Abstract: This invention describes an apparatus and a method for integrity monitoring of a borehole and the seal integrity of a caprock suitable for sequestration of greenhouse gases. The apparatus includes plural neutrally buoyant sensors for placement outside of a casing, placement including distribution within at least mud filter cake, cement, and proppant. This invention also includes a method for monitoring integrity of a borehole suitable for sequestration of greenhouse gases or other types of well using the described apparatus.

Abstract: This invention relates to an apparatus and a method for a wireless sensor to monitor barrier system integrity, such as used or employed during sequestration of greenhouse gases. This invention includes an apparatus for integrity monitoring of a borehole suitable for sequestration of greenhouse gases. The apparatus includes one or more sensors for placement outside of a casing to monitor a borehole, and a tool for movement within the casing to power and interrogate the one or more sensors. This invention also includes a method for monitoring integrity of a borehole suitable for sequestration of greenhouse gases or other types of well. The method includes the step of disposing one or more sensors outside a casing and the step of powering the one or more sensors with a tool inside the casing. The method also includes the step of interrogating the one or more sensors with the tool to monitor an engineered borehole and/or a natural caprock seal.