APPLICATION OF GEOMIMICRY TO ENGINEERING PROBLEMS:GILSONITE AS A SOLUTION TO LEAKY WELLBORES

Abstract

As complexity of wells, environmental regulations and the need to be as economically efficient as possible in the petroleum industry increases, it is more prevalent than ever to ensure and maintain wellbore integrity. The purpose of the cement sheath is to maintain wellbore integrity by providing total isolation between surrounding formations and the wellbore. One factor opposing the purpose of a cement sheath is hydrocarbon migration through a micro-annulus located at either the cement/casing interface or the cement/formation interface. Hydrocarbon migration hazards can be as minor as a few psi increase at surface to total blowout which in turn can be timely to repair, if possible, and create unwanted environmental concerns which ultimately effect economic returns. This study focuses on the use of a wellbore cement additive: Gilsonite as a potential agent in the mitigation of micro-annular flow through its unique affinity to hydrocarbons. Gilsonite’s affinity and potential to absorb hydrocarbons in the cement matrix is analyzed thoroughly through microstructural analysis of hydrocarbon interaction with Gilsonite grains. The goal of this project is to provide a proof of concept for further microstructural analysis of Gilsonite’s ability to mitigate microannular flow. To accomplish this, experimentation was broken into two sperate phases. Phase 1 consists of experimentation on pure Gilsonite to gauge if there was an affinity between Gilsonite and hydrocarbons, while Phase 2 consists of experimentation on Gilsonite rich cement.