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Liu L.,State Key Laboratory of Offshore Oil Exploitation | Zhang J.,China National Offshore Oil Corporation
Xinan Shiyou Daxue Xuebao/Journal of Southwest Petroleum University | Year: 2012

The effect of equipment of rapid dissolution of polymer on the dissolution time of the hydrophobic association water-soluble polymer (AP-P4) is studied. Experimental results indicate that stretching device would shorten the dissolution time of the hydrophobic association water-soluble polymer (AP-P4). Moreover, the best spacing of the stretching device is 200 μm, at which the shortest dissolution time of the hydrophobic association water-soluble polymer (AP-P4) is 25 mins. The hydrophobic association water-soluble polymer (AP-P4) after treatment with equipment of rapid dissolution of polymer would dissolve in 30 mins. And the dissolution time of the hydrophobic association water-soluble polymer (AP-P4)decrease with water temperature increasing.


Zhang J.,State Key Laboratory of Offshore Oil Exploitation | Zhang J.,China National Offshore Oil Corporation
Advanced Materials Research | Year: 2013

A novel kind of activated polymer flooding (APF) composing activated agent and polymer components designed for the target reservoir is studied for the first time. Interactions between the activated agent and natural surfactant from heavy oil, and the synergistic effect between the activated agent and polymer are existed. APF could enhance more oil recovery with less investment, compare to polymer-surfactant flooding (PSF) in the offshore heavy oilfield. The optimum formulation of APF is 1200mg/L polymer + 500mg/L activated agent. Experimental results implies that (1) the contained amide groups and sulfonic groups in APF can form hydrogen bonds with -NH2 groups contained in PM, (2) the apparent viscosity of APF was higher than PM along with the increase of shear rate, (3) the viscoelasticity, deformation capability and solubility of APF were much better than PM. © (2013) Trans Tech Publicutions, Switzerland.


Li R.,State Key Laboratory of Offshore Oil Exploitation | Li R.,China National Offshore Oil Corporation
Applied Mechanics and Materials | Year: 2013

The solvent flotation technique adopts organic solvent with low volatility as the second liquid phase, which could dissolve the components including emulsified crude oil, surfactant in the water. The modification of pH value, ion intensity, temperature, speed of air flow, and species of solvent could improve the efficiency of the flotation. The proposed method has been successfully applied to produced water treatment, the pharmaceutical industry sewage disposal and so on. It also has potential usage in sewage disposal of offshore oil field. © (2013) Trans Tech Publications, Switzerland.


Bai Y.,China National Offshore Oil Corporation | Bai Y.,State Key Laboratory of Offshore Oil Exploitation | Li Q.,China National Offshore Oil Corporation
Science China Technological Sciences | Year: 2010

Gas production from hydrate reservoir by the combination of warm water flooding and depressurization is proposed, which can overcome the deficiency of single production method. Based on the combination production method, the physical and mathematical models are developed to simulate the hydrate dissociation. The mathematical model can be used to analyze the effects of the flow of multiphase fluid, the kinetic process of hydrate dissociation, the endothermic process of hydrate dissociation, ice-water phase equilibrium, the convection and conduction on the hydrate dissociation and gas and water production. The mechanism of gas production by the combination of warm water flooding and depressurization is revealed by the numerical simulation. The evolutions of such physical variables as pressure, temperature, saturations and gas and water rates are analyzed. Numerical results show that under certain conditions the combination method has the advantage of longer stable period of high gas rate than the single producing method. © 2010 Science China Press and Springer-Verlag Berlin Heidelberg.


Bai Y.,State Key Laboratory of Offshore Oil Exploitation | Bai Y.,China National Offshore Oil Corporation | Zhang X.,State Key Laboratory of Offshore Oil Exploitation | Zhang X.,China National Offshore Oil Corporation
Shiyou Xuebao/Acta Petrolei Sinica | Year: 2011

The microscopic mechanism of oil displacement by viscoelastic polymer solution flooding was theoretically analyzed with a mechanical method in order to recover residual oils bound by capillary pressure in the pore throat, sudden-expanded pore space and dead-end. Microscopic increment expressions for the availability of residual oils in different pores under the viscoelasticity of polymer solutions were individually derived. The results showed that the critical radius of the pore throat for available residual oils with the presence of viscoelastic polymer solutions was greater than that with the mere presence of viscous polymer solutions, because the former could result in the partial flow of the previously immobile residual oil and the more facile flow of the previously mobile residual oil, consequently, more residual oils could be displaced in viscoelastic polymer solution flooding. Analytical results demonstrated that residual oils in the sudden-expanded pore space and dead-end could be hardly displaced when viscous polymer solution flooding was applied alone, however, they could be partially displaced under the effect of extruded swelling behavior caused by the viscoelasticity of polymer solutions. The dimensionless parameter denoting the relative dominance of gravity and capillary pressure was then suggested, i. e. the greater the dimensionless parameter, the more accurate the increment expression theoretically deduced for the availability of residual oils in the sudden-expanded pore space and dead-end.


Zhang X.-S.,China National Offshore Oil Corporation | Zhang X.-S.,State Key Laboratory of Offshore Oil Exploitation | Ding M.-A.,Sinopec
Xinan Shiyou Daxue Xuebao/Journal of Southwest Petroleum University | Year: 2011

Complex structure well, which increases the steam effective displacement area, can greatly enhance oil re-covery by developing heavy oil reservoir. The study on flow mechanism of complex structure well is far behind the field application. It is difficult to establish the productivity prediction model and obtain analytical solution for complex structure well considering many factors. Forecasting results differ significantly from the actual production results especially for complex structure well in thermal recovery. By using gray relational approach to the initial production as a reference sequence,reservoir thickness,permeability,branch well length,well spacing,angle,injection parameters etc. are regarded as comparison sequence according to the actual data, the correlation degree and controlling factors are obtained in this paper. The main controlling factors are optimized for complex structure well of heavy oil using steam huff and puff. The research results will provide the necessary technical reference for complex structure.


Zhao H.,Yangtze University | Kang Z.,Sinopec | Sun H.,Yangtze University | Zhang X.,State Key Laboratory of Offshore Oil Exploitation | Li Y.,Yangtze University
Petroleum Exploration and Development | Year: 2016

In view of the limitations that the current connectivity model can only forecast the fluid production dynamic change, can't calculate the dynamics of oil and water phases, and can't analyze the connectivity between wells layer by layer, this study establishes a new interwell connectivity model for multilayer reservoirs which can simulate dynamics of oil and water between wells. The model hierarchically separates the reservoir system into a series of interwell connecting units characterized by parameters such as conductivity and control volume, and by using the material balance equation, the pressure and interwell flow at constant liquid production or constant pressure mode is calculated regarding the connecting unit as a simulation object, which are combined with the frontal advance theory to establish interwell saturation tracking calculation, and finally water production dynamics of every layer at well points can be worked out. On this basis, using simultaneous perturbation stochastic approximation method and gradient projection method, a model parameter inversion method is set up by dynamic fitting. The application cases show that the model has good dynamic fitting and prediction effect, inversed model parameters coincide with the actual geological parameters, verifing the validity of the method. Compared with the current connectivity method, it can obtain the real-time model of hierarchical interwell flow rate distribution coefficient, liquid production of single well and oil split coefficient and other information, and reflect the reservoir horizontal and vertical oil-water flow relation more accurately, providing guidance for production measure adjustment in oilfield. © 2016 Research Institute of Petroleum Exploration & Development, PetroChina.


Zhang P.,CAS Beijing National Laboratory for Molecular | Wang H.,CAS Beijing National Laboratory for Molecular | Liu X.,CAS Beijing National Laboratory for Molecular | Shi X.,CAS Beijing National Laboratory for Molecular | And 4 more authors.
Colloids and Surfaces A: Physicochemical and Engineering Aspects | Year: 2014

The dynamic surface tension and dilational viscoelasticity properties of amphiphilic polyamidoamine (PAMAM) dendrimers were investigated to probe the hydrophobic chain effect on the interfacial properties and the demulsification behaviors. The values of dynamic parameters n and t* representing diffusion speed of the molecules obtained according to the Rosen equation decreased with the increasing of bulk concentration. Taking the hydrophobic effect into consideration, the t* values decreased and n values increased with the increase of alkyl chain length, suggesting easier adsorption and faster diffusion for longer hydrophobic chain which was opposite to the tendency of traditional surfactants. Further dilational viscoelasticity studies demonstrated that the properties referring to adsorption and exchange-diffusion were probably affected by the aggregates conformation at the interface. Subsequently, from the demulsification experiments a conclusion can be drawn that the amphiphilic dendrimers with branched dendritic structure possesses superior properties of breaking W/O crude oil emulsions, showing a certain correlation to the dilational viscoelasticity properties. © 2013 Elsevier B.V.


Wang D.,State Key Laboratory of Offshore Oil Exploitation
Wei sheng wu xue bao = Acta microbiologica Sinica | Year: 2012

The aim of this study was to isolate bacterial strains with high-efficiency to degrade resins. We used resin-plate to isolate resin-degrading bacteria from the formation water of Nanbao35-2 oil field, China National Offshore Oil Corporation. The morphological properties and the sequence homology of 16S rRNA were used to identify the strains. The changes of four fractions contents and the infrared spectrometry of the heavy oil were used to analyze the degradation properties. Four strains, Q4, QB9, QB26 and QB36, were isolated using resin as the sole carbon source. Based on the high sequence similarities (more than 99%) of 16S rDNA sequences analysis. These strains were identified as member of the Petrobacter sp., Geobacillus stearothermophilus, Bacillus licheniformis, Geobacillus pallidus, respectively. QB26, a Bacillus licheniformis, was the most efficient strain, it can grow well under anaerobic conditions, emulsify heavy oil well, and degrade resin and asphaltene in heavy oil. The relative content of saturated hydrocarbons in heavy oil increase after degradation, and the relative content of resin and asphaltene in heavy oil decreased 5.1% and 2.7%, respectively. The strains isolated from Nanbao 35-2 oil field formation water could degrade resin and heavy oil. They have potential values in microbial enhanced oil recovery and oil pollution treatment.


Hu J.,South China University of Technology | Li S.,South China University of Technology | Wang Y.,South China University of Technology | Lang X.,South China University of Technology | And 2 more authors.
Journal of Natural Gas Chemistry | Year: 2012

In oil and gas field, the application of kinetic hydrate inhibitors (KHIs) independently has remained problematic in high subcooling and high water-cut situation. One feasible method to resolve this problem is the combined use of KHIs and some synergists, which would enhance KHIs' inhibitory effect on both hydrate nucleation and hydrate crystal growth. In this study, a novel kind of KHI copolymer poly(N-vinyl-2-pyrrolidone-co-2-vinyl pyridine)s (HGs) is used in conjunction with TBAB to show its high performance on hydrate inhibition. The performance of HGs with different monomer ratios in structure II tetrahydrofuran (THF) hydrate is investigated using kinetic hydrate inhibitor evaluation apparatus by step-cooling method and isothermal cooling method. With the combined gas hydrate inhibitor at the concentration of 1.0 wt, the induction time of 19 wt THF solution could be prolonged to 8.5 h at a high subcooling of 6°C. Finally, the mechanism of HGs inhibiting the formation of gas hydrate is proposed. © 2012 CAS/DICP.

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