A new method for preparation of polystyrene nanoparticles by using a method of RAFT living polymerization was studied.Firstly,small molecular reversible addition⁃fragmentation chain transfer agent,three thiocarbonate (DBTTC),was synthesized for active polymerization.Then the emulsifier free emulsion polymerization method was used to prepare styrene polystyrene latex with narrow particle size distribution using itaconic acid as the monomer and ammonium persulfate as initiator.Effects of the molar ratio of St/IA,molar ratio of acetone/water,reaction temperature and amount of DBTTC on the latex particle size were studied respectively.The latices were characterized by Malvern nanosizer,TEM,GPC,surface tension and conductometric titration.The results show that when the temperature is 78 ℃,the molar ratio of St/IA is 10,and the molar ratio of DBTTC/St is 0.064,the molar ratio of acetone/water is 4∶6,the polystyrene nanometer latex particles with average particle size of 98 nm can be obtained.
Brønsted acid in Y zeolite plays a key role in the processes of catalyst,and the structure reflects the strength of B acid.The stable structures of Brønsted acid sites of HY,[AlO]+/HY,and [Al(OH)]2+/HY were simulated by periotic models.The relationship between the structures of Brønsted acid sites and its environments was identified by combination of dynamic simulation with DFT calculation.By analyzing the structure and electronic permanent,together with the statistical results of molecular dynamics,it can be found that the strength of Brønsted acid can connected with the number of H atoms in the 12 membered ring that the small number.The weaker the binding ability of H atoms to O atoms in B acid center is,and the more electrons H atoms lose,the stronger the B acid acidity is.The addition of extra⁃framework aluminum can enhance the acidity of B acid,and [Al(OH)]2+ has more obvious effect on B acid properties.These results can lead the synthetic and modification of B acid site in a theoretical support.
The use of ionic liquid to catalyze the alkylation of isobutane and 2⁃butene has become a hot topic in recent years. The investigation on the formation mechanism of chlorinated hydrocarbons during the production process of alkylated oil catalyzed by ionic liquid is of great significance to improve the clean and environmental performance of gasoline. A set of independent reactions of chlorinated hydrocarbon formation system were determined by atomic coefficient matrix method. The Gibbs free energy change and equilibrium constant of each independent reaction in different reacting conditions were calculated by thermodynamics analysis method, which can be used to evaluate the occurrence possibility of the specified independent reaction in the given reacting conditions, and the results can be used to insight the formation mechanism of chlorinated hydrocarbons during the production process of alkylated oil catalyzed by ionic liquid.
MoS2 (labeled as MoS2⁃1 and MoS2⁃2) was prepared by in⁃situ decomposition of water⁃soluble molybdenum⁃based catalyst and oil⁃soluble molybdenum⁃based catalyst.In order to explore the effect of two types of molybdenum catalyst in slurry⁃bed hydrocracking and preliminary theoretical analysis,the catalysts were characterized by XRD analysis,particle size analysis,SEM analysis and evaluation of reaction performance.Autoclave evaluation results showed that,compared with adding oil⁃soluble catalysts,the transformation rate and coke yield rate were better than that by adding water⁃soluble catalyst.The results of XRD analysis showed that the crystalline state of MoS2⁃1 was poor.The characteristic peaks of MoS2⁃2 were sharp and the crystalline state was good,so the hydrogen could be activated to activate hydrogen and the coke yield rate was reduced.The results of SEM analysis and particle size analysis showed that the MoS2⁃2 was smaller and the diameter was mainly 1~5 μm.MoS2⁃1 was larger and the diameter was mainly 6~10 μm.MoS2⁃2 catalyst had smaller particle size and uniform particle size distribution which could provide more hydrogenation active centers to improve the conversion rate of the reaction.
The catalytic performance of ZSM⁃5,beta and USY zeolites for the preparation of low⁃carbon olefins from F⁃T synthetic distillate oil was investigated in ACE experimental facility.The effects of temperature,mass oil⁃to⁃solvent ratio and mass space velocity on the catalytic performance of beta zeolites were also investigated.The results showed that the ethylene yield was 4.22%,the propylene yield was 31.08%,the butylene yield was 19.96%,and total light olefin yield (ethylene + propylene + butylene) was 55.24% when the reaction temperature was 620 ℃,the mass of catalyst to oil ratio was 8 and the mass of space velocity was 8 h⁃1.
In order to quantitatively describe the changes of adsorption retention pore volume and Inaccessible pore volume in polymer flooding process, and provide an important basis for the optimization of Bohai J oilfield polymer flooding project, the experimental that research on polymer flooding and test of polymer output concentration is carried out according to the similarity principle, referring to the characteristic parameters of Bohai J oilfield. The experimental results show that there is preferably linear relationship between polymer solution concentration and absorbance， under the same concentration of injection polymer solution, the adsorption retention pore volume and inaccessible pore volume increase with decrease of core permeability， for the cores of same permeability, the adsorption retention pore volume and inaccessible pore volume increase with the increase of polymer injection concentration. The adsorption retention pore volume is about 0.04~0.02 PV and the inaccessible pore volume is about 0.12~0.22 PV of Bohai J oilfield.
Fault block M belongs to heavy oil reservoir with thick layer. How to further tap potential and improve oil recovery after entering polymer flooding development is particularly important. In the past, the influence of sweep volume and displacement efficiency on oil recovery has been the main concern in the theoretical study of enhanced oil recovery, while the contribution of sweep volume and displacement efficiency to enhanced oil recovery has been less studied. The characteristics of oil displacement efficiency and sweep volume in the polymer flooding process of M fault block were studied using the method of reservoir engineering which adopted the experimental method of indoor physical simulation, based on the relationship between resistance and oil saturation. And the contribution generated from oil displacement efficiency and sweep volume to enhance oil recovery was discussed. The results showed that the main contribution of polymer flooding was to enlarge the sweep volume of each layer. The contribution generated from the medium permeability layer to enhance oil recovery was 61.79%. And secondly, the contribution generated from high and extra⁃high permeability layer was 34.48%, while the low permeability layer was only 3.73%.
Honghe oilfield is a typical ultra⁃low porosity and tight oil reservoir, and it is difficult to use conventional water injection development method economically and effectively. By using indoor physical simulation experiments, the feasibility of CO2 flooding method in Honghe oilfield was explored from the aspects of compatibility of CO2 with crude oil and reservoirs, formations injection capacity and reservoir injection limits. The results show that CO2 fluids injection in the reservoirs of Honghe oilfield does not block and the compatibility of CO2 with reservoir crude oil is good. Under the same permeability, the CO2 flooding injection index is 8 times of the water injection index, and the CO2 injection is a relatively stable process. The breakthrough time of CO2 injection is relatively longer than N2 injection. At the lower permeability stage, there is no rapid breakthrough; combined with non⁃linear percolation and constant⁃velocity mercury injection experiment technology, we find pressure gradient of CO2 injection is obviously increased when the permeability is lower than 0.08 mD. It is determined that 0.08 mD is the lower limit of reservoir permeability for CO2 injection. The comprehensive experimental results show that the development of CO2 injection in the Honghe tight reservoir is technically feasible.
For the problem of low reservoir prediction accuracy near the fault, the fault area is divided into “stable area” and “complex area”. By precisely interpreting the “stable area” of faults and establishing a high⁃precision 3D geological model, it has changed the interpretation of traditional horizons to avoid the phenomenon of sandbodies in adjacent layers through smooth interpolation, which ensures that the “stable area” near the fault is as accurate as the one far from the fault zone. The position of the “complex area” of the fault is determined by the coherent properties of the mudstone layer, the range of the “complex area” of the fault is identified by the amplitude attribute, and the inverse attribute interpolation method is used to realize the calculation of the inversion attribute value of the fault crushing zone, thereby reducing the effect of faults on seismic inversion accuracy. Using this method, the accuracy of prediction of sand thickness near the fault was increased from 80.4% to 91.3%, an increase of 10.9%. This method improves the description accuracy of the sand body near the fault and provides a new idea and method for the fine description of sand bodies in the fault attachment.
Liaoxi salient has great potential for oil and gas exploration, and it is a favorable area for oil and gas exploration in the future. A view of the unclear understanding of geology, stratigraphy and sequence in this area, the sequence stratigraphic framework was established by using the methods of sequence stratigraphy, sedimentary petrology and provenance system analysis, and the distribution law of the sedimentary system of the main target sequence Dongying formation was discussed. Through structural sequence stratigraphy and sedimentary facies, a comprehensive and systematic study is carried out. According to the different geological characteristics of the system domain and the seismic reflection characteristics of different system interfaces, the middle and lower sequence system tracts, the Lake flood system tract and the high system tract of the eastern two sequence are divided. On this basis, the types of sedimentary facies and the distribution and distribution of favorable sand bodies in sequence framework are discussed. The delta, lake and sublacustrine fan systems are mainly developed in the study area. and the distribution regularity of favorable sand bodies, the favorable exploration direction for oil and gas reservoirs in the study area is pointed out by synthesizing the physical and organic geochemical characteristics of reservoirs. Based on the analysis of sequence, tectonic activity and sedimentary environment, the development characteristics of sedimentary system tracts in different system tracts and the distribution regularity of favorable sand bodies, the favorable exploration direction for oil and gas reservoirs in the study area is pointed out by synthesizing the physical and organic geochemical characteristics of reservoirs.
In the process of solid⁃state mining of deep⁃sea natural gas hydrates, when the balance of temperature and pressure is broken, the hydrate slurry in the production pipeline changes from liquid⁃solid (hydrate, seawater) two⁃phase to gas⁃liquid⁃solid (natural gas, hydrate,seawater). The three⁃phase flow of particles and seawater is the main research object in gas⁃liquid⁃solid three⁃phase flow. The Fluent simulation of the hydrate slurry flow in the vertical production pipe is performed using the CFD⁃PBM model, and the model is verified. The simulation results are in good agreement with the experimental values. The results show that the distribution of flow patterns simulated by PBM model is relatively uniform, and the size of bubbles in the flow process is mainly from small to large， the initial velocity of bubbles has a great influence on the hydraulic lifting speed of the pipeline， the turbulent kinetic energy in the slurry is 0.5 m2/s3. When the content is 0.3, bubbles will appear to be secondarily broken and broken. The bubble size distribution in the hydrate slurry system can be predicted by CFD⁃PBM to better predict the flow characteristics of the hydrate slurry after it is decomposed by natural gas.
The oil depot stores a large number of flammable and explosive materials. The operation process of the equipment is relatively complex and prone to accidents. Therefore, employees can only get on the job after training. The traditional training system is biased theory, and the training effect is poor. Taking Unity3D as the development platform, this paper develops an interactive virtual oil depot training system. The system adopts C# as the development language of interactive script and SQL Server for data management. It implements the functions of equipment attribute query, equipment interaction operation, and important process flow simulation in the form of first person view roaming. The system has a very real three⁃dimensional effect and interaction function, and strengthens the training effect of the oil depot staff.
In Changqing oilfield,the pipelines between Jingsi and Jingsan consociation station is vital for the waxy crude oil pipelining.The wax deposition,however,triggers huge economic,safe and efficient problems to the pipeline operation.A series of polyacrylate paraffin inhibitor (WI) with various side chain carbon number distributions were first synthesized by free radical polymerization,and the structural properties and crystallization properties were characterized by using the FTIR and DSC method.Then,the effects of the WIs on the rheological properties of the Changqing waxy crude oil were studied.The results show that after adding 400 mg/kg WI⁃2,the pour point of Changqing crude oil can be reduced by 10 ℃,the anomalous point can be decreased by 8 ℃,and the viscosity of non⁃Newtonian fluid region can be greatly reduced.After that,based on the indoor wax deposition experiment,the influences of the WI on the Changqing crude oil wax deposit properties were studied by settling various conditions and the wax deposition models of Changqing crude oil undoped /doped with WIs were developed.Using the wax deposition models to predict the wax deposit under the field operation condition,it is found that without adding WIs,the prediction error of the wax deposit thickness at different time is less than 5%,and the wax inhibition efficiency can reach 88%~95% after adding 400 mg/kg WI⁃2.
Hydrate is easily generated in natural gas deep⁃water pipelines. It is of great significance to study the formation of influencing factors on the safe operation of pipelines. PVTsim was used to establish a numerical model, and based on five experimental data, the reliability of the model was analyzed. Using this model, the boundary conditions of natural gas hydrate formation under different gas composition and salinity conditions were simulated. At the same time, based on experimental data and OLGA simulation data, the quantitative relationship between hydrate volume fraction and molecular concentration of medium was obtained. The rusults show that hydrate formation is more affected by temperature than pressure. For natural gas, the addition of ethane, propane, carbon dioxide, and hydrogen sulfide all increases the range of hydrate formation, and the addition of nitrogen will reduce the range of hydrate formation. As the salinity in the water increases, the range of hydrate formation decreases. External temperature and pressure have little influence on the amount of hydrate formation and are almost negligible. Based on the research results of the hydrate slurry transportation technology, the critical methane mole fraction that ensures the safety of the HCFC⁃141b and THF hydrate slurry flow was obtained.
The two zones of water injection after X well repair in Bozhong 25⁃1 oilfield are confronted with two major problems. First, the injection pressure difference between two layers is 18 MPa, and secondly, the application of steel wire or coiled tubing is used to replace the horizon. The operation cycle is long and the cost is high. In order to solve the above problem, a new type of non⁃throwing fishing periodic water injection technology is applied, and the underground water injection level and water injection volume are adjusted by surface hydraulic control. The optimum design of sand control pipe string and water injection pipe string is matched to replace repeated steel wire operation. The problem has been solved, which guarantees the safety of water injection operation in high pressure differential layer, and saves 100% of the time and cost of steel wire allocation.
This investigation focused on the analysis of the cracks in the expansion joints for a chemical plant. It was found that the cracks formed because the allowable displacement was insufficient to relieve the thermal stress originating from the heat exchanger. In this regard,a new⁃type expansion joint was designed providing a fast and effective approach to solve the problems concerning the leaking of flammable and explosive gas. Based on the successful operation within 12 years,this expansion joint of new type was verified to be secure,economical and practical. Furthermore,with an expansion range exceeding that of the standard ones with the same specification,it can be used to replace the expansion joint with single wave,and applied in structures where the compensation is moderate.
