Method for sensing and estimating the shape and location of oil-water interfaces in a well
US5767680A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 11, 1996 |
| Grant date | Jun 16, 1998 |
| Priority date | — |
| Expiry date | Jun 11, 2016 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02A90/30
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
Inception of hydrocarbon extraction from a reservoir causes the oil-water interface to warp and cusp toward the extraction gates along a well. This invention proposes time-lapse DC/AC measurements with an array of permanently deployed sensors in order to detect and estimate the change in geometry and proximity of the oil-water interface as a result of production, and therefore as a function of time. The estimation is carried out with a parametric inversion technique whereby the shape of the oil-water interface is assumed to take the form of a three-dimensional surface describable with only a few unknown parameters. A nonlinear optimization technique is used to search for the unknown parameters such that the differences between the measured data and the numerically simulated data are minimized in a least-squares fashion with concomitant hard bound physical constraints on the unknowns. The proposed estimation procedure is robust in the presence of relatively high levels of noise and can therefore be used to anticipate deleterious water breakthroughs, as well as improve the efficiency with which the oil is produced from the reservoir.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.