Uncertainty assessment of wellbore stability analysis in horizontal sections

Abstract

Over the last years, horizontal wells have found applications in many different geological and technical situations to enhance the production rate from the oil and gas reservoirs. However, well instability problems are often reported during construction of these types of wells. To mitigate instability problems, which are usually difficult and costly to solve, well stability analysis are conducted before the construction process begins. Different geomechanical and mathematical models that are used in the well stability studies, do not include the uncertainty assessments of the models. As majority of input parameters into the geomechanical models are subjected to some extent of errors and uncertainties, therefore, it is essential to quantify the uncertainty associated with the output of the geomechanical models. In this work, a Monte Carlo simulation technique is applied to quantify the uncertainty in the output of a poroelastic model to make more reliable decisions in the well construction process.