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Fuller G.A.,PE | Mercado S.,Royal Dutch Shell | Mead C.,Royal Dutch Shell
SPE/IADC Drilling Conference, Proceedings | Year: 2016

Performing cementations in a deepwater environment poses many unique challenges during the drilling and completion operational phases in the Gulf of Mexico. These challenges add further difficulty and risk to an already complex operation. During the course of constructing the wellbore, it may be necessary to perform un-scheduled remedial cementing operations to acheive the main objectives. Squeeze cementing performed to remediate undesireable well conditions which may have resulted during the drilling phase (major mud losses) or as a result of a poor primary cement job (insufficient zonal isolation) must be thoroughly analyzed during planning to understand all the critical parameters needed to execute the right plan. When designing for a squeeze job, key decision factors during the planning process must be addressed for a successful outcome. The success or failure of a squeeze cement operation relies on 1) understanding what is the objective of the squeeze operation 2) determination of the optimum cement placement depth, 3) development of an effective placement procedure with proper technique and down-hole tools employed, 4) proper design of cementing fluids including washes and spacers, 5) flawless execution with a detailed pressure/rate/volume record of fluid injection, and 6) a meaningful post evaluation of the squeeze operation's results to determine if objective was met. This paper will provide guidance on addressing the key decision factors, development of a proper placement strategy, general design guidelines for appropriate cementing fluids to employ, and how to evaluate if the objective was met. Results will be presented from recent deepwater case histories to demonstrate the successful application of this methodology for squeeze jobs and the techniques used. Copyright 2016, IADC/SPE Drilling Conference and Exhibition. Source

Wen H.,Washington State University | Wu M.,Washington State University | Uhlmeyer J.,PE
Journal of ASTM International | Year: 2011

The use of recycled materials for construction is beneficial to both the environment and the economy. Recycled asphalt pavement (RAP) is one of the most commonly used recycled materials. Different state departments of transportation allow the use of RAP in base materials at different percentages. Characterization of the resilient modulus of base materials with RAP is important for proper pavement design. In addition, the models used in the Mechanistic-Empirical Pavement Design Guide (MEPDG) for traditional materials need to be verified for base materials with RAP, due to the unique properties of asphalt in RAP. This study evaluated the effects of moisture and temperature on the resilient modulus of base materials with different percentages of RAP. The models for the effects of moisture content on the resilient modulus of unbound materials were evaluated using crushed aggregates with RAP. In addition, models were proposed to account for the effects of temperature on the resilient modulus of base materials with RAP. The effects of the percentage of RAP on frozen moduli were also investigated. Copyright © 2011 by ASTM International. Source

Andracsek R.,PE
Power Engineering (Barrington, Illinois) | Year: 2010

Coal-fired utiliies are under attack from multiple environmental fronts such as greenhouse gases, mercury and routine maintenance violations. A fundamental provision of the Clean Air Act requires EPA to set NAAQS for pollutants considered harmful to public health and the environment. The longer the averaging time, the more resilient the standard is to short-term upsets. The 1-hour NO2 NAAQS is the lesser of the two problems. Here the standard is 100 ppb (188 mg/rn3). This is based on a 3-year average of the 98th percentile of daily values. The target of the 1-hour NO2 NAAQS is pollution near major roads. The revised standard requires more NO2 monitors to be placed near major roadways. It will be nearly impossible for an unscrubbed coal-fired boiler to demonstrate compliance with the proposed 1-hour SO2 NAAQS. Source

Belli C.M.,PE | Bruggi M.,Polytechnic of Milan
Periodica Polytechnica: Civil Engineering | Year: 2015

A numerical approach is presented to assess the seismic vulnerability of barrel masonry vaults and evaluate the effectiveness of a traditional retrofitting intervention consisting in the reinforcement of the extrados. A linear elastic no-tension model is adopted to cope with the negligible strength in tension of ancient brick and stone masonry and perform a two-dimensional finite element analysis of arch-like sections. Instead of implementing conventional load history analysis or limit load analysis, the minimization of the relevant strain energy function is implemented to solve the non-linear equilibrium under the effect of different load scenarios. A segmental barrel vault made of stone masonry is investigated in an ancient building under static and seismic loads. The collapse load of the structural element is computed before and after the intervention and the reduction achieved in terms of seismic vulnerability is evaluated as prescribed by technical codes. © 2015, Technical University of Budapest. All rights reserved. Source

Varava A.,Buzzi Unicem | Schaadt J.L.,PE
IEEE Cement Industry Technical Conference (Paper) | Year: 2013

Cement plants strive to produce the most product for the least cost and impact to the environment. With each project comes an opportunity to address these goals. This paper is a case study of how cement plants can implement main process fan and drive projects to achieve such goals with positive results. © 2013 IEEE. Source

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