Method of evaluating fluid loss in subsurface fracturing operations
US5241475A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 26, 1990 |
| Grant date | Aug 31, 1993 |
| Priority date | — |
| Expiry date | Oct 26, 2010 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B49/006
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
An implementation of the present invention will typically be performed through use of two test fracturing or "mini-frac" operations to determine formation parameters. A first mini-frac operation will be performed to determine the fluid efficiency of the formation, and a second mini-frac operation will be performed to determine a late time fluid leak-off coefficient. The data thus obtained will be functionally related to simultaneously solve integral expressions to determine the total volume of fluid lost during pumping and the total volume of fluid lost during shut-in in response to an assumed spurt time. The fluid loss values will then be functionally related to the established fluid efficiency to estimate an early time fluid leak-off coefficient. The early time fluid leak-off coefficient thus determined will then be applied in a balance equation to verify the accuracy of such value in response to the assumed spurt time. The assumed spurt time may then be varied and the above fluid loss values iteratively reevaluated until the balance equation is satisfied within an acceptable range of tolerance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.