Browsing by Subject "Criteria"
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Item Closed-form van der waals critical point for petroleum reservoir fluids(2005-05) Hassoun, Talal H.; Lawal, Akanni S. L.; Henize, Lloyd R.; Lea, James F.The prediction of critical points is of great practical importance because the classification of petroleum reservoir fluids as a dry gas, gas condensate, volatile oil, and crude oil depends largely on the knowledge of the critical properties of the reservoir fluid. Also, the critical pressure and critical temperature of reservoir fluids are important properties for describing the reservoir fluid phase behavior, predicting volumetric properties of reservoir fluids and designing supercritical fluid processes. Previous work for determining critical pressure, and critical temperature for reservoir fluids include, empirical correlations, corresponding states method, and pseudo-critical property methods. The generality of these previous correlations is limited to the range of conditions and parameters used in the establishment of the correlations. Methods based on the Gibbs criteria have also been used with Redlich-Kwong and Peng-Robinson equations for prediction of critical properties. However, the Gibbs criteria have not been applied to predicting critical properties of reservoir fluids. A closed-form equation is developed for predicting the critical properties (Tc, Pc) of complex reservoir fluids by using the Lawal-Lake-Silberberg (LLS) equation of state with the criticality criteria established by Nobel Laureates van der Waals (VDW) in 1873. By inverting the parameters of the LLS EOS in terms of the mixing parameters that are based on the constituent substances and composition of the reservoir fluids, experimental critical pressures and temperatures are predicted with interaction parameters expressed in terms of molecular weight ratios of the binary constituent of reservoir fluids. The prediction results of critical pressures and temperatures based on the VDW criticality criteria show that experimental data consisting of 85 reservoir fluid mixtures are within average absolute percent deviation of 3% to 5% of the measured critical pressures and temperatures. In contrast to the previous work, this research project provides an accurate method for computing the critical properties of reservoir fluids and it is easy to use because the parameters of the criticality equation are readily available. This project is useful for unifying near-critical flash routine with phase equilibria of the compositional reservoir models. The project is also very attractive for establishing reservoir models that are based on the critical composition convergence pressure concept.Item Closed-form van der waals critical point for petroleum reservoir fluids(Texas Tech University, 2005-05) Hassoun, Talal H.The prediction of critical points is of great practical importance because the classification of petroleum reservoir fluids as a dry gas, gas condensate, volatile oil, and crude oil depends largely on the knowledge of the critical properties of the reservoir fluid. Also, the critical pressure and critical temperature of reservoir fluids are important properties for describing the reservoir fluid phase behavior, predicting volumetric properties of reservoir fluids and designing supercritical fluid processes. Previous work for determining critical pressure, and critical temperature for reservoir fluids include, empirical correlations, corresponding states method, and pseudo-critical property methods. The generality of these previous correlations is limited to the range of conditions and parameters used in the establishment of the correlations. Methods based on the Gibbs criteria have also been used with Redlich-Kwong and Peng-Robinson equations for prediction of critical properties. However, the Gibbs criteria have not been applied to predicting critical properties of reservoir fluids. A closed-form equation is developed for predicting the critical properties (Tc, Pc) of complex reservoir fluids by using the Lawal-Lake-Silberberg (LLS) equation of state with the criticality criteria established by Nobel Laureates van der Waals (VDW) in 1873. By inverting the parameters of the LLS EOS in terms of the mixing parameters that are based on the constituent substances and composition of the reservoir fluids, experimental critical pressures and temperatures are predicted with interaction parameters expressed in terms of molecular weight ratios of the binary constituent of reservoir fluids. The prediction results of critical pressures and temperatures based on the VDW criticality criteria show that experimental data consisting of 85 reservoir fluid mixtures are within average absolute percent deviation of 3% to 5% of the measured critical pressures and temperatures. In contrast to the previous work, this research project provides an accurate method for computing the critical properties of reservoir fluids and it is easy to use because the parameters of the criticality equation are readily available. This project is useful for unifying near-critical flash routine with phase equilibria of the compositional reservoir models. The project is also very attractive for establishing reservoir models that are based on the critical composition convergence pressure concept.Item Operational criteria for battlefield vehicles(2014-08) Hamill, Scott Bowes; Tesar, DelbertModern military ground vehicles are no longer able to respond effectively to the rapidly changing mission requirements of modern military conflicts. Military vehicle architectures, which utilize passive suspension components and traditional drivetrain/steering systems, do not provide the operational flexibility to meet the demands of the operator. Advances in intelligent actuation technology allow for the development of a new vehicle architecture - the Intelligent Corner Vehicle (ICV). The ICV utilizes intelligent actuator technology to actively control the four degrees of freedom of each wheel of the vehicle - drive, camber, steering, and suspension. The utilization of intelligent actuation requires the characterization of the motions and behavior of the tire and the vehicle chassis in order to effectively apply the tire to the road surface - the development of vehicle performance criteria. A brief review of the state of wheeled military systems is presented. Many modern military vehicles were designed to improve protection at the expense of mobility - a process that has had negative effects on vehicle capability. An overview of the pneumatic tire used for wheeled vehicles is presented, highlighting the nonlinearities of tire behavior. The complexity of tire force generation drives the need for the application of intelligent actuation. Traditional actuation of wheel motion is presented along with a variety of current efforts to apply intelligent actuation to individual degrees of freedom of the tire. These efforts can be shown to improve vehicle performance, but intelligent actuation must be applied to all aspects of tire motion, requiring the use of the ICV architecture and the generation of performance criteria by which the complex motion of the vehicle may be evaluated. The Robotics Research Group has a history of developing and evaluating performance criteria for complex dynamic systems. and review of performance criteria developed for serial chain robotics is presented. These criteria address task independent actuator motion in addition to actuator ranges and limits, and their application to the ICV is discussed. A brief overview of several important concepts of classical vehicle dynamics are presented. The application of criteria derived from these concepts to the ICV architecture is discussed. This report presents the complexities of tire behavior and vehicle motion, the need for alternative architectures (the ICV), and a variety of performance criteria required to evaluate vehicle motion in real time. Criteria that are presented are summarized along with their definition and physical meaning. Future work for the development of the ICV involves the generation of a vehicle model for evaluating the application and range values of the presented criteria.Item Stand-alone-screen candidate selection methodology(2011-12) Christine, Chichi Ola; Gray, Kenneth E., Ph. D.; Prodanovic, MasaAn operator has some deepwater horizontal oil producing wells with stand-alone-screens (SAS) or unintentional SAS (incomplete open hole gravel packs). The objective of this project is to review sand control and production in these wells; to assess selection criteria for SAS; review factors that influence SAS performance such as bean up, fluids and contingency planning; and to provide recommendations with respect to SAS criteria. This project could save $ 6 - 8 million per well for the deepwater operator. SAS offers reduced cost, skin, complexity and logistics, which are necessary to make some well projects economical. The risk in deepwater subsea operations is an earlier workover costing about $39.2 million. In the past, this has made some operators recommend SAS for land and shallow offshore only. However, there are deepwater wells where open hole gravel packs are not preferred such as low cost wells, wells with unstable formations that bridge off the hole quickly, wells with narrow pore pressure-fracture pressure windows, high pressure/high temperature wells with fluid compatibility issues, tortuous wells seeking multiple targets, extended reach wells, etc. More recently, some operators are now using SAS for carefully selected non-traditional SAS candidates based on tests and other important factors. At the end of the study of the operator’s wells, it was concluded that six out of seven wells with SAS were successful because they had zero to minimal sand production and good oil flow as expected. This is an 85% success rate. The operator had more conservative selection criteria for SAS than the wells parameters. Shales were isolated with blank pipes in the wells. Well surveillance will be continued to see how the wells perform over the years. The operator was advised to adjust their selection criteria by a moderate percentage, as long as the SAS to be used is physically tested with a laboratory model to validate use of the SAS in such wells.