In the grim situation of global water shortages and environmental pollution, it is necessary to find a clean way to obtain clean water. Solar energy is an inexhaustible, clean and pollution⁃free energy source. Its applications include photothermal, photovoltaic, photocatalytic oxidation, etc. Among them, photothermal is the most efficient way of energy conversion. Carbon material, as a material which has been paid attention to in recent years, has many advantages, such as convenient approach, low price and environmental friendliness.The carbon materials and composites with good photothermal effect which have been studied at home and abroad in recent years are reported, and some new research ideas and materials which can be used for photothermal conversion are also reported.
Phase change material microcapsules (MicroPCMs) with polystyrene as shell material and paraffin as core material were prepared by suspension polymerization. The influence of emulsifying time, the dosages of crosslinking agent (DVB), polymerization times and the mass ratios of core and shell has been studied on the properties of phase change microcapsules, such as chemical compositions, surface morphologies, thermal storage properties and stabilities of the microcapsules were characterized by fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), respectively. The results showed that the emulsifying time had no significant influence on the thermal properties of microcapsules. The microcapsule showed better morphology with less wrinkles and less debris when the dosage of divinybenzene(DVB) was 6∶1. The microcapsule prepared with the polymerization time of 3 h had good morphology, relatively uniform size, high latent heat of phase change and high content of core wax. As the mass ratio of the core and wall material increases, the melting temperature of the content of core material (paraffin) increases successively. When the mass ratio of the core and wall material is 3∶1, the latent heat of prepared microcapsule with good thermal stability increases to 125.2 J/g and the content of core material(paraffin) reaches up to 80.9%.
The Ce⁃SBA⁃15 adsorbent was prepared by impregnation method. The physicochemical properties of the adsorbent were characterized by N2 adsorption⁃desorption technique and NH3⁃TPD technique. The desulfurization effect of adsorbent was investigated by static adsorption experiment, fixed bed dynamic adsorption penetration experiment and extraction experiment. The physical and chemical properties of the adsorbent were correlated with the desulfurization effect, and the influence of the solvent pH value on the acid active site construction and desulfurization performance of Ce⁃SBA⁃15 adsorbent was investigated. The results showed that the pH value of the solvent had two effects (the strong electrostatic adsorption and oxidation reaction ) on the construction of acid active sites of Ce⁃SBA⁃15 desulfurization adsorbent. Strong acidic conditions can inhibit the occurrence of oxidation reaction, and high dispersion of Ce species can be achieved due to strong electrostatic adsorption. Under weak acidic conditions, it is difficult to form effective thiophene adsorption sites due to the transformation of Ce species caused by oxidation. The optimal pH value was 3, and the Ce⁃SBA⁃15(3) adsorbent prepared under this condition maintained the optimal physicochemical properties and the adsorption and removal capacity of thiophene.
In order to enhance the effect of acid fracturing and provide possibility for oil and gas production increase in oilfield,the dissolution rate, dissolution ratio,dissolution quality, permeability improvement rate and fracture conductivity of the FF⁃01 acid system to core were studied by means of dissolution and acid dissolution,with the core of Yanchang oilfield as the main source. The damage to the core and the corrosion of the pipe fittings were analyzed.In addition, the surface tension of the residual acid and the apparent viscosity before and after the acid reaction were investigated.The results show that 25% of the FF⁃01 environmental acid has a better corrosion inhibition effect,the permeability improvement rate of the core after treatment with FF⁃01 is 288%,and the conductivity of the core is enhanced. After the reaction with cuttings, the residual amount of FF⁃01 environmental acid is 1/6 of the amount of HCl residue.The corrosion rate of the FF⁃01 environment⁃friendly acid on steel and the surface interfacial tension after acid reaction and the viscosity of residual acid are all low,which meet the requirements of environmental protection.
In order to study the interlayer interference mechanism of water drive reservoir, the development plan of multi⁃layer co⁃production is developed. The core hole and permeability data of Gaotaizi core in the western Daqing central region are statistically analyzed, and the four⁃pipe parallel constant pressure displacement experiment is carried out with artificial cores with different permeability. The effects of injection and production pressure difference and permeability grade difference on recovery and water cut are studied. It is found that there is a reasonable injection⁃production pressure difference in core co⁃production with different permeability. The larger the permeability gradient is, the smaller the overall recovery is. The influence rule of permeability difference on interlayer disturbance is clarified from the mechanism, which provides theoretical basis for subdivision adjustment and water quantity adjustment.
Extra high water cut has been the main development stage of bottom⁃water reservoir, due to water cut highly with great escalating rate in the initial. At present, the relative permeability curve endpoint has become a serious distortion. This paper presents a method to calculate the performance of water cresting with two phases flowing using the streamlines theory, good for solving the existing problems in the common method, as no pertinence, ineffectiveness and less affecting factors considered. Meanwhile, optimized relative permeability curve was calculated based on the research coupling genetic algorithm with bottom⁃water drive model. The result of numerical calculation based on optimized relative permeability curve showed that the histogram of technical reserves was matched basically with the real practice. This research could provide some instructional meaning to the application of dynamic prediction and developing the oilfield in bottom⁃water reservoir.
This article mainly discusses the target reservoir after injection of medium and high molecular weight polymer into different well groups under the condition of relatively serious water accumulation interference. Based on the analysis of field data, the effectiveness, water cut change and stage recovery degree of oil wells around the well group are summarized. The appropriate parameter setting for the second oil reservoir well group are obtained to ensure the quality and the effect of the injected polymer, thereby greatly improving the recovery rate and the development benefit of the target block. The results show that the oil layer is more suitable for injecting 1 200~1 600 million molecular weight polymers, and the viscosity should be in the range of 30~50 mPa∙s; in the case of similar background conditions, the medium fraction is more suitable for the use of thin⁃difference oil layers, the high concentration of water in Class II oil reservoirs has a large decline in water cut, and the effect of increasing oil production is very good. The adoption of this technology can increase oil recovery, which is more than 10 percentage points higher than the conventional concentration.
Fine provenance analysis and clear provenance system characteristics are of great value and significance for restoring the type and distribution characteristics of paleosedimentary system and searching for sandstone enrichment areas. Based on the data of heavy minerals, seismic attributes,sand⁃land ratio and palaeogeomorphology, this study systematically analyzed the characteristics of the ancient provenance system of Shahezi Formation in Xuxi⁃Xunan area from different perspectives and levels. The study shows that the Shahezi Formation in Xuxi⁃Xunan area mainly develops two provenance systems, east and west. The provenance of the Xuxi fault terrace zone in the west is the main provenance direction of the study area, with greater provenance intensity and wider influence. The eastern provenance has a small influence range, mainly concentrated near the north and south ends, and is the secondary provenance direction. Generally speaking, the provenance direction of the study area has the characteristics of pointing from the east and west to the middle. The Shahezi formation in the study area mainly develops fan delta, Braided river delta and lake sedimentary system. The fan delta deposits are mainly controlled by the provenance of the Xuxi fault terrace belt in the west and distributed evenly along the fault terrace belt. The braided river delta deposits are controlled by the eastern provenance, mainly developed near the uplift at the north and south ends. The provenance influences and controls the development types and plane distribution of the sedimentary system from the source.
Nearshore subaqueous fan is developed with limited distribution during the deposition period of K1N1 member in hanging side of Huoduomoer tectonic zone in Hailar basin. In order to further understand the regularity of its deposition, technical measures such as rock slice, particle size analysis, SEM, core observation and paleogeomorphic restoring are used. According to analyse and research on the feature of petrology and clay mineral, diagenesis, sedimentary structure, sedimentary facies, logging response and seismic facies. Nearshore subaqueous fan has the feature, such as low maturity of texture and component, under⁃compacted diagenesis, short⁃distance transportation and quick sedimentation. The idea is proposed that the mainly control factors of formation about nearshore subaqueous fan are the large terrain elevation difference of original landform, close to the source and strong tectonic uplift during the deposition period. Meanwhile, it is pointed out that the enrichment of oil and gas is nothing to do with the size of fan, it is mainly controlled by the development of the facies belt and sand⁃body. The midfan of nearshore subaqueous fan and sublacustrine fan in the basin which developmented along Huoduomoer fault, are the main areas of the further exploration of K1N1⁃3 sand set reservoir in hanging side of Huoduomoer tectonic zone.
When polymer solution is injected into reservoir, if the radius of polymer molecule thread is much larger than the radius of pore throat, it will cause the blockage of polymer in reservoir pore. Selecting a typical block in Sabei oil field, sampling the blocked injection wellbore backflow, and analyzing the composition of backflow by laboratory, it is determined that the main component of backflow blockage is polymer soft micelle. According to the geological structure, sedimentary facies, reservoir property of geological data, the geological model of plugging wells was establish，the concentration of polymer distribution in the reservoir was utilized, the polymer solution flowing trajectory was simulate and the distance of the polymer blockage was confirm. The advancing distance of direction provides a basis for improving the blocking condition of injection wells and taking pertinent measures.
The effects of water vapor on the adiabatic flame temperature, premixed flame temperature and laminar premixed flame velocity of methane combustion were studied by using Chemkin 17.0, and the effect of water vapor on the chain reaction process of methane combustion was also studied. The results show that with the increase of water vapor content, the temperature of methane flame and premixed laminar flame speed decrease, and the concentration of H,O,OH free radicals is also reduced, while the proportion of OH free radical is raised, leading to the dominance of reactions transmitted by OH free radicals. The addition of water vapor changes the chain reaction of methane combustion, enhances the reaction of CH3 to CH2(s),CH2(s) to CH2,CH2 to CH,CH to CH2O, and enhances the reaction of CH3 to CH3O,CH3O to CH2O at the same time.
In this paper, Changqing crude oil was emulsified under pressure in different dissolved gas environments (CO2, CH4, N2) by using crude oil emulsifier with pressure dissolved gas. The solubility (Rs) , water separation rate (fv), interfacial tension (γ), interfacial modulus of elasticity (εd), viscosity of dissolved gas crude oil (μ) and apparent viscosity of dissolved gas crude oil emulsion (μap) were measured by means of solubility measurement device, emulsion stability analysis device, interfacial tension tester and high pressure rheometer. The results show that the presence of oil⁃water interfacial film inhibits the migration of gas from the outer phase to the inner phase to a certain extent, so that the solubility of the dissolved gas oil emulsion is less than the solubility of the internal and external phases. Under the environment of dissolved CO2, because of the minimum interfacial tension between oil and water, the best emulsification effect is obtained, and the W/O emulsion droplets with pressure are the most compact. Under the environment of dissolved CO2, because of its minimum interfacial tension between oil and water, the smallest droplets are formed in W/O emulsion and the emulsifying effect is the best. At the same time, due to the elastic modulus of oil⁃water interface is the largest, the emulsion system is the most stable, and the viscosity ratio of emulsion system is the most obvious than that of crude oil system. In contrast, in the environment of N2 dissolution, the stability of the emulsion system is poor, and it is easy to demulsify.
The corrosion behavior of 20# steel in oilfield production fluid was studied by corrosion weight loss method, tow electrode technology and electrochemical measurement technology. The results show that the corrosion development process can be divided into the initial corrosion stage, the corrosion development period and the corrosion stability period during the experimental period. The corrosion is the most serious in the initial stage of corrosion. The polarity reversal of cathode and anode occurs at the same position of metal with the prolongation of experimental time, and as the temperature increases, the inversion period becomes shorter. Through the electrochemical measurement of the corrosion metal as a whole and in part, it is found that the types of corrosion occur at different temperatures and locations.
A selfdeveloped high⁃pressure CO2⁃crude mixing container is used to mix up CO2 and waxy crude oil respectively under reservoir condition, and gelling and yielding properties of the waxy crude oil are studied by gas chromatograph, DSC, rheological measurement, microscopic observation and other instruments. A brief summery about the effect of CO2 pretreatment on waxy crude oil was given. After treated by CO2, the reduction of light component in the waxy crude oil can inhibit the wax dissolution and increase the wax appearance temperature of waxy crude oil. The size of wax crystals becomes smaller and disperser after treated by CO2, which gives rise to the enhancement of the gel structure and the depravation of the low⁃temperature rheological property. With the increase of the pressure of CO2 during mixing process, the gelling and yielding properties of waxy crude oil are changed more and more obviously.
Under the background that the onshore oil fields have generally entered the stage of high water cut, it is imperative that the main oil layer gradually transit from class Ⅰ reservoirs to class Ⅱ and Ⅲ. On the basis of the existing technology, how to allocate production and injection rationally for water flooding and chemical flooding under the mode of "two⁃three combination" has become the focus of the "two⁃three combination" optimization technology. Combined with the actual physical parameters of the fault zone in the north district, the orthogonal design was designed for the water flooding and chemical flooding in the two⁃three combined mode, and the numerical simulation and multiple regression analysis of the single⁃well daily blending amount were carried out. The reasonable water injection formula for each layer of the second and third types of oil wells was determined. The production method of the wells in each single well was calculated by using the production method of well group injection and production balance and formation coefficient. The simulation results show that the recovery rate of water flooding after production and distribution is 2.52% higher than that of the actual scheme; the results of chemical flooding production and distribution are compared with the effects of chemical flooding development using the current water flooding injection parameters. The rate is 3.54% higher.
The Bozi block of the Tarim Oilfield is a typical tight sand condensate gas reservoir with serious wax plugging. So it is necessary to study the phase behavior and the wax deposition pattern of well fluids in Bozi gas reservoir, which will provide the phase enveloping diagram of the condensate gas and then help to control the paraffin deposition. In this study, the PVT tester and the self⁃designed microscopic solid deposition tester with visualized windows are used to get the phase enveloping line of the condensate gas of Well Bozi 104. The condensate oil and wax precipitation are analyzed based on the results of software simulation and production data. The results show that in the process of condensate gas changing with temperature and pressure, different phase states are produced, such as gas phase region, gas⁃liquid two phase region, gas⁃solid two phase region and gas⁃liquid⁃solid three phase region. The experimental results are used to correct the software simulation results to obtain different temperature and pressure phase. The state envelope is used to predict the conditions for liquid and wax precipitation when the production wells are in different production stages; the condensate and wax deposition areas of the Bozi 104 wells are located on the ground transmission pipelines, and appropriate anti⁃wax measures should be made
