STRESS ESTIMATION AROUND WELLBORE IN PARIGI AND BATURAJA CARBONATE FORMATION WITH KIRSCH'S EQUATION AND FINITE ELEMENT

• Main Author: Mochamad Ramdan, Fajar
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/60317
• Institution: Institut Teknologi Bandung

The three main subsurface stresses that affect the wellbore stress are the overburden stress, the maximum horizontal stress and the minimum. In-situ stress consists of overburden stress in the vertical direction due to loading from the overlying rock layers, maximum and minimum horizontal stress due to the movement of tectonic plates. In addition, there is also pore pressure caused by fluids trapped in the pores of rock formations. The stress around the wellbore is one of the factors in the instability of the wellbore. Instability in the wellbore can cause several problems, including loss of circulation, tensile fractures due to too high drilling mud pressure, wellbore breakouts, and wellbore collapse. The research conducted in this final project is to model the wellbore to determine the stress distribution around it. In this final project, modeling using the finite element method is carried out to determine the stress distribution around the wellbore, then it will be compared with the estimated stress from the Kirsch equation. The angle of inclination of the wellbore to be modeled is 0° (vertical) and 90° (horizontal). The finite element modeling parameters use tetrahedral elements, with 184.071 nodes and 132.715 elements. The geometry of the 3D model is a cube measuring 100 ????????×100 ????????×100 ???????? and a cylinder diameter of 4 ????????. The case study was carried out on a wellbore that entered the carbonate rock of the Parigi and Baturaja Formation. The depth of the wellbore in the Parigi Formation is about 998 ???? and 1022 ????. Then, the depth of the wellbore in the Baturaja Formation is around 1927 ???? and 1929 ????. The results obtained in the form of estimation of hoop stress and radial stress in the vertical wellbore of the Parigi and Baturaja Formation and the horizontal wellbore of the Baturaja Formation.