The evaluation of downhole well integrity is an important business for the oil and gas industry. It is driven primarily by the need to optimize production while maintaining a safe environment despite the inexorable corrosion of casing strings and other harsh downhole conditions. Furthermore, with aging infrastructure, evaluating well integrity to plan plug and abandonment or slot recovery projects is critically important. Many technologies have been developed to address the challenges of evaluating casing and cement integrity under varied downhole conditions. These technologies are necessarily growing increasingly more sophisticated to meet the requirements of evaluating multiple cemented casing strings. In particular, wireline cased-hole logging techniques based on electromagnetic (EM) and acoustic techniques have been applied to casing corrosion and cement integrity evaluation. The acoustic measurement techniques deployed for well integrity evaluation typically include the sonic frequency range of tens of kilohertz up to the ultrasonic frequency range of megahertz. The frequency ranges are appropriate for characteristic resolutions of decimeters down to millimeters for sonic and ultrasonic measurements, respectively. These techniques are sensitive to the elastic properties of materials in the well completion and crucial for assessing zonal isolation. In the domain of evaluating corrosion in one or multiple casing strings, the traditional measurement approach uses EM techniques, which are sensitive to the metal thickness, the electrical conductivity (the inverse of electrical resistivity), and the magnetic permeability of ferromagnetic pipes. The spectrum of common EM casing inspection techniques encompasses a frequency range between quasi-static (direct current) up to about 100 kHz. More recently, transient EM or pulsed-field eddy current tools have been introduced. Specific physics and challenges associated with well integrity measurements must be understood and considered in existing and emerging technology solutions.

The Stal'proekt Institute has developed state-of-the-art plants for drying and high-temperature heating of steel-teeming ladles. Two new plants for drying tundish ladle lining have been designed for machine No. 6 for continuous billet casting at the Oskol'skii Electrometallurgical Works. Plants for drying and heating 30-ton teeming ladles to a temperature of 800°C and for high-temperature heating of ladle lining (1200°C) have been designed for a currently constructed metallurgical works. All these plants recover flue gas heat and use it for heating air supplied for combustion, thus decreasing the consumption of fuel. The process of drying and heating of lining is analyzed using a mathematical model developed at the institute. The plants are equipped with automatic control systems controlling the temperature schedule of drying and heating the lining. The specified plants ensure cost-effective operation in an automatic mode The Stal'proekt Institute has designed state-of-the-art plants for drying and high-temperature heating of teeming ladles. The use of flue gas heat, modern burners, and automation instruments provide for cost-effective and safe performance of these plants in different operating modes.The lining division of the electric steel-melting shop of the Oskol'skii Electrometallurgical Works (OEMW) at the moment has four plants for drying tundish ladles that cast steel for machines for continuous billet casting Nos. 1 -5. In connection with the construction of a new machine for continuous billet casting (No. 6), two additional plants (Nos. 5 and 6) are required to dry the lining of tundish ladles produced by Concast (Switzerland). The design of these drying plants have been developed at the Stal'proekt Institute.The new plants are located on two sides of the four existing tundish-drying stands and use the existing fume duct to deflect flue gases.The main difficulties in designing were related to the existence of a common flue gas duct for six plants, since it was necessary to provide safe gas combustion, cost efficiency, and compliance with preset lining-heating schedules for the plants simultaneously operating in different working regimes. The fuel flow rate and the type of burners were chosen using a mathematical model developed at the institute, which, in addition to heat analysis, also performs hydraulic analysis of the gas system.We have developed a mathematical model for calculating the process of tundish ladle lining by gas burners in accordance with a preset drying schedule, taking into account that air used for natural gas combustion is heated in the loop recuperator using flue gases exiting from the tundish ladle.In the mathematical sense, the model is based on a combined solution of a system of integral and nonstationary differential equation, describing the following thermophysical processes occurring in the volume of the tundish ladle and in its lining; -heat exchange by radiation between all inner surfaces of the tundish ladle and the gaseous space inside the ladle, taking into account the re...

Now, more than ever, the integrity of the wellbore before the recommencement of drilling operations or production of reservoir fluids, is fundamental to safe operations. Stricter well control policies have been instated in recent years, so it is critical to perform casing inspection, and cement evaluation measurement surveys to ensure adherence to regulatory codes. As exploration and development drilling activity breach new horizons, it brings new challenges to cementing operations and subsequent cement evaluation surveys. Heavy drilling muds, extra-large casing sizes, and narrow drilling windows: cement to mud weight ratios which can led to cement contamination are just a few. Until recently these constraints limited the usefulness and reliability of ultrasonic measurements under the said conditions. This paper describes a new generation of ultrasonic sensors and technology that fills the gaps left by predecessor technologies and allows operators to feel confident and at ease with the integrity of their wellbores, even under the most taxing conditions. The advantages and associated cost savings enabled through the utilization of this technology are illustrated in the case studies at the end of the paper.

Noble Energy, Inc. successfully drilled a deepwater exploration Middle Miocene well in November 2012 and discovered the Big Bend Field, located in the Gulf of Mexico Mississippi Canyon Block 698. As the production liner was being run in the MC 698 No. 1 discovery well, tight hole conditions were encountered near total depth. While pumping the primary cement job, lost returns were observed. Prior to the drilling rig leaving location, a cement bond log was run to evaluate the primary cement job. There was no evidence of cement bond across the main oil-bearing zone or directly above it. This was a concern since there are water sands above the main oil-bearing zone which could compromise future production with behind pipe communication issues, in addition to potentially complicating the completion. Plans were made to pump squeeze cement to remediate the primary cement job. When the rig returned to complete the well, a second cement bond log was run February 2014 and compared to the original cement bond log. The second cement bond log showed a zone of sufficient bonding above the main oil-bearing zone, where no bonding was evident on the previous bond log. There was still no evidence of cement across the main oil-bearing sand. Even though preparations were made to remedial squeeze the primary cement job, the decision was made to not engage in remedial cement operations and to continue with the completion. This paper compares the two cement bond logs and discusses the operational considerations leading to the successful completion of the well and producing a prolific oil well safely with no water production.