We investigate the possibility of using the center-edge asymmetry to distinguish graviton exchange from other new physics effects at hadron colliders. Specifically, we study leptonpair production within the ADD and RS scenarios. At the Tevatron, the graviton-Z interference is the most important contribution to the center-edge asymmetry, whereas at the LHC, the dominant contribution comes from gluon fusion via graviton exchange, which has no analogue at e + e − colliders. We find that spin-2 and spin-1 exchange can be distinguished up to an ADD cut-off scale, M H , of about 5 TeV, at the 95% CL. In the RS scenario, spin-2 resonances can be identified in most of the favored parameter space.

We discuss photon bremsstrahlung induced by virtual graviton exchange in proton-proton interactions at hadronic colliders, resulting from the exchange of Kaluza-Klein excitations of the graviton. The relevant subprocesses gg→G→e ϩ e Ϫ ␥ and qq →e ϩ e Ϫ ␥ are discussed in both the Arkani-Hamed-Dimopoulos-Dvali and the Randall-Sundrum scenarios. Although two-body final states ͑or real graviton emission͒ would presumably be the main discovery channels, a search for three-body final states could be worthwhile since such events have characteristic features that could provide additional confirmation. In particular, the k Ќ distribution of the photon is in both scenarios harder than that of the standard-model background.

Recent developments in drilling technology, such as increased sensory information, enhanced data processing and transmitting capacity and capability, and developments in computer controlled machinery, together with adaptation of already available process technology and know-how, are opening up new possibilities for drilling operations. Application of these combined technologies, together with advanced computer modeling, enables enhanced monitoring and increased optimization and control of drilling operations. This paper presents such an integrated system for monitoring and control of the drilling process, currently in the test phase. A key element in the methodology used here is that the models for fluid flow and drilling mechanics are continuously updated in real-time according to the measured data using Kalman filtering techniques. By comparing the calibrated models to real-time data, unwanted occurrences can be detected quickly, and mitigating actions may be taken, either through system control or through manual intervention. Using the calibrated models, safe limits for the drilling operation are computed and enforced, and procedures are optimized. The modules developed cover tripping and reaming, pump start up, friction tests, stick-slip prevention, bit load optimization and monitoring. The methodology may be applied to drilling operations where the drilling equipment is computer controlled. Surface and preferably downhole data must be available in real time. Rigorous testing with drilling data from offshore drilling operations has been performed, and several full-scale tests have been run on a test rig. The ability to maintain the drilling operation within critical limits has been demonstrated. The methodology may contribute to increased safety and reduced down time during drilling operations. Introduction A large part (25%, [1]) of the overall cost associated with drilling operations is a result of non-productive time due to unplanned well incidents. The main problems during drilling are related to events such as kick, stuck pipe, wellbore collapse, lost circulation and equipment failures, see [2]. Proper use of real time data has the potential to reduce the down time caused by these events significantly. Availability of real time drilling data is increasing, both from surface instruments and downhole gauges. Open standards for real time data access are being developed. Computer controlled drilling machinery like pumps, draw-work and top drive are available. High band-width communication between the rig sites and the office like fiber optic, high band width VHF and satellite are used. All these combined developments enable enhanced monitoring through data processing, and optimization and control of drilling operations through computer modelling and drilling machinery automation. For many years IRIS has developed advanced computer models for the oil industry. Among these are multiphase well flow models and torque and drag models. Testing and verification is done through studies with comparison to field data. Additional sub models have been incorporated to handle special effects and give the models special features. During the last few years the models have been developed in order to run real time and use available measurements of operational data such as flow rate, inlet temperature, surface torque and hook load. In order to run real time and to be a corner stone in a control system for the drilling operation, the models need to be fast and robust. Drilltronics - A Software System for Monitoring and Control IRIS (former RF-Rogaland Research) and National Oilwell Varco (NOV) have developed a new drilling, monitoring, control and prediction system called Drilltronics [3]. The main feature of the system is to combine existing hardware and software for monitoring and controlling the drilling process (system environment) with advanced mathematical models for the drilling process. In the implementation of the system we have used existing and upgraded system environment from NOV.

Summary A new system for real-time optimization and automated control of the drilling process has been tested successfully on the Statfjord C platform in the Norwegian sector of the North Sea. The demonstrated system uses continuously calibrated dynamic process models combined with real-time drilling-data input to calculate available parameter windows, and forward-model simulations are applied to provide optimized operational parameter sequences. The calculation results are applied directly in machine control. The system further applies automated testing combined with continuous diagnostics to provide process advisory. In the field test, pipe-movement control automation, pump-rate control automation, and automated wellbore-condition diagnostics were demonstrated, proving fail-safe application of process safeguard enforcement and optimization of operational procedures. Results from active and passive testing indicated that the new methodology has the ability to improve drilling-process reliability, safely increase drilling efficiency, and reduce the risk of human error. The authors provide a thorough description of the preparations and testing and present an evaluation of the test results, with reference to success criteria that were developed in cooperation with the field operator and drilling contractors involved in the test. Implications for the work organization are also discussed, particularly in relation to control of data input, decision making, and responsibility. The demonstrated technology applies direct integration of current know-how and best practices into the drilling-control system, and available real-time information is applied directly in controlling the drilling process.

Summary During drilling operations, downhole conditions may deteriorate and lead to unexpected situations that can result in significant delays. In most cases, warning signs of the deterioration can be observed in advance, and by taking proactive actions, drillers can avoid serious incidents such as packoffs or stuck pipes. A new analysis methodology, relying on an automatic real-time computer system, has been developed to detect those early indicator conditions. The methodology involves constantly computing the various physical forces acting inside the well (mechanical, hydraulic, and thermodynamic). These physical forces are coupled by an automatic model calibration, which then gives a reliable picture of the expected well behavior. Through analysis of the deviations between modeled and measured values, an estimation of the current state of the well is derived in real time. Changes in the well condition are an early warning of deteriorating well conditions. This paper precisely describes the real-time analysis and the results during some drilling operations. The software has been used for monitoring 15 unique wells located in five different North Sea fields. All major situations were signaled in advance at different event time scales: Rapidly changing downhole conditions (such as pulling a drillstring into a cuttings bed) were typically detected 30 minutes ahead of the actual event, medium-duration deteriorations were detected up to 6 hours before the incident, and slow-changing downhole conditions were signaled up to 1 day in advance. Several examples that illustrate the detected incidents over distinct time periods are described. The availability of good-quality real-time data streams makes it possible to implement such analysis tools in an integrated operation setup. Early symptom detection can be used to make decisions in a timely fashion, on the basis of quantitative performance indicators rather than subjective feelings and personal experience.