Toroidal choke inductor for wireless communication and control

Abstract

An induction choke in a petroleum well where a voltage potential is developed across the choke to power and communicate with devices and sensors in the well. Preferably, the induction choke is a ferromagnetic material and acts as an impedance to a time-varying current, e.g. AC. The petroleum well includes a cased wellbore having a tubing string positioned within and longitudinally extending within the casing. A controllable gas lift valve, sensor, or other device is coupled to the tubing. The valve sensor, or other device is powered and controlled from the surface. Communication signals and power are sent from the surface using the tubing, casing, or liner as the conductor with a casing or earth ground. For example, AC current is directed down a casing or tubing or a lateral where the current encounters a choke. The voltage potential developed across the choke is used to power electronic devices and sensors near the choke. Such induction chokes may be used in many other applications having an elongated conductor such as a pipe, where it is desirable to power or communicate with a valve, sensor, or other device without providing a dedicated power or communications cable.

Description

CROSS-REFERENCES TO RELATED APPLICATIONS[0001] This application claims the benefit of the U.S. Provisional Applications in the following table, all of which are hereby incorporated by reference:1 U.S. PROVISIONAL APPLICATIONS Serial T&K # Number Title Filing Date TH 1599 60 / 177,999 Toroidal Choke Inductor Jan. 24, 2000 for Wireless Communication and Control TH 1599x 60 / 186,376 Toroidal Choke Inductor Mar. 2, 2000 TH 1600 60 / 178,000 Ferromagnetic Choke in Jan. 24, 2000 Wellhead TH 1600x 60 / 186,380 Ferromagnetic Choke in Mar. 2, 2000 Wellhead TH 1601 60 / 186,505 Reservoir Production Mar. 2, 2000 Control from Intelligent Well Data TH 1602 60 / 178,001 Controllable Gas-Lift Well Jan. 24, 2000 and Valve TH 1603 60 / 177,883 Permanent, Downhole, Jan. 24, 2000 Wireless, Two-Way Telemetry Backbone Using Redundant Repeater, Spread Spectrum Arrays TH 1668 60 / 177,998 Petroleum Well Having Jan. 24 2000 Downhole Sensors, Communication, and Power TH 1669 60 / 177,997 System and Method for Jan. 24, 2000 ...

AI Technical Summary

Problems solved by technology

It is undesirable and in practice difficult to use a cable along the tubing string either integral with the tubing string or spaced in the annulus between the tubing and the casing because of the number of failure mechanisms present in such a system.

But such standard electrical conduits can be difficult to route at great depths, around turns for deviated wells, along multiple branches for a well having multiple lateral branches, and / or in parallel with coil production tubing.

Therefore, the method and system described in U.S. Pat. No. 4,839,644 is expensive, has problems with brine leakage into the casing, and is difficult to use as a scheme for downhole two-way communication.

Other downhole communication schemes such as mud pulse telemetry (U.S. Pat. Nos. 4,648,471; 5,887,657 have shown successful communication at low data rates but are of limited usefulness as a communication scheme where high data rates are required or it is undesirable to have complex, mud pulse telemetry equipment downhole.

Such protection chokes work well for their intended purpose, but do not operate to define a power or communication circuit.

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