Raju Gandikota

• Polytechnic University of Catalonia

In the new digital age, improving drilling economics with tools like simulation and predictive analytics are key to enabling digital transformation. A novel real time digital twin has been developed to predict drilling dysfunctions and improve operational efficiencies. Real time surface (EDR) data with full physics time domain models are used to pr...

A numerical technique based on a CFD-DEM method is presented for the analysis of particle impact drilling (PID) systems. The method is built from a preexisting finite element Navier–Stokes solver for the fluid phase and a discrete element method module for the steel particles which this drilling technology utilizes to enhance the penetration rate....

A West Texas operator historically used four to seven PDC bits to TD their Ward County, Wolfcamp B laterals. Formations there are lithologically more challenging when compared to the same interval in adjacent Reeves County. Drilling performance in Reeves County Wolfcamp A laterals averages approximately 1,091 Feet/Day while those in Ward County sel...

The drilling industry has substantially improved performance based on knowledge from physics-based, statistical, and empirical models of components and systems. However, most models and source code have been recreated multiple times, which requires significant effort and energy with little additional benefit or step-wise improvements. The authors...

In fluid-structure interactions (FSI), one or more structures interact with incompressible or compressible fluids. These problems are non-linear multi-physics phenomena. Most FSI problems require a numerical solution rather than an analytical solution (Gene, 2012). This is particularly true for problems involving large deformations of elastomers an...

Testing elastomeric materials that undergo large strains pose challenges especially when establishing failure criteria. The failure criterion for composites and polymers based on finite elasticity published by Feng (1) requires testing under uniaxial and biaxial stretching modes. The classic inflation of a circular disk for biaxial stretch mode pos...

The authors present results on the use of the discrete element method (DEM) for the simulation of drilling processes typical in the oil and gas exploration industry. The numerical method uses advanced DEM techniques using a local definition of the DEM parameters and combined FEM-DEM procedures. This paper presents a step-by-step procedure to build...

This paper presents a local constitutive model for modelling the linear and non linear behavior of soft and hard cohesive materials with the discrete element method (DEM). We present the results obtained in the analysis with the DEM of cylindrical samples of cement, concrete and shale rock materials under a uniaxial compressive strength test, diffe...

This paper presents a brief review of misconceptions on industry-standard brittleness/ductility definitions; geomechanical aspects and numerical evaluation of pulse fracturing by use of an advanced constitutive model implemented within the ANSYS® Autodyn® (ANSYS 2014); and fracture-network patterns because of pulse loading in shale that show ductil...

Surface equipment for Managed Pressure Drilling operations handles a multiphase mixture of drilling mud, cuttings and reservoir fluid influx. It is mandatory for safe MPD operations that surface equipment be able to handle pressure surges, pressure drops as well as any phase change of the fluid without causing any safety issues. In MPD operations,...

Surface equipment for Managed Pressure Drilling operations handles a multiphase mixture of drilling mud, cuttings and reservoir fluid influx. It is mandatory for safe MPD operations that surface equipment be able to handle pressure surges, pressure drops as well as any phase change of the fluid without causing any safety issues. In MPD operations,...

A dynamic stiff-string torque-and-drag (T&D) model is presented that assumes steady-state motion of the drillstring as its basis for calculations. Results are compared with previously published T&D models that are based on static equilibrium. The novelty of the new dynamic model is the ability to solve T&D operations of the entire drillstring from...

Two approaches for simulation of dynamics of complex beam structures such as drill strings are considered. In the first approach, the drill string is presented as a set of uniform beams connected via force elements. The beams can undergo arbitrary large displacements as absolutely rigid bodies but its flexible displacements due to elastic deformati...

Drilling with PDC bits can cause severe torsional and axial oscillations. These oscillations are accompanied by periodic sticking of the bit followed by accelerated rotation. The so-called “stick-slip” increases bit wear and fatigue and causes premature failure of BHA and drillstring components. It is well known that these torsional oscillations ar...

The paper focuses on application of multibody system approach for the torque and drag analysis of long drill strings. The approach is used to get improved results as compared with those obtained by soft-string models. The analysis is carried out by integration of equations of motion of the drill strings till reaching equilibrium under externally ap...

One of the main requirements to casing that provides cementing of oil and gas wells during drilling and operation is their optimum centralization, which allows achieving a better homogeneity of the slurry flow in the annulus. Optimum standoff between the borehole wall and the casing is ensured with special devices, centralizers put on the casing an...

Many engineering dynamic problems can be simulated as beam structures. For example, such models are applied in well drilling. Dynamic simulation allows optimizing shape of well bore and operations parameters of the drilling. Calculation speed of simulation of dynamics of a drill string depends on size of matrices of a model and on effectiveness of...

Previous theoretical formulations for sinusoidal and helical buckling of drill strings vary significantly and are mostly proposed for frictionless pipes without tool joints. Finite element analysis (FEA) methods have the ability to consider geometric details and large deflections. However, traditional FEA methods use shell or solid dimensional elem...

A dynamic stiff string torque and drag (T&D) model is presented that assumes steady state motion of the drillstring as its basis for calculations. Results are compared to previously published T&D models that are based on static equilibrium. The novelty of the new dynamic model is the ability to solve T&D operations of the entire drillstring from bi...

Understanding drill string buckling behavior is a significant challenge to the petroleum industry. In this paper, the explicit finite element method implemented in Abaqus software is employed to study the buckling of drill strings for inclined straight wellbores. Classic solutions for the critical buckling length of self-weighted columns as well as...

Openhole, multi-stage fracturing systems are commonly used today in many applications, including unconventional shale gas reservoirs. As many as forty stages have been successfully completed in a single horizontal well and the industry is aiming even higher. One problem that has a major impact on job success is the ability to accurately calculate m...

The selection of optimal operational parameters for drilling oil and gas wells is a complex dynamic problem that depends on multiple parameters. Numerous physical and mechanical processes such as rock cutting, friction, hydraulics, and different modes of vibrations, occur during drilling, which should be accounted for in numerical models. It is wid...

Since the introduction almost fifteen years ago of today's solid expandable liner systems, threaded connection technologies have advanced very little compared to the development of sophisticated, state-of-the-art expansion tools and systems. The severity of damage caused to threaded connections during the downhole expansion process leaves some thre...

Several studies conducted in oil wells at Saudi Arabia provide new insights into the expandable installation and performance of the openhole expandable liners in the high-angle trajectories and long horizontal wellbores. A fixed-fixed expansion ensures that the length of casing is not free to move that can be occurred if the casing is differentiall...

Investigation is underway to enhance potential production rates by actualizing a method of frac-packing multi-zone slim holes and sidetracks using solid and slotted expandable casing. This innovative technique replaces the production liner and the cementing and perforating phases in a normal completion. The increased completion ID and flow areas pr...

Solid Expandable liners have been used extensively over the past 10 years for drilling liners, but rarely as production liners, much less in high risk environments where the expandable liner becomes differentially stuck as soon as it reaches the end of the horizontal hole section. This environment requires the liner to be cemented and expanded in o...