| Popis: |
Can unconsolidated sands, with no intergranular cohesion forces, really be hydraulically fractured? Does conventional hydraulic fracturing theory adequately explain treatment behavior and production results? If the unconsolidated formation is considered to be a fluidized sand bed, is the classical linear-elastic two-wing hydraulic frac assumption still valid? Alternative proppant stimulation mechanisms may better describe the process, including squeezing or forcing by viscous fingering of the high-permeability proppant slurry into the formation. In this scenario, traditional fracturing design parameters such as pad volume, pump rate, proppant concentration and especially fluid viscosity will have new and significantly different effects on the treatment outcome. This paper explores these concepts and shows how they can explain both treating behavior and production responses of so-called "frac jobs" or "sand-oil-squeezes". Alternative treatment and fluid design criteria are proposed to achieve more consistent and predictable production responses, based on field performance. |
