In this paper, the promoting effect of green biological surfactant octylbetaDglucopyranoside on ethylene hydrate formation was experimentally investigated, in futher, the mechanism of promoting was also briefly explored. First, the effect of octylbetaDglucopyranoside on ethylene hydrate formation condition was researched. Then, the effect of octylbetaDglucopyranoside on ethylene hydrate formation rate and storage capacity was also tested. At last, the solubility of ethylene under the condition of phase equilibrium through Hysys was studied. The results show that compare with deionized water system, OctylbetaDglucopyranoside has little effect on ethylene hydrate formation in thermodynamics. While in the kinetics, it can dramaticlly decrease the induction time of ethylene hydrate formation and increase the rate of ethylene hydrate formation more than three times. In addition, the storage capacity can be increased by 50%, under the condition of 283.15 K and 2.20 MPa with storage capacity of 164.71, which is close to the theory storage volume. Under the condition of phase equilibrium, the dissolved value of ethylene in octylbetaDglucopyranoside solution is significantly higher than that in deionized water system, but is far less than the consumption of hydration.
The density functional theory has been employed to study the influence rule of the catalytic cleavage activity of C—H bond in hydrocarbons affected by adjacent groups under the copper acetate catalyst. The computed results suggested that the order of catalytic cleavage activity of C—H bond of methyl and methyne linking with different adjacent groups was: phenyl>nhexyl > cyclohexyl, while the order of catalytic cleavage activity of C—H bond of methylene was: phenyl>cyclohexyl>nhexyl. It was found that the effect of adjacent groups on catalytic cleavage activity of C—H bondwas related with charge value and space steric hindrance of adjacent groups before and after the adsorption on catalyst.
Heteropoly acid type ionic liquid BMAI［HPW12O40］ was synthesized as catalyst for simulate diesel oxidative desulfurization which was characterized by 1HNMR,13CNMR,IR and TG. The optimal reaction conditions were as follows: reaction temperature of 40 ℃, 15 mL oil sample, 1.75 mL hydrogen peroxide and 0.028 g heteropoly acid type ionic liquid. Under this conditions, good desulfurization ratio (95.5%) can be achieved. After the reaction, diesel oil and catalyst can be separated by simple decantation, and the activity of catalysts would not change obviously after recycling for 5 times. Furthermore, the oxidation kinetics of 4,6dimethyldibenzothiophen was investigated. The oxidation of 4,6DMDBT can be treated as a firstorder reaction, with the apparent activation energy Ea 31.55 kJ/mol and the preexponential factor
K0 2.36×104 min-1.
The Y/MCM41 composite molecular sieve was prepared by postsynthesis method and its performance was characterized by XRD, BET, N2 adsorptiondesorption and so on. In addition, its hydrothermal stability was studied. The results showed that the optimized synthesis conditions are as follows: pH 11,CTAB and SiO2 molar ratio of 0.15,crystallization time 48 h,and the composite molecular sieve had the properties of both mesoporous MCM41 and microporous Y. The acidity and hydrothermal stability of composite molecular sieve were better than that of pure mesoporous MCM41.
A new diesel pour point depressant (PPD) was synthesized using αmethacrylic acid ester, maleic anhydride, and styrene as raw materials.The results showed that the optimum reaction conditions were as follows: the mass fraction of azodiisobutyronitrile (AIBN) was 0.8%, the mole ratio of αmethacrylic acid ester, maleic anhydride and styrene was 6∶1∶1, the reaction temperature was 80 ℃, and the reaction time was 8 h. Meanwhile, the effect of depressants was best when its mass fraction was 0.1%. At the same time, A, B, and C surface active agent were added into PPD according to the different proportion, respectively. It was found diesel pour point was decreased by 17 ℃ when PPD and B surfactant was compounded with mass ratio of 4∶1.
Nanosilicon dioxide was organic modified with silane coupling agent KH550. The influence of modification conditions on surface ζpotential of nanosilicon dioxide was characterized by Zetasizer 3000. The modified nanosilicon dioxide was respectively compounded with petroleum sulfonate. The ability of the composite system for reducing the oil water interfacial tension was measured by interfacial tensiometer TX500. Turbiscan Lab was applied to analyze the stability of oilwater emulsion. The results showed that petroleum sulfonate system could reduce the oil water interfacial tension to about 2.30×10-2mN/m, and modified nanosilicon dioxide and petroleum sulfonate composite system could reduce that to about 5.42×10-3 mN/m, when the concentration of surfactant was 0.5% and the modified nanosilicon dioxide surface zeta potential was
-50.1 mV. The oilwater interfacial tension change and mechanism of emulsion stability were analyzed through the changes of surface zeta potential of modified nanosilicon dioxide.
The high water cut oil wells were unable to product normally because of the existance of fracture and natural microfracture in the low permeability fractured reservoir. In order to avoid the injected water going across to the old seam of oil wells in the process of water flooding and enhancing the sweep efficiency and oil recovery, the superfine cement plugging technology was put forward. Based on the optimization of water cement ratio of superfine cement, the concentration of corrosion inhibitor, reducing agent and defoaming agent in the plugging system was optimized, and the mechanical deformation capacity was also evaluated. The results showed that the optimum water cement ratio of superfine cement was 0.7 and the optimum cement slurry was the mixture of 800 head superfine cement, 0.4% corrosion inhibitor, 0.5% reducing agent and 0.5% defoaming agent. Because of the double efficacy of plasticizing and toughening, the slurry system had good mechanical deformation capacity and the flexural strength reached 48.9 MPa. This can completely met the plugging strength requirements in the field. This system has good application prospect in the old seam plugging of oil well in the fractured reservoir.
The traditional rod pumping unit with high share and low efficiency is still dominant in the energy consumption of oilfield, thus, the accurate evaluation of rod pumping unit energy consumption is significance to guide oilfield energy saving. Based on fuzzy mathematic theory and combined with the related standard, evaluation index system of energy consumption is established. Then, rod pumping unit energy consumption fuzzy evaluation model is set up by calculating index weight and membership function. The well of Xinjiang Oilfield is chosen for example analysis. The results show that the motor is not match and out of balance. The field specialist shows that the valuation model is comprehensive and accurate.
A calculation of formation capacity in QK oilfield was carried out to identify the distribution of main water injection layers. A comprehensive core flowing test based on orthogonal design with 15 core samples (2 000 mD approximately) was carried out and the core permeability damage rate indicated that the damage degree was caused by particle size distribution, concentration and oil concentration. Take all these factors into consideration, the impact on the damage degree in decreasing order was oil concentration, particle concentration and particle size. Meanwhile damage rate was predict applying statistical analysis under other conditions then the error range between the predictive value and the true value, was obtained and verified. The results can be concluded that when particle size, concentration and oil concentrations were of 4 μm, 3 mg/L and 18 mg/L or 4 μm, 7 mg/L and 15 mg/L, damage rate were 22.5% and 25%.
Molecular aggregation state of saltresistance polymer was changed by intermolecular association, which transparently enhanced its property of saltresistance. However, molecular size was increased while the state of molecular aggregation was changed. Thus the question of worse adaptability between saltresistance polymer and reservoir came out. By means of instrument analysis, chemical analysis and modern physical simulation method, taking reservoir geology, fluids and polymersurfactant agent of Daqing as research platform, regarding polymersurfactant solution viscosity, molecular thread size and seepage characteristics as evaluation index, the research on the adjusting method and effect of the state of molecular aggregation of polymersurfactant agent was carried out. The results showed that βCD could restrain the association of polymersurfactant molecules, thus reduce the size of molecular aggregation of polymersurfactant agent. All this led to the wider range of the permeability that could be flowed through. There existed a best matching relationship between polymersurfactant/βCD and core heterogeneity. On this point, the effect of enlarging sweeping volume of polymersurfactant agent was optimal and recovery efficiency reached a climax.
For the phenomenon that the rapid rise of water cut and a big difference in using degree between various layer types in the late stage of polymer injection, a new method that has achieved good results in field test is proposed. The flow pressure can be reasonably adjusted by stage andproduction levels can also be determined. For example, Lamadian Daqing Oilfield, variation of development indicators(such as production, pressure profile, etc) is studied after adjusting flow pressure through numerical simulation techniques. Compared to development effect, it is showed that when flow pressure is kept 6 MPa(higher)2 MPa(lower)6 MPa(higher), water cut is reduced by 1.46 percentage points, and degree of polymer flooding cumulative recovery is reduced by about 2.43 percentage points after 1.0 PV is injected, of which producing degree is best
Water sensitive damage and liquid trap caused by waterbased drilling fluid invasion are very prominent problems in the process of shale gas drilling and exploitation, which seriously affect drilling safety and production of shale gas well. According to the shale gas reservoir characterization and reservoir damage factor, based on nanoemulsion theory and basic reservoir protection principle, a novel nanoemulsion agents named SDME2 were developed by employing Gemini hyamine surfactant GTN, plus Tween 80, namyl alcohol and noctane as major raw materials. The results showed that the novel nanoemulsion agent could effectively reduce the surface tension of external fluid, increase contact angle, decrease water saturation in core, and increase recovery of low permeability reservoir permeability. The novel nanoemulsion agent was also conducive to shale gas desorption. Taking the newly developed shale gas reservoir protection agent as one of primary treatment agents, a new type of waterbased drilling fluid for shale gas reservoir protection was developed and its performance was good.
Cyclic waterflooding is an important method to improve oil recovery of vertically heterogeneous reservoir. The experiment results showed that it was difficult to enhance oil recovery by means of imbibition after a certain degree of waterflooding. Coreflooding experiments confirmed the effectiveness of cyclic waterflooding to increase oil recovery for the vertically heterogeneous reservoir and the increase trend to lower as more cycles were applied. The mechanical mechanism of cyclic waterflooding was investigated by means of capillary bundle model. Imbibition will play a role until the force field on the fluid is balanced. The main mechanism for the cyclic waterflooding method is related to the change of capillary pressure instead of the absolute value of the capillary pressure. Additional pressure between the layers with different permeability which is induced by the change of water injection scheme can cause the corresponding change of capillary pressure in the reservoir. The research provides some insight to improve the understanding and practice of cyclic waterflooding.
Cores experiments were conducted to study the effect of permeability and oil saturation of porous media on the characteristics of a number of plugging/profile modifying compositions. The results show that the effective plugging/profile modifying compositions are capable of selectively reducing the permeability of heterogeneous porous media by the greatest influence on the permeability of porous media, which has high water permeability and minimum oil saturation. It is found that the ability of compounds to selectively influence on the permeability of porous media is related to the presence of polymer globules or colloidal particles. Colloidchemical mechanism is proposed to explain the ability of profile modifying agent to selectively regulate the permeability in heterogeneous reservoir.
Methods of improving oil recovery of transition zone in Daqing oil field was studied. The adaptability of polymer flooding and ASP flooding transition zone was researched by water flooding development effect, core displacement experiment and numerical simulation method, etc. The results show that transition zone water flooding development effect is poorer than single oil area. Three or four stripes of water flooding effect are significantly lower than one or two stripes. One or two stripes polymer flooding can increase oil recovery by more than 12%, and ASP flooding can increase oil recovery by more than 20%. The polymer flooding and ASP flooding are suitable for one or two stripes. The ASP flooding is suitable for three or four stripes transitional zone. The fivepoint well pattern is suitable for one or two stripes, and ninepoint well pattern is suitable for three or four stripes. The optimum injectionproduction well spacing of one stripes is 106 meters, and three stripes injectionproduction well spacing is 75 meters.
The mathematical model was developed to describe the physical process of batching cool and hot crud oil. The hydraulic and thermal variation process of Jinhua pipeline batching transportation of Jidong crude oil and imported crude oil was simulated by selfdeveloped calculation program. Different transportation schemes were compared to determine an appropriate operation scheme of Jinhua pipeline. The results showed after the number of batching transportation cycle reaches to 2 or 3, the suction oil temperature of the next station changed periodically. The batching transportation safety of cool and hot crude oil can all be improved by heating the front cool crude oil or increasing the throughput of hot crude oil. By comparing different scheme, the appropriate batching transportation scheme for Jinhua pipeline in winter was determined.
A winwin purpose of Carbon Dioxide(CO2 ) emissions and efficient reservoir development can be achieved by injecting CO2 into reservoir. How to effectively reduce miscibility pressure between CO2 and crude oil, is one of the major hot and difficult problems for enhancing oil recovery by CO2 flooding. The methods of miscibility pressure reduction using CO2 flooding are compared, and new efficient CO2 philic surfactants are explored. Currently, mixing cosolvent with CO2 is limited by the price. Supercritical CO2 micromulsion can also reduce the miscibility pressure, while the main study is focused on reducing oil/water interfacial tension of ionic surfactants. Nonionic surfactants that can reduce oil/CO2 interfacial tension are rarely reported. Dissolving capacity of polar compounds in CO2 is small for the poor compatibility between CO2 and nonionic surfactant. So, the key to reduce miscibility pressure is CO2 philic surfactant.
