Sinusoidal pressure pulse generator for measurement while drilling tool
US4847815A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 22, 1987 |
| Grant date | Jul 11, 1989 |
| Priority date | — |
| Expiry date | Sep 22, 2007 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B47/18
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A pressure pulse generator which generates relatively sinusoidal pressure pulses in a fluid flowing in a borehole is disclosed. The pressure pulse generator for a MWD tool broadly comprises: a housing adapted to be connected in a tubing string so that fluid flowing in the string will at least partially flow through the housing; a stator mounted within the housing and having a plurality of lobes with intervening gaps; a rotor coaxial to the stator which rotates relative to the stator and which is mounted within the housing and has a plurality of lobes with intervening gaps between adjacent lobes, wherein the lobes of the rotor and stator are arranged such that as the rotor rotates relative to the stator, the area of the adjacent gaps between the lobes of the stator and rotor through which the fluid may flow in a direction parallel to the borehole varies approximately with the inverse of the square root of a linear function of a sine wave. Preferably, the geometrical arrangement of the stator and rotor are substantially identical with a plurality of lobes with intervening gaps around a central circular hub. A first side of each lobe is defined by a radial extension from the circular …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.