Patent US2788200A successfully refreshed from Google Patents.
US4328705A
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Method of determining characteristics of a fluid producing underground formation
Assignee: Schlumberger Technology Corp
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Filing: 1980-08-11
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Granted: 1982-05-11
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Expires: 2000-08-11
Abstract
Abstract A graphical plot of pressure versus time during pressure build-up in a temporarily closed well is matched to a type-curve on a graph of such curves to determine if the well is fractured, acidified, fissured or damaged.
Inventors
- 👤 Alain C. Gringarten
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 21:35
CPC Classifications
E; E21; E21B; E21B49/00; E21B49/008
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
139 words
A method for determining physical parameters of a fluid producing underground formation traversed by a wellbore comprising: changing the fluid flowrate from the formation, plotting the subsequent variations in fluid pressure versus time change as a curve in log-log axes on an experimental graph, matching the curve on the experimental graph to one of a series of type-curves representing, on one axis, the pressure change times the product permeability-thickness of a formation, and on the other axis, the time change times the ratio of the product permeability-thickness to the wellbore storage constant, and determining from the matched type-curve and the shifts of the axes between the experimental graph and the axes of the matched type-curve at least one of the following values of the fluid producing underground formation: the product permeability-thickness, the wellbore storage constant, and the skin value.
Claim 2
Independent Claim
139 words
A method for determining physical parameters of a fluid producing underground formation traversed by a wellbore comprising: changing the fluid flowrate from the formation, plotting the subsequent variations in fluid pressure versus time change as a curve in log-log axes on an experimental graph, matching the curve on the experimental graph to one of a series of type-curves representing, on one axis, the pressure change times the product permeability-thickness of a formation, and on the other axis, the time change times the ratio of the product permeability-thickness to the wellbore storage constant, and determining from the matched type-curve and the shifts of the axes between the experimental graph and the axes of the matched type-curve at least one of the following values of the fluid producing underground formation: the product permeability-thickness, the wellbore storage constant, and the skin value.
Claim 3
Dependent Claim
47 words
The method of claim 1 wherein said matching step further comprises matching the curve on the experimental graph to one of a series of type-curves wherein each type-curve represents a value proportional to Ce 2S , C being the wellbore storage constant and S the skin value.
Claim 4
Dependent Claim
45 words
The method of claim 1, wherein the value proportional to Ce 2S is C D e 2S , C D being the dimensionless wellbore storage, said graph of type-curves being produced for values of C D e 2S greater than and less than substantially 0.5.
Claim 5
Dependent Claim
29 words
The method of claim 3 further comprising determining that the formation is a fractured formation if the maximum value of C D e 2S is equal to substantially 0.5.
Claim 6
Dependent Claim
29 words
The method of claim 3 further comprising determining that the formation is an acidified formation if the value of C D e 2S is between substantially 0.5 and 5.
Claim 7
Dependent Claim
44 words
The method of claim 3 further comprising determining that the formation is a fissured formation if the value of C D e 2S is less than substantially 0.5, the value of C is greater than approximately 0.1, and the value of S is negative.
Claim 8
Dependent Claim
27 words
The method of claim 3 further comprising determining that the formation is a damaged formation if the value of C D e 2S is greater than 1000.
Claim 9
Independent Claim
196 words
A method for determining the condition of a fluid producing underground formation traversed by a wellbore comprising: changing the fluid flowrate of the well, plotting the subsequent variations in fluid pressure versus time change as a curve in log-log axes on an experimental graph, matching the experimental graph with one of a series of type-curves, of the same size as the experimental graph, the type-curves representing with an additive constant the logarithm of p·kh in one axis and the logarithm of ##EQU13## on the other axis, each type-curve representing a value proportional to C D e 2S , p being the fluid pressure, t being the time, kh being the product permeability-thickness of the formation, C the wellbore storage constant and S the skin value, the graph of type-curves being produced for values of C D e 2S at least comprised between 0.5 and 1000, and determining that the formation is fractured if the value of C D e 2S represented by the matched type-curve is less than 0.5, that the formation has been acidized if this value is between 0.5 and 5 and that the formation is damaged if this value is greater than 1000.
Claim 10
Independent Claim
196 words
A method for determining the condition of a fluid producing underground formation traversed by a wellbore comprising: changing the fluid flowrate of the well, plotting the subsequent variations in fluid pressure versus time change as a curve in log-log axes on an experimental graph, matching the experimental graph with one of a series of type-curves, of the same size as the experimental graph, the type-curves representing with an additive constant the logarithm of p·kh in one axis and the logarithm of ##EQU13## on the other axis, each type-curve representing a value proportional to C D e 2S , p being the fluid pressure, t being the time, kh being the product permeability-thickness of the formation, C the wellbore storage constant and S the skin value, the graph of type-curves being produced for values of C D e 2S at least comprised between 0.5 and 1000, and determining that the formation is fractured if the value of C D e 2S represented by the matched type-curve is less than 0.5, that the formation has been acidized if this value is between 0.5 and 5 and that the formation is damaged if this value is greater than 1000.
References Cited (Backward Citations)
US3636762A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-05-10 | 1985-11-09 | 1986-05-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-05-10 | 1989-11-09 | 1990-05-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-05-10 | 1993-11-09 | 1994-05-11 | $7700.00 | Window Closed / Lapsed |