Browsing by Subject "Torque"

Now showing 1 - 5 of 5

Application of Euler-Bernoulli finite element methods for torque and drag model verification
(2022-12-02) Elyas, Odai Alaa; Foster, John T., Ph. D.; Landis, Chad
As the industry extends its search for hydrocarbons in remote locations, efficient extended reach drilling operations become crucial to reaching subsurface targets. This starts with enhanced simulation and monitoring of real time data measurements. Torque and drag are two of the most important parameters that are monitored continuously throughout any oil and gas drilling operations. Where torque is defined as the force of rotation between the drill pipe and the wellbore wall and drag is defined as the force required to push or pull the drill pipe through the wellbore and formations. The two parameters are often used as indicators for downhole conditions and must be maintained within certain ranges to ensure successful drilling to the targeted depths and running in hole the required completion equipment. Prior to any drilling operation, an estimate of both torque and drag are calculated based on the known drilling fluid properties, and formation parameters. Which is then used as an indicator of drilling issues such as wellbore collapse, cuttings accumulation, and change in drilling fluid properties. Several analytical models are utilized for torque and drag calculation. The first, and widely used approach is the soft string model which assumes the drill pipe acts as soft string taking the shape of the wellbore. This assumption neglects additional forces that cause the drill pipe to bend in deviated locations, which often results in underestimating torque and drag measurements in complex well designs. To address this, a stiff string model was implemented which considers the pipe’s bending stiffness and its effects on torque and drag calculations. Additionally, finite elements analysis (FEA) has been implemented to validate torque and drag calculations throughout the industry. However, the application of FEA often includes mesh generations which creates a 3D model of the drill pipe and subdivides the object into smaller domains to perform the calculations across the entire volume. This approach typically requires special software or large computational power to perform the calculations in a timely manner for real time monitoring applications. This thesis presents an approach to FEA that utilizes the Euler-Bernoulli beam equations, with the addition of an axial forces component to address both axial and transverse forces and deformations. The outcome of this thesis provides an accurate representation of torque and drag calculations, performed efficiently which could be used for planning, and real time monitoring during drilling operations.
Friction reduction optimization for extended reach and horizontal wells
(2019-04-30) Rostagno, Ian; Oort, Eric van
With conventional oil and gas reservoirs declining, energy companies are constructing more complex wells to economically produce natural resources that were not accessible previously. Extended reach Offshore wells and horizontal unconventional land wells are just two examples of technologies developed to unlock challenging reserves. However, torque and drag in extended reach and horizontal wells with departures of ten thousand feet or more still constitute one of the main challenges and technical limitations for drilling. Offshore wells can experience high friction even with the use of rotary steerable systems. Additionally, directional land wells drilled with downhole steerable motor experience high friction because only the bit rotates while the rest of the string slides against the wellbore wall. This friction can produce complications such as low sliding and rotating rates of penetration, high tortuosity, poor hole cleaning, vibrations, premature downhole tools failure or bit damaging and connection back-offs. Additionally, it can stop the string from moving backwards or forwards and rotating, potentially ending up with an irreversibly stuck drillstring and a shorter-than-planned well. In this work, we try to understand the influence of different agents on friction behavior and mitigation in deviated and horizontal wells, and how these agents can be used most effectively while drilling to improve drilling performance and wellbore quality
Isogeometric analysis : applications for torque and drag models, drillstring and bottom-hole assembly design
(2018-05) Hanson, Katy Lynn; Oort, Eric van; Foster, John T., Ph. D.
The drilling industry today relies on torque and drag models to analyze and ensure success during all phases of well construction and operations, including planning, drilling, and completion. Analytical models are based on equations that are undergoing constant development and improvement. The finite element method is an alternative to complex analytical calculations that is used often to determine torque and drag forces that are present when a drillstring is lowered, raised, and rotated in a wellbore. Traditional finite element analysis (FEA), however, is not time efficient or computationally able to simulate the complexities of a real wellbore. Thus, we introduce an alternative to the traditional finite element approach: isogeometric analysis. Isogeometric analysis is similar to finite element analysis except that it uses NURBS (Non-Uniform Rational B-Splines), as opposed to interpolatory polynomials used in traditional FEA, as the basis functions. NURBS functions are the same as those used in CAD programs, and they are able to construct exact conic shapes, such as circles and ellipses. Adopting NURBS basis functions allows finite element analysis to be performed directly on the exact geometrical surface - not on an approximate geometric surface mesh, as in traditional FEA. IGA yields a significantly faster and more accurate simulation. This thesis presents a real-world application of IGA to a drag force model to determine the resultant surface hook load during run-in-hole (RIH) operations. Real well data is used, and IGA results are compared to a similar FEA analysis. The outcome shows that IGA is indeed a superior finite element method that has immense potential for further application in the industry
Prediction of muscle force patterns in elbow flexion/extension and comparison with electromyography
(1990) Gonzalez, Roger Valles, 1963-; Barr, Ronald E., 1946-
The purpose of this study was to determine the contribution of the musculotendon actuators in human elbow flexion/extension. For this study, two experiments were conducted using video analysis and a third using electrogoniometer analysis. The video and electrogoniometer records of arm movements were analyzed and converted into kinematic data which were then used to calculate the net elbow joint torque. The methodology used in the experiments to study muscle contribution to flexion/extension at the elbow joint is discussed and the results of the experiments are presented. These torques were then partitioned among the muscles studied by assuming equal muscle stress across all muscles. Physiologic cross-Sectional Area (PSA) was used in calculating the stress in each muscle, therefore yielding individual muscle force patterns from the net joint torque. Predicted individual muscle force patterns were evaluated and compared to the integrated electromyogram (EMG) signals of each respective muscle by using a qualitative similarity analysis. In general, the results showed good qualitative profile correlation between the muscle force patterns predicted and the respective integrated EMG
Testing geologic and geometric effects on drilling operations using torque and drag models
(2015-12) Ho, Anthony, M.S. in Engineering; Gray, Kenneth E., Ph. D.; Daigle, Hugh
Intuitively, geologic and geometric effects on torque and drag should be significant. But literature suggests otherwise. Lesage et al. (1988) wrote that friction coefficients are not affected by lithology and hole angle, among other things. And if friction coefficients are similar for all of these factors, then only inclination, azimuth, and pipe specifications affect torque and drag. My thesis looks to test this statement using Johancsik’s torque and drag model and data provided by our sponsors. Johancsik’s model was chosen to test these effects because it is the most widely used torque and drag model in industry. Johancsik’s model also only relies on surface data in order to conduct an analysis. This contributes to the widespread use of Johancsik’s model and therefore increases the applicability of this paper. Once Johancsik’s model was chosen, it became natural to choose the minimum curvature method to interpolate the wellbore trajectory because Johancsik’s model was designed using the minimum-curvature method. Also, the minimum curvature method is the most widely used wellbore-interpolation method in industry. By using the minimum curvature method, this paper increases its applicability to industry. The analyses were conducted by examining the friction coefficients of each individual formation and lithology and geometric section. Friction factors encompass all factors that are not explicitly captured by the model and any factors affecting torque and drag that are not in the model will be captured by the friction factors. This study found lithology effects to affect drag consistently, though more data is needed. Drag friction factors were consistent by lithology, though they did appeared less predictable in Dataset 1 than the Datasets 2 and 3. Lithology affected torque less consistently than it did drag, though again more data is needed. Again, the results from Dataset 1 appeared to differ from Datasets 2 and 3. Further analyses are needed to conclude if this is caused by factors unrelated to lithology or individual geologies. The geometric effects of curved versus straight sections appear to not affect torque and drag. The results from the curved sections from the analyses have little relation to each other. As for more specific geometries, more analyses are needed before conclusions can be reached.