Initiation and Extension of Hydraulic Fractures in Rocks

作者：B.C. Haimson, C. Fairhurst · 发表于：Society of Petroleum Engineers Journal · 年份：1967 · DOI：10.2118/1710-pa · 被引用次数：744 · 研究领域：Hydraulic Fracturing and Reservoir Analysis、Geotechnical and Geomechanical Engineering、Seismic Imaging and Inversion Techniques

Abstract A criterion is proposed for the initiation of vertical hydraulic fracturing taking into consideration the three stress fields around the wellbore. These fields arise from - nonhydrostatic regional stresses in earth - the difference between the fluid pressure in the wellbore and the formation fluid pressure and - the radial fluid flow through porous rock from the wellbore into the formation due to this pressure difference. The wellbore fluid pressure required to initiate a fracture (assuming elastic rock and a smooth wellbore wall) is a function o/ the porous elastic constants of the rock, the two unequal horizontal principal regional caresses, the tensile strength of the rock and the formation fluid pressure. A constant injection rate will extend the fracture to a point where equilibrium is reached and then, to keep the fracture open, the pressure required is a function of the porous elastic constants of the rock, the component of the regional stress normal to the plane of the fracture, the formation fluid pressure and the dimensions of the crack. The same expression may also be used to estimate the vertical fracture width, provided all other variables are known. The derived equations for the initiation and extension pressures in vertical fracturing may be employed to solve for the two horizontal, regional, principal stresses in the rock. Introduction Well stimulation by hydraulic fracturing is a common practice today in the petroleum industry. However, this stimulat...