Method for hydraulic fracturing cased wellbores
This patent describes a method of hydraulically fracturing a cased wellbore in an earth formation. It comprises determining the angle with respect to the wellbore axis and a reference point on the circumference of the wellbore which will provide for initiation of a hydraulic fracture in the formation which will turn with the largest radius of curvature into a fracture plane normal to the minimum in situ stress in the formation; perforating the wellbore casing at the angle with respect to the reference point; initiating a hydraulic fracture in the formation by pumping a liquid through the perforation and into the formation to force the initiation of a fracture in the formation at a point which develops the highest tensile stress in the formation in relation to increasing the hydraulic pressure in the wellbore; extending the fracture by pumping a relatively proppant-free quantities of proppant per unit volume of pumped fluid and in successive discrete stages of increasing proppant density to provide a propped portion of increasing proppant density to provide a propped portion of the fracture in the near wellbore region of the fracture which will prevent reclosing of the fracture in the near wellbore region.
- Assignee:
- Atlantic Richfield Co., Los Angeles, CA (United States)
- Patent Number(s):
- A; US 5074359
- Application Number:
- PPN: US 7-596633
- OSTI ID:
- 5594615
- Country of Publication:
- United States
- Language:
- English
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