Technology Focus: Formation Damage (March 2021)

Abstract

Formation damage has received significant attention over many decades, but what about completion damage? Before we discuss this question, we first need to define these terms. Formation damage could be considered as damage to the near-wellbore (e.g., mud solids invasion, plugging). In contrast, completion damage is damage to the lower completion (e.g., plugging of screens). The combined effect of formation and completion damage is the observed well productivity development with associated skin and productivity index. Completion damage has the potential to affect well productivity to the same degree as formation damage. However, at a basic level, there is not even a classification system for completion damage, and yet one has been available for formation damage at least 30 years, possibly longer. Within Equinor, we are trying to address this imbalance by having increased focus on completion damage. We have an ongoing project to develop the following: A classification system—We have focused on lower completion design and damage that can occur over a well’s lifetime. A review of testing procedures used and development of new ones where appropriate. Use of computation fluid dynamics (CFD) more in completion damage evaluations—This approach has provided invaluable new insights. We are using CFD, for example, to visualize displacement efficiency from drilling to completion fluids. We also are incorporating data from coreflooding and completion-damage testing into a single CFD simulation that will enable us to assess what effect formation and completion damage will have on future well productivity.