US3851709A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulic fracturing method to control vertical fracture heights
Assignee: Mobil Oil AS
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Filing: 1973-11-21
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Granted: 1974-12-03
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Expires: 1993-11-21
Abstract
Abstract This specification discloses a method of hydraulically fracturing a subterranean earth formation to form therein a vertically disposed fracture. More particularly, this specification discloses a method of controlling the height of the formed vertically disposed fracture such that the fracture does not extend into formations that are superjacent or subjacent to the subterranean formation. Hydraulic pressure is applied via a well to the formation to initiate a vertical fracture therein. The hydraulic pressure is then reduced to a pressure no greater than a predetermined pressure and the vertically disposed fracture is propagated into the subterranean formation.
Inventors
- 👤 J Fitch
- 👤 M Biot
- 👤 L Masse
- 👤 W Medlin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 07:26
CPC Classifications
E; E21; E21B; E21B43/00; E21B43/25; E21B43/26
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
201 words
A method of fracturing a subterranean formation that is located adjacent another formation having different mechanical characteristics, comprising the steps of: a applying an initiation hydraulic pressure via said well to said subterranean formation to initiate in said subterranean formation a vertically disposed fracture; b reducing said initiation pressure to a propagation pressure that is no greater than a predetermined pressure defined by the relationship p2 soE/4a91- Nu 2) square root a2G2/a1G1 where: p2 the predetermined propagation pressure which f not exceeded will limit the vertical extension of the fracture to the subterranean formation; wo the maximum width of the fracture in the subterranean formation; E Young''s modulus in the subterranean formation; Nu Poisson''s ration i the subterranean formation; L the thickness orlength in a vertical direction of the subterranean formation; a fracture surface energy; energy required to generate unit area of new surface by fracturing (subscript 1 refers to the subterranean formation, subscript 2 refers to the other formation).; G shear modulus (subscript 1 refers to the subterranean formation, subscript 2 refers to the another formation); and c. applying said selected propagation pressure via said well to said subterranean formation to propagate said vertically disposed fracture into said subterranean formation.
Claim 2
Independent Claim
201 words
A method of fracturing a subterranean formation that is located adjacent another formation having different mechanical characteristics, comprising the steps of: a applying an initiation hydraulic pressure via said well to said subterranean formation to initiate in said subterranean formation a vertically disposed fracture; b reducing said initiation pressure to a propagation pressure that is no greater than a predetermined pressure defined by the relationship p2 soE/4a91- Nu 2) square root a2G2/a1G1 where: p2 the predetermined propagation pressure which f not exceeded will limit the vertical extension of the fracture to the subterranean formation; wo the maximum width of the fracture in the subterranean formation; E Young''s modulus in the subterranean formation; Nu Poisson''s ration i the subterranean formation; L the thickness orlength in a vertical direction of the subterranean formation; a fracture surface energy; energy required to generate unit area of new surface by fracturing (subscript 1 refers to the subterranean formation, subscript 2 refers to the other formation).; G shear modulus (subscript 1 refers to the subterranean formation, subscript 2 refers to the another formation); and c. applying said selected propagation pressure via said well to said subterranean formation to propagate said vertically disposed fracture into said subterranean formation.
Claim 3
Dependent Claim
13 words
The method of claim 1 wherein said another formation is a subjacent formation.
Claim 4
Dependent Claim
83 words
The method of claim 2 wherein said subterranean formation is also bounded by a superjacent formation further comprising the steps of: a. determining a first predetermined pressure based upon said subterranean formation and said subjacent formation; b. determining a second predetermined pressure based upon said subterranean formation and said superjacent formation; c. comparing said first predetermined pressure with said second predetermined pressure and determining the lesser predetermined pressure; and d. applying a propagation pressure that is no greater than said lesser predetermined pressure.
Claim 5
Dependent Claim
104 words
In the method of claim 3 wherein said subterranean formation contains an internal stratum that has mechanical characteristics that differ from those of said subterranean formation and from those of said subjacent and superjacent strata, said internal stratum being subject to being fractured at a lower pressure than said subjacent and superjacent strata, further comprising the steps of: determining a third predetermined pressure based upon said subterranean formatio and said internal stratum; and selecting as a propagation pressure at a pressure that is greater than said third predetermined pressure but is not greater than said less propagation pressure of step (c) of claim 3.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-12-02 | 1978-06-03 | 1978-12-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-02 | 1982-06-03 | 1982-12-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-02 | 1986-06-03 | 1986-12-03 | $7700.00 | Window Closed / Lapsed |