Wellbore Integrity Mapping using Well-Casing Electrodes and Surface Based Electrical Fields

Among the most serious issues facing the oil and gas industry is the condition of older wells. Once a well has been in use for some time the casing and cement are subject to chemical aging and corrosion and this weakens the well. In addition if a well is used for production, near‐well saturation changes can result in local ground compaction and the well can become mechanically unstable. These compromised wells can release toxic substances into the ground, contaminating water supplies and causing other environmental damage. Current methods of assessing wells are elaborate and expensive, and thus generally only implemented when obvious leakage is observed, which is often too late to prevent environmental effects. In this project GroundMetrics will examine an alternative, non‐invasive and lower cost screening method for evaluating the integrity of a well completion. This method will identify whether well integrity has degraded and can identify if there is a clear break in the casing. The proposed technology will allow operators to quickly and efficiently screen a field for potential problem wells that require more detailed assessment. GroundMetrics will use numerical models to establish the optimum equipment configuration and measurement schedule and outline a data inversion strategy. Next, using available instrumentation GroundMetrics will test and validate the models with local field measurements using wells of known characteristics and casing depths. This project will develop a new way to assess casings in oil and gas wells. Breached casings can leak contaminants into soil and water. The proposed system will give oil and gas production companies a quick and efficient way to identify potentially problem wells. Commercial Applications and Other Benefits: The ability to identify at‐risk casings in a quick, efficient and lower cost manner will be of interest to oil and gas production companies. There is a benefit to society in that this service will help these resource production companies prevent/lessen environmental damage of drilling activities.