Overbalance perforating and stimulation method for wells
AssigneeOryx Energy Company
InventorsJohn M. Dees, Patrick J. Handren, Terence B. Jupp
Life of this patent
Estimating the term…
Abstract
A method if disclosed for decreasing the flow resistance of a subterranean formation surrounding a well. A high fluid pressure is suddenly applied to the formation and fluid is pumped into the high pressure fractures. The fluid may contain proppant particles.
Claims49
A method for decreasing the resistance to fluid flow in a subterranean formation around a well having unperforated casing fixed therein, the casing extending at least partially through the formation, comprising:
- (a) providing a liquid in the casing opposite the formation to be treated;
- (b) placing perforating means in the casing at a depth opposite the formation to be treated;
- (c) injecting gas into the well until the pressure in the liquid opposite the formation to be treated will be at least as large as the fracturing pressure of the formation when the liquid pressure is applied to the formation;
- (d) activating the perforating means;
- and
- (e) at a time before pressure in the well at the depth of the formation to be treated has substantially decreased, injecting fluid at an effective rate to fracture the formation.
A method for decreasing the resistance to fluid flow in a subterranean formation around a well having an optionally perforated casing fixed therein, the casing extending at least partially through the formation, comprising:
- (a) placing a tubing string in the well, the tubing string having a packer, perforating means and pressure release means attached thereto, such that the perforating means is opposite the formation to be treated;
- (b) setting the packer so as to seal the annulus between the casing and the tubing string;
- (c) injecting a fluid into the tubing string such that when pressure within the tubing string is released the fluid pressure at the depth of the formation to be treated is greater than the fracture pressure of the formation;
- d) activating the perforating means and near simultaneously activating the pressure release means to release pressure from the tubing string into the casing below the packer such that pressure is applied to the formation through existing or newly created perforations.
A method for decreasing the resistance to fluid flow in a subterranean formation around a well having casing fixed therein, the casing extending at least partially through the formation, comprising:
- (a) placing a tubing string in the well, the tubing string having a packer attached thereto;
- (b) setting the packer so as to seal the annulus between the casing and the tubing string;
- (c) placing perforating means below the tubing string and located opposite the formation to be treated, the perforating means being conveyed into the well on wireline;
- (d) injecting a gas phase into the tubing string until the pressure in the casing opposite the formation to be treated is at least as large as the fracturing pressure of the formation;
- (e) activating the perforating means to form at least one perforation in the casing;
- and
- (f) at a time before pressure in the well at the depth of the formation to be treated has dropped substantially below fracturing pressure, injecting a fluid at an effective rate to fracture the formation.
A method of decreasing the resistance to fluid flow in a subterranean formation surrounding a well having casing fixed therein, the casing extending at least partially through the formation and having at least one perforation in the casing opposite the formation, comprising:
- (a) placing a tubing string in the well, the tubing string having a packer and a means for containing high pressure, said means being located in proximity to the lower end of said tubing;
- (b) setting the packer so as to seal the annulus between the casing and the tubing string;
- (c) injecting a gas phase into the tubing string such that when pressure within the tubing string is released the fluid pressure in the well at the depth of the formation to be treated is greater than fracture pressure of the formation;
- (d) activating the means for containing high pressure such that pressure is instantaneously applied to the formation through the perforations;
- (e) at a time before pressure at the perforations has dropped substantially below fracturing pressure of the formation, injecting a fluid at an effective rate to fracture the formation.
A method for decreasing the resistance to fluid flow in a subterranean formation surrounding a well having casing fixed therein, the casing extending at least partially through the formation, comprising:
- (a) providing a liquid in the casing at the depth of the formation to be treated;
- (b) placing perforating means in the casing at a depth opposite the formation to be treated;
- (c) injecting a gas into the well until the pressure in the liquid opposite the formation to be treated is at least as large as the fracturing pressure of the formation;
- (d) activating the perforating means;
- and
- (e) at a time before pressure in the well at the depth of the formation to be treated has substantially decreased, injecting fluid at an effective rate to fracture the formation.
Dependencies are inferred from the claim text.