Hydraulic fracturing in medium and high-permeability reservoirs differs significantly from conventional fracturing, since the optimal placement of proppant requires shorter and wider fractures. The optimal fracture dimensions are achieved by executing a tip screenout design technique. Successful application of this technique assumes realistic description of the fluid leakoff process. Fracture calibration treatments (minifracs) have been used to identify leakoff characteristics. In addition to the application of data obtained from such tests (i.e. incorporation into the fracture job design) an increasingly important use is to obtain reservoir engineering parameters, such as formation permeability. This paper is based on two methods, used for the determination of the leakoff parameters from the pressure fall-off stage of a calibration treatment. The first method is the well known technology, which we have called the Nolte-Shlyapobersky method to determine an overall leakoff coefficient. The second method is a modified form of the Mayerhofer et al. technique, which attempts to de-couple the two main elements of the leakoff process: the filtercake resistance and the transient flow in the formation. For other methods concentrating more on the pressure fall-off after the fracture closes see References 3 and 5. Field examples will be used to demonstrate the basic steps of the presented methodology. Emphasis is on limitations and possible pitfalls with suggested remedies. A detailed sensitivity analysis is presented which underlines the data quality required to determine reservoir and treatment parameters with any accuracy.
|Number of pages||11|
|State||Published - 1998|
|Event||Proceedings of the 1998 International Symposium on Formation Damage Control - Lafayette, LA, USA|
Duration: Feb 18 1998 → Feb 19 1998
|Conference||Proceedings of the 1998 International Symposium on Formation Damage Control|
|City||Lafayette, LA, USA|
|Period||02/18/98 → 02/19/98|