Miniaturized Annular Sensor Aids in Well Integrity, Production Monitoring
Authors: Carpenter Chris 
Published: August 2023

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This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper OTC 31160, “Intelligent Pipe: A New Monitoring Solution for Your Wells,” by Francois-Xavier Bulard, Vallourec; Emmanuel Tavernier, OpenField Technology; and Antoine Deroubaix, Vallourec, at al. The paper has not been peer reviewed. Copyright 2021 Offshore Technology Conference. Reproduced by permission.

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The integration of a pressure and temperature sensor element in tubulars is possible as the result of microelectromechanical systems (MEMS) technology. Low-power consumption combined with an adapted transmission technology allows use of this technology inside an oil and gas well. Operators can use embedded sensors to access previously inaccessible well areas in real time. The qualification of this technology is completed to ensure the integrity of the system and its long-term viability. The complete paper presents the development, qualification, and applications of an intelligent tube solution using the described technology.

Technology Description
The development of this solution was the result of a partnership between OpenField Technology and Vallourec. While one section of the complete paper is dedicated to qualification tests performed during the development of the intelligent-pipe solution, this synopsis concentrates on the design of the solution and its potential deployment.
The concept involves positioning a microsensor on the outside of a mandrel that can measure nearby annulus pressure, temperature fluids, or formation behavior. This system is composed of a pressure and temperature sensor connected to a battery module and a transmitting coil. This system (sensor, battery, and coil) is doubled to meet customer requirements for redundancy. Each mandrel contains two distinct monitoring modules. Positioned in each string of a well, this monitoring module tracks pressure and temperature changes at different depths throughout the well life cycle.
This module is simple to install and is run with the casing string like any other oil and gas tubular-goods pipe. This module is set up for the entire life of the well, with two options for data retrieval: a temporary option with the use of a logging tool and a permanent option with the use of a specific tubing-transmission mandrel (Fig. 1). This tubing-transmission mandrel is connected to the surface by an electrical cable and designed to permanently supply power to the other casing module located at the same depth. The tubing-transmission mandrel furthermore ensures data retrieval from each sensor.
The operating principle of the solution is based on the fact that each casing module is connected by an electromagnetic field to a logging tool or a tubing-transmission mandrel. This electromagnetic link is ensured by using a nonmagnetic (high-alloy) material for the casing module. This nonmagnetic material allows the electromagnetic field to pass from the tubing string up to the larger casing where monitoring is performed. It defines the horizontal transmission of the solution (as opposed to the vertical transmission) that is ensured by the use of a permanent downhole electrical cable connected to the surface. This cable brings power from the surface to the tubing-transmission mandrel in the case of deployment of the permanent option for data retrieval and allows data retrieval from the monitoring devices connected to this tubing mandrel. Horizontal transmission is only ensured if the different tubing and casing mandrels meet certain horizontal alignment tolerances.