Drilling Simulator Research Articles

Effect of drilling fluids on coal permeability: Impact on horizontal wellbore stability

The objective of this study was to evaluate a series of mud systems and additives typically used in coalbed methane drilling in terms of formation of an instantaneous filter cake, ability of the coal reservoir to rid itself of the filter cake during production, and overall impact on coal permeability. To achieve this, a series of laboratory tests were conducted initially using artificially cleated gypstone rock (to simulate coal). This was followed by the use of large-diameter coal cores, which, unfortunately, did not allow for the tests to be done under in-situ confining stress conditions. The three mud systems tested against coal (Xantham Gum, HEC and Na-CMC) did not have a negative impact on coal permeability, in contrast to previous laboratory data that showed large decreases. Two fluid loss control additives, which have been used successfully in drilling clastic and carbonate rocks, were also tested using a non-ionic polymer mud system. During simulated drilling, these additives (FLC 2000™ and Q-Stop) were very effective in building a thin filter cake on the coal surface almost instantaneously, to the point that no solids were detected in the downstream fluid accumulator. During simulated production, a small pressure drop was sufficient to remove the filter cake. Coal permeability (to water) returned to its original (pre-test) value, which suggested that there was no permanent permeability damage caused by the two additives. When coal-derived fines were added to the drilling mud in another experiment using the same coal, the near wellbore coal permeability was reduced by 87.5%, indicating severe damage to the cleat system and in agreement with previously reported laboratory data. Following the very good performance of FLC 2000™ and Q-Stop in the laboratory tests, these two additives were then used in field applications. Their presence in the drilling fluid resulted in the successful drilling of 953 m and 1400 m of total horizontal length in the deep Mannville coals in Alberta (at True Vertical Depth of 1400 m and 1150 m, respectively). No borehole instability problems were encountered during drilling of the two horizontal wellbores. The monitored mud losses were low in both cases, with the horizontal well #2 experiencing lower mud loss possibly as a result of the absence of large fractures encountered along the horizontal path. Horizontal well #1 remained stable, which allowed sufficient time to insert a production liner.

Establishing aerosol exposure predictive models based on noise measurements—using concrete drilling as an example

This study used a full scale mockup of a concrete drilling simulator to simulate drilling processes in an exposure chamber. Six drilling conditions were selected with rotating speeds and drill bit sizes varied from 265 to 587 rpm and 16 to 32 mm, respectively. For each drilling condition, the emitted noise power spectrums were measured and dust exposure concentrations of the fractions of the total (C(tot)), inhalable (C(inh)), thoracic (C(tho)), and respirable (C(res)) were estimated. We find that neither the resultant dust exposure levels nor the noise levels can be explained simply by the involved drilling mechanical energy. By dividing the emitted noise power spectrums into the high and low frequency noise (i.e., W(H) and W(L)), we find that 86.3%, 85.6%, 81.5%, and 77.6% variations of C(tot), C(inh), C(tho), and C(res) could be explained by the combination of W(H) and W(L), respectively. We also find that the emissions of coarse particles and W(L) were possibly contributed by two mechanisms of the impact wear and brittle fracture wear, whereas fine particles and W(H) could be contributed by the mechanism of abrasive wear. Although the predictive models obtained from this study could not be directly used in other dust emission sources, the developed methodology would be beneficial to industries in the future for aerosol exposure assessment, particularly when conducting conventional personal aerosol samplings is not possible in the field.

Science Results from a Mars Drilling Simulation (Río Tinto, Spain) and Ground Truth for Remote Science Observations

Science results from a field-simulated lander payload and post-mission laboratory investigations provided "ground truth" to interpret remote science observations made as part of the 2005 Mars Astrobiology Research and Technology Experiment (MARTE) drilling mission simulation. The experiment was successful in detecting evidence for life, habitability, and preservation potential of organics in a relevant astrobiological analogue of Mars. SCIENCE RESULTS: Borehole 7 was drilled near the Río Tinto headwaters at Peña de Hierro (Spain) in the upper oxidized remnant of an acid rock drainage system. Analysis of 29 cores (215 cm of core was recovered from 606 cm penetrated depth) revealed a matrix of goethite- (42-94%) and hematite-rich (47-87%) rocks with pockets of phyllosilicates (47-74%) and fine- to coarse-grained loose material. Post-mission X-ray diffraction (XRD) analysis confirmed the range of hematite:goethite mixtures that were visually recognizable (approximately 1:1, approximately 1:2, and approximately 1:3 mixtures displayed a yellowish-red color whereas 3:1 mixtures displayed a dark reddish-brown color). Organic carbon was poorly preserved in hematite/goethite-rich materials (C(org) <0.05 wt %) beneath the biologically active organic-rich soil horizon (C(org) approximately 3-11 wt %) in contrast to the phyllosilicate-rich zones (C(org) approximately 0.23 wt %). GROUND TRUTH VS. REMOTE SCIENCE ANALYSIS: Laboratory-based analytical results were compared to the analyses obtained by a Remote Science Team (RST) using a blind protocol. Ferric iron phases, lithostratigraphy, and inferred geologic history were correctly identified by the RST with the exception of phyllosilicate-rich materials that were misinterpreted as weathered igneous rock. Adenosine 5'-triphosphate (ATP) luminometry, a tool available to the RST, revealed ATP amounts above background noise, i.e., 278-876 Relative Luminosity Units (RLUs) in only 6 cores, whereas organic carbon was detected in all cores. Our manned vs. remote observations based on automated acquisitions during the project provide insights for the preparation of future astrobiology-driven Mars missions.

Relationship Between Standards of Procedures for Pandemic Flu and Level of Hospital Performance in Simulated Drills

Standard operating procedures are the basis of a consistent response to varied threats. The aim of this study is to investigate the relationship between the quality of standard operating procedures developed by hospitals for the management of a pandemic influenza outbreak and the level of performance in a H5N1 flu drill. Standard operating procedures developed by all general hospitals in Israel for the management of pandemic influenza were evaluated with a tool developed for this purpose. The hospital standard operating procedure score was then compared with the score obtained by the hospital in a simulated drill. Cronbach's alpha was used to determine the reliability of the standard operating procedure evaluation scores and the scores obtained on the drill. Reliability of both scores was high (>0.70). Hospital standard operating procedure scores were found to be moderately related to the scores obtained on the simulated drill. An important relationship was found between performance on the drill and the following components of the standard operating procedure: protection of staff and patients, staffing coordination and control, and infrastructure maintenance and minimizing overload. Hospital characteristics were not found to be important in determining either the hospital standard operating procedure score or performance on the simulated drill. A reasonably strong relationship was found between quality of the standard operating procedures developed by hospitals to deal with a pandemic influenza and performance on a pandemic drill. Components of the standard operating procedure that dealt with areas that were relatively unfamiliar to staff or topics that were perceived by personnel as posing a risk to their well-being were found to be more important. The quality of the standard operating procedures was found to be important in relation to performance in a pandemic flu drill; therefore, we suggest investing effort in developing standard operating procedures that are comprehensive and cover relatively new domains in detail.

Influence of the ploughing effect on the dynamic behaviour of the self-vibratory drilling head

The vibratory drilling process enables the chip to be split into small elements thanks to axial vibrations of the drill self-maintained by the cutting energy. The vibrations should remain stable when machining, and damping be removed or very limited—particularly the ploughing force induced by the chisel edge and the flank face. To predict the behaviour of the self-vibratory drilling head, a new ploughing model has been developed. In this model, the interaction of the tool flank face with the machined material can be perceived as a virtual cutting edge that produces an additional thrust force and an additional removal of material. This model improves the cutting force models and is integrated into a numerical vibratory drilling simulator. The model shows a good correlation with experimental results.

The friction and wear of various hard-face claddings for deep-hole drilling

Hard-face claddings are used for banding drill shafts that rotate against well casings while lubricated by drilling mud. This tribosystem should have the lowest friction possible in order to minimize drilling power requirements, and the lowest total system wear to maximize component life. Blocks representing a variety of hard-face claddings were slid against rotating rings of AISI 4140 casing material and lubricated by simulated drilling mud that consisted of a slurry of silica sand, clay, and water. The cladding specimens included currently used alloys and several candidate compositions. There was an excellent correlation between the friction coefficient and the wear, by weight loss, of both the cladding and the casing alloys. There was also a good direct correlation between the wear of the cladding and the wear of the casing. Claddings with finer grain sizes and finer, more uniformly distributed hard carbides had higher hardness and produced lower wear on both the cladding and the casing counter-face. The complex mechanisms involved with three-body wear and friction in interfaces lubricated by slurries present a challenge for further study.

Pre-operative Drilling Simulation Method for Dental Implant Treatment

The position, depth and direction of implant placement are often planned based on evaluation of radiographs and study casts. Insertion planned in such a manner may not be adequate for precise and safe surgery in some cases due to inadequate working clearance in the oral cavity. In order to obtain high initial stability and ensure osseointegration at the implant-bone interface, careful and precise drilling must be performed at the implant placement site. Therefore, we propose the necessity of evaluating the operability of implant treatment-devices prior to surgery. The amount of handling space needed during implant placement surgery was determined. The results showed that for implants with a length of 7-18 mm, a vertical distance of as much as 50-60 mm was required, depending on the implant platform. These results suggest the necessity of pre-operative drilling simulation in each individual. Handling space was measured with angled heads and probes fabricated on a trial basis for pre-surgical drilling simulation in the oral cavity. We believe that these instruments may be clinically useful in estimating the amount of handling space required prior to surgery and ensuring precise implant placement. Evaluation of the intra-oral environment for handling of treatment devices should be included in the pre-surgical intra-oral evaluation of dental implant cases to avoid changes in treatment planning due to intra-oral interference during the course of surgery.

0247 NEUROCOGNITIVE REHABILITATION –A FOUR-CASE PILOT STUDY

With the advent of probing systems and their integration with machining centers, coordinate metrology-based datum establishment is eliminating the need for precision hard-contact locators in many machining applications. Unfortunately, the coordinate data collected by these systems are often subject to noise in the form of random and biased errors of the workpiece datum features and measurement system. Consequently it is important to use datum-establishment algorithms that are insensitive to noise and that lead to the least measurable machined-feature error.This paper describes a simulation analysis that was carried out to evaluate the performance of three datum-establishment methods: 3–2–1, sequential least-squares (SQLS) and simultaneous least-squares (SMLS). The analysis involved the simulated drilling of three holes in a two set-up process. Simulated coordinate data were obtained from three planar, nominally orthogonal surfaces subject to perpendicularity errors and random roughness errors. Workpiece datum reference frames were fitted to this data using the three methods, the holes were drilled relative to these reference frames, and their position errors were computed relative to an ANSI-Y14.5M-defined reference frame.This analysis demonstrated that the SMLS method results in significantly less hole-position error [0.0173 mm average, 0.0146 mm standard deviation (SD)] than either the 3–2–1 method (0.0943 mm average, 0.0143 mm SD) or the SQLS method (0.0904 mm average, 0.0245 mm SD). This is despite the fact that the datum reference planes (ANSI Y14.5M) used to define these errors are defined sequentially relative to the extrema of the datum features, whereas the SMLS method defines the datum reference planes simultaneously with the purpose of minimizing fitting error.

On the possible effect of pedestal pulse on material removal by ultrahigh intensity laser pulses

The results of the interaction of 200 fs and 4 ns laser pulses produced by a Ti : Sapphire commercial laser system with various materials are reported. The drilling rates were measured as a function of laser pulse energy and material thickness. Saturation of the material removal rate was observed for high laser pulse energy. The dependence of the material removal rate on the sample thickness was measured. The results of numerical simulation of laser drilling with femtosecond and nanosecond laser pulses using a theoretical model which includes phase transition at the critical temperature are reported. The computed drilling rates are in agreement with the data of measurements. The effect of a suspected nanosecond pedestal pulse containing approximately 30% of total pulse energy on the rate of drilling with femtosecond laser pulses is numerically simulated and the computed results are discussed.

Ultradeepwater Hydraulics and Well-Control Tests with Extensive Instrumentation: Field Tests and Data Analysis

Summary Detailed measurements of downhole pressures and temperatures have been performed during simulated drilling operations at ultradeepwater offshore Brazil. Sensors were placed at six different positions along the drillstring,which made high-frequency recordings of pressure and temperature during Surges and swabs at different depths. Gel-breaking tests. Circulation sweeps. Migration of gas in the riser. It was expected that the special conditions in ultradeep wells with low temperature along most of the very long riser would cause some significant deviations from corresponding measurements in more-normal wells. The measurements aimed at identifying, understanding, and quantifying such effects. This is considered very important because a narrow window between pore and fracture pressure is common in very deep waters. Advanced transient models were used to identify the most interesting effects. Effects that are reliably reproduced by advanced transient models are also important, but operators are able to do calculations to prepare for them. A remote-operated vehicle (ROV) recorded temperature outside the riser during experiments to give input to a detailed study of heat transfer from drilling fluid inside the riser to the seawater outside. The purpose of the tests was to obtain detailed measurements of physical effects that may be important in ultradeepwater wells. This paper presents a detailed analysis of the recorded data, including comparing them to advanced computer models for transient pressure and temperature during drilling, circulation, and surge/swab. In addition, the gas migration is simulated with an advanced kick simulator.

Surface pressure in the hand when holding a drilling machine under different drilling conditions

The aim was to study how different using conditions influence the surface pressure in the hand while performing simulated drilling tasks using an ordinary impact drilling machine. The pressure on the hand was measured at 16 points. The following parameters were changed and compared with two reference sessions: feed force, working direction, vibration level, balance and the use of an additional handle. Furthermore, the subjects tested four handles covered with rubber of different hardness. Finally, the subjects used impact drills with a narrower, an original and a wider handle. The results showed that the pressure in all situations was highest on the web between the index finger and the thumb. The pressure on this part of the hand increased with increasing feed force and with increasing handle size. The total pressure level increased with increasing feed force compared with the reference sessions. Using a supporting handle, gloves or handles covered with compressible rubber decreased the total pressure level. Vibrations, changed direction of action and changed weight distribution did not influence the total pressure level. Using a narrower or wider handle did not influence the total pressure level compared with the original handle. Relevance to industry Information concerning the design of handles for power tools is essential for tool designers.

Physical constraints on the foraging ecology of a predatory snail

We studied the effects of aerial exposure and high summer temperatures on the southern oyster drill (Stramonita haemastoma), feeding on the American oyster, Crassostrea virginica. In the laboratory, oyster drill feeding rates and growth were highest at 25 and 30°C, some mortality occurred at 35°C, all snails died at 40 and 45°C, and the 28-day LC 50 was 35.7°C. In a second experiment where both water temperature (25 vs . 33°C) and aerial exposure were varied, only simulated tidal exposure lowered oyster drill feeding and growth rates. In field cage experiments, oyster drills had reduced feeding rates and growth at intertidal sites, but snail growth rates increased in late summer with warmer water temperature. We therefore conclude that aerial exposure, not high temperature, is the major factor limiting oyster drill feeding and growth in intertidal oyster reefs. Field experiments with partial cages also suggested that ambient predation rates were much higher at a subtidal than at a nearby intertidal site. Because southern oyster drills have depressed feeding, growth, and possibly lower fitness in intertidal oyster reefs during the summer, this reduced predation risk may provide a refuge for intertidal oysters.

An analysis of the effect of datum-establishment methods on the geometric errors of machined features

With the advent of probing systems and their integration with machining centers, coordinate metrology-based datum establishment is eliminating the need for precision hard-contact locators in many machining applications. Unfortunately, the coordinate data collected by these systems are often subject to noise in the form of random and biased errors of the workpiece datum features and measurement system. Consequently it is important to use datum-establishment algorithms that are insensitive to noise and that lead to the least measurable machined-feature error. This paper describes a simulation analysis that was carried out to evaluate the performance of three datum-establishment methods: 3–2–1, sequential least-squares (SQLS) and simultaneous least-squares (SMLS). The analysis involved the simulated drilling of three holes in a two set-up process. Simulated coordinate data were obtained from three planar, nominally orthogonal surfaces subject to perpendicularity errors and random roughness errors. Workpiece datum reference frames were fitted to this data using the three methods, the holes were drilled relative to these reference frames, and their position errors were computed relative to an ANSI-Y14.5M-defined reference frame. This analysis demonstrated that the SMLS method results in significantly less hole-position error [0.0173 mm average, 0.0146 mm standard deviation (SD)] than either the 3–2–1 method (0.0943 mm average, 0.0143 mm SD) or the SQLS method (0.0904 mm average, 0.0245 mm SD). This is despite the fact that the datum reference planes (ANSI Y14.5M) used to define these errors are defined sequentially relative to the extrema of the datum features, whereas the SMLS method defines the datum reference planes simultaneously with the purpose of minimizing fitting error.

Surface Pressure in the Hand When Holding a Drilling-Machine under Different Drilling Conditions

Six male and six female subjects performed simulated drilling tasks using an ordinary impact drilling-machine. Meanwhile the pressure on the hand was measured in 16 points. The influence on the pressure distribution and the total pressure level from changes in feed force, working direction, vibration level, balance, number of handles, gloves, handle material and handle width, was studied. The results showed that the pressure was in all situations highest on the web between the index finger and the thumb. The pressure on this part of the hand increased with increasing feed force and also with increasing handle size. The total pressure level increased, as expected, with increasing feed force compared with the reference sessions. Using a supporting handle, gloves or softer handle material decreased the total pressure level. Working direction, vibrations, balance and handle width, however, did not influence the total pressure level.

Corrosion Fatigue Behavior of Carbon Steel in Drilling Fluids

Abstract Corrosion fatigue of carbon steel (CS) in drilling fluids was studied using a self-made rotary bending corrosion fatigue testing apparatus under simulated drilling conditions. Mechanisms o...

Real time numerical simulation and visualization of electrochemical drilling

Gas turbines have to be provided with holes in order to provide cooling; these holes are made using an electrochemical drilling technique. Since this process is tedious and expensive, computer simulations are very useful. Such a model needs to incorporate the relevant physical processes. A simulation system including real time user interaction and visualization together with efficient numerical techniques has been developed using an object oriented design.

Simulation of light propagation in optical linear and nonlinear resist layers by finite difference beam propagation and other methods

This article presents a new method for the calculation of light propagation in resist layers and compares it with scaled defocus and transfer matrix algorithms. Our method is not restricted to homogeneous resist and substrate layers. For the first time, a simulation of focus drilling is presented.

The lubricating mechanisms of lubricating drilling fluids on synthetic diamond bit

The functions of lubricants in diamond drilling were discussed in this paper. The influences of lubricant on drilling efficiency and bit’s life were compared and analyzed with simulated drilling test and lubrication test apparatus. Lubricating mechanisms were also discussed.

Simulation of Surgical Approaches to Cerebral Aneurysms Using Three

In four difficult aneurysms cases, preoperative views of surgical approach were obtained by three-dimensional and multiplanar reconstruction imaging methods using helical CT scanner. Simulation of various surgical approach views are also possible and an appropriate surgical approach is selected by comparing various surgical views. With this imaging technique, elimination of skull base bone, namely, simulation of bone drilling including the site and extent of bone resection is freely available. The diameter of the orifice of aneurysms and calcified portion of the wall are also visualized. One of the limitations is that small vessels less than 1 mm in diameter are not visualized.

Transmission Line Modelling of Simulated Drill Strings Undergoing Water-Hammer

Drill strings and oil production lines are examples of fluid systems for which time-dependent (dynamic) as well as steady state (static) analysis is increasingly needed. These systems are difficult and expensive to instrument and test experimentally. Developments of fluidic non-moving-part controllers to produce water-hammer pulsations stimulated a need to simulate the fluid dynamics of such drill strings to aid the design work. The method of simulation chosen was transmission line modelling (TLM). It is essentially a time-delay method, borrowing its main concepts and the fundamentals of its computational solution scheme from early work by others in the field of electrical power lines. In its elementary form, a fluid network is treated as a set of pipes (or pipe segments) where waves travel with pure time delay. Connecting the pipes are junctions of various types at which the waves are scattered (transmitted, reflected and/or attenuated). The merits and limitations expected with this methodology in comparison with the method of characteristics (MOC) and other wave-analysis methods are discussed. The first adaptations of TLM were for small perturbation analysis. The presentation here takes such work further forward to model large-scale waves in pipe networks of almost arbitrarily complex topology. The basic theory behind the method is presented and the solution schemes are formulated mathematically with comments on the type of data structure and algorithms needed to undertake computationally such solutions. With the aid of modules described elsewhere, providing comprehensive steady state modelling capability, the software provides a powerful tool for implementing static and dynamic TLM simulations of networks. One of the novel aspects of considerable benefit is the ease of implementation of time-varying junctions capable of representing the overall action of control elements such as the fluidic controllers mentioned earlier. A large experimental laboratory facility with a simple circuit containing the essential hydrodynamics of drill strings was used to gather data on water-hammer pulsations. A controlled solenoid valve with a high-resistance bypass acted as an alternating high and low resistance in the main pipe loop. A simplified version of the circuit was simulated with TLM to compare and discuss the results. The TLM time-domain results took a few seconds of computer processing time and revealed the basic features of the circuit dynamics quantifying water-hammer to a fair and useful accuracy. Such results were encouraging and confirmed the power of this computational method as an aid in the design process.