Severe problems accompany the production of abnormal oils with high pour point (with a paraffin content of over 30% by weight) in Kraynego Severa, Russia, due to the intensive formation of asphalt-resin-paraffin deposits (ARPD) in the bottom hole zone of the productive formation and downhole equipment. Possessing many advantages, the existing methods and technologies for coping with ARPD cannot fully solve this problem. As a result, complications arising from the production of high-wax oils lead to a significant decrease in oil production, a reduction in the production wells' maintenance and intertreatment periods, and an increase in dewaxing unit operating costs. The obtained results of theoretical and laboratory studies show that one of the promising approaches to improve the efficiency of wells equipped with electric submersible pumps when exploitation of abnormal oils with high pour point from multilayer deposits of the Timan-Pechora oil and gas province is the use of the new integrated technology based on the joint production of abnormal oil with high pour point with the oil, characterized by a lower wax content and the manifestation of structural and mechanical properties, in conjunction with regulating the parameters of the electric submersible pump. In this paper, the authors also describe a promising scheme of downhole equipment for the simultaneous-separate production of high-wax oil from multilayer deposits. The proposed downhole equipment allows us to separate the perforation zones of two productive formations using a packer-anchor system during simultaneous-separate exploitation of the formations by a double electric submersible pump installation.
Under conditions of the same type of oil deposits with hard-to-recover reserves in Jurassic terrigenous reservoirs of the West Siberian oil and gas province, a study was made about the influence of the geological structure features of objects and water flooding technologies on the response degree of production wells to water injection. Response degree of the wells was determined by analyzing the time series of production rates and injection volumes of injection wells with the calculation of inter-correlation function (ICF) values. It was believed that with ICF values in a given injection period of more than 0.5, production well responds to the injection. Factors that have a prevailing effect on water flooding success have been identified. Among them: effective oil-saturated thickness of the formation in production wells; relative amplitude of the self polarization of the formation in both production and injection wells; grittiness coefficient of the formation in injection wells; monthly volume of water injection and distance between wells. Methodological approach is proposed based on the application of the proposed empirical parameter of water flooding success, which involves the use of indirect data in conditions of limited information about the processes occurring in the formation at justification and selection of production wells for transferring them to injection during focal flooding; drilling of additional production and injection wells – compaction of the well grid; shutdown of injection and production wells; use of a transit wells stock; use of cyclic, non-stationary flooding in order to change the direction of filtration flows; determining the design of dual-purpose L-shaped wells (determining length of the horizontal part); limitation of flow rate in highly flooded wells with a high degree of interaction; determination of decompression zones (without injection of indicators), stagnant zones for drilling sidetracks, improving the location of production and injection wells, transferring wells from other horizons; choosing the purpose of the wells during implementation of the selective water flooding system in order to increase the efficiency of using the resource base of liquid hydrocarbons.
The analysis results of the hydrochloric acid treatment of the bottomhole zone efficiency along the deposits of high-viscosity oil in the carbonate reservoirs of the Tournaisian stage are presented in the paper. Based on the use of the non-parametric Kulbak criterion, the most informative geological and technological parameters, which affect most the success of hydrochloric acid treatments, assessed by the criteria of increased oil production and reduced water cut, are revealed. The generalization of the hydrochloric acid treatments experience in the conditions of the high-viscosity oil reservoirs of the Tournaisian Stage allows for efficient forecasting, selection of wells, control and regulation of the treatment process to reduce the number of inefficient operations and improve the technical and economic parameters of fuel and energy enterprises at the investigated sites and the ones with similar field-geological characteristics.
The article presents the results of the filtration tests of the developed polymeric waterproofing compound GPS-1, which is a mixture of a water-alkaline hydrolyzed acryl-containing polymer solution with a nonionic surfactant. The obtained results indicate significant improvements of main operational parameters – penetrating and water-insulating power of the developed polymeric composition GPS-1 in comparison with the original one: addition of the nonionic surfactant reduced the pressure gradient of injection twice. Also, considerable (5 times) increase of the residual resistance factor, that is explained by deeper and more uniform penetration of the solution into the porous medium and the corresponding raise of isolation efficiency of pore channels, is established. Experiments on the model of a heterogeneous oil-filled formation showed that after the injection of the polymeric solution water mobility decreases in a highly porous interlayer and increases in a low-permeability interlayer indicating a redistribution of filtration flows in the model of a heterogeneous bed. The decrease of water mobility in a high-permeability zone contributes to the leveling of the displacement front and, ultimately, the additional extraction of oil from the less permeable area. As a result of the complex of filtration tests conducted, the efficiency of the developed polymeric composition GPS-1 for the regulation of filtration flows in low-permeability heterogeneous reservoirs is proved.
This work presents results of research and development of technology for producing effective emulsifiers of inverse water-in-oil emulsions (EN-1) from distillates and residues of deep oil refining processes. The distillate cracking residue from a thermal cracking plant is chosen as the active component of the emulsifiers together with the highly aromatized heavy gasoil (as the solvent) from catalytic and thermal cracking plants.
The paper deals with field and laboratory studies of the effect of a magnetic field on the rate of corrosion of metal tubing, and rheological studies to establish the dependence of properties of well production of the magnetic field. The laboratory results showed an increase in the rate of corrosion of the metal with the growth of its residual magnetization with and without inhibition by different amounts. The dependence of the magnetic field effect on the rheological properties of well products Urmanskoye field.
The investigations of thermostability and rheological properties of the hydrophobic emulsion compositions; modeling the process of filtration in interstratificated and heterogenetic layers, and filtration in conditions maximally approximated to formation conditions were provided. The optimal composition of process liquids which is able to regulate filtration properties of reservoir-formation of the bottom hole formation zone is developed.
Based on the investigations of stability and rheological properties of the hydrophobic emulsion compositions, and on modeling the process of filtration in conditions maximally approximated to formation conditions, the optimal composition of process liquids which is able to regulate filtration properties of reservoir-formation of the bottom hole formation zone was developed.
The method of calculation pumped volumes of flow angularity compositions in injection wells, which based on combination of the seepage theory, laboratory investigation and field experience is developed.
The experience of oil field development shows that filtration parameters of bottomhole formation zone are gradually decreasing as a result of killing and operation of wells. The main reason for this is the use of water-based process fluids, which are now widely used in the oil industry. Currently, considerable attention is being paid to increasing reservoir penetration area by using active acids to stimulate oil and gas wells. Hydrocarbon-based compositions, in particular invert emulsions, are alternative systems for solving these problems.