Method and apparatus for communicating with devices downhole in a well especially adapted for use as a bottom hole mud flow sensor
US6105690A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 29, 1998 |
| Grant date | Aug 22, 2000 |
| Priority date | — |
| Expiry date | May 29, 2018 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B47/18
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A method and apparatus for communicating with a device downhole in a well, such as a bottom hole assembly in a drill string. Pressure pulses, such as those generated by the pistons of the mud pump, are transmitted through the drilling mud to a pressure pulsation sensor in the bottom hole assembly. The pressure pulsation sensor features a piezoceramic element that generates a varying voltage signal in response to the received pressure pulsations. The pressure pulsation sensor also has electronic components that allow it to analyze a characteristic of the pressure pulsations, such as their frequency. Based on its analysis of the pressure pulsations, the sensor can decipher a command from the surface, for example, that directs the steering of a steerable drill string, or that can determine whether the mud pumps are operating. If the mud pumps are not operating the sensor directs a microprocessor to reduce power to the bottom hole assembly electrical components, such as a measurement while drilling tool, thereby conserving battery power. The method and apparatus can also be used to control the operation of flow control valves in a multilateral well.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.