Expandable casing portions are provided, such as casing slip joints or expansion joints, on opposite sides of a fracture initiation location to accommodate casing and formation movement during fracturing of a well. The fracture initiation location may be provided by forming openings through the well casing and then forming fan-shaped slots in the formation surrounding the casing. These slots may be formed by a hydraulic jet which is directed through the opening and then pivoted generally about the point of the opening. These fan-shaped slots circumscribe an angle about the axis of the casing substantially greater than the angle circumscribed by the opening itself through which the slot was formed. These techniques are particularly applicable to fracturing of horizontal wells, but are also useful on vertical wells.