Advanced Materials Research Vols. 361-363

Abstract: The wind power generation pumping unit has environmental protection and the energy-saving function with wind power generation complementary power supply system. Based on the calculation of the pumping power consumption during the oil production, the essential wind-power generation electric quantity for pumping equipment runs stable was analyzed, wind-electricity and electric network complementary energy transmission and control circuit were designed, When the wind speed changes, by the energy transmission and control circuit related parameters and taking the historical meteorological statistics of the corresponding period as the comparison reference, the system can control wind power generation and the battery charge and discharge flexibly to ensure the equipment runs stable, which lays a firm foundation for the wide application of the off-grid wind power. The economic analysis shows that the wind-electricity and electric network complementary pumping machine has good economic efficiency and application prospect in oilfield.

Abstract: Conducted by the results of numerical simulation and reservoir engineering method, the limit of layers combination and the optimum starting time of water injection are present in this paper. It was shown that in order to improve the development effect of relatively low permeability formation and increase economic efficiency of this kind of field, the reasonable multiple factor after subdividing layers should be less than 5, which means that the permeability difference should be less than 8. Meanwhile, in view of the actual situations and difficulties of offshore development, the injection and production project should be started synchronously.

Abstract: The fluid loss control additive plays a key role in reducing reservoir damage and improving the cementing quality of an oil well. Aiming at good fluid loss control ability and excellent dispersibility, a new dispersive type fluid loss control additive was synthesized through orthogonal experiment with 2-acrylamido-2- methyl propane sulfonic acid, acrylamide, N, N-dimethylacrylamide and maleic anhydride. The orthogonal experiment result shows that the influence on the properties of FLCA decreases in the order: PH value > monomer concentration > monomer mole ratio > initiator concentration > temperature. The result indicates that the optimal conditions for FLCA were 4/2.5/2.5/1 of mole ratio of AMPS/AM /NNDMA/MA, 32.5% total monomer concentration in deionized water, 1.0% (by weight of monomer) ammonium persulfate/sodium bisulfite, 4 of PH value, 40°Cof temperature. The synthesized copolymer was identified by FTIR analysis. The results show the dispersive type fluid loss control additive has excellent dispersibility, fluid loss control ability, thermal resistant and salt tolerant ability. As the temperature increases, the thickening time of the slurry containing the synthesized additive reduces. The copolymer is expected to be a good fluid loss control additive.

Abstract: Through parallel cores with different permeability contrast, the displacement process of foam flooding after polymer flooding is experimental studied. Using the experiment technology of nuclear magnetic resonance, the fluid distribution in cores with different diameter was studied. The distribution area of bore diameter in which oil is sweepouted of water flooding, polymer flooding and foam flooding under different processes and various heterogeneity conditions. The results show, against water flooding and polymer flooding, the distribution area of bore diameter in which oil is sweepouted is broadened. Foam can plugging the wide aperture in which water and polyer channeling，and foam can sweep the bore diameter which can’t be swept by water and polymer. Foam can not only advance the recovery of low permeability core but also sweep the oil in microbore of high permeability core.

Abstract: To the present status and difficulties of complex oilfields, like low-permeability and ultralow-permeability reservoir, abnormally high formation pressure reservoir and formation vulnerability, liquid powder fracturing stimulation technology is tested in low-permeability oilfields. This paper introduced the study of the performance of liquid powder and process optimization, including the performance optimization experiment of liquid powder, formula optimization study of insulating liquid, design of the ignition process and optimization design of construction process. The loading rate of the optimal liquid powder increased significantly so as to meet the fracture of abnormally high-pressure formation. Its active mechanism and characteristics are also analyzed in this paper. In FY block of Daqing Oilfield, the application test of liquid powder fracturing was used in six vertical wells and a horizontal well called CP-2 well (for the first time), and good results have been observed. Combined with the tests, we carried out research and analysis. Field tests show that the liquid powder fracturing stimulation technology can achieve significant stimulation goals for low-permeability oil reservoir and offer a new technological method to low-permeability oil reservoir fracturing and development.

Abstract: Uplift of pipeline due to buckling deformation and the resultant soil resistance are key concerns in its design. This paper investigates the particle-size effect on uplift resistance of a pipe buried in sand and the ground deformation mechanism using the distinct element method (DEM). Two granular grounds, one for coarse-sand ground and the other for fine-sand ground, were examined in this simulation. The results show that both cases exhibit similar deformation mechanism of four featured stages: mobilization of peak uplift resistance, infilling of soils beneath pipe, formation of shear bands, and flow of soils around pipe. The uplift resistances in both cases gradually increase to a peak and then drop to a constant value with the upward displacement of the pipe. However, higher peak resistance and shear bands with gentler slope are observed in the coarse case.

Abstract: There are many factors affecting the fracture measures in low permeable fractured reservoir.And there are different effects and complex relationship between them.In order to analyze the various factors, the paper uses the grey correlation analysis method to determine the main factor. And it uses the method to analyze the fracture affecting factors in low permeable fractured reservoir in the ×× oil production of ×× oil field .This method is simple convenient and accurate.It can be use to guide the optimal design of fracture measures.

Abstract: Miscible and/or near miscible gas injection processes are among the most widely used enhanced oil recovery techniques. The successful design and implementation of a miscible gas injection project is dependent upon the accurate determination of minimum miscible pressure (MMP), the pressure above which the displacement process becomes multi-contact miscible. Analytical methods, which are inexpensive and quick to use, have been developed to estimate MMP for complex fluid characterizations. However, many problems still existed in the analytical calculation, which will lead to the failure of calculation, or wrong result. This paper shows how the initial tie line could be calculated when the component of injection gas doesn’t included in the crude oil. And moreover, how to get a complete set of initial value for the equations of crossover tie lines, and the influence of EOS for the result of key tie lines is analyzed simultaneously.

Abstract: Physical simulation experiments were made to research on the stress sensitivity on physical property of low permeability reservoir rocks. The experimental results shown that effective pressure had good exponential relationship with reservoir permeability. Combining with materaial balance method, reservoir engineering and rational deducation was made to reserach on water-flooding timing of low permeability reservoir development. Several production targets were obtained by these method, such as formation pressure, water and oil production, water cut and so on. The results shown that advanced water-flooding was very important in low permeability reservoir development to reduce the bad impact of stress sensitivity on formation permeability and maintain formation pressure.

Abstract: In this article, the viscosifying abilities, rheological properties, flow characteristics of pectinate hydrophobically associating polymer (PHAP) solutions with different hydrophobe content were studied using technical methods of viscosity measurement, rheological and core flow experiments. Researches on viscosifying of different PHAPs at 20°C and 65°C in distilled water and saline indicate that, with the raise of hydrophobe content, viscosity of polymer solutions increases first and then decreases, which means that there should be a critical hydrophobe content( CHC). Below CHC, the anti-shear ability of polymer solutions enhances as hydrophobe content rises; while the shear resistance would fall down when and after the content reaches CHC. In high permeability porous media, all polymer solutions take on greater injectivity, and RFF can all be higher than 5, yet with the increasing of hydrophobe content, RF goes up first and then declines. It could be an effective way to enhance mobility control ability, improve polymer flooding effect in high permeability reservoirs and design polymer molecular structure more reasonably, using the pectinate structure and hydrophobic association interaction between polymer moleculars.