The purpose of this study was to establish and validate a driving simulator method for assessing drug effects on driving. To achieve this, we used ethanol as a positive control, and examined whether ethanol affects driving performance in the simulator, and whether these effects are consistent with performance during real driving on a test track, also under the influence of ethanol. Twenty healthy male volunteers underwent a total of six driving trials of 1h duration; three in an instrumented vehicle on a closed-circuit test track that closely resembled rural Norwegian road conditions, and three in the simulator with a driving scenario modelled after the test track. Test subjects were either sober or titrated to blood alcohol concentration (BAC) levels of 0.5g/L and 0.9g/L. The study was conducted in a randomised, cross-over, single-blind fashion, using placebo drinks and placebo pills as confounders. The primary outcome measure was standard deviation of lateral position (SDLP; "weaving"). Eighteen test subjects completed all six driving trials, and complete data were acquired from 18 subjects in the simulator and 10 subjects on the test track, respectively. There was a positive dose-response relationship between higher ethanol concentrations and increases in SDLP in both the simulator and on the test track (p<0.001 for both). In the simulator, this dose-response was evident already after 15min of driving. SDLP values were higher and showed a larger inter-individual variability in the simulator than on the test track. Most subjects displayed a similar relationship between BAC and SDLP in the simulator and on the test track; however, a few subjects showed striking dissimilarities, with very high SDLP values in the simulator. This may reflect the lack of perceived danger in the simulator, causing reckless driving in a few test subjects. Overall, the results suggest that SDLP in the driving simulator is a sensitive measure of ethanol impaired driving. The comparison with real driving implies relative external validity of the simulator.

Summary Standalone screens (SASs) in open hole can provide highly reliable sand-control completions at a lower cost and with less operational complexity than other openhole sand-control completions and can provide long-term productivity performance comparable to other openhole completions when applied in the "right environment with the right procedures." Although many in the industry would agree with the preceding statement, there is no consensus on what the right environment is and what the right procedures are. Even when there is agreement on the applicability of SASs for a particular sand-size distribution, there are considerable differences in the recommended screen type and screen opening between various laboratories. In this paper, we critically review the various laboratory testing procedures used in the industry and the interpretations made to evaluate screen performance and screen selection for SAS applications. We demonstrate that the way some of the laboratory tests are performed makes them biased toward one type of screen (wire wrap) and that some are interpreted without sufficient information such that they almost always favor another type of screen (premium mesh). We show that severe screen plugging with clean formation sand is almost never an issue and that the probability of screen plugging because of other factors can be minimized when proper precautions are taken. We propose that candidates for SAS applications be initially selected on the basis of sand-retention performance, with the final selection confirmed on the basis of screen/sand pack permeability measurements. In addition, on the basis of approximately 185 laboratory tests performed on various types of wire-wrap (6 to 16 gauge) and premium mesh (60 to 600 μm) screens for unconsolidated sands and using a set criterion for sand retention, we conclude that many of the currently used criteria in the industry for selection between gravel packing and SAS are highly conservative and unduly limit the possible application of SASs.

The results suggest that the driving-related measures explored in this study are less sensitive to alcohol-mediated driving impairment than SDLP, especially during real (test track) driving. The discrepancy in effect sizes between simulated and real driving may imply low external validity of these measures in simulator studies.

This paper discusses a study into the effects of annular flow in standalone screen completions. Conventional stand alone screen designs do not constrain flow to within the basepipe. Flow is able to enter the toe of any joint and travel along the annulus before entering again at the heel section of the joint. The paper discusses the use of computation fluid dynamics (CFD) modelling carried out to illustrate the significance of the annular component on the flow and how this will affect annular solids transport and subsequently the erosion and lifetime performance of conventional screens.This work is particularly significant in high rate gas completions. The conventional approach in the industry when using stand alone screens in gas wells is to maximize the flow area from annulus to basepipe by utilising the highest possible basepipe perforation density. This paper illustrates the fallacy in using this conventional approach and how this will significantly increase the potential for erosion.The paper will show that the use of conventional standalone screens, and also conventional inflow control device (ICD) screens will result in a significantly high potential for erosion in the screens. This paper will propose an alternative screen philosophy for standalone screen completions in high rate gas wells, and illustrate how this philosophy will be an improvement on the current approach.

This paper discusses the PLT-correlated results of two test wells completed during 2006; one in sandstone and one in a carbonate reservoir, with the new completion technology of nozzle-based passive inflow control devices (ICD) which improves performance of wells with reservoir challenges as described:In highly productive sandstone reservoirs, horizontal wells suffer from uneven flow profile and subsequent premature cresting/coning effects. In general, there is a tendency to produce more at the heel than at the toe of horizontal wells, which contributes to poor well cleanup at the toe. Additionally, excessively increasing the rate and/or horizontal well length can increase the risk of limiting sweep efficiency, resulting in bypassed reserves1.In carbonate reservoirs, permeability variations and fractures can cause uneven inflow profile and accelerate water and gas breakthroughs. Wells with early gas or water breakthrough have to be shut-in until remedial plans are decided and implemented, resulting in deferred production. The main reservoir objectives for applying passive ICD technology in the two test wells are:Sandstone: Decrease the influence of heel-toe effects and high permeability zones; hereby deferring water/gas breakthrough, improving well cleanup and sweep efficiency.Carbonate: Control flow rates from high permeability intervals and to limit production from each compartment based on lateral offset from the gas-oil contact to prevent premature gas breakthrough. The test well PLT-logs were correlated to static reservoir simulations. Analyses of the well performances show that the objectives of both completions were achieved. By having proper matches of the completions with ICD, the value over standard completions can be evaluated. Post-evaluation of the completion designs based on the PLT-log results has increased our understanding of the nozzle-based ICD performance. As a result several approaches for completing wells in both sandstone and carbonate reservoirs with ICD have been recommended in order to achieve optimized inflow performance. Introduction Two trial wells with nozzle-based passive ICD systems were designed and completed in 2006; one for sandstone and one for carbonate reservoirs. To evaluate and approve the new ICD completion, these wells were production logged and the results were carefully analyzed. The most important feature of the ICD completion is the self-adjusting effect of flow variations anywhere along the well trajectory and whenever they occur during entire well life. The key benefits are:Increased well life and reserves due to improved sweep efficiency.Delayed gas and water breakthrough.Decreased water/gas rates after breakthrough when water/gas mobility is higher than oil.Improved well cleanup.