Challenging the Status Quo Leads to Enhanced Drilling Performance

The technology described in this paper has been developed to challenge the shortcomings of the 40+ year old conventional blade stabilizer. The focus of this paper is to compare drilling performance on two lateral well sections against conventional spiral blade stabilizers. The comparison will highlight the noticeable improvement in drilling performance through analysis of relevant drilling parameters. The new design stabilizer, referred to in this paper as Innovative Drillstring Stabilizer (IDS), can be positioned in the drill string as you would typically do with a conventional spiral blade stabilizer or roller reamer. The design, however, is considerably different. The opened profile, placement and contour of the blades are designed to enhance energy transfer and flow along the tool, improving the transportation of cuttings around the tool while minimizing the occurrences of balling up. The orientation and dome shape of the blades is designed to reduce friction and torque, reduce vibration, improve weight transfer and when slide drilling minimizing the occurrence of hanging up and motor stalls. The engineered drillstring stabilizer was deployed in two wells for trial and technology acceptance purpose. An 8" OD innovative drillstring stabilizer was used as part of a steerable motor bottom hole assembly (BHA) in an integrated operations project. An in-depth performance comparison study was conducted by a specialized and independent third party between two identical BHAs. One (BHA-1), however, included conventional spiral blade stabilizers while the other (BHA-2) adopted the innovative drillstring stabilizers. The pioneering design of the IDS in BHA-2 contributed to reducing the overall torque and aiding in better weight transfer and drilling efficiency. It was possible to apply more weight and the energy transfer to the bit, based on mechanical specific energy (MSE) calculations, showed more efficient drilling conditions. As a result, the ROP, both rotating and sliding showed significant improvement with an overall increase of more than 30%. Better stabilization with BHA-2 aided in less vibration and no motor stalls. In addition, while pulling out of hole, lower hook loads were observed due to the enhanced hole cleaning features, improved hole condition and less friction along the string components. When back on surface no indications of balling-up were observed either. Today, drilling related inefficiencies, in the form of low ROP, non-productive time, damages beyond repair or stuck pipe and lost in hole incidents costs the oil and gas industry millions of dollars on an annual basis. The IDS is designed and proved to address such dysfunctions and improve drilling performance and efficiency while simultaneously stimulates a lower MSE drilling environment.

Biomechanical Comparison of Lag Screw and Non-spiral Blade Fixation of a Novel Femoral Trochanteric Nail in an Osteoporotic Bone Model

PurposeThere is no consensus regarding the advantages of the lag screw type over the blade type for treating femoral trochanteric fractures. We aimed to investigate whether non-spiral blade (Conventional-Blade, Fid-Blade) nails provide better biomechanical fixation than lag screws in a severe osteoporotic bone model.MethodsDifferent severities of osteoporotic cancellous bone were modelled using polyurethane foam blocks of three densities (0.24, 0.16, and 0.08 g/cm3). Three torsional tests were performed using each component for each bone density and the maximum torque was recorded, and the energy required to achieve 30° rotation was calculated. Using a push-in test, the maximum force was recorded, and the energy required to achieve 4-mm displacement was calculated. ResultsFor 0.08-g/cm3 density, the peak torques to achieve 30° rotation, energy required to achieve 30° rotation, peak force to achieve 4-mm displacement, and energy required to achieve 4-mm displacement were significantly greater for Conventional-Blade and Fid-Blade than for Lag Screw. ConclusionsConventional-Blade and Fid-Blade nails exhibited significantly higher values than Lag Screw under any test condition. The blade-type nail component may have a better fixation capability than the lag screw type in a severe osteoporotic bone model.

Multiple parameters and target optimization of splitter blades for axial spiral blade blood pump using computational fluid mechanics, neural networks, and particle image velocimetry experiment

The blood pump is an implantable device with strict performance requirements. Any effective structural improvement will help to improve the treatment of patients. However, the research of blood pump structure improvement is a complex optimization problem with multiple parameters and objectives. This study takes the splitter blade as the object of structural improvement. Computational fluid mechanics and neural networks are combined in research and optimization. And hydraulic experiments and micro particle image velocimetry technology were used. In the optimization study, the number of blades, axial length and circumferential offset are optimization parameters, and hydraulic performance and hemolytic prediction index are optimization targets. The study analyzes the influence of each parameter on performance and completes the optimization of the parameters. In the results, the optimal parameters of number of blades, axial length ratio, and circumferential offset are 2.6° and 0.41°, respectively. Under optimized parameters, hydraulic performance can be significantly improved. And the results of hemolysis prediction and micro particle image velocimetry experiments reflect that there is no increase in the risk of hemolytic damage. The results of this study provide a method and ideas for improving the structure of the axial spiral blade blood pump. The established optimization method can be effectively applied to the design and research of axial spiral blade blood pumps with complex, high precision, and multiple parameters and targets.

Continuous Medium Hypothesis Based Study on the Screw Flight Wear Model and Wear Regularity in Screw Ship Unloader

The screw flight on the vertical screw conveyor which is the spiral blade welded on the axial cylinder is the core component of the screw ship unloader and can be seriously worn by the materials during long-term conveying. The damaged screw flight will make the screw ship unloader unable to unload materials or even lead to an accident. Hence, we established a new screw flight wear model based on the Archard wear model and Continuous Medium Hypothesis. Two influencing factors, including speed and filling rate were selected to study the wear law of the screw flight, and the wear law was verified by experimental. Results indicate that the experimental results were consistent with the calculation model. The wear rate of screw flight was approximately parabola increased with the increase of rotational speed and the screw flight wear rate positively and linearly correlated with the filling rate.

Analysis of the Screw Flight Wear Model and Wear Regularity of the Bulk Transport in Screw Ship Unloader

The screw flight, spiral blade welded on the axial cylinder, is the core component of the screw ship unloader and can be seriously worn by the materials during long-term conveying. The damaged screw flight will make the screw ship unloader unable to unload materials or even lead to an accident. However, the existing wear model cannot be directly applied to predict the wear of the screw flight under different working conditions. Hence, we established a new screw flight wear model based on the Archard wear model and Continuous Medium Hypothesis to predict the service life of the screw flight. Three influencing factors, including speed, filling rate, and pitch, were selected to study the wear law of the screw flight, and the wear law was verified by EDEM simulation. Results indicate that the simulation results affected by the changes in various factors were consistent with the calculation model. With the increase of rotation speed and filling rate, the screw flight wear rate increased. Nevertheless, with the increase of pitch, the screw flight wear rate first increased and then decreased. The screw flight wear model can be used to calculate the wear rate under different working conditions for the screw flight life prediction.

Advanced Dynamics Analysis of a Drilling Stabilizer

Discrete models of two drilling stabilizer designs are subject to analytical mechanics treatments to examine dynamic behavior and amplify insights into contribution to bottom-hole drilling assembly (BHA) dynamics stability. The spiral blade and straight blade design stabilizers are essential components of oil and gas BHA included to functionally provide stabilization during rotation of the BHA and stand-off from the walls of the oil and gas wellbore. Attempts are made from the onset to simplify model complexity and as a consequence ease of computational simulation. The answer to the seemingly intuitive question of the mechanical advantage offered by a spiral blade compared to a straight blade stabilizer design in a constrained dynamics representation is revealed by computing forces generated at the interface between the functional elements of the devices and the inelastic boundary (wellbore) to keep the constraint satisfied. Analytical mechanics approaches have been used to carry out 3-D dynamics analysis of bottom hole drilling assemblies using 3-D Euler-Bernoulli or Timoshenko beam-column finite-element representations and lumped-parameter model approximations of rigid body dynamics behavior. In this work, phase portraits of angular velocity versus displacement — parsed for torque generated — from numerical simulations for torque-free and applied external load states, and discussion, offer illuminating insights into downhole operating dynamics of these ubiquitous components of oil and gas well bottom hole assembly (BHA) drilling devices.