Regional safety program managers face a daunting challenge in the attempt to reduce deaths, injuries, and economic losses that result from motor vehicle crashes. This difficult mission is complicated by the combination of a large perceived need, small budget, and uncertainty about how effective each proposed countermeasure would be if implemented. A manager can turn to the research record for insight, but the measured effect of a single countermeasure often varies widely from study to study and across jurisdictions. The challenge of converting widespread and conflicting research results into a regionally meaningful conclusion can be addressed by incorporating “subjective” information into a Bayesian analysis framework. Engineering evaluations of crashes provide the subjective input on countermeasure effectiveness in the proposed Bayesian analysis framework. Empirical Bayes approaches are widely used in before-and-after studies and “hot-spot” identification; however, in these cases, the prior information was typically obtained from the data (empirically), not subjective sources. The power and advantages of Bayesian methods for assessing countermeasure effectiveness are presented. Also, an engineering evaluation approach developed at the Georgia Institute of Technology is described. Results are presented from an experiment conducted to assess the repeatability and objectivity of subjective engineering evaluations. In particular, the focus is on the importance, methodology, and feasibility of the subjective engineering evaluation for assessing countermeasures.

With increasing measured depths and horizontal displacements in extended reach (ERD) wells, good hole cleaning remains one of the major concerns in the oil and gas industry. While the methods currently used to increase cuttings transport capacity seek to increase the drag force applied to drilled cuttings, they are unable to significantly increase the cuttings transport capacity in horizontal and inclined wellbores because the gravitational force causes the cuttings to settle to the bottom side of the borehole. The proposed technology works to counteract the gravitational force while simultaneously increasing the drag force by attaching gas bubbles to drilled cutting particles with chemical surfactants. The gas bubbles will pull the cuttings upward because of their buoyancy in the drilling mud thereby counteracting the gravity force. Furthermore, the gas bubble/cutting aggregation will have a larger surface area than the cutting alone, resulting in an increase in the drag force. In addition to the theory behind this technology, this paper also focuses on laboratory development. Laboratory experiments were conducted to determine the effects of chemical surfactants, pH, and cutting particle size on the attachment of air bubbles to cutting particles. Two types of chemical surfactants, one to attach air bubbles to cutting particles and another to strengthen the air bubble, were necessary for attachment to occur. The corresponding chemical solution, with a pH range of 9 to 11, resulted in the optimal attachment of air bubbles to drilled cuttings up to 1.4mm in diameter that can be floated to the top of the fluid. Thereafter, experiments were conducted on a laboratory-scale flow loop with a horizontal test section. While conducting the flow loop experiments in the base solution without chemical surfactants, no cuttings were moved along the horizontal section. However, with the use of straight chain chemical surfactants up to 30% of the cuttings were carried completely across the horizontal tube by air bubbles and many other cuttings were carried partially across the horizontal tube. Further experiments showed that the use of certain branched chemical surfactants can greatly increase (about 58% of the cuttings were transported) the strength of attachment between air bubble and drilling cuttings compared to straight chain surfactants. These results show that this technology has the potential to make a "step-wise" improvement of cuttings transport capacity in horizontal and inclined wells. Introduction As the need for directional and horizontal wells increased, the interest in cuttings transport problems has shifted from vertical to inclined and horizontal geometries in the last 20 years. With increasing measured depths and horizontal displacements in extended reach (ERD) wells, good hole cleaning remains one of the major factors affecting cost, time, and quality of directional, horizontal, extended reach, and multilateral oil and gas wells. It has been recognized for many years that removal of cuttings from the wellbore during drilling of highly inclined and horizontal wells presents special problems. Poor hole cleaning can result in expensive drilling problems such as stuck pipe, lost circulation, slow drilling, high torque and drag, lost control of density, poor cement jobs, etc. If the situation is not handled properly, these problems can ultimately lead to the loss of a well. A single stuck pipe incident may cost over one million dollars. Combined stuck pipe costs for industry, was reported in the range of 100 to 500 million US dollars per year1. In attempts to avoid such problems, drilling operators often include such practices as "washing and reaming" wherein the drilling fluid is circulated and the drill string is rotated as the bit is introduced into the wellbore, and "back reaming" wherein the drilling fluid is circulated and the drill string is rotated as the bit is withdrawn from the wellbore. Other operations such as "wiper trips" or "pumping out of the hole" are often performed to attempt to control the amount of cuttings accumulated in the wellbore. All these operations require time and can significantly increase the cost of drilling a highly inclined or horizontal well. As a result, the search for more effective methods to improve directional and horizontal borehole cleaning is of great concern in the oil and gas industry.

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Forensic Engineering Analyses Of Collision Events Often Focus On Physics Models And Calculation Methods Governing The Forces Occurring During An Impact And After The Separation Of The Vehicles. However, Physics Models And Calculation Methods Governing The Motion Of Vehicles In Normal Linearnd Rotational Dynamics, Outside Of The Impact Phase, Can Be Applied To A Forensic Engineering Analysis To Gain Insight Into The Collision Events. Techniques From The Fields Of Automotive Engineering And Highway Engineering, When Applied By The Forensic Engineer, Can Answer Critical Questions About Aarticular Case, Or May Be Able To Eliminate Hypothetical Scenarios Proposed By Others. He Mechanical Systems And Dynamics Of Commercial Vehicles, Especially Articulated Vehicles, Differreatly From The Dynamics Of Typical Utomobiles. The Limitations And Performance Capabilities Ofommercial Vehicles In Acceleration, Lateral Motion, Rotational Yaw, Roll And Pitch, And Handling Characteristicsan Be Used To Analyze Events Leading Up To A Collision Or To Evaluate Avoidance Capabilities. Annderstanding Of Factors Such As Articulation, High Enters Of Gravity, Rollover Propensity, Off-Tracking Inurns, Jack-Knifes, Trailer Swingouts, Acceleration Rates, And Lane Change Performance Is Essential In Thenvestigation And Reconstruction Of Commercial Vehicle Collisions. This Paper Will Provide An Introductiono Vehicle Dynamics Concepts Applicable To Commercial Vehicle Collisions, With A Combination Ofcientific Theories That Are Unique To Heavy Vehicles.

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