This work aimed to present a detailed workflow for building a geomechanical model. For a case study, the workflow is then applied to a horizontal well X. The first step in building a geomechanical model is gathering data regarding well information (tubing, casing, deviation ), geological information (type of fault, permeability, reservoir radius, skin ), logs data (density, resistivity, sonic, caliper ), in-situ test data (leak-off test, formation test, ) and core data (tensile strength test, fracture toughness test, tri-axial test ). | TAÏP CHÍ PHAÙT TRIEÅN KH&CN, TAÄP 19, SOÁ K1- 2016 Geomechanical modeling - workflow and Applications Pham Son Tung Mai Cao Lan Faculty of Geology & Petroleum Engineering, Department of Drilling & Production, Ho Chi Minh city University of Technology, VNU-HCMC (Manuscript Received on July 05th, 2015; Manuscript Revised on September 30th, 2015) ABSTRACT This work aimed to present a detailed workflow for building a geomechanical model. For a case study, the workflow is then applied to a horizontal well X. The first step in building a geomechanical model is gathering data regarding well information (tubing, casing, deviation ), geological information (type of fault, permeability, reservoir radius, skin ), logs data (density, resistivity, sonic, caliper ), in-situ test data (leak-off test, formation test, ) and core data (tensile strength test, fracture toughness test, tri-axial test ). The second step is to build the geomechanical model using data analysis so that information about state of stress (vertical and principal horizontal stresses, pore pressure, concentration stress around wellbore) and rock mechanical properties (unconfined compressive strength, tensile strength, fracture toughness, Young modulus, Poisson ratio) can be determined. Moreover, the differences in data analysis for vertical and horizontal wells were also mentioned in this work. Furthermore, it is evident that the more data we get, the more accurately a geomechanical model can be built. However, in reality, not all necessary data can be obtained, so this work also explained how to draw the most information from available data so that we can minimize the number of assumptions and uncertainties. An accurate geomechanical model is very essential for others works such as well bore stability or performance prediction of a well stimulation technique. The case study of this work presented the geomechanical modeling for the well X. The paper then presented the application of geomechanical .