Analysis of vertical, horizontal and deviated wellbores. Comprehensive wellbore stability analysis utilizing quantitative risk assessment daniel moos1 pavel peska1 thomas finkbeiner1 mark zoback2 1geomechanics international, palo alto, ca 94303. Software for wellbore stability background to reach many petroleum reserves, operators often drill through shale formations or other unpredictable or unstable media. Simulias approach to bsp using abaqus finite element code. Maintaining wellbore stability is an important issue in oil and gas industry 110. Prior to drilling, the mechanical stresses in the formation are less than the strength of the. The analyses consider planar deformations in the plane orthogonal to the wellbore using a quasi threedimensional 3d finite element model that represents coupled flow and deformations within the soil mass. Wellbore stability archives hxr drilling services, inc.
Jan 04, 2016 the finite element analysis fea technology by hydraulicmechanicaldamage hmd coupling is proposed in this paper for wellbore stability analysis of transversely isotropic rock, developed basing on the recently established fea technology for isotropic rock. Pdf finite element analysis for wellbore stability of transversely. Download abaqus for students, researchers or educators. Wellbore stability requires a proper balance between theuncontrollable factors of earth stresses, rock strength, and pore pressure, andthe controllable factors of wellbore fluid pore pressure, and the controllablefactors of wellbore fluid pressure and mud chemical composition. Probabilistic approach in wellbore stability analysis. Buy wellbore stability modeling in vertical and horizontal boreholes. The fluid system always has been a vital part of drilling engineering, dating back to spindletop, when a herd of cattle was turned loose in a partiallyfilled water pit to grind the saturated soil into mush with their hooves. Using wellbore deformation to optimize drilling performance.
Topics geomechanical model need of geomechanical model. Comprehensive wellbore stability analysis utilizing. Slope stability equilibrium and stress states with abaqus. Ppt advanced wellbore stability model wellstabplus. The halliburton baroid ecosystem wellbore stability. Wellbore instability during drilling is a major problem in the application of rock mechanics in petroleum engineering.
Wellbore size is measured using calliper logs 2, 4, 6 arms callipers are used helps to determine stress anisotropy and orientation callipers reflect the mechanical, chemical and hydraulic effects of the drilling process on the finished wellbore fundamentals of near wellbore deformation presentation devex 20140505 jc 7. Safe mud weight also depends on their relative orientation. To closely simulate the actual stress state and rock deformation around the wellbore during drilling, a 3d finite elementbased wellbore model was built. This also can be used to explain the mechanism of the anisotropy of wellbore stability. Wellbore instability is a major cause of nonproductive time during the wellbore construction phase. Enhancing well bore stability, focus of fluid system advances. The noncoaxiality theory is incorporated into casm to analyse the wellbore stability. Prediction of wellbore stability using 3d finite element. The key factor to control the wellbore stability is the rate of sanding. Coupled thm modelling of wellbore stability with drilling unloading. Ppt wellbore instability types powerpoint presentation. Impact of voids on mechanical stability of well cement core. The geomechanical analysis combines wellbore parameters, such as inclination, azimuth and hole size, with rock properties, so as to develop a specific solution for each section of the wellbore. Geomechanics, wellbore stability, buckling, contact interface.
The paradigm integrated wellbore stability workflow begins with an initial petrophysical analysis to identify minerals and fluid volumes, including fluid types. Project topics, complete project material, free topics in education, business administration projects, computer science topics, science and engineering project topics, complete project material in nigeria. Mar 21, 2017 safer drilling log based pore and fracture pressure prediction and modelling of in situ stress duration. Prediction of wellbore stability using 3d finite element model in a shallow unconsolidated heavyoil sand in a kuwait field.
Mud loss is frequently encountered while drilling and happens when the mud weight essential to maintain. The effect of field coupling on pore pressure, stress redistribution, and temperature around a wellbore has been analyzed in detail. Abaqusstandard, and table 1 lists the parameters of the wellbore rock. Ensuring wellbore stability with geomechanics and pore. The relationship between the intermediate principle stress and the rate of sanding documented in relevant literatures. Wellbore stability refers to the structural integrity of a wellbore that prevents it from collapsing. This project is aimed at improving the accuracy of wellbore stability analysis.
Evaluation of stress and strain induced by the rock. Wellbore failure depends on the relative orientation between well paths and weak planes. Wellbore stability analysis and well path optimization based. Unfortunately, wellbore stability problems, such as unexpected low fracture gradient, are.
Azim1, sankar chowdhuri1, salah alanezi1, anar abdulkarim2, ahmet aki2, and mohamed samie2. There is a series of data that provide information about the in situ stresses, pore pressure and the rock strength. The performance of stochastic designs in wellbore drilling. Numerical simulations for wellbore stability and integrity. A wellbore stability model for formations with anisotropic. Current software offerings employ insufficient science. However, it was found that the influence of noncoaxiality on wellbore stability depended on initial conditions of wellbore. Coupled thm modelling of wellbore stability with drilling. The failure wellbore pressure, borehole closure, plastic zone distribution of different direction wells are given in this paper.
A study of wellbore stability in shales including poroelastic, chemical, and thermal effects guizhong chen, martin e. It is also reported that shale account for 75% of all formations drilled by the oil and gas. Stability analysis of a horizontal oil well in a strike slip fault regime. Posted on september 12, 2018 september 12, 2018 by lharrower19. Buckling analysis for the longterm integrity evaluation of a. Borehole stability and field stress analysis with azimuthal. The abaqus student edition is available free of charge to students, educators, and researchers for personal and educational use. Once a geomechanical model has been developed that quantifies the principal stress magnitudes and orientations, the pore pressure. Generally an updip drilling is more stable than other drilling directions. So this quick look handbookmanual specially was compiled and prepared for students in order to help them to get into the swing of things in regards of reservoir geomechanics, geomechanical evaluation and wellbore stability. The wellbore stability model implemented in the psi software combines input parameters describing formation conditions, formation properties and wellbore data to predict the stability of the well over time.
Analytical and numerical methods on free shipping on qualified orders. Borehole instabilities can be encountered at any stage in the life of a well and they are the main cause of drilling. After collecting data, a pore pressure 1d model and a wellbore stability wbs model can be generated based on client goals and data availability. Introducing optimized validated meshing system for. When a well is drilled in a formation, stressed solid material is removed and replaced with a fluid under.
Juan tovar innovative engineering systems limited devex 2014. When drilling overbalance through a porous and permeable formation, there is flow of wellbore fluid into the formation, leaving behind a solid mud cake on the formation. Psi estimates the probability for mechanical failure inside the borehole wall. Through the study of wellbore stability in different conditions, it is found.
Wellbore stability in oil and gas drilling with chemical. This gives you the opportunity to have access to the most advanced finite element analysis tool free of charge, so you can learn or improve your skills in this field using abaqus. Wellbore stability in geomechanics connecting repositories. Nonlinear coupled consolidation analyses are performed to simulate the postdrilling, timedependent deformations and pore pressures around the wellbore.
This paper describes numerical analyses of the deformations and stability of deviated wellbores within a k 0consolidated clay. Borehole instabilities can be encountered at any stage in the life of a well and they are the main cause of drilling difficulties, resulting in substantial expenditures, expensive loss of time, sometimes even in the. Compared with coaxial model, noncoaxial model gives more pessimistic results. Pbore3d is a userfriendly software that analyzes and simulates the timedependent effects on wellbore stability while drilling. The finite element code abaqus is applied to analyse the mechanical behaviour of wells with different inclinations and different azimuths. Buckling analysis for the longterm integrity evaluation. Donato milanese, mi, italy now politecnico di torino, italy. However, it is necessary while drilling to maintain stability over the entire openhole section between casing points. Near wellbore deformation is an old and well established. Overview wellcheck wellbore stability analysis software. Wellbore stability analysis acts an important role in the drilling design to avoid stuckpipe. Sep 09, 2016 this paper describes numerical analyses of the deformations and stability of deviated wellbores within a k 0consolidated clay.
Geomechanical analysis of the wellbore instability. The maximum contour of mises stress can be considered as mark of the slip surface location while fos is computed by a criterion established by the analyst. The hm coupling module and thermal module in abaqus software is. Formation strengthening by drilling fluids has been discussed extensively in. Wellbore stability analysis acts an important role in the drilling design to avoid pipestuck, lost circulation and the other instabilityinduced problems. The wellbore stability model implemented in the psi software combines input parameters describing formation conditions, formation properties and wellbore data to predict the stability of the well over. Buckling analysis for the longterm integrity evaluation of a hydrocarbon well c. Advanced wellbore stability model wellstabplus 1 advanced wellbore stability modelwellstabplus dea9 dr. In many cases, wellbore stability analysis can be carried out with very simple models that are timeindependent and relate stress and pore pressure, only through the effective stress law. Predrill wellbore stability analysis using rock physical. The magnitude of sv is equivalent to integration of rock densities from the surface to the depth of interest, z.
Probabilistic approach in wellbore stability analysis during. Highlights developed is a wellbore stability model in which anisotropic strength and two shear failure modes are considered. The development plan of a hydrocarbon field includes the design of all the productioninjection wells forecasted for the scenario considered. These do not account for the fact that stress changes induce pore pressure changes, and vice versa. It is also reported that shale account for 75% of all formations drilled by the oil and gas sector, and 90% of wellbore stability problem occur mainly in the shale formations lal et al,1999. There is a series of data that provide information about the in situ stresses, pore. The results indicated that the biggest impact factor in wellbore stability is the well trajectories followed by the rock strength parameters. Hydration is produced in shale formation owing to the influence of the chemical property of. Using wellbore deformation to optimize drilling performance by. Constitutive relationships definition isotropicanisotropic faults weakness. Workflow carried out for wellbore stability analysis. This software applies the coupled fluid flow and rock deformation analyses in the studies of wellbore stability and drilling mud design.
Accurate wellbore collapse initiation pressure is necessary for a robust wellbore bridging study. Download abaqus and access to the training material for. However, the conventional linear elastic model used by the. Thus, the changes of well path lead to the variation of the maximum and minimum principal stress, this is so called the turning of the principal stress trajectory. Wellbore stability in geomechanics nottingham eprints. A numerical investigation of wellbore stability problems using an. Wellbore stability analysis and well path optimization. It can be very effective in improving the accuracy of wellbore stability predictions, omw and fluid design. Rock compaction on a hydrocarbon well completion using contact interfaces with abaqus g. Nonlinear coupled consolidation analyses are performed to simulate the postdrilling, timedependent deformations and. Specifically, you can plan wells by calculating a critical mud weight. A generalized plane strain model is used in the calculation. The techlog wellbore stability module comprises mechanical earth model 1dmem building, wellbore stability, sand management, and fracture stability computation.
Pbore3d is a userfriendly software that analyzes and. Together with the documentation, this is the perfect way to learn abaqus with no associated cost. The analyses consider planar deformations in the plane. A numerical investigation of wellbore stability problems.
A calibrated regional area, using analogue wells, can provide sufficient data to study subsurface pore pressures and to analyze characteristics contributing to wellbore instability. Wellbore instability in oil and gas drilling is resulted from both mechanical and chemical factors. Stability analysis of a horizontal oil well in a strike slip fault. Therefore, analyses of stability must be carried out over that entire depth range. Wellbore instability can occur due to either a physical pressure differential or. Opinions may vary as to the value of lost equipment and time arising directly from. I am wondering if any of you has conducted slope stability analysis with abaqus. Stability analyses for deviated wellbores in unconsolidated. Sharma, mengjiao yu1 center for petroleum and geosystems. The 1dmem is the backbone of every geomechanical workflow for which it provides the stress field, pore pressure, and mechanical properties. The commercial processing package abaqus is used to solve the 3d finite element model of one of the existing oil wells of the iranian central carbonate reservoirs. Wellbore instability can result in lost circulation figure 1a where.
The geomechanical analysis combines wellbore parameters, such as. Using the results, the positions of casings can be adjusted to maximize wellbore stability while staying within engineering constraints. The analysis was performed for a range of mud weights to analyze the sensitivity of wellbore stability to mud weight variations. The physical model and solver was executed by a finite element software, abaqus 6. Introducing optimized validated meshing system for wellbore stability analysis using 3d finite element method. Comprehensive wellbore stability analysis utilizing quantitative risk assessment daniel moos1 pavel peska1 thomas finkbeiner1 mark zoback2 1geomechanics international, palo alto, ca 94303 2stanford university, stanford, ca 94305 abstract utilization of a comprehensive approach to wellbore stability requires knowledge of rock. This solution is valid when it is assumed the assumptions of plane strain condition and material with behavior. Because the field was not yet under production, simulated stresses accurately represented current insitu stresses. Pdf prediction of wellbore stability using 3d finite.
Enter your mobile number or email address below and well send you a link to download. Analytical and numerical methods on free shipping on. Borehole instabilities can be encountered at any stage in the life of a well and they are the main cause of drilling difficulties, resulting in substantial expenditures, expensive loss of time, sometimes even in the loss of part of or even whole boreholes. However, the conventional linear elastic model used by the industry is too conservative in predicting the mud weight window. Thus, they could be used to predict wellbore stability at any subsequent well location. Guidelines for papers to be presented at the abaqus users. Part three studies the effects of consolidation on longterm wellbore stability. A similar predrill pore pressure and wellbore stability analysis project was successfully conducted in the western zagros foothills in iraq.
Numerical wellbore stability numerical wellbore stability traditionally, the wellbore stability is performed based on analytical solution to calculate the stress state around the wellbore. Safer drilling log based pore and fracture pressure prediction and modelling of in situ stress duration. Wellbore stability requires a proper balance between theuncontrollable factors of earth stresses, rock strength, and pore pressure, andthe controllable factors of wellbore fluid pore pressure, and the. A free powerpoint ppt presentation displayed as a flash slide show on id. The analyses consider two different boundary conditions on seepage at the cavity. Nov 15, 2016 ensuring wellbore stability with geomechanics and pore pressure prediction. Wellbore stability modeling in vertical and horizontal. Jul 24, 20 buy wellbore stability modeling in vertical and horizontal boreholes. Then the wellbore stability is simulated with the proposed model by considering the drilling unloading, fluid flow, and thermal effects between the borehole and the formation. Finite element is powerfull tool for observing slope stability behavior with time. Enhancing well bore stability, strengthening and cleanout focus of fluid system advances by ryen caenn laguna beach, ca.
Wellbore stability is greatly affected by various factors, such as the formation fluid, and the properties and temperature of the drilling fluid, and is critical to petroleum drilling. Unfortunately, wellbore stability problems, such as unexpected low fracture gradient, are relatively common while drilling close and out of these salt structures. Transient thermoporoelastoplasticity finite element analysis of. In all cases, the borehole stability was satisfied by minimum. Wellbore stability is also impacted by chemical interactions between drilling fluids mud and the host rock. Tp0009 5 wellbore stability problems high torque and drag bridging and fill stuck pipe directional control problem slow penetration rates high mud costs cementing failures and high cost difficulty. Figure 2 shows the work flow of the wellbore stability analysis. In the process of drilling, the economic losses caused by wellbore instability reaches more than one billion dollar every year, and the lost time is accounting for over 40% of all drilling related nonproductive time.
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