Abstract:The AM/Starch graft copolymer was synthesis using the ceric ammonium sulfate/potassium persulfate redox system, and then the antioxidant was added to prepare the HRS as the water-based drilling fluid filtrate reducer. The properties of HRS were evaluated in laboratory. The experimental results showed that HRS had excellent capacities of depressing the filter loss, thermal stability, saturated-salt resistance. At the high temperature of 150℃, HRS could be used in the operating environment that the maximum content of Ca2+ and Mg2+ was 2300 mg/Land 900 mg/L, respectively. In addition, HRS had microbial toxicity and was easy to be biodegradated.

Abstract:Terpolymer of fluid loss reducer for oil well cement was synthesized by acrylamide (AM), 2-acrylamido-2-methyl-propane sulfonic acid (AMPS) and N-vinyl pyrrolidone (NVP). The effects of the monomer concentration, monomer ratio on the fluid loss performance of polymer were investigated. Under the condition of 75℃ and 6.9 MPa, the API fluid loss of the cement slurry first decreased and then increased with increasing monomer content, increased with increasing AMPS dosage, and changed slightly with increasing NVP dosage. The optimum reaction condition was obtained as follows: 12% monomer mass fraction, 8.5:1.0:0.5 monomer mole ratio of AM:AMPS:NVP, 70℃ reaction temperature, 5 h reaction time, 0.7% initiator and 12 pH value. The fluid loss of cement mortar containing 4.2% (BWOC) polymer at 160℃ was of 60 mL with good slurry stability, 14 Bc initial consistency and rapid development of cement stone strength.

Abstract:Conventional acidizing treatment with HCl-HF system had bad efficiency of removing plugs and short effective period. For the above considerations and aiming at solving the problem of high water injection pressure and sever formation pore blockage in Huanxiling oil extraction factory of Liaohe oilfield, a non-HF retarded acid was synthesized with phosphide, organic acid and acetone. This organic phosphate’s capability of reducing injection pressure and enhancing injection was well when used alone without HF or fluoride salt. Indoor experiment results showed that the corrosion capacity of 20% retarded acid in aqueous solution to rock was 23.25% at 60℃ after 48 hrs treatment, which had a better retarding effect than HCl-HF and HBF4. The pH value of acid solution when the scale formed was between 7 and 8, and the complexing ability of that was 500~600 g/L, which could effectively prevent forming of secondary precipitations, such as Fe(OH)3 and Al(OH)3. Core flow test results showed that the permeability recovery could reach up to 173%. After retarded acidizing process, the core strength loss rate was 22.7%, which was 0.56 times that of mud acid treatment at the same condition. The retarded acid system, composed of 20% retarded acid, 3% clay stabilizer BSA-101, 0.1% corrosion inhibitor BSA-602, 0.5% discharge aiding agent EL-11, 0.1% demulsifier YBP-1, was applied in 2 wells on Liaohe oilfield. The water injection pressure was reduced by more than 5 MP and daily water injection volume was increased above 10 m3.

Abstract:Dealing with the study of Chang-8 oilfield group sandstone reservoir，the damage evaluation of fracturing fluid was discussed，and two experiment evaluations of dynamic damage for fracturing fluid were conducted，including the permeability damage of fracturing fluid filtrate for sample rock，and the dynamic filtration of fracturing gel breaking liquid for the flow back rate measurement of fracture-making rock. At the same time，several related experiment evaluations of static damage for fracturing fluid were finished，such as the compatibility between fracturing fluid and formation fluid or working fluid，the wettability between fracturing fluid and crude oil，the emulsification rate and the residue. The formula of fracturing fluid was 0.4% HPG（guar gum ）+0.4% AS-6（clay stabilizer ）+ 0.3% CX-307（demulsify-cleanup additive）+ 0.1% HCHO（microbicide）. The experiment results showed that the emulsifying rates were more than 60% when the volume ratios of oil and gel breaking liquid were of 3:1，3:2，1:1，and the emulsion breaking rates were only 12.00%—23.77%. The average content of fracturing fluid residue was of 703 mg/L，and the throat was easily blocked. The flow back recovery rate of fracturing rock was of 1.48%—85.83% ，and that was only 0.02%—42.9% when the fractures were supported by proppant. The emulsification damage of basic rock for fracturing fluid was strong with 89.83% average damage rate. The damage of liquid residual was strong with 73.71% average damage rate. The damage of fracturing fluid filtrate was medium-low with 44.85% average damage rate. The wettability of rock reversal from water-wet into oil-wet had been generated by fracturing fluid. The solid-phase invasion，alkali sensitivity and wettability reversal were the main factors of reservoir damage. The damage rate of solid phase intrusion was of 28.86%， that of wettability was of 44.98%，and that of alkali-sensitive for basic rock and fracturing rock was of 26.38% and 32.18%，respectively. It was suggested that using clean fracturing to reduce the damage of residue and choosing appropriate surfactant to improve the flow back rate for the reservoir protection and effective development of Zhenjing oilfield.

Abstract:A new kind of sulfonic anionic surfactant, palmitic acid methyl ester sulfonate, was synthesized according to the disadvantage of the cationic surfactant fracturing fluid, such as the greater loss of the cation and the reduction of permeability. The thicker JL was obtained by mixing palmitic acid methyl ester sulfonate and octadecanol at mass ratio of 1:2. the crosslinked reaction took place soon when adding a certain amount of JL to the 3.5% NaCl solution, resulting in forming the clean fracture fluids(CFFs). The performance of the CFFs, such as heat and shear resistance, viscoelasticity, sand-carrying property, flitration, gel-breaking property,et al, was investigated. The results showed that JL crosslinked reaction of 5% JL took place quickly in the 3.5%NaCl solution and the gel could be formed within 1~2 minutes, which had better temperature and shear resistance. The viscosity of the CFFs was 40 mPa·s at 80℃. The sand-carrying ability was increased by 48.7% compared to that of the macromolecule fracturing fluids. The gels could be broken with the addition of kerosene, and the gel breaker fluid was clear and had no residue. Hence, the degree of formation damage was low, being of 7.6%. In addition the CFFs belonged to neutral, so it could be used in acid and alkaline sensitivity reservoirs. The system could satisfy the demands of oil-gas the reservoir with low pressure and low permeability.

Abstract:A method of manufacturing high strength and low density resin coated ceramic proppants was developed, and the effects of dosage of phenolic resin and coupling agent, et al, on the sphericity, roundness, acid solubility, turbidity, density, crush resistance and short term flow conductivity of the procured resin coated ceramic were also discussed. The results showed that the apparent density and bulk density of the resin coated ceramic particles(RCCP) decreased by 8.1% and 11.2%, respectively, compared to that of the resin coated quartz sand(RCQZ); and the crushing rate of the RCCP and RCQZ under 69 MPa was1.7% and 8.1%, respectively. The roundness of the RCCP was better than that of the RCQZ; as a result, the short term flow conductivity of the RCCP could be improved more than one time compared to that of the RCQZ. Based on conductivity data, the mechanism that the oil flow conductivity of the RCCP to was bigger than the water flow conductivity was proposed. The field test of the RCCP was conducted in 5 wells of Wenmi oil field. It was proved by field construction that the average yield of crude oil per well was increased by 1.35 t and the water cut per well decreased by 7.9%.

Abstract:The stability of nano-scale polymer particles is the key factor on its application. In view of the requirements of nano-sclale polymer particles applied in profile modification, the desired nano-particles coded MG-50 with initial state of reverse microemulsion was selected from three like products according to the performance of dispersion stability tests and radius analysis by scanning electron telescope, and then was testified by thermal resistance and shear stability. The results showed that MG-50 exhibited great stability both in formation water and in injection water with 7 times of initial radius and wide distribution range in 22 days. And MG-50 with 0.3% mass fraction had a plugging efficiency more than 75% in low permeability sandpack after aging for 3 month at 85℃; nevertheless it became fragile and less rigid. In addition, though 0.3% MG-50 solution was shear thinning emulsion, it was evident that shear velocity calculated with evolution of injection velocity by combination of Darcy Law and Poiseuille Law in medium-low permeability core had a little effect on residual resistence factor, indicating good performance of shear resistence.

Abstract:Aimed at the serious problems of steam channeling and water channeling in Gudao oilfield development process due to formation heterogeneity, the silicate particulate plugging technology was developed. The compressive strength and the permeability of the consolidation body prepared from silicate particulate with different particle sizes of≤0.8 mm, 0.8～1.2 mm and≥1.2 mm were measured and other performance evaluation and core flow experiments were carried out. The results showed that under the same experimental condition, the smaller the silicate particles, the higher the compressive strength of the consolidation body, and the lower the permeability of the consolidation body. The temperature-resistance of the consolidation body was excellent. From oil sand controlling experience in the field, the silicate particles size and combination was selected according to the reservoir permeability and formation sand median. Generally, the silicate suspensions which the particle size was less than 0.8 mm and in range of 0.8～1.2 mm were used as ahead slug and post slug, respectively. 8 wells were implemented using the silicate particulate plugging technology. Field test proved that the technology could improve gas injection, production profile and steam injection effect, lower water content in oil wells.

Abstract:Block 7 in Jiangsu oilfield was a high temperature and low permeability reservoir. In order to enhance reservoir development effect, the application feasibility of polymer flooding in such reservoirs was studied through the performance evaluation and injection experiment of polymer solution. The comb polymer, sulfonated polymer and regular polymer with low molecular weight were compared through original selection. The results showed that comb polymer had good thermal and salinity resistance. The viscosity of 1000mg/L comb polymer in clean water solutions was 22.4 mPa·s（25℃）and 10.1 mPa·s（83℃）, and that in waste water solutions was 10.6 mPa·s（25℃）and 5.7 mPa·s（83℃）. Four kinds of comb polymers （M=480×104—1550×104）were further screened. The shear viscosity retention rate was of 89%—100%, the viscosity retention rate aging 90d at 83℃ was of 88.5%—95.1%, which indicated that the polymer had good shear and thermal resistance. Injection experiments showed that the injection pressure of polymer solution increased with increasing polymer molecular weight and concentration. The comb polymer solution with molecular weight of 10 million could be injected into artificial core with permeability of 50×10-3μm2. With the increase of polymer concentration, low molecular weight polymer solution also had good flow control ability. The comb polymer with 10 million molecular weight could block natural core with permeability less than 30×10-3μm2, and that with 6.16 million molecular weight could meet the injection requirement of natural core with 20×10-3μm2 permeability. Considering the flow control ability, injection and polymer controlling scope, it was suggested that comb polymer HF 62208 with molecular weight of 6.16 million was suitable for the polymer flooding of Block 7 in Jiangsu oilfield.

Abstract:The wettability of a porous medium had significant effects on microscopic and macroscopic displacement efficiency. Visual microscopic model and image processing technique were conducted to investigate displacement efficiency and displacement mechanism of polymer flooding. The effect of micro aspect and distribution of bound water and heavy oil on polymer solution adsorption, trapping, continuous and discontinuous flowing, displacement frontier and pore to pore sweep oil had been analyzed under strongly oil-wet and water-wet medium. The results conducted by microscopic model indicated that in water-wet medium, the formation water tended to distribute in the surface of rock skeleton and form thick water film near the wall of hole. Also, polymer tended to adhere to the wall of pore hole which had higher sweep efficiency. On the contrary, in oil-wet medium, bound water mainly distributed to the porous medium in continuous phase and crude oil absorbed on the pore throat. Snap-off effect of polymer solution resulted in a small part of sweep oil, and emulsion formed by oil and polymer solution assisted to polymer flooding. Microscopic displacement efficiency of polymer flooding in water-wet medium was apparently higher than that in oil-wet medium. The experiment results of core flooding accorded with that of microscopic model. On the one hand, longer frontier breakthrough time was observed in strong water-wet cores and the breakthrough leading edge was more uniform with 21.5%OOIP oil recovery for water flooding, compared with oil-wet ones (15%OOIP). On the other hand, in oil-wet medium, the threshold of polymer viscosity was higher than that in water-wet medium. After water flooding, 23%OOIP and 17%OOIP oil recovery of water-wet and oil-wet cores was improved by 500 mPa·s polymer flooding respectively.

Abstract:The effect of heterogeneity variation coefficient of reservoir （Vk）on polymer displacement effect and dynamic characteristics of every thin stratum was investigated by numerical simulation technology. The results indicated that when Vk was the same, especially Vk≥0.3，the ultimate recovery degree of high permeability stratum was high（61%～62%）and the recovery ratio increment of polymer flooding was low（5%OOIP～15%OOIP）. The final recovery degree of each small stratum was about 62% when the reservoir was relatively homogeneous (Vk=0~0.3), which had high efficiency by water flooding. With increasing Vk, the recovery ratio increment of high permeability zone (6, 7 single layer) reduced from15.71%OOIP and 16.27%OOIP to 13.78%OOIP and 6.47%OOIP respectively, that of middle-high permeability layer (4, 5 single layer) increased from 14.68%OOIP and 15.14%OOIP to 30.35%OOIP and 23.52%OOIP, and that of middle-low permeability layer (1—3 single layer) increased first and then reduced. When the water cut was of 98%, the high permeability layer input polymer solution more and the water cut was high, the low permeability layer input polymer solution less and the water cut was low. Remaining oil mainly existed in relatively lower permeability layer (1—4 single layer). The quantity of polymer solution pouring into 2—4 single layer was of 17%, 22% and 28% accounting for the small layer pore volume, and 5%, 7% and 10% accounting for the injection amount. 2—4 single layers were the main contribution horizon which improved oil recovery by polymer flooding on the scheme conditions.

Abstract:In order to improve the development effect of high-temperature low-permeability reservoir，the influence factors of surfactant flooding were researched. At the temperature of 114℃，the influence of interfacial tension（IFT），emulsification，wettability reversal and injection time on the injection pressure，displacement efficiency were proded by carrying out the surfactant flooding experiments in water-wet and oil-wet cores. The results showed that the lower the IFT between surfactant and crude oil，the clearer the increment of displacement efficiency and decrement of injection pressure. The faster the emulsion rate of surfactant，the higher the oil recovery; and the stronger the ability to reduce viscosity by emulsification，the better the pressure reduction effect. Meanwhile，it was beneficial to decrease properly the emulsion stability as for displacement. The wettability reversal of surfactant made the displacement become more effective even when the IFT was higher. Moreover，it made the effect of increasing oil production and decreasing injection pressure in oil-wet core better than that in water-wet core. Furthermore，the surfactant flooding at medium water cut stage could obtain maximal oil recovery via minimal input.

Abstract:A compound surfactant system of carboxybetaine/alkylamide at mass ratio of 1:1 was achieved, and then the interfacial activity, adsorption resistance and the alteration of three-phase contact angle were studied, besides, flooding experiments were conducted. The results showed that the system could reduce interfacial tension between water and Linpan crude oil to 10-3 mN/m magnitude. After the static adsorption of the quartz sand, the surfactant system still had the lower interfacial tension and good emulsification property. With monitoring three-phase contact angle, the surfactant system made the surface of the core change form hydrophilic to lipophilic, which could reduce the Jamin effect of oil droplets in the low permeability pore and improve the development?result of water injection. Based on weak alkaline water flooding in the field, the oil recovery further was increased by 13% after injecting 1.5 PV surfactant system slug with mass fraction of 0.5%, and the injection pressure dropped. This surfactant system had a certain application value in low permeability oilfield.

Abstract:A new HPLC stationary phase was prepared by directly physical coating hydrophobically associating water-soluble polymers (HAWP) on the surface of silica. Elements analysis of the stationary phase showed that HAWP was successfully coated onto the surface of silica. The retention parameters of single-chain alkylbenzene sulfonate, alkylnaphthalene sulfonate and double-chain alkylbenzene sulfonate with different carbon number on this stationary phase were investigated in the mobile phases of water and simulation formation water of different mineralization, respectively. The thermodynamics of the interaction between sulfonates surfactants and HAWP were investigated by HPLC. The result indicated that the HAWP was spread in distilled water, so the interaction between HAWP and sulfonates was mainly effected by the competition of hydrophobic effect and steric effect; while the HAWP was in the state of contraction in the simulation formation water, so the interaction between HAWP and sulfonates was mainly effected by hydrophobic effect, and the higher the mineralization, the severer the contraction of the polymers, the smaller the hydrophobic effect.

Abstract:At first, the betaine surfactants new 2# for the binary oil displacement system suitable for Changqing oilfield was chosen from the sulfosalicylic-hydroxyl amphoteric surfactant（new1#、new2# and new3#）, whose carbon atomic are 12, 14 and 16, respectively, by determining the interfacial tension between the Changqing crude oil and SP binary system containing 1500 mg/L HPAM and surfactant with different concentration. Using oil sand of Changqing reservoir as adsorbent, the interfacial tensions between the binary system with different surfactant concentration and the Changqing crude oil were determined by means of static oscillation adsorption after multilevel adsorption and the changing trend of interfacial tension was studied. The research results showed that The changing trend of minimum interfacial tension was the same as S-type of adsorption isotherm. With the increase of adsorption times, the higher the concentration of surfactant was, the more slowly the minimum interfacial tension increase. The lower the concentration was, the larger the changing range of interfacial tension was. With the increase of adsorption times, the range became smaller; and the lower the concentration was, the faster the decrease of the range was. The result of displacement experiments indicated that based on the water flooding (oil recovery being of 25%), the oil recovery was increased 10% by injecting the binary system containing 1500 mg/L HPAM and 2000 mg/L new2#, which met the demands of the SP binary flooding in Changqing oilfield.

Abstract:The influence of the oil reservoir heterogeneity variation coefficient (Vk) on surfactant/polymer (S/P) displacement effect and dynamic characteristics of every thin stratum was researched by numerical simulation under the conditions of Daqing oilfield at 45℃ . The ideal geological model was established by the reservoir numerical simulation software, which was divided into seven single layers. When Vk（Vk>0）was the same，the permeability of 1—7 single layer increased gradually. When Vk was from 0 to 0.3, the recovery degree of every single layer and all-region was stability in 60% or so and was affected little by Vk. The final recovery degree of 1—4 single layer and all-region decreased with increasing Vk and that of 5—7 single layer was stable basically. The greater Vk, the lower recovery degree of low permeability single layer was. When Vk was of 0.9, the recovery degree （OOIP） of 1—7 single layer was 3.39%， 8.22%， 21.13%， 41.83%， 63.38%， 63.95% and 63.97%，respectively. Correspondingly, S/P system injection quantity of 1—7 single layer was 0.0014, 0.0031, 0.0077, 0.02, 0.051, 0.1183 and 0.1971 PV, respectively. Compared with water-flooding, the recovery ratio increment of S/P displacement of medium, low permeability layer was higher than that of high permeability layer. Vk corresponded the maximum of recovery ratio increment was different with different permeability. Vk corresponded the maximum of 1—5 single layer recovery ratio increment was 0.3, 0.3, 0.5, 0.72 and 0.9, respectively, and that of 6 and 7 single layer was affected little by Vk. When the comprehensive water cut was up to 98%, the water cut curve of every thin stratum was in line with the corresponding curve of eventually recovery degree in different Vk conditions. So as to further illustrate, the water cut of the layer with low final recovery degree was low also.

Abstract:Metabolic ingredients of the strains of HD-322-2 and T103 were analyzed by Infrared spectrum and high performance liquid chromatography, respectively, and core simulation flooding experiments were conducted using the strains of HD-322-2 and T103. The results showed that the strains of HD-322-2 and T103 could yield a lot of surfactant and the yield of the surfactant were about 321 mg/L and 195 mg/L, respectively. After fermentation for 20 h, the strain T103 mainly produced mini-molecule organic acids, such as acetic acid(1.10 g/L), propionic acid(0.24 g/L)), and butyric acid (1.57 g/L). The experiments of physical simulation flooding showed that the strains of HD-322-2 and T 103 had strong flooding performance and the mixing strains could improve the oil recovery about 5% to 7% based on water flooding.

Abstract:It was found that the sulfate reducing bacterium (SRB) increased by two order of magintitude and the nitrate reducing bacteria (NRB ) change little by examining the produced water of the Baolige oilfield. In order to restrain the growth of them SRB, the denitrification inhibition technology was probed. The experiment results indicated that the additive nutrient substance in different concentrations could produce microbiologically influenced corrosion, and the nutrient substance with low concentration could promote SRB. The addition of 0.25% nitrate into the production water made the number of bacterial (NB) of NRB increased from 1.4×103 to 6.5×105 units per milliliter , and the NB of SRB decreased from1.5×104 to1.0×101 units per milliliter. At last, the corrosion of N20 steel in the production water containing nutrient substances decreased by 21.41% by adding 0.25% nitrate. As a result, the denitrification inhibition could restrain the growth of SRB effectively.

Abstract:Based on the geological conditions, Water flooding characteristic and the current difficult of stable yield of Ba-19 fault block, Huabei Oilfield Company have employed the overall microbial circulating oil displacement technology by established stable microbial field in this block. Firstly, four strains of efficient production microbes were screened from target reservoir. The laboratory study indicated that the four kinds of microbes could not only well adapted to the reservoir environment, but also had the good viscosity reduction and emulsifying effect for crude oil. The gas chromatography (GC) analysis showed that the screened strains could use the crude oil as carbon source, and degrade long-chain hydrocarbons effectively. Especially by compounded these microbes according to equal proportions, the viscosity reduction rate reached up to 52.8% and based on 49.5% oil recovery of the water flooding, the oil recovery was enhanced by 9.1% by physical model experiment. The microbial concentration in target reservoir reached 105—106 cells /mL and maintained over 8 months. The results demonstrated that the injected target microbes could grow and reproduce effectively in reservoir. The water cut was controlled lower than 85% and the oil recovery improved obviously. The cumulative incremental oil was 15000 t within 12 months, and the input-output?ratio?was up to 1: 2.5.

Abstract:According to the heavy oil reservoir geology and the characteristics of heavy oil of Zhongyuan oilfield, through the orthogonal experimental design method, the optimal recipe of the titled viscosity reducer system was obtained as follows: 0.05% nonylphenol polyethylene ether NP-10+0.1%amphoteric ionic surface active agent CS-B+0.1% sodium dodecylbenzenesulfonate ABS, in other words, when the mass ratio of NP-10,CS-B and ABS was 1:2:2, the viscosity-reducing effect of the system was the best. Moreover, the effects of pH value, water content, water salinity, bivalent cation concentration, temperature, et al, on the viscosity reduction of the heavy oil were investigated. The viscosity reduction rate of the heavy oil was up to 99% when the mass ratio of the heavy oil to the viscosity reducer solution was 7:3,in addition, the system was resistant to high temperature of 110℃, and tolerant to Ca2+ and Mg2+. In a word, the viscosity reducer was suitable for the heavy oil well of Zhongyuan oilfield.

Abstract:The oil viscosity reducing properties of oil-soluble solvents(Y-1—Y-7) and their compound system were studied according to the heavy oil of Xianhe area in Shengli oilfield. The effect of these solvents dosage and water cut of oil on viscosity reducing was investigated, and that of the solvents on steam flooding process was also studied. The results showed that the viscosity reducing rate of heavy oil increased rapidly with increasing solvents dosage when the mass concentration of the solvents was less than 5%, and then increased slowly. When the mass concentration of solvents was up to 15%, the viscosity reducing rate of these solvents except Y-4 was greater than 90%. A combination of Y-3 and Y-7 in mass ratio 1:1 achieved the best viscosity reduction effect whose viscosity reduction rate was 76.1% and 93.14 % with the sum dosage of 5% and 10%, respectively. The viscosity of heavy crude oil without viscosity reducing solvent increased first and then decreased with increasing water cut. The viscosity of oil with 50% water cut was 3.9 times than that of pure oil, and W/O emulsion was developed. After adding viscosity-reducing solvents, the viscosity of oil greatly decreased and the viscosity reduction rates of oil-water system decreased first and then increased with increasing water cut which achieved the minimum with 10% water cut except Y-1. The recovery factor increase of steam flooding of heavy oil was 3.1%—6.3% when 0.009—0.027 PV viscosity-reducing solvents were injected in advance.

Abstract:The major factors affecting the viscosity of the crude oil from Jilin oilfield were figured out by using modern physical analysis technology. A type water soluble viscosity reducer was selected, and the emulsification method was used. By the static performance evaluation experiments, the emulsion stability, particle size distribution, interfacial tension, viscosity reduction rate and washing oil efficiency were studied and the viscosity reducing effect of A type water soluble viscosity reducer was evaluated. The results indicated that wax content of Jilin crude oil was up to 14.7%, which was the major factor affecting the viscosity. The higher the concentration of the reducer was, the smaller the water separation was; the sharper the size distribution of the emulsion, the lower the interfacial tension was and the more stable the emulsion was. The water separation of oil emulsion decreased with the increase of the concentration of the reducer; moreover, the trend was notable with the higher oil-water ratio. The viscosity reduction rate of the crude oil increased with creasing the concentration of the reducer and lowering oil water ratio, and which could reach up to 91.5%. Besides, the reducer had a good washing oil efficiency of 61.1%.

Abstract:No.1 and No.2 polyether with molecular mass of 1500 and 3000, chain arrangement PO-EO and PO-EO-PO, were synthesized with KOH as catalyst, fatty alcohol, ethylene oxide(EO) and propylene oxide(PO) as raw materials. Then, 12 kinds of polyether esters defoaming agent were prepared with lauric acid or stearic acid as esterification agent, p-toluene sulfonic acid as catalyst. The effect of reaction time, the molar ratio of polyether and esterification agent and catalyst dosage on the esterification rate of defoaming agent was investigated. The optimum reaction condition was obtained as follows: 140—160℃ reaction temperature, 1.2:1 polyether and esterification agent molar ratio, 7 h esterification time. The defoaming agent was used to handle the manifold sample of Lüda 5-2 comprehensive wellhead in Bohai Sea. Experiment results showed that the defoaming rate of polyether ester defoaming agent was 87.8% with p-toluene sulfonic acid and No.2 polyether as raw materials, which was superior to that of general organic silicon defoaming agent (66.7%) and slightly weaker than that of fluorine alkyl silicone defoamer (91.1%). The application development prospect was good.

Abstract:Aimed at the difficulty in demusification of crude oil from Shanbei Chang4 + 5 oil layer characteristic of high viscosity, high content of asphaltene, the silicon polymer emulsifier WD -56was screened from 9 kinds of silicon polymer emulsifier via bottle experiments, and the effect of the dosage of WD-56and temperature on demulsification were investigated and the microstructure of the water-in -oil emulsion was observation during the process of the demulsification. The results indicated that silicon polymer demulsifer WD-56gave a higher separation of water from water-in -oil emulsion than that of demulsifer Y which was currently widely used in Changqing oil field. The dehydration rate of emulsion was up to 94.26% when adding100 mg/L of WD -56at the temperature of 45℃ for 2 hours. The mechanism of demulsification was characterized by studying interfacial properties and the chemical structures of the emulsifiers, suggesting that solubility of the demulsifers in the oil phase determined their variations in demulsification efficiencies.

Abstract:In order to solve pretreatment problem of reverse osmosis membrane methods which were used for the secondary effluent from the oilfield sewage, the combined process of flocculation and ultrafiltration was used for the advanced treatment of the secondary effluent from the oilfield sewage, and the removal effect of flocculation, ultrafiltration and the combined process of the two on TOC and turbiditywere studied, respectively. The results showed that with flocculation only, the removal rate of turbidity was 90.6% while that of TOC was below 20% on condition that the optimal dosing quantity of PAC was 40 mg/L and PAM was 0.5mg/L. With the combined process of flocculation and ultrafiltration, the removal effect of TOC and turbidity reached above 98% and 30%, respectively, which could not only improve the quality of the treated water but also produce a remarkable effect on the increase of water flux and the reduction of membrane fouling. ?The product water silt density index (SDI) of the combined process of flocculation and ultrafiltration was less than 3, which could meet the requirements of reverse osmosis feed.

Abstract:Advanced treatment of Fenton oxidation was used to treat heavy oil wastewater which was hard to make effluent COD meet the discharge standard by conventional treatments due to its complexity, poor biodegradability and great toxicity. The effects on COD removal by dosages of H2O2 and Fe2+, oxidation time, pH value and dosing mode were studied. Experiment results showed that under the operating conditions with 1:1 mole ratio of H2O2:Fe2+, 1:1 mass ratio of H2O2:COD, 2 h oxidation time, 3 initial pH value, 18~20℃reaction temperature and adding chemicals once for all, the removal efficiency of COD was higher than 74% and effluent COD was of 58.9 mg/L, which could meet the discharge standard completely. In addition, increasing of addition times of reagents could improve the removal of COD in wastewater.

Abstract:Phosphotungstic acid method is a classical method to measure the Cationic degree of zwitterionic surfactant, and the method can be also used to determine the content of cations or zwitterions of the drilling fluid materials. It is not easy to determine the organic cationic degree of drilling fluid materials containing organic cationic groups accurately due to the complex composition and the deeper colour of sample solution. In this paper, products was purified first by cation exchange resin of sodium type, then the phosphotungstic acid standard solution was used to determine the organic cation degrees quantitatively with congo red as indicator in weak acidic conditions. The experimental relative error was 0.59%. In the paper, the method, principle, operating procedure and method validation was introduced. The results showed that the organic cation content of the drilling fluid could be determined with phosphotungstic acid method, which is free of anion and inorganic cations. The core relative recovery experiment also showed that the measurement results fitted in well with the usability, and the results were reliable.

Abstract:Aluminium citrate was widely used in water shut-off, profile control and oil displacement operation in oilfield. It was necessary to determine aluminum content during the process of producing and using. But the related determination method hadn’t been found in industrial standard or research report. Citric acid would interfere with the determination of aluminum when routine complexometric titration was adopted. The content of aluminum in aluminium citrate could be determined precisely by the way of complexometric titration if the interfere produced by citrate ions was removed by preprocessing with acids. The twelve hydrated aluminum potassium sulfate samples containing citric acid were treated with sulphuric acid and nitric acid whose volume fraction was more than 50% for digestion in the room. Xylenol orange had been put into the samples before titrated. Then an appropriate amount of sodium hydrate solution was added into the test solution whose color changed from yellow to purple. Finally 8% nitric acid solution was used for changing the color of test solution to light yellow. The pH value was between 5.5 and 6.0. Titration end point was clear, and the absolute relative error was less than 1%. The recovery rate with standard sample ranged from 99.46% to 100.28%, and the absolute value of relative error for every determination was less than 2%, which showed good parallelization and had solved the problem of controlling product quality of aluminium citrate timely and effectually.

Abstract:Based on the complex principle of phosphotungstic acid (PTA)-magnesium chloride (MgCl 2)-demulsifier，a new determining method of polyether demulsifier TA 1031by spectrophotometry was established. The optimum determination condition was obtained as follows: 480 nm measurement wavelength ，0.4 mL10% MgCl2，1 mL10% PTA ，3 mL5% hydroquinone sulfuric acid solution，2.0 pH value of solution，5 minutes reaction rest time. When the mass concentration of TA1031was 0—30mg/L，the nlinear relationship was good with the equation of linear regression A=0.0378c + 0.0083and 0.9912correlation coefficient. When distilled water was replaced by trihydroxy methyl amino methane-hydrochloric acid (Tris-HCl) buffer solution，the PTA-MgCl2 precipitation agent system could be simplified with 0.050 mol/L Tris dosage of 0.7 mL. TA1031solution mixed with formulated sewage of Chenzhuang was determined by improved method. When the mass concentration of TA 1031was in the range of 0—36mg/L，the linear relationship was better with the equation of linear regression A=0.0283c + 0.1135 ，0.9904correlation coefficient ， and <5% relative error. When the demulsifier LE-28E and CZ mixed with Chenzhuang sewage were determined by this improved method，the linear range was0—40mg/L and 0—45mg/L，and correlation coefficient was 0.9953and 0.9929，respectively.

Abstract:In this work, the methods of determining oil displacement efficiency were introduced. As for four different crude oils, the oil displacement efficiency of different oil displacement agents was determined by UV-vis, TG-DTA, and Muffle furnace, respectively. The compositions of the oils were analyzed by UV-vis and IR, the complication of the oils was known. In theory, the elution rate of different compositions of the crude oils should be the same in order to avoid the error cause. The UV-vis spectrum of the crude oils the oils eluted by oil displacement agents was analyzed and big differences were found. Besides, it was found from IR spectrum that the main compositions of oil are saturated hydrocarbon, which cannot be detected by UV-vis absorption, in other words, the main compositions of oils can't be detected by UV-vis, hence, there will be big errors in oil displacement efficiency determining by UV-vis method. By comparing the results of oil displacement efficiency determining by UV-vis, TG-DTA and Muffle furnace, it was found that the test results by TG-DTA and Muffle furnace was similar, but different from that by UV-vis method. Through reasoning and experimental confirmation, the method of TG-DTA was better than the method of UV-vis in this experimental condition.

Abstract:The research progress of fluid loss additive used in domestic oilfield which was prepared by modified natural products, polymers, synthetic resin, and organic-inorganic composite materials based on drilling fluids was introduced. The research of film-forming fluid loss additive and other new types were also reviewed. The research thinking and study methods of fluid loss additive used for drilling fluids in recent years were summarized. The development trends of fluid loss additive based on drilling fluids were discussed.

Abstract:Cationic starch was a green chemical which synthesized using starch as primary raw materials and was more and more widely used nowadays. The preparation techniques of cationic starch at home and abroad including wet process, dry process and half-dry process were briefly summarized. The applications of cationic starch in oilfield，especially the applications as drilling fluid additive, water treatment agent, profile control and water shutoff agent and oil-displacing agent were reviewed. Development prospect of cationic starch was discussed, and the important practical significance of developing the study of cationic starch greatly was pointed.

Abstract:The theory of heavy oil colloidal system was extensively researched at home and abroad and the application progress was reviewed. The characters of heavy oil colloidal system such as electric double layer effect ，stability，rheological property and so on were analyzed. And the applications of this system in heavy oil exploitation ，transportation and processing were introduced. Based on these studies，the existing problems of the theory research of heavy oil colloidal system were advanced，and the future research direction was discussed.

Abstract:Taking the papers published in Oilfield Chemistry during 2006 to 2010 as the data source, by means of the bibliometric method, the published article volume, citation quantity, year distribution of citations, citations language and citation type were analyzed statistically, which provided quantitative basis to further enhance the quality of journals. The results showed that 521 papers were published during 5 years which the published article volume increased every year. The citation quantity was of 4830, the average citation rate was of 99.04%, and the average number of citations per article was of 9.27. The year distribution of citations focused on 10 years before the papers published. The average Price Index was of 34.62%. Citations languages were mainly Chinese and English. The citations in Chinese covered 72.90% with 3521 pieces, and that in English covered 27.02% with 1305 pieces. The main type of citations was journal literature which covered 74.16% of the total citations with 3582 pieces. The citations form book covered 9.50% with 459 pieces, patent literature covered 4.41% with 213 pieces and SPE paper covered 7.93% with 383 pieces. Network resources were not quoted.

Abstract:A bibliographic management software, EndNote, is briefly introduced. The template of reference format meeting the standard of Oilfield Chemistry is established. The usage of the template in MS Word is introduced, which can avoid the common problems of references in the manuscripts. The authors are strongly encouraged to use EndNote and the template in the manuscripts before submission.