Wellbore stability in oil and gas drilling with chemical. Numerical simulations for wellbore stability and integrity. Wellbore stability is also impacted by chemical interactions between drilling fluids mud and the host rock. This paper describes numerical analyses of the deformations and stability of deviated wellbores within a k 0consolidated clay. Buy wellbore stability modeling in vertical and horizontal boreholes. A study of wellbore stability in shales including poroelastic, chemical, and thermal effects guizhong chen, martin e. 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. Mud loss is frequently encountered while drilling and happens when the mud weight essential to maintain.
However, the conventional linear elastic model used by the. Posted on september 12, 2018 september 12, 2018 by lharrower19. The analyses consider two different boundary conditions on seepage at the cavity. The development plan of a hydrocarbon field includes the design of all the productioninjection wells forecasted for the scenario considered. Numerical wellbore stability numerical wellbore stability traditionally, the wellbore stability is performed based on analytical solution to calculate the stress state around the wellbore. The results indicated that the biggest impact factor in wellbore stability is the well trajectories followed by the rock strength parameters. Enter your mobile number or email address below and well send you a link to download. The paradigm integrated wellbore stability workflow begins with an initial petrophysical analysis to identify minerals and fluid volumes, including fluid types. Coupled thm modelling of wellbore stability with drilling unloading. Wellbore stability refers to the structural integrity of a wellbore that prevents it from collapsing. In all cases, the borehole stability was satisfied by minimum. Together with the documentation, this is the perfect way to learn abaqus with no associated cost. Ppt advanced wellbore stability model wellstabplus. 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.
Wellbore instability in oil and gas drilling is resulted from both mechanical and chemical factors. Introducing optimized validated meshing system for. Thus, they could be used to predict wellbore stability at any subsequent well location. 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. Wellbore instability during drilling is a major problem in the application of rock mechanics in petroleum engineering. Juan tovar innovative engineering systems limited devex 2014.
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. The finite element code abaqus is applied to analyse the mechanical behaviour of wells with different inclinations and different azimuths. Enhancing well bore stability, strengthening and cleanout focus of fluid system advances by ryen caenn laguna beach, ca. Download abaqus and access to the training material for. Borehole instabilities can be encountered at any stage in the life of a well and they are the main cause of drilling.
Wellbore stability archives hxr drilling services, inc. Pbore3d is a userfriendly software that analyzes and simulates the timedependent effects on wellbore stability while drilling. 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. 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. 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. Analytical and numerical methods on free shipping on qualified orders. When a well is drilled in a formation, stressed solid material is removed and replaced with a fluid under. Constitutive relationships definition isotropicanisotropic faults weakness. A numerical investigation of wellbore stability problems using an.
The key factor to control the wellbore stability is the rate of sanding. Through the study of wellbore stability in different conditions, it is found. Introducing optimized validated meshing system for wellbore stability analysis using 3d finite element method. Using wellbore deformation to optimize drilling performance. Psborehole stability and field stress analysis with azimuthal loggingwhiledrilling technology. 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. The relationship between the intermediate principle stress and the rate of sanding documented in relevant literatures. 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.
The noncoaxiality theory is incorporated into casm to analyse the wellbore stability. Nonlinear coupled consolidation analyses are performed to simulate the postdrilling, timedependent deformations and pore pressures around the wellbore. Specifically, you can plan wells by calculating a critical mud weight. Software for wellbore stability background to reach many petroleum reserves, operators often drill through shale formations or other unpredictable or unstable media. Enhancing well bore stability, focus of fluid system advances. Geomechanical analysis of the wellbore instability. Maintaining wellbore stability is an important issue in oil and gas industry 110. The analyses consider planar deformations in the plane. Finite element is powerfull tool for observing slope stability behavior with time. Current software offerings employ insufficient science.
A generalized plane strain model is used in the calculation. Wellbore stability analysis acts an important role in the drilling design to avoid pipestuck, lost circulation and the other instabilityinduced problems. 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. This project is aimed at improving the accuracy of wellbore stability analysis. 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. This software applies the coupled fluid flow and rock deformation analyses in the studies of wellbore stability and drilling mud design. Probabilistic approach in wellbore stability analysis.
Analytical and numerical methods on free shipping on. Formation strengthening by drilling fluids has been discussed extensively in. Sep 09, 2016 this paper describes numerical analyses of the deformations and stability of deviated wellbores within a k 0consolidated clay. Slope stability equilibrium and stress states with abaqus. 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.
However, it is necessary while drilling to maintain stability over the entire openhole section between casing points. Buckling analysis for the longterm integrity evaluation of a hydrocarbon well c. Highlights developed is a wellbore stability model in which anisotropic strength and two shear failure modes are considered. 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. Stability analysis of a horizontal oil well in a strike slip fault. Predrill wellbore stability analysis using rock physical. Opinions may vary as to the value of lost equipment and time arising directly from.
Psi estimates the probability for mechanical failure inside the borehole wall. Wellbore stability in geomechanics connecting repositories. Prediction of wellbore stability using 3d finite element. Geomechanics, wellbore stability, buckling, contact interface. Wellbore stability analysis and well path optimization. This solution is valid when it is assumed the assumptions of plane strain condition and material with behavior. Borehole stability and field stress analysis with azimuthal. 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. Evaluation of stress and strain induced by the rock. The hm coupling module and thermal module in abaqus software is. However, the conventional linear elastic model used by the industry is too conservative in predicting the mud weight window.
After collecting data, a pore pressure 1d model and a wellbore stability wbs model can be generated based on client goals and data availability. 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. Download abaqus for students, researchers or educators. Figure 2 shows the work flow of the wellbore stability analysis. 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.
Donato milanese, mi, italy now politecnico di torino, italy. Compared with coaxial model, noncoaxial model gives more pessimistic results. Using the results, the positions of casings can be adjusted to maximize wellbore stability while staying within engineering constraints. Nov 15, 2016 ensuring wellbore stability with geomechanics and pore pressure prediction. Nonlinear coupled consolidation analyses are performed to simulate the postdrilling, timedependent deformations and. Part three studies the effects of consolidation on longterm wellbore stability. Prior to drilling, the mechanical stresses in the formation are less than the strength of the. Wellbore stability in geomechanics nottingham eprints. Topics geomechanical model need of geomechanical model. Wellbore stability analysis acts an important role in the drilling design to avoid stuckpipe. Jul 24, 20 buy wellbore stability modeling in vertical and horizontal boreholes. These do not account for the fact that stress changes induce pore pressure changes, and vice versa.
Stability analysis of a horizontal oil well in a strike slip fault regime. Advanced wellbore stability model wellstabplus 1 advanced wellbore stability modelwellstabplus dea9 dr. Azim1, sankar chowdhuri1, salah alanezi1, anar abdulkarim2, ahmet aki2, and mohamed samie2. It is also reported that shale account for 75% of all formations drilled by the oil and gas. I am wondering if any of you has conducted slope stability analysis with abaqus. There is a series of data that provide information about the in situ stresses, pore. Pbore3d is a userfriendly software that analyzes and. A free powerpoint ppt presentation displayed as a flash slide show on id. Analysis of vertical, horizontal and deviated wellbores. Using wellbore deformation to optimize drilling performance by. Transient thermoporoelastoplasticity finite element analysis of. Stability analyses for deviated wellbores in unconsolidated. It can be very effective in improving the accuracy of wellbore stability predictions, omw and fluid design.
Once a geomechanical model has been developed that quantifies the principal stress magnitudes and orientations, the pore pressure. 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. The analysis was performed for a range of mud weights to analyze the sensitivity of wellbore stability to mud weight variations. Wellbore failure depends on the relative orientation between well paths and weak planes. Overview wellcheck wellbore stability analysis software. Guidelines for papers to be presented at the abaqus users. 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. Wellbore instability can occur due to either a physical pressure differential or. The 1dmem is the backbone of every geomechanical workflow for which it provides the stress field, pore pressure, and mechanical properties. The techlog wellbore stability module comprises mechanical earth model 1dmem building, wellbore stability, sand management, and fracture stability computation.
Hydration is produced in shale formation owing to the influence of the chemical property of. Near wellbore deformation is an old and well established. The failure wellbore pressure, borehole closure, plastic zone distribution of different direction wells are given in this paper. The effect of field coupling on pore pressure, stress redistribution, and temperature around a wellbore has been analyzed in detail. Wellbore stability modeling in vertical and horizontal. 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. Accurate wellbore collapse initiation pressure is necessary for a robust wellbore bridging study. 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. 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. Unfortunately, wellbore stability problems, such as unexpected low fracture gradient, are relatively common while drilling close and out of these salt structures. The physical model and solver was executed by a finite element software, abaqus 6. 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. Safer drilling log based pore and fracture pressure prediction and modelling of in situ stress duration.
Ppt wellbore instability types powerpoint presentation. Wellbore stability analysis and well path optimization based. 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. A calibrated regional area, using analogue wells, can provide sufficient data to study subsurface pore pressures and to analyze characteristics contributing to 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.
Wellbore instability can result in lost circulation figure 1a where. The performance of stochastic designs in wellbore drilling. Buckling analysis for the longterm integrity evaluation. Comprehensive wellbore stability analysis utilizing quantitative risk assessment daniel moos1 pavel peska1 thomas finkbeiner1 mark zoback2 1geomechanics international, palo alto, ca 94303.
Rock compaction on a hydrocarbon well completion using contact interfaces with abaqus g. The abaqus student edition is available free of charge to students, educators, and researchers for personal and educational use. The geomechanical analysis combines wellbore parameters, such as. Unfortunately, wellbore stability problems, such as unexpected low fracture gradient, are. There is a series of data that provide information about the in situ stresses, pore pressure and the rock strength. Safe mud weight also depends on their relative orientation. Ensuring wellbore stability with geomechanics and pore. Impact of voids on mechanical stability of well cement core. To closely simulate the actual stress state and rock deformation around the wellbore during drilling, a 3d finite elementbased wellbore model was built. Sharma, mengjiao yu1 center for petroleum and geosystems. Workflow carried out for wellbore stability analysis. A numerical investigation of wellbore stability problems.
Coupled thm modelling of wellbore stability with drilling. Abaqusstandard, and table 1 lists the parameters of the wellbore rock. Comprehensive wellbore stability analysis utilizing. This also can be used to explain the mechanism of the anisotropy of wellbore stability. Probabilistic approach in wellbore stability analysis during. Buckling analysis for the longterm integrity evaluation of a. A wellbore stability model for formations with anisotropic. With the aim to prevent lost circulation and wellbore instability in drilling, this. However, it was found that the influence of noncoaxiality on wellbore stability depended on initial conditions of wellbore. Because the field was not yet under production, simulated stresses accurately represented current insitu stresses. Pdf prediction of wellbore stability using 3d finite. The magnitude of sv is equivalent to integration of rock densities from the surface to the depth of interest, z.
Generally an updip drilling is more stable than other drilling directions. Mar 21, 2017 safer drilling log based pore and fracture pressure prediction and modelling of in situ stress duration. Wellbore instability is a major cause of nonproductive time during the wellbore construction phase. 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. Prediction of wellbore stability using 3d finite element model in a shallow unconsolidated heavyoil sand in a kuwait field. Simulias approach to bsp using abaqus finite element code. Pdf finite element analysis for wellbore stability of transversely. Therefore, analyses of stability must be carried out over that entire depth range. The halliburton baroid ecosystem wellbore stability. A similar predrill pore pressure and wellbore stability analysis project was successfully conducted in the western zagros foothills in iraq.
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