اثرات تراكم پذيري سيال و مجاورت با گمانه بر شروع و گسترش ترك هيدروليكي

COMPRESSIBILITY AND WELLBORE EFFECTS ON THE lNITIATION AND PROPAGATION OF HYDRAULIC FRACTURES

This paper is concerned with the problem of a plane strain hydraulic fracture transverse to aborehole. Compressibility and near borehole effects are considered to explaiu the early unstable phase of the fracture growth observed in laboratory experiments , which are potentially a pplicable to micro fracture experiments conductediu order to determine in-situ stresses . The fracture grows in an imperm eable elastic material. A solution is obtaiued in terms of fluid net pressure , fracture engthaud opening. It is shown that the problem depends only on a dimensionless viscosity and an evolution parameter (hat are related to the compressibility and borehole effect . Instability is identified in the problem after breakd own for an iuviscid fluid. The potential for unstable growth depends on th e initial Bow length , the fluid compressibility, the volume of the fluid and the material elastic modulus.