimum miscibility pressure (MMP) between CO2 and formation oil at water contents of 0%, 60%, 70%, 80%, and 90%. The research employed slim-tube model simulation experiments and theoretical analysis to explore the impact of different water contents on the physical properties of formation oil and the changes in the interaction mechanism between CO2 and crude oil. The results indicate that the MMP of CO2 flooding is the lowest at 31.11 MPa in the absence of water, reaching the highest value of 37.94 MPa at 90% water content. The MMP of the CO2-formation oil system shows a significant upward trend with increasing water content in the formation, which is related to the stability of the water film, the solubility of CO2, and the interfacial tension between oil and water. Meanwhile, high water content leads to the expansion of formation oil volume, increased viscosity, and compositional changes, collectively influencing the results. This study provides theoretical support for the field application of CO2 flooding and offers critical references for optimizing the oil displacement process.

Fluidic Diode AICD Characteristic Curve Testing and Mathematical Modeling

In order to investigate an efficient water control method suitable for the bottom water occurring during the production process of horizontal wells in bottom water reservoirs, the characteristic curves of a Fluidic Diode AICD (Automatic Inflow Control Device) were tested, and a mathematical modeling method is proposed. First, the working principle of a Fluidic Diode AICD was analyzed; subsequently, a Fluidic Diode AICD test platform was designed and built independently, and pressure test experiments of the Fluidic Diode AICD under different flow conditions were carried out to obtain characteristic curves of the Fluidic Diode AICD. Finally, a mathematical model of the flow–pressure drop characteristic curves of the Fluidic Diode AICD was developed and applied to the simulation of water control production in horizontal wells in bottom water reservoirs. The results of the study showed that the Fluidic Diode AICD produces a more significant pressure drop under high water content conditions, and has a better oil and water stabilization function in production. In this study, the reservoir flow, annulus flow, AICD flow, and horizontal wellbore flow are considered, and an integrated coupling model for horizontal wells in bottom water reservoirs is established. This study provides a basis for using Fluidic Diode AICDs in horizontal wells in bottom water reservoirs.

Inhibiting effect of a composite formulation of kinetic and thermodynamic inhibitors for gas hydrate formation in high water cut oil–water emulsion

AbstractIn oil and gas exploitation and transportation, it is essential to avoid hydrate blockage in the wellbores and pipelines. Using kinetic inhibitors in composite with thermodynamic inhibitors can reduce the operational expenditure for oil and gas pipelines under high water content conditions. The phase equilibria of pure water natural gas system, oil–water natural gas system, and oil–water monoethylene glycol (MEG) natural gas system were first investigated by experiments and combined with software predictions in this study. The results showed that both mineral oil and MEG shifted the phase equilibrium of the system to high‐pressure and low‐temperature directions. The oil phase increased the effective temperature range of the compounding inhibitor. Then the hydrate inhibition performance and natural gas hydrate generation characteristics of the composite formulation of Luvicap 55w and MEG in oil–water emulsions and natural gas mixtures were investigated. With the increased subcooling, the induction time decreased sharply, and the gas consumption increased. The induction time increased with increasing MEG concentration, which verified the synergistic effect of MEG in oil–water emulsion for Luvicap 55w. The hydrate generation characteristics did not change much with increasing Luvicap concentration at the same temperature. In contrast, the hydrate induction time rose from 142.8 to >3500 min as the MEG concentration increased from 10 to 20 wt%.

Preparation and alkaline stability of polyethylene composite hydroxide exchange membranes with different cations

Hydroxide exchange membrane fuel cells (HEMFCs) are a cost-effective alternative to proton exchange membrane fuel cells due to the advantages on fast oxygen reduction reaction kinetics, low cost and weak corrosion. Hydroxide exchange membrane (HEM) is the core component for HEMFC. At present, lacking highly robust and chemically stable HEMs is the main challenge to realizing durable HEMFCs. Polyethylene composite HEMs are considered as the-state-of-the-art HEM candidates due to their excellent mechanical properties, thus allowing for the use of ultrathin HEMs in HEMFCs to achieve a high cell and stack performance. Yet, the chemical stability of polyethylene composite HEM still needs to be improved for more durable HEMFC. In this study, we report that the preparation and chemical stability understanding of three polyethylene composite HEMs (named AEH-TMA, AEH-DMP and AEH-TMI) functionalized with trimethylamine (TMA), N-methylpiperidine (DMP) and 1, 2, 4, 5-tetramethylimidazole (TMI), respectively. We find that AEH-TMI exhibits a low conductivity and inferior chemical stability in comparison to AEH-TMA and AEH-DMP. To gain insight into chemical stability behavior, we have also prepared three organic chemicals (named Bn-TMA, Bn-DMP and Bn-TMI) as cations model by reacting benzyl chloride with TMA, DMP and TMI cations and elaborately studied their chemical stability in various water content systems. The results show that the overall chemical stability of cations can be strongly improved with increasing the surrounding water, and Bn-TMI suggests a lower chemical stability than Bn-TMA and Bn-DMP at high water content condition.

A SOCT-ISC type photosensitizer coumarin-BODIPY promoted by AIE effect: Mechanism of singlet oxygen generation, simulated PDT in A-549 cells and fluorescence imaging in zebrafish

A spin−orbit charge-transfer intersystem crossing (SOCT-ISC) type photosensitizer coumarin-BODIPY (CM-BDP) was reported in this paper. Due its aggregation induced emission (AIE) effect, CM-BDP could work under high water content condition. Besides that, another important phenomenon was discovered. In DMSO solvent, the fluorescence emission and the singlet oxygen yield of CM-BDP were almost negligible, while, in 90% water content system, the singlet oxygen yield of CM-BDP was up to 20.9% and a strong TICT fluorescence emission at 648 nm was observed, which indicated the AIE effect could also promote the generation of singlet oxygen by preserving the energy. In terms of the mechanism of generating singlet oxygen, the D-A configuration of CM-BDP could facilitate the process of charge separation, as well as the generation of TICT state. Then, the orthogonal configuration of CM-BDP in TICT state and the small △Est between the TICT state and T2 state could promote the SOCT-ISC process effectively. Combining the femtosecond transient absorption spectra and the DFT theoretical calculations, the photophysical process of CM-BDP was proposed in simplified Jablonski diagram. Moreover, the CM-BDP was also applied to intracellular experiment and zebrafish imaging. In the photo/dark toxicity experiment, cell survival rate of dark toxicity experiment was basically higher than 90%, while its decreased significantly under irradiation. The result of acridine orange/ethidium bromide (AO/EB) stain experiment indicated that the CM-BDP could kill A-549 cancer cells effectively under irradiation and the fluorescence imaging in zebrafish proved that CM-BDP could be further applied in organisms.

Carboxylic Acid Reductase Can Catalyze Ester Synthesis in Aqueous Environments.

Most of the well-known enzymes catalyzing esterification require the minimization of water or activated substrates for activity. This work reports a new reaction catalyzed by carboxylic acid reductase (CAR), an enzyme known to transform a broad spectrum of carboxylic acids into aldehydes, with the use of ATP, Mg2+ , and NADPH as co-substrates. When NADPH was replaced by a nucleophilic alcohol, CAR from Mycobacterium marinum can catalyze esterification under aqueous conditions at room temperature. Addition of imidazole, especially at pH 10.0, significantly enhanced ester production. In comparison to other esterification enzymes such as acyltransferase and lipase, CAR gave higher esterification yields in direct esterification under aqueous conditions. The scalability of CAR catalyzed esterification was demonstrated for the synthesis of cinoxate, an active ingredient in sunscreen. The CAR esterification offers a new method for green esterification under high water content conditions.

Carboxylic Acid Reductase Can Catalyze Ester Synthesis in Aqueous Environments

AbstractMost of the well‐known enzymes catalyzing esterification require the minimization of water or activated substrates for activity. This work reports a new reaction catalyzed by carboxylic acid reductase (CAR), an enzyme known to transform a broad spectrum of carboxylic acids into aldehydes, with the use of ATP, Mg2+, and NADPH as co‐substrates. When NADPH was replaced by a nucleophilic alcohol, CAR from Mycobacterium marinum can catalyze esterification under aqueous conditions at room temperature. Addition of imidazole, especially at pH 10.0, significantly enhanced ester production. In comparison to other esterification enzymes such as acyltransferase and lipase, CAR gave higher esterification yields in direct esterification under aqueous conditions. The scalability of CAR catalyzed esterification was demonstrated for the synthesis of cinoxate, an active ingredient in sunscreen. The CAR esterification offers a new method for green esterification under high water content conditions.

Numerical simulation of water content dependent undrained shear strength of clays

A nonlinear mathematical model for estimating the water content dependent undrained shear strength of clayey soils was developed. Three types of clay mixtures (kaolinite, bentonite, and kaolinite-bentonite) were considered. The shear strength of the given soil samples was determined via torvane tests. Experimental results were compared with three numerical results: (i) the analytical function fit, (ii) modeling without the water content effect, and (iii) modeling with the water content effect using the Mohr-Coulomb (M-C) model. There was good agreement among the experimental, analytical, and numerical results with and without the water content effect in the fully softening zone. However, there was a large difference between the numerical results obtained from the developed model with and without the water content effect in the flow zone with a high liquidity index, because the shear strength may decrease significantly to low value in the case of an abrupt increase of the water content. The greatest advantage of the developed model is that it can simulate the reduction of the shear strength and shear band development under the high water content condition, which may trigger a large mobile mass movement.

Coupling Analysis of Low-Speed Multiphase Flow and High-Frequency Electromagnetic Field in a Complex Pipeline Structure

Accurate estimation of water content in an oil-water mixture is a key technology in oil exploration and production. Based on the principles of the microwave transmission line (MTL), the logging probe is an important water content measuring apparatus. However, the effects of mixed fluid flow on the measurement of electromagnetic field parameters are rarely considered. This study presents the coupling model for low-speed multiphase flow and high-frequency electromagnetic field in a complex pipeline structure. We derived theS-parameter equations for the stratified oil/water flow model. The corresponding relationship between theS-parameters and water holdup is established. Evident coupling effects of the fluid flow and the electromagnetic field are confirmed by comparing the calculatedS-parameters for both stratified and homogeneous flow patterns. In addition, a multiple-solution problem is analyzed for the inversion of dielectric constant from theS-parameters. The most sensitive phase angle range is determined to improve the detection of variation in the dielectric constant. Suggestions are proposed based on the influence of the oil/water layer on measurement sensitivity to optimize the geometric parameters of a device structure. The method proposed elucidates how accuracy and sensitivity can be improved in water holdup measurements under high water content conditions.

Experimental Study of Loess Structural Strength and Resistance Coefficient

The paper proposes a calculation method of soil particles framework structural strength, and provides a new parameter, defined as resistance coefficient, which can quantitatively describe the relationship between active stress and passive stress on soil particles framework. The research of the impact of water content, binding materials content and dry density on structural strength and resistance coefficient is conducted under confined compression test with undisturbed and man-made cement structural loess from Yangling. The research shows that structural strength of loess particles framework increases with the increasing of deformation, and with the same deformation, the structural strength of loess particles framework increases with the increasing of water content ; loess particles framework is sensitive to the weakening role of water. The resistance coefficient is smaller and more instability with the increasing of deformation under high water content conditions. The binding material has significant effect on structural strength and resistance coefficient. Moderate cement mixed with loess particles framework cannot only improve the structural strength but also decrease the sensitivity of loess particles framework to the weakening role of water. By controlling the binding material content, water content and dry density, the structural strength and resistance coefficient of man-made cement structural loess will be the same as the undisturbed loess. Increasing dry density can make the structural strength of loess particles framework higher, but the value and the stability of resistance coefficient of loess particles framework structure with high dry density is lower than that in the initial dry density.

Molecular engineering of microporous crystals: (III) The influence of water content on the crystallization of microporous aluminophosphate AlPO 4-11

The influence of water content on the crystallization of the microporous aluminophosphate AlPO 4-11 was investigated by a combination of in situ UV Raman and ex situ XRD and NMR characterizations. Under high water content conditions (Al 2O 3:H 2O = 1:20–69), an AlPO 4-5 intermediated formed first and later co-existed with AlPO 4-11. In the last stage of crystallization, the crystalline AlPO 4-5 completely disappeared and well-crystallized AlPO 4-11 was obtained. The position of the three signals observed in the 31P MAS NMR spectra of the isolated solid samples did not change during the hydrothermal treatment, suggesting that the fragments containing the P site in the junction of 6- and 4-membered rings of both AlPO 4-5 and AlPO 4-11 formed first and that the environments of the P sites were very similar to those in the final structure. A significant increase of Al concentration in liquid media was observed before the appearance of XRD detectable AlPO 4-11. Under low water content conditions (Al 2O 3:H 2O = 1:15), the AlPO 4-11 was directly crystallized from the initial mixture. In situ Raman spectra showed that the 10-membered rings were complete by the time the transformation of octahedral Al to tetrahedral Al was finished and that the conformation of the protonated di-( i-propyl)amine changed little during the crystallization. The present study showed that the composition of the liquid phase is critical to the formation of a specific structure.

Extension of an Existing Model for Soil Water Evaporation and Redistribution under High Water Content Conditions

Most crop, hydrology, and water quality models require the simulation of evaporation from the soil surface. A model developed by J.T. Ritchie in 1972 provides useful algorithms for estimating soil evaporation, but it does not calculate the soil water redistribution resulting from evaporation. A physically‐based model using diffusion theory, described previously by Suleiman and Ritchie in 2003, provides efficient algorithms for soil water redistribution and soil evaporation. However, the model is appropriate only for second stage drying when the soil in the entire profile being simulated is below the drained upper limit (θDUL) and no more drainage occurs due to gravity. This paper extends the Suleiman–Ritchie model for soil water contents higher than θDUL where soil evaporation rates are usually higher than second stage drying. New algorithms were developed for these wetter conditions that are functions of soil depth and the wetness of the near‐surface soil. New model parameters were calibrated with data measured in laboratory soil column studies. The resulting model was integrated into DSSAT‐CSM (Decision Support System for Agrotechnology Transfer Cropping Systems Model). Simulated soil evaporation rates and soil water contents obtained using the Suleiman–Ritchie model with the developed extensions and the previous DSSAT soil evaporation model were compared and evaluated with field measurements of soil water content during several drying cycles for parts of 3 yr in North Central Florida. Computed soil water contents from the model agreed well with the measured soil water contents near the surface, and provided more accurate estimations than the original DSSAT soil evaporation model, especially for the 5‐cm surface layer.

A block-copolymer hydrogel encapsulates bacteriorhodopsin and produces the longest photochromic response of the membrane protein under high water content conditions

Here we report, for the first time, that an amphiphilic block copolymer could surprisingly prolong the decay time of the M intermediate of bacteriorhodopsin (BR) upon excitation with light, as a demonstration that some synthetic polymers can significantly tune protein functions in a wet material.

Effect of water and stress on the lattice-preferred orientation of olivine

The influence of water and stress on the lattice-preferred orientation (LPO) of olivine aggregates was investigated through large strain, shear deformation experiments at high pressures and temperatures ( P = 0.5–2.1 GPa, T = 1470–1570 K) under both water-poor and water-rich conditions. The specimens are hot-pressed synthetic olivine aggregates or single crystals of olivine. Water was supplied to the sample by decomposition of a mixture of talc and brucite. Deformation experiments were conducted up to γ (shear strain) ∼ 6 using the Griggs apparatus where water fugacity was up to ∼ 13 GPa at the pressure of 2 GPa. The water content in olivine saturated with water increases with increasing pressure and the solubility of water in olivine at P = 0.5–2 GPa was ∼ 400–1200 ppm H/Si. Several new types of LPO in olivine are found depending on water content and stress. Samples deformed in water-poor conditions show a conventional LPO of olivine where the olivine [100] axis is subparallel to the shear direction, the (010) plane subparallel to the shear plane (type-A). However, we identified three new types (type-B, C, and E) of LPO of olivine depending on the water content and stress. The type-B LPO of olivine which was found at relatively high stress and/or under moderate to high water content conditions is characterized by the olivine [001] axis subparallel to the shear direction, the (010) plane subparallel to the shear plane. The type-C LPO which was found at low stress and under water-rich conditions is characterized by the olivine [001] axis subparallel to the shear direction, the (100) plane subparallel to the shear plane. The type-E LPO which was found under low stress and moderate water content is characterized by the olivine [100] axis subparallel to the shear direction, the (001) plane subparallel to the shear plane. Observations by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) show that the dislocations in water-poor samples (type-A) are curved and both b = [100] and b = [001] dislocations have a similar population. Numerous subgrains are seen in water-poor samples in backscattered electron images. In contrast, water-rich samples (both type-B and type-C) contain mostly b = [001] dislocations and dislocations are straight and sub-grain boundaries are rare compared to those in water-poor samples. These observations suggest that (1) dominant slip systems in olivine change with water fugacity (and stress) and (2) grain boundary migration is enhanced in the presence of water. Seismic anisotropy corresponding to the fabrics under water-rich condition is significantly different from that under water-poor condition. Consequently, the relationship between seismic anisotropy and flow geometry in water-rich regions is expected to be different from that in water-poor regions in which type-A fabric dominates (i.e., the lithosphere). A few cases are discussed including anisotropy in the subduction zone and in the deep upper mantle.

The effect of truck traffic and road water content on sediment delivery from unpaved forest roads

A study investigated the effect of truck-traffic intensity and road water-content on the quality of runoff water from unsealed forest roads. Three sections of a gravel-surfaced forest road were instrumented and exposed to low and high levels of truck traffic during wet winter conditions and dry summer conditions between July 2001 and December 2002. Rainfall, runoff, road moisture, and traffic were measured continuously, and suspended and bedload sediments were integrated measurements over 2-week site-service intervals. The median suspended sediment concentration from the three road segments under low truck-traffic conditions (less than nine return truck passes prior to a storm) was 269 mg l-1, increasing 2.7-fold to a median of 725 mg l-1 under high truck-traffic conditions (greater than or equal to nine return truck passes prior to a storm). These concentrations, and increases due to traffic, are substantially less than most previously reported values. When these data are expressed as modified universal soil loss equation (MUSLE) erodibility values K, accounting for differences in rainfall energy, site characteristics and runoff, high traffic resulted in a road surface that was four times more erodible than the same road under low traffic conditions. Using multiple regression, traffic explained 36% of the variation in MUSLE erodibility, whereas road water content was not significant in the model. There was little difference in the erodibility of the road when trafficked in low water-content compared with high water-content conditions (MUSLE K values of 0.0084 versus 0.0080 respectively). This study shows that, for a good quality well-maintained gravel forest road, the level of truck traffic affects the sediment concentration of water discharging from the road, whereas the water content of the road at the time of that traffic does not (note that traffic is not allowed during runoff events in Victoria). These conclusions are conditional upon the road being adequately maintained so that trafficking does not compromise the lateral drainage of the road profile. Copyright © 2005 John Wiley & Sons, Ltd.

A study of three-body particle generation and subsequent pole tip recession in linear tape recording heads

The Pole Tip Recession (PTR) and transferred material (stain) are major causes of magnetic spacing losses in magnetic recording system. The recorded signal amplitude is only independent of the data being read if the spacing is zero. Thus, the level and more specifically the variation in head media spacing with device life must be a minimum to maximise signal output and minimised errors. It was the purpose of this research to isolate and identify the mechanisms responsible for pole tip recession using the Linear Tape Open format as an experimental platform, but the results have implications for any head where the tape-bearing surface is Al 2O 3/TiC (AlTiC). All experiments were conducted within a matrix of pressure and humidity, which encompassed the system operating extremes. Atomic force microscopy (AFM) was used to analyse the surface topography of the heads and monitor the development of PTR after 100, 1000 and 5000 passes of tape. Auger electron spectroscopy (AES) was employed to analyse the chemical changes on the surface of the heads after 5000 passes of tape and X-ray Photoelectron Spectroscopy (XPS) was used to identify the chemical changes that occurred at the head surfaces. Optical Microscopy was employed to identify the head surface changes before and after wear. Environment was found to have a significant influence on the head/tape interface. Head wear and PTR were highest at high temperature and humidity. Wear between the head and tape was found to transform the surface layers on the TiC grains in the tape-bearing surface to TiO 2. This process results in the production of TiO 2 fragments that become trapped in the recessed pole tip region, acting as three-body abrasive particles. The presence of Ti on the surface of head thin film region confirmed that the three-body particles originated from the head AlTiC ceramic. The TiO 2 (thickness and possible areal coverage) increased with the water content increase, wear of head increased in the high water content condition.

Effects of Micrometeorological Conditions on Ecosystem Respiration Derived from CO<sub>2</sub> Flux above a Japanese Cypress Forest

Canopy photosynthesis, which expresses productivity for forest ecosystems, can not be measured directly, since daytime CO2 flux is the result of photosynthesis and respiration. Thus ecosystem respiration needs to be calculated from night-time CO2 flux in advance. Relationships between night-time CO2 flux and soil temperature were obtained for three seasons beginning in September 2002. Q10, derived in the spring (March to May 2003) was the highest (3.1). On the other hand, the value in autumn (September to November 2002) was the lowest (1.7), despite a relatively large amount of litter. The temperature dependences of CO2 flux varied with changes in soil water content. Q10 increased rapidly with soil temperature under low water content conditions, and slowly under high water content conditions.

Stratified fuel-Water Injection for Low-NOx Diesel Combustion. 1st Report. Test Results on High-Speed Diesel Engine.

Newly developed Stratified Fuel-Water Injection System was tested for the NOx reduction on high-speed diesel engine. Compared with ordinary emulsified fuel oil combustion, this system enables to confirm the auto-ignition characteristics under the high water content condition, by means of primary injected pure fuel. Test results show that not only the broad reduction of exhaust NOx, but also the improvement of B.S.F.C. and smoke density are achieved simultaneously. They also indicate that the exhaust NOx in high-speed diesel engine could be less than 100 ppm (Excess O2=13%).