| 摘要 |
A method for producing multiple fractures in earth formations in which the lines of least principal stress deviate substantially from vertical is described. A generally vertical borehole is drilled into the formation, the formation is hydraulically fractured from the vertical borehole, the plane in which the fracture lies is determined, a slanted borehole is drilled out from the vertical borehole in a direction such that the azimuth of slanted borehole is generally perpendicular to the plane of the fracture and then the formation adjacent the slanted borehole is hydraulically fractured at a plurality of positions along the length of the slanted borehole. When the direction of lines of least principal stress is known for the formation, the steps of hydraulically fracturing from the vertical borehole and determining the plane in which the fracture lies may be omitted and the slanted borehole is drilled in the azimuth parallel to the known lines of least principal stress.
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