23 research outputs found
10.1063/1.3549932.8
Get PDFPublisher statement: Copyright (2011) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in: Gelfgat, A.Y. and Molokov, S. (2011) Quasi-two-dimensional convection in a three-dimensional laterally heated box in a strong magnetic field normal to main circulation. Physics of Fluids, volume 23 (3): 034101 and may be found at http://dx.doi.org/10.1063/1.3549932
Superdeep Scientific Drilling ‐ Lessons Learned for the Development of Modern Drilling Technologies
No full textEXPERIENCE IN THE DEVELOPMENT AND USE OF ALUMINUM ALLOY CASING FOR CONDITIONS OF HIGH CONTENT OF ACID GASES IN FORMATION FLUIDS
No full textWhen selecting a casing material for fields with a high content of H2S and CO2, it is recommended to use specialized corrosion-resistant tubulars with high content of chrome of the Sanicro 29 type. The high cost of the material can be critical for the project economy. A promising approach for these problems elimination could be the application of aluminium alloy casing pipes. They are remain inert to corrosion even if the formation environment is fully saturated with H2S and/or CO2. They are also lightweight, have high strength-to-weight ratio, and thus decrease the existing tensions in the string and reduce well construction costs
Corrosion and the role of structural aluminum alloys in the construction of oil and gas wells
No full textThis paper presents the main research results and examples of structural aluminium alloys (SAA) effective use in the oil and gas wells construction onshore and offshore. The known application cases are drill pipes, tubing and casing. Competitive properties of SAA for hydrocarbons exploration and production were identified as strength-to-weight ratio, high total corrosion resistance, including dissolved hydrogen sulphide and carbon dioxide, absence of cold-shortness effect. The issues with the natural properties of aluminum alloys requiring process and structural corrections were addressed as well. Technical solutions to neutralize characteristics, which limited SAA use in the wells construction have been advised and examples of implementation shown. Among them, technology of surface layers modification, coatings and methods of isolation contacts with other material, system of integrated corrosion protection and optimization of operation environment. Aluminum drilling riser (ADR) is one of the most striking examples of the object from SAA. ADR presents integrated solution of SAA application problems. Finally, SAA could successfully address well construction corrosion issues
Protection enhancing of threaded connections of light-alloy drill pipes against contact corrosion
No full textWhen using light-alloy drill pipes (LAIDP) with steel tool joints, the development of contact corrosion is observed under certain operating conditions. The value of corrosion mainly depends on the difference in electrochemical potential (ECP) of the contacting metals. One of the effective methods for increasing the corrosion resistance of aluminum alloys is the micro-arc oxidation (MAO) method. This is an electrochemical process in combination with micro-arc-discharges phenomena at the anode-electrolyte border, which allows forming ceramic coatings of aluminum oxides on the surface, including its high-toughness and wear-resistant phase - α-Al2O3 (corundum). MAO-technology is a highly efficient and environmentally friendly process. At the forming of such a coating on the threaded part and in the tool joint zone of the pipe, a barrier for contact corrosion between the steel tool joint and the surface of the aluminum pipe is created. In this work, contact corrosion on samples in a pair of 1953T1 aluminum alloy - 40KhN2MA steel in a 5% NaCl solution at 80 °C was investigated. The data obtained showed the effectiveness of using protective MAO-coating to reduce contact corrosion and increase the reliability of the tool joint threaded connection of LAIDP
Refinement of the Drillpipe-Slip Mechanical Model
No full textAbstract
Slips, slip elevators, spiders, etc. have been widely used as oilfield service tools to grip and hold drill pipe, drill collars and casings by acting as a wedge. A pipe in a slip with a conical bearing surface is subjected to complex loads comprised of tensile, compressional, radial and bending stresses. To increase the holding force, the bearing surface of the gripping device in the form of a dies set is provided with teeth penetrating into the pipe body. This generates additional drag force on the contact surface that supplements the friction force.
This paper presents a new slip model, which uses the dependence of the drag force on the teeth penetration depth. The model is based on an improved dependence of the drag of wedge-shaped die teeth not only on the friction force in the "die-pipe" pair but also on the shearing force arising during teeth penetration in the pipe body. Equation parameters have been verified by multiple finite element (FE) calculations and experimental studies of dependence of the penetration force on the drag of a single tooth. The developed equations are used in the complete drillpipe-slip model. It accounts for pipe wall deformation under compressive stress generated by the slip and the drillstring weight and determines the active bearing length of the slip under load. The paper presents calculations of allowable areas for a slip of a specified length equipped with toothed dies based on the load carrying capacity and pipe strength.
The proposed model can be used for operative calculations of the slip carrying capacity, as well as for the development of new slip designs.</jats:p
Comparative Strength Analysis of Aluminum Drill Pipes With Steel Connectors Assembled by Different Methods
No full textAluminum alloys continue to be among the promising materials for manufacture of drill pipes and risers for deepwater and ultra-deepwater environment. Steel tool-joints attached to aluminum alloy pipes increase the number of make-ups and break-outs. Currently, aluminum drill pipes (ADP) are assembled by “cold” or “hot” methods. By the first method, the pin and box are screwed on the pipe with a “sufficiently” high specified make-up torque. By the second method, the pin and box of the tool joint are heated and screwed on the ends of the pipe without effort. After cooling, the shrinkage of the tool joint units creates a reliable permanent threaded “pipe – tool joint” connection. The first method is easier than the second one; however the comparative strength of these ADP connections has not been enough clear. The paper presents the results of comparative strength analysis of both types of connection after assembly at applying tensile load and alternating bending load. The theoretical aspect of the study includes a detailed FEA of “hot” and “cold” assembly connections at applying tensile load and alternating bending load with SCF evaluation. The experimental data are presented as the results of tensile testing of small-scale specimens, removed from different aluminum pipe sections that were heated during “hot” assembly. Finally, full-scale specimens of both types of connections were tested for tensile capacity and fatigue. The comparative strength of both types of connections is concluded.</jats:p
