Mechanical Integrity Test (MIT) & Interface Detection

Introducing our new-and-improved proprietary interface tool and cavern MIT system

Cavern Mechanical Integrity Test

An MIT is commonly performed to evaluate the mechanical integrity of a cavern’s wellhead, casing, tubing, and cemented annulus between the production casing and the formation at the casing seat area. Generally, the test is conducted by injecting nitrogen into the well to below the casing seat at the desired test pressure. Brine and nitrogen pressures are recorded, and the interface level is located by running an interface detection tool. This interface will be used to calculate and evaluate the well/cavern integrity.

BGES has developed a proprietary Gamma-Density Interface Tool, GDI-2, (patent pending) capable of detecting fluid interfaces behind 1 or 2 sets of casings. It is specifically designed to detect various types of gas-liquid and liquid-liquid interface in salt caverns. The tool has a vertical resolution of up to 2” (or 5cm), and is approved by the CNSC with no well abandonment requirements if it becomes unrecoverable in a well / cavern.

Applications

In accordance with the CSA Z341, prior to commissioning a new cavern or abandoning a cavern/wellbore, the MIT must be conducted to identify leaks in the wellhead seals, production casing, and casing seat.

Features & Benefits

The GDI-2 tool allows continuous reading of the interface and does not energize the formation. Real-time downhole pressure & temperature measurements can eliminate assumptions and approximations, which is greatly beneficial for MITs.

Operations

During an MIT, brine and nitrogen pressures as well as interface levels are continuously recorded and are used to determine a leak rate. BGES’ MIT system allows real-time viewing of pressure and temperature data online through satellite data streaming.

Interface detection in caverns

BGES’ proprietary GDI-2 is a multi-receiver density measurement tool capable of detecting fluid interfaces behind 1 or 2 sets of casings. It is specifically designed to detect various types of gas-liquid and liquid-liquid interface in salt caverns. The tool has a vertical resolution of up to 2” (or 5cm), and is approved by the CNSC with no well abandonment requirements if it becomes unrecoverable in a well / cavern.

This new development offers various financial and environmental advantages:

Cost advantage – because the operating cost for this tool is low compared to a Pulse Neutron tool, BGES is able to transfer the savings to our clients to reduce their overall costs especially on multi-day projects.

Low financial risks – the replacement cost of the GDI is approx. 25% of that of a typical Pulse Neutron tool. If in a rare case the tool is lost in hole, the cost would be significantly lower.

Low environmental risks – since this tool uses a gamma source with a very short half-life, there is no abandonment required by the CNSC if this tool is irretrievable in a cavern or well.

Applications

This log can be run as a standalone service or as part of a cavern Mechanical Integrity Test (MIT) to detect gas-liquid interfaces such as nitrogen/brine, butane/brine, as well as liquid-liquid interfaces such as diesel/brine and condensate/brine, etc.

Features & Benefits

The GDI-2 tool allows continuous reading of the interface and does not energize the formation, thereby improving logging efficiency. Additionally, it offers cost advantage and lower financial as well as environmental risks when compared to other conventional tools.

Operations

Real-time downhole pressure & temperature measurements coupled with continuous interface reading can eliminate assumptions and approximations, which is greatly beneficial for MITs. Furthermore, there is no abandonment requirement if tool is lost in hole.
BGES GDI-2 Info Sheet

Integration of Services

From wellsite core collection, geotechnical lab testing, cased-hole logging, reservoir and caprock injection testing, data analyses, project management, regulatory reporting, to computer simulation and numerical modelling, our comprehensive and customizable service model offers maximum flexibility for our clients.

Related Services

Sonar Survey and Cased-hole Logging