Improving the waterproofing efficiency by using a plugging compound

Increasing the efficiency of water shut-off works is one of the important tasks for the sustainable well operation. The article discusses the use of various plugging compositions for water inflow into a well isolating, their advantages and disadvantages, conditions of use, and presents the results of a study of the proposed composition. The composition of an aqueous solution of polyaluminium chloride and a suspension of gypsum anhydrite is considered. The composition contains 45-55 mass percent of 15-25 percent aqueous solution of polyaluminium chloride and 45-55 mass percent suspension of gypsum anhydrite at a water-solid ratio of 0.9. The technical result is an increase in the efficiency of water inflow into the well isolating by obtaining a homogeneous, dense plugging mass formed by mixing the components of the composition and gaining maximum strength over time. Keywords: well; water cut; isolation; water inflow; plugging mass; bottomhole formation zone; oil production; polyaluminium chloride; anhydrite.

Novel U-Pb isotopic zircon data on the rhyolite of the Saf’yanovskoe Cu-Zn deposit (Middle Urals)

Research subject. Zircons from the Saf’yanovskoe Cu-Zn deposit rhyolite (Middle Urals). For the first time, zircon U-Pb dating for the rhyolite of the ore-bearing volcanic-sedimentary rocks of the Saf’yanovskoe deposit was performed. The volcanites are characterized by an andesite-rhyodacite composition and are localized at the southern edge of the Rezhevskaya structural-formation zone (SFZ) of the Eastern Ural megazone. A number of publications assign these rocks either to the basalt-rhyolite formation of the Middle Devonian, or to the basalt-andesite-dacite-rhyolite formation of the Lower-Middle Devonian.Aim. To estimate the age of the ore-bearing volcanic rocks under study using the U-Pb SHRIMP-II isotop ic system of zircon from the rhyolite of the eastern side of the Saf’yanovskoe deposit. By its chemical composition, the rhyolite belongs to the silicic varieties of subvolcanic rocks. Methods and results. The U-Pb isotopic system of zircon was studied by 5-collector mass-spectrometer of high precision and emission of the secondary ions SHRIMP-II (ASI, Australia) in the VSЕGEI Institute. U-Pb relations were investigated by a procedure developed by I.S. Williams. The U-Pb data obtained based on 13 zircon grains showed the age of 422.8 ± 3.7 Ma. Conclusions. The U-Pb dating of zircon obtained previously from the lens-shaped andesite bodies of the western side of the Safyanovskoe deposit gave the age of 422.8 Ma, which corresponds to the Przydoli series epoch of the Upper Silurian. We established that, among the volcanic rocks of the Saf’yanovskoe deposit, the effusive formations of the Upper Silurian are present.

Numerical investigation on crack analysis of H13 fixed die and structural analysis of moving die with two different materials

Die casting is forcing molten metal into a mould with high pressure. Die casting has two dies namely moving die and fixed die where the moving one will move over the fixed die. Die casting is majorly used for high-volume production. This paper focused on the physical phenomenon of die casting for two dies (moving die and fixed die) using two different alloy materials with variable material chemical compositions. The numerical analysis is carried out for the die casting process to determine the crack formation zone by temperature distribution and structural analysis by stress-strain relationship. The numerical analysis is carried out for both the dies. The fixed die is analyzed with an H13 tool steel material with two moving die materials as aluminum alloy (A356) and magnesium alloy (AZ91D). Both the dies (fixed and moving) were designed by using design software and meshing is carried out followed by analysis using the analysis software. The physical parameter for the dies is applied that is temperature distribution is carried out by applying a temperature of 850 °C and 650 °C over the fixed die for aluminum and magnesium alloy, respectively. Structural analysis is carried out for the moving die with a load of 1,000 N for both aluminum and magnesium alloys with 1000 number of iterations. The results from the numerical analysis are derived and analyzed for both temperature distribution and structural analysis. The crack formation zone is found out by means of temperature gradient and the stress-strain relationship is found out by means of structural analysis. From the results, it was concluded that the crack zone is obtained at 1.22E-10 °C/mm and 6.856E-14 °C/mm of thermal gradient and structural analysis in terms of maximum stress of 446.94 MPa and 448.52 MPa for aluminum and magnesium alloys, respectively.

Study of Compositions for Selective Water Isolation in Gas Wells

A hydrophobic composition containing water repellents and highly volatile solvents is shown in this study to isolate water from the bottomhole formation zone of gas wells and reduce as much as possible the saturation of pore spaces with water. During injection, this composition shows selectivity and mostly penetrates water-saturated porous media. The study shows that the injection of such composition into porous media has a high water-insulating effect, reducing the water permeability of water-saturated porous media by 35 times with a degree of water isolation of 97%. Moreover, while injecting, it has selective action, mainly penetrating water-saturated media rather than gas-saturated media. As a result of injecting 0.91 to 0.99 pore volumes (pv) of the composition, the Qwater/Qgas ratio reaches 5.22 to 5.26, indicating high selectivity.

A Study of Compositions Relevant to Selective Water Isolation in Gas Wells

A hydrophobic composition containing water repellents and highly volatile solvents is shown in this study to isolate water from the bottom hole formation zone of gas wells and reduce as much as possible the saturation of pore spaces with water. During injection, this composition shows selectivity and mostly penetrates water-saturated porous media. The study shows that the injection of such composition into porous media has a high water-insulating effect, reducing the water permeability of water-saturated porous media by 35 times with a degree of water isolation of 97%.Moreover, while injecting, it has selective action, mainly penetrating water-saturated media rather than gas saturated media. As a result of injecting 0.91 to 0.99 pore volumes (pv) of the composition, the Qwater/Qgas ratio reaches 5.22 to 5.26, indicating high selectivity.

On the Characteristics of the Super-Critical Wake behind a Circular Cylinder

The flow topology of the wake behind a circular cylinder at the super-critical Reynolds number of Re=7.2×105 is investigated by means of large eddy simulations. In spite of the many research works on circular cylinders, there are no studies concerning the main characteristics and topology of the near wake in the super-critical regime. Thus, the present work attempts to fill the gap in the literature and contribute to the analysis of both the unsteady wake and the turbulent statistics of the flow. It is found that although the wake is symmetric and preserves similar traits to those observed in the sub-critical regime, such as the typical two-lobed configuration in the vortex formation zone, important differences are also observed. Owing to the delayed separation of the flow and the transition to turbulence in the attached boundary layer, Reynolds stresses peak in the detached shear layers close to the separation point. The unsteady mean flow is also investigated, and topological critical points are identified in the vortex formation zone and the near wake. Finally, time-frequency analysis is performed by means of wavelets. The study shows that in addition to the vortex shedding frequency, the inception of instabilities that trigger transition to turbulence occurs intermittently in the attached boundary layer and is registered as a phenomenon of variable intensity in time.

Improving the Efficiency of Oil and Gas Wells Complicated by the Formation of Asphalt–Resin–Paraffin Deposits

A number of difficulties may be encountered in the final stages of oil field exploitation, including the formation of asphalt–resin–paraffin deposits (ARPDs). It is expedient to use complex technologies to remove the already formed deposits and prevent the formation of ARPDs. This paper focuses on the complex technology of oil field exploitation. This technology combines both the removal of organic deposits and the prevention of the formation of these deposits in the well bottomhole formation zone (BHFZ) system. The calculations for determining the process parameters of selling the ARPD inhibitor solution into the BHFZ are presented in this article. This complex technology includes the process of ARPD removal by flushing the well and the subsequent injection of the developed ARPD solvent into the BHFZ. In addition, the technology is complemented by a method of preventing the formation of these deposits. This method consists of squeezing the ARPD inhibitor and then pumping it by the selling fluid from five to ten times of the volume. This article contains a detailed calculation of the methodology and provides the diagrams for the solvent and inhibitor injection.

Analytical review of underground equipment of water impact operation for well development

Rational indicators for the development of oil and gas fields are related to the systemic maintenance of a given level of perfection of formation opening in bottomhole zones of producing or injection wells. This need arises with the colmatation of the natural collector by mechanical, asphalt and tar-paraffinic particles, leading to a decrease in productivity, acceptance of wells and the need to restore the inflow by methods of artificial action on the bottomhole formation zone. Analysis of the effectiveness of the application of various methods of stimulating the flow of reservoir products in the fields of the Timan-Pechora oil and gas province (based on field data) allowed to argue the success of using hydraulic fracturing, thermogas chemical, and shock-depressive effects on the bottomhole formation zone. The prospect of the development of technical means for impact-depressive (implosion) impact on the bottomhole formation zone favorably distinguished by simplicity, cheapness, manufacturability and accessibility is shown. The designs of implosion hydrogenerators of single and multiple pressure are analyzed, shortcomings of technical devices are identified and ways of improving mechanisms are outlined. The results of effective application of various downhole generator devices for increasing productivity and well acceptance are presented.

METHODS FOR BOTTOM BOREHOLE ZONE TREATMENT IN WELLS CHECHEN REPUBLIC

Состояние призабойной зоны пласта (ПЗП) имеет для интенсификации притока очень важное значение. По мере эксплуатации скважины постепенно ухудшаются фильтрационно-емкостные свойства пласта. В качестве кольматанта могут быть механические примеси (кварцевый песок, кристаллы солей, смолы, асфальтены, незакрепившийся пропиант, частицы бурового раствора и т.д.). Авторами предложены технологии и технические средства проведения обработок пласта. The state of the bottomhole formation zone (BHZ) is very important for the stimulation of the inflow. As the well is operated, the reservoir properties gradually deteriorate. Mechanical impurities (quartz sand, salt crystals, resins, asphaltenes, loose propant, particles of drilling mud, etc.)can be used as a bridging agent. The authors proposed technologies and technical means for carrying out treatment of the formation