The 3D simulation of the effect of casing standoff on cement integrity by considering the direction of horizontal stresses in one of the wells of Iranian oil fields

Abstract

Drilling engineers must conduct predictive tests before the occurrence of integrity issues to save time and money. A successful casing standoff helps boost well integrity and cement integrity, both of which are critical factors during a well's production life. The casing standoff is 100 percent in several books and computational simulations. However, it should be remembered that this standoff is never 100 percent, and the casing is still inclined to one side of the well wall. Also, with the use of centralizers, the casing shifts, and the standoff deviates from ideal conditions In this study, a 3D simulation was analyzed using ABAQUS Software, using the geomechanical modeling data and considering the well's environmental conditions. The effect of casing standoff on cement integrity was investigated using sensitivity analysis and parametric tests. According to the simulation results in the studied well, the plastic strain in the cement sheath increases as the casing standoff decreases, resulting in the highest strain at the cement-casing interface. The plastic pressure increases as the cement's narrow side face the direction of most minor horizontal tension. As a result, having adequate information about the conditions and direction of in-situ stresses is needed before driving the casing in the well drilling stage.