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US4890487A
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Method for determining horizontal and/or vertical permeability of a subsurface earth formation
Assignee: Schlumberger Technology Corp
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Filing: 1987-04-07
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Granted: 1990-01-02
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Expires: 2007-04-07
Abstract
Abstract Pressure and flow measurements made during extraction of fluid samples from a subsurface earth formation using a borehole logging tool having a single extraction probe are analyzed to derive separate values for both horizontal and vertical formation permeability. Build-up measurements are used to derive the slope of variation of formation pressure with respect to a spherical time function, and this value is incorporated in an expression for a dimensionless variable relating pressure, flowrate, porosity, compressibility and probe radius. The resulting value of the dimensionless constant provides an index into a look-up table obtained by a new analysis of the fluid dynamics in the immediate vicinity of the probe for an anisotropic formation. The table gives values for two or more dimensionless variables from which the permeability values are derived.
Inventors
- 👤 Elizabeth B. Dussan V.
- 👤 Yogeshwar Sharma
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 22:55
CPC Classifications
E; E21; E21B; E21B49/00; E21B49/08; E21B49/10; E21B49/008
Claims Analysis
Total Claims: 64
Claim 1
Independent Claim
231 words
A method of estimating horizontal and/or vertical permeability of a formation traversing a borehole, said method comprising the steps of: drawing fluid from the formation at a first rate Q 1 through a probe having a radius r p for a first time period T 1 ; measuring a pressure P 1 of the fluid substantially at the end of said first time period; drawing a fluid from the formation at a second rate Q 2 through said probe for a second time period T 2 ; measuring a pressure P 2 of the fluid substantially at the end of said second time period; recording the build-up pressure of the fluid in the formation over a third time period, the pressure measured substantially at the end of said third time period being P f ; calculating a first factor m which correlates a predetermined pressure build-up model to said recorded build-up pressure; calculating a second factor S D based on said flow rate Q 1 , pressure P 1 , probe radius r p , pressure P f and first factor m; calculating a dimensionless quantity K H , representative of the horizontal permeability of the formation, based on said second factor S D ; and calculating a horizontal permeability k H of the formation based on said quantity K H , probe radius r p and pressure P f .
Claim 2
Independent Claim
231 words
A method of estimating horizontal and/or vertical permeability of a formation traversing a borehole, said method comprising the steps of: drawing fluid from the formation at a first rate Q 1 through a probe having a radius r p for a first time period T 1 ; measuring a pressure P 1 of the fluid substantially at the end of said first time period; drawing a fluid from the formation at a second rate Q 2 through said probe for a second time period T 2 ; measuring a pressure P 2 of the fluid substantially at the end of said second time period; recording the build-up pressure of the fluid in the formation over a third time period, the pressure measured substantially at the end of said third time period being P f ; calculating a first factor m which correlates a predetermined pressure build-up model to said recorded build-up pressure; calculating a second factor S D based on said flow rate Q 1 , pressure P 1 , probe radius r p , pressure P f and first factor m; calculating a dimensionless quantity K H , representative of the horizontal permeability of the formation, based on said second factor S D ; and calculating a horizontal permeability k H of the formation based on said quantity K H , probe radius r p and pressure P f .
Claim 3
Dependent Claim
29 words
The method of claim 1, said method of calculating said quantity k H is based on the following equation: ##EQU3## where μ represents the dynamic viscosity of the fluid.
Claim 4
Dependent Claim
37 words
The method of claim 1, wherein said step of calculating said dimensionless quantity K H is based on second factor S D and Table 1, wherein said value of K H is determined by interpolation, where necessary.
Claim 5
Dependent Claim
61 words
The method of claim 1, said method further comprising the steps of: calculating a dimensionless quantity K V , representative of the vertical permeability of the formation, based on said second factor S D ; and calculating a vertical permeability k V of the formation based on said quantity K V , probe radius r p and pressure P f .
Claim 6
Dependent Claim
29 words
The method of claim 4, said method of calculating said quantity k V is based on the following equation: ##EQU4## where μ represents the dynamic viscosity of the fluid.
Claim 7
Dependent Claim
37 words
The method of claim 4, wherein said step of calculating said dimensionless quantity K V is based on second factor S D and Table 1, wherein said value of K V is determined by interpolation, where necessary.
Claim 8
Dependent Claim
46 words
The method of claim 4, wherein the steps of calculating said dimensionless quantities K H and K V are by solving two simultaneous equations, said simultaneous equations based on the following two simultaneous equations: ##EQU5## where F denotes the complete elliptic integral of the first kind.
Claim 9
Dependent Claim
45 words
The method of claim 1, wherein said step of calculating said first factor m is based on the following equation: ##EQU6## where P(t) represents the recorded build-up pressure of the fluid in the formation; and Δt represents the instantaneous time in said third time period.
Claim 10
Dependent Claim
36 words
The method of claim 1, wherein said step of calculating said second factor S D is based on the following equation: ##EQU7## where φ represents the formation bulk porosity; and c t represents the total compressibility.
Claim 11
Independent Claim
231 words
A method of estimating horizontal and/or vertical permeability of a formation traversing a borehole, said method comprising the steps of: drawing fluid from the formation at a first rate Q 1 through a probe having a radius r p for a first time period T 1 ; measuring a pressure P 1 of the fluid substantially at the end of said first time period; drawing a fluid from the formation at a second rate Q 2 through said probe for a second time period T 2 ; measuring a pressure P 2 of the fluid substantially at the end of said second time period; recording the build-up pressure of the fluid in the formation over a third time period, the pressure measured substantially at the end of said third time period being P f ; calculating a first factor m which correlates a predetermined pressure build-up model to said recorded build-up pressure; calculating a second factor S D based on said flow rate Q 1 , pressure P 1 , probe radius r p , pressure P f and first factor m; calculating a dimensionless quantity K V , representative of the vertical permeability of the formation, based on said second factor S D ; and calculating a vertical permeability k V of the formation based on said quantity K V , probe radius r p and pressure P f .
Claim 12
Independent Claim
231 words
A method of estimating horizontal and/or vertical permeability of a formation traversing a borehole, said method comprising the steps of: drawing fluid from the formation at a first rate Q 1 through a probe having a radius r p for a first time period T 1 ; measuring a pressure P 1 of the fluid substantially at the end of said first time period; drawing a fluid from the formation at a second rate Q 2 through said probe for a second time period T 2 ; measuring a pressure P 2 of the fluid substantially at the end of said second time period; recording the build-up pressure of the fluid in the formation over a third time period, the pressure measured substantially at the end of said third time period being P f ; calculating a first factor m which correlates a predetermined pressure build-up model to said recorded build-up pressure; calculating a second factor S D based on said flow rate Q 1 , pressure P 1 , probe radius r p , pressure P f and first factor m; calculating a dimensionless quantity K V , representative of the vertical permeability of the formation, based on said second factor S D ; and calculating a vertical permeability k V of the formation based on said quantity K V , probe radius r p and pressure P f .
Claim 13
Dependent Claim
29 words
The method of claim 10, said method of calculating said quantity k V is based on the following equation: ##EQU8## where μ represents the dynamic viscosity of the fluid.
Claim 14
Dependent Claim
37 words
The method of claim 10, wherein said step of calculating said dimensionless quantity K V is based on second factor S D and Table 1, wherein said value of K V is determined by interpolation, where necessary.
Claim 15
Dependent Claim
61 words
The method of claim 10, said method further comprising the steps of: calculating a dimensionless quantity K H , representative of the horizontal permeability of the formation, based on said second factor S D ; and calculating a horizontal permeability k H of the formation based on said quantity K H , probe radius r p and pressure P f .
Claim 16
Dependent Claim
29 words
The method of claim 13, said method of calculating said quantity k H is based on the following equation: ##EQU9## where μ represents the dynamic viscosity of the fluid.
Claim 17
Dependent Claim
37 words
The method of claim 13, wherein said step of calculating said dimensionless quantity K H is based on second factor S D and Table 1, wherein said value of K H is determined by interpolation, where necessary.
Claim 18
Dependent Claim
46 words
The method of claim 13, wherein the steps of calculating said dimensionless quantities K H and K V are by solving two simultaneous equations, said simultaneous equations based on the following two simultaneous equations: ##EQU10## where F denotes the complete elliptic integral of the first kind.
Claim 19
Dependent Claim
45 words
The method of claim 10, wherein said step of calculating said first factor m is based on the following equation: ##EQU11## where P(t) represents the recorded build-up pressure of the fluid in the formation; and Δt represents the instantaneous time in said third time period.
Claim 20
Dependent Claim
36 words
The method of claim 10, wherein said step of calculating said second factor S D is based on the following equation: ##EQU12## where φ represents the formation bulk porosity; and c t represents the total compressibility.
Claim 21
Independent Claim
191 words
A method of estimating horizontal and/or vertical permeability of a formation traversing a borehole, said method comprising the steps of: drawing fluid from the formation at a first rate Q 1 through a probe having a radius r p for a first time period T 1 ; measuring a pressure P 1 of the fluid substantially at the end of said first time period; recording the build-up pressure of the fluid in the formation over a second time period, the pressure measured substantially at the end of said second time period being P f ; calculating a first factor m which correlates a predetermined pressure build-up model to said recorded build-up pressure; calculating a second factor S D based on said flow rate Q 1 , pressure P 1 , probe radius r p , pressure P f and first factor m; calculating a dimensionless quantity K H , representative of the horizontal permeability of the formation, based on said second factor S D ; and calculating a horizontal permeability k H of the formation based on said quantity K H , probe radius r p and pressure P f .
Claim 22
Independent Claim
191 words
A method of estimating horizontal and/or vertical permeability of a formation traversing a borehole, said method comprising the steps of: drawing fluid from the formation at a first rate Q 1 through a probe having a radius r p for a first time period T 1 ; measuring a pressure P 1 of the fluid substantially at the end of said first time period; recording the build-up pressure of the fluid in the formation over a second time period, the pressure measured substantially at the end of said second time period being P f ; calculating a first factor m which correlates a predetermined pressure build-up model to said recorded build-up pressure; calculating a second factor S D based on said flow rate Q 1 , pressure P 1 , probe radius r p , pressure P f and first factor m; calculating a dimensionless quantity K H , representative of the horizontal permeability of the formation, based on said second factor S D ; and calculating a horizontal permeability k H of the formation based on said quantity K H , probe radius r p and pressure P f .
Claim 23
Dependent Claim
29 words
The method of claim 19, said method of calculating said quantity k H is based on the following equation: ##EQU13## where μ represents the dynamic viscosity of the fluid.
Claim 24
Dependent Claim
37 words
The method of claim 19, wherein said step of calculating said dimensionless quantity K H is based on second factor S D and Table 1, wherein said value of K H is determined by interpolation, where necessary.
Claim 25
Dependent Claim
61 words
The method of claim 19, said method further comprising the steps of: calculating a dimensionless quantity K V , representative of the vertical permeability of the formation, based on said second factor S D ; and calculating a vertical permeability k V of the formation based on said quantity K V , probe radius r p and pressure P f .
Claim 26
Dependent Claim
29 words
The method of claim 22, said method of calculating said quantity k V is based on the following equation: ##EQU14## where μ represents the dynamic viscosity of the fluid.
Claim 27
Dependent Claim
37 words
The method of claim 22, wherein said step of calculating said dimensionless quantity K V is based on second factor S D and Table 1, wherein said value of K V is determined by interpolation, where necessary.
Claim 28
Dependent Claim
46 words
The method of claim 22, wherein the steps of calculating said dimensionless quantities K H and K V are by solving two simultaneous equations, said simultaneous equations based on the following two simultaneous equations: ##EQU15## where F denotes the complete elliptic integral of the first kind.
Claim 29
Dependent Claim
45 words
The method of claim 19, wherein said step of calculating said first factor m is based on the following equation: ##EQU16## where P(t) represents the recorded build-up pressure of the fluid in the formation; and Δt represents the instantaneous time in said third time period.
Claim 30
Dependent Claim
36 words
The method of claim 19, wherein said step of calculating said second factor S D is based on the following equation: ##EQU17## where φ represents the formation bulk porosity; and c t represents the total compressibility.
Claim 31
Independent Claim
191 words
A method of estimating horizontal and/or vertical permeability of a formation traversing a borehole, said method comprising the steps of: drawing fluid from the formation at a first rate Q 1 through a probe having a radius r p for a first time period T 1 ; measuring a pressure P 1 of the fluid substantially at the end of said first time period; recording the build-up pressure of the fluid in the formation over a second time period, the pressure measured substantially at the end of said second time period being P f ; calculating a first factor m which correlates a predetermined pressure build-up model to said recorded build-up pressure; calculating a second factor S D based on said flow rate Q 1 , pressure P 1 , probe radius r p , pressure P f and first factor m; calculating a dimensionless quantity K V , representative of the vertical permeability of the formation, based on said second factor S D ; and calculating a vertical permeability k V of the formation based on said quantity K V , probe radius r p and pressure P f .
Claim 32
Independent Claim
191 words
A method of estimating horizontal and/or vertical permeability of a formation traversing a borehole, said method comprising the steps of: drawing fluid from the formation at a first rate Q 1 through a probe having a radius r p for a first time period T 1 ; measuring a pressure P 1 of the fluid substantially at the end of said first time period; recording the build-up pressure of the fluid in the formation over a second time period, the pressure measured substantially at the end of said second time period being P f ; calculating a first factor m which correlates a predetermined pressure build-up model to said recorded build-up pressure; calculating a second factor S D based on said flow rate Q 1 , pressure P 1 , probe radius r p , pressure P f and first factor m; calculating a dimensionless quantity K V , representative of the vertical permeability of the formation, based on said second factor S D ; and calculating a vertical permeability k V of the formation based on said quantity K V , probe radius r p and pressure P f .
Claim 33
Dependent Claim
29 words
The method of claim 28, said method of calculating said quantity k V is based on the following equation: ##EQU18## where μ represents the dynamic viscosity of the fluid.
Claim 34
Dependent Claim
37 words
The method of claim 28, wherein said step of calculating said dimensionless quantity K V is based on second factor S D and Table 1, wherein said value of K V is determined by interpolation, where necessary.
Claim 35
Dependent Claim
61 words
The method of claim 28, said method further comprising the steps of: calculating a dimensionless quantity K H , representative of the horizontal permeability of the formation, based on said second factor S D ; and calculating a horizontal permeability k H of the formation based on said quantity K H , probe radius r p and pressure P f .
Claim 36
Dependent Claim
29 words
The method of claim 31, said method of calculating said quantity k H is based on the following equation: ##EQU19## where μ represents the dynamic viscosity of the fluid.
Claim 37
Dependent Claim
37 words
The method of claim 31, wherein said step of calculating said dimensionless quantity K H is based on second factor S D and Table 1, wherein said value of K H is determined by interpolation, where necessary.
Claim 38
Dependent Claim
46 words
The method of claim 31, wherein the steps of calculating said dimensionless quantities K H and K V are by solving two simultaneous equations, said simultaneous equations based on the following two simultaneous equations: ##EQU20## where F denotes the complete elliptic integral of the first kind.
Claim 39
Dependent Claim
45 words
The method of claim 28, wherein said step of calculating said first factor m is based on the following equation: ##EQU21## where P(t) represents the recorded build-up pressure of the fluid in the formation; and Δt represents the instantaneous time in said third time period.
Claim 40
Dependent Claim
36 words
The method of claim 28, wherein said step of calculating said second factor S D is based on the following equation: ##EQU22## where φ represents the formation bulk porosity; and c t represents the total compressibility.
Claim 41
Independent Claim
192 words
A method of estimating horizontal and/or vertical permeability of a formation traversing a borehole, said method comprising the steps of: drawing fluid from the formation at a first rate Q 1 through a probe having a radius r p for a first time period T 1 ; measuring a pressure P 1 of the fluid substantially at the end of said first time period; drawing a fluid from the formation at a second rate Q 2 through said probe for a second time period T 2 ; measuring a pressure P 2 of the fluid substantially at the end of said second time period; allowing the pressure of the fluid in the formation to build-up over a third time period, the pressure measured substantially at the end of said third time period being P f ; estimating a value of formation anisotropy, said anisotropy being the ratio of horizontal permeability k H and vertical permeability k V ; and determining a value of horizontal permeability k H based on first rate Q 1 , radius r p , said estimated value of formation anisotropy, and pressures P 1 and P f .
Claim 42
Independent Claim
192 words
A method of estimating horizontal and/or vertical permeability of a formation traversing a borehole, said method comprising the steps of: drawing fluid from the formation at a first rate Q 1 through a probe having a radius r p for a first time period T 1 ; measuring a pressure P 1 of the fluid substantially at the end of said first time period; drawing a fluid from the formation at a second rate Q 2 through said probe for a second time period T 2 ; measuring a pressure P 2 of the fluid substantially at the end of said second time period; allowing the pressure of the fluid in the formation to build-up over a third time period, the pressure measured substantially at the end of said third time period being P f ; estimating a value of formation anisotropy, said anisotropy being the ratio of horizontal permeability k H and vertical permeability k V ; and determining a value of horizontal permeability k H based on first rate Q 1 , radius r p , said estimated value of formation anisotropy, and pressures P 1 and P f .
Claim 43
Dependent Claim
28 words
The method of claim 37, said method further comprising the step of: determining a value of vertical permeability k V based on said estimated value of formation anisotropy.
Claim 44
Independent Claim
192 words
A method of estimating horizontal and/or vertical permeability of a formation traversing a borehole, said method comprising the steps of: drawing fluid from the formation at a first rate Q 1 through a probe having a radius r p for a first time period T 1 ; measuring a pressure P 1 of the fluid substantially at the end of said first time period; drawing a fluid from the formation at a second rate Q 2 through said probe for a second time period T 2 ; measuring a pressure P 2 of the fluid substantially at the end of said second time period; allowing the pressure of the fluid in the formation to build-up over a third time period, the pressure measured substantially at the end of said third time period being P f ; estimating a value of formation anisotropy, said anisotropy being the ratio of horizontal permeability k H and vertical permeability k V ; and determining a value of vertical permeability k V based on first rate Q 1 , radius r p , said estimated value of formation anisotropy, and pressures P 1 and P f .
Claim 45
Independent Claim
192 words
A method of estimating horizontal and/or vertical permeability of a formation traversing a borehole, said method comprising the steps of: drawing fluid from the formation at a first rate Q 1 through a probe having a radius r p for a first time period T 1 ; measuring a pressure P 1 of the fluid substantially at the end of said first time period; drawing a fluid from the formation at a second rate Q 2 through said probe for a second time period T 2 ; measuring a pressure P 2 of the fluid substantially at the end of said second time period; allowing the pressure of the fluid in the formation to build-up over a third time period, the pressure measured substantially at the end of said third time period being P f ; estimating a value of formation anisotropy, said anisotropy being the ratio of horizontal permeability k H and vertical permeability k V ; and determining a value of vertical permeability k V based on first rate Q 1 , radius r p , said estimated value of formation anisotropy, and pressures P 1 and P f .
Claim 46
Dependent Claim
28 words
The method of claim 39, said method further comprising the step of: determining a value of horizontal permeability k H based on said estimated value of formation anisotropy.
Claim 47
Independent Claim
208 words
A method of estimating horizontal and/or vertical permeability of a formation traversing a borehole, said method comprising the steps of: drawing fluid from the formation at a first rate Q 1 through a probe having a radius r p for a first time period T 1 ; measuring a pressure P 1 of the fluid substantially at the end of said first time period; drawing a fluid from the formation at a second rate Q 2 through said probe for a second time period T 2 ; measuring a pressure P 2 of the fluid substantially at the end of said second time period; allowing the pressure of the fluid in the formation to build-up over a third time period, the pressure measured substantially at the end of said third time period being P f ; estimating a value of formation anisotropy, said anisotropy being the ratio of horizontal permeability k H and vertical permeability k V ; determining a value of factor K H based on said estimated value of formation anisotropy and Table 1; and determining a value of horizontal permeability k H based on first rate Q 1 , radius r p , factor K H , and pressures P 1 and P f .
Claim 48
Independent Claim
208 words
A method of estimating horizontal and/or vertical permeability of a formation traversing a borehole, said method comprising the steps of: drawing fluid from the formation at a first rate Q 1 through a probe having a radius r p for a first time period T 1 ; measuring a pressure P 1 of the fluid substantially at the end of said first time period; drawing a fluid from the formation at a second rate Q 2 through said probe for a second time period T 2 ; measuring a pressure P 2 of the fluid substantially at the end of said second time period; allowing the pressure of the fluid in the formation to build-up over a third time period, the pressure measured substantially at the end of said third time period being P f ; estimating a value of formation anisotropy, said anisotropy being the ratio of horizontal permeability k H and vertical permeability k V ; determining a value of factor K H based on said estimated value of formation anisotropy and Table 1; and determining a value of horizontal permeability k H based on first rate Q 1 , radius r p , factor K H , and pressures P 1 and P f .
Claim 49
Dependent Claim
28 words
The method of claim 41, said method further comprising the step of: determining a value of vertical permeability k V based on said estimated value of formation anisotropy.
Claim 50
Independent Claim
208 words
A method of estimating horizontal and/or vertical permeability of a formation traversing a borehole, said method comprising the steps of: drawing fluid from the formation at a first rate Q 1 through a probe having a radius r p for a first time period T 1 ; measuring a pressure P 1 of the fluid substantially at the end of said first time period; drawing a fluid from the formation at a second rate Q 2 through said probe for a second time period T 2 ; measuring a pressure P 2 of the fluid substantially at the end of said second time period; allowing the pressure of the fluid in the formation to build-up over a third time period, the pressure measured substantially at the end of said third time period being P f ; estimating a value of formation anisotropy, said anisotropy being the ratio of horizontal permeability k H and vertical permeability k V ; determining a value of factor K V based on said estimated value of formation anisotropy and Table 1; and determining a value of vertical permeability k V based on first rate Q 1 , radius r p , factor K V , and pressures P 1 and P f .
Claim 51
Independent Claim
208 words
A method of estimating horizontal and/or vertical permeability of a formation traversing a borehole, said method comprising the steps of: drawing fluid from the formation at a first rate Q 1 through a probe having a radius r p for a first time period T 1 ; measuring a pressure P 1 of the fluid substantially at the end of said first time period; drawing a fluid from the formation at a second rate Q 2 through said probe for a second time period T 2 ; measuring a pressure P 2 of the fluid substantially at the end of said second time period; allowing the pressure of the fluid in the formation to build-up over a third time period, the pressure measured substantially at the end of said third time period being P f ; estimating a value of formation anisotropy, said anisotropy being the ratio of horizontal permeability k H and vertical permeability k V ; determining a value of factor K V based on said estimated value of formation anisotropy and Table 1; and determining a value of vertical permeability k V based on first rate Q 1 , radius r p , factor K V , and pressures P 1 and P f .
Claim 52
Dependent Claim
28 words
The method of claim 43, said method further comprising the step of: determining a value of horizontal permeability k H based on said estimated value of formation anisotropy.
Claim 53
Independent Claim
152 words
A method of estimating horizontal and/or vertical permeability of a formation traversing a borehole, said method comprising the steps of: drawing fluid from the formation at a first rate Q 1 through a probe having a radius r p for a first time period T 1 ; measuring a pressure P 1 of the fluid substantially at the end of said first time period; allowing the pressure of the fluid in the formation to build-up over a second time period, the pressure measured substantially at the end of said second time period being P f ; estimating a value of formation anisotropy, said anisotropy being the ratio of horizontal permeability k H and vertical permeability k V ; and determining a value of horizontal permeability k H based on first rate Q 1 , radius r p , said estimated value of formation anisotropy, and pressures P 1 and P f .
Claim 54
Independent Claim
152 words
A method of estimating horizontal and/or vertical permeability of a formation traversing a borehole, said method comprising the steps of: drawing fluid from the formation at a first rate Q 1 through a probe having a radius r p for a first time period T 1 ; measuring a pressure P 1 of the fluid substantially at the end of said first time period; allowing the pressure of the fluid in the formation to build-up over a second time period, the pressure measured substantially at the end of said second time period being P f ; estimating a value of formation anisotropy, said anisotropy being the ratio of horizontal permeability k H and vertical permeability k V ; and determining a value of horizontal permeability k H based on first rate Q 1 , radius r p , said estimated value of formation anisotropy, and pressures P 1 and P f .
Claim 55
Dependent Claim
28 words
The method of claim 45, said method further comprising the step of: determining a value of vertical permeability k V based on said estimated value of formation anisotropy.
Claim 56
Independent Claim
152 words
A method of estimating horizontal and/or vertical permeability of a formation traversing a borehole, said method comprising the steps of: drawing fluid from the formation at a first rate Q 1 through a probe having a radius r p for a first time period T 1 ; measuring a pressure P 1 of the fluid substantially at the end of said first time period; allowing the pressure of the fluid in the formation to build-up over a second time period, the pressure measured substantially at the end of said second time period being P f ; estimating a value of formation anisotropy, said anisotropy being the ratio of horizontal permeability k H and vertical permeability k V ; and determining a value of vertical permeability k V based on first rate Q 1 , radius r p , said estimated value of formation anisotropy, and pressures P 1 and P f .
Claim 57
Independent Claim
152 words
A method of estimating horizontal and/or vertical permeability of a formation traversing a borehole, said method comprising the steps of: drawing fluid from the formation at a first rate Q 1 through a probe having a radius r p for a first time period T 1 ; measuring a pressure P 1 of the fluid substantially at the end of said first time period; allowing the pressure of the fluid in the formation to build-up over a second time period, the pressure measured substantially at the end of said second time period being P f ; estimating a value of formation anisotropy, said anisotropy being the ratio of horizontal permeability k H and vertical permeability k V ; and determining a value of vertical permeability k V based on first rate Q 1 , radius r p , said estimated value of formation anisotropy, and pressures P 1 and P f .
Claim 58
Dependent Claim
28 words
The method of claim 47, said method further comprising the step of: determining a value of horizontal permeability k H based on said estimated value of formation anisotropy.
Claim 59
Independent Claim
168 words
A method of estimating horizontal and/or vertical permeability of a formation traversing a borehole, said method comprising the steps of: drawing fluid from the formation at a first rate Q 1 through a probe having a radius r p for a first time period T 1 ; measuring a pressure P 1 of the fluid substantially at the end of said first time period; allowing the pressure of the fluid in the formation to build-up over a second time period, the pressure measured substantially at the end of said second time period being P f ; estimating a value of formation anisotropy, said anisotropy being the ratio of horizontal permeability k H and vertical permeability k V ; determining a value of factor K H based on said estimated value of formation anisotropy and Table 1; and determining a value of horizontal permeability k H based on first rate Q 1 , radius r p , factor K H , and pressures P 1 and P f .
Claim 60
Independent Claim
168 words
A method of estimating horizontal and/or vertical permeability of a formation traversing a borehole, said method comprising the steps of: drawing fluid from the formation at a first rate Q 1 through a probe having a radius r p for a first time period T 1 ; measuring a pressure P 1 of the fluid substantially at the end of said first time period; allowing the pressure of the fluid in the formation to build-up over a second time period, the pressure measured substantially at the end of said second time period being P f ; estimating a value of formation anisotropy, said anisotropy being the ratio of horizontal permeability k H and vertical permeability k V ; determining a value of factor K H based on said estimated value of formation anisotropy and Table 1; and determining a value of horizontal permeability k H based on first rate Q 1 , radius r p , factor K H , and pressures P 1 and P f .
Claim 61
Dependent Claim
28 words
The method of claim 49, said method further comprising the step of: determining a value of vertical permeability k V based on said estimated value of formation anisotropy.
Claim 62
Independent Claim
168 words
A method of estimating horizontal and/or vertical permeability of a formation traversing a borehole, said method comprising the steps of: drawing fluid from the formation at a first rate Q 1 through a probe having a radius r p for a first time period T 1 ; measuring a pressure P 1 of the fluid substantially at the end of said first time period; allowing the pressure of the fluid in the formation to build-up over a second time period, the pressure measured substantially at the end of said second time period being P f ; estimating a value of formation anisotropy, said anisotropy being the ratio of horizontal permeability k H and vertical permeability k V ; determining a value of factor K V based on said estimated value of formation anisotropy and Table 1; and determining a value of vertical permeability k V based on first rate Q 1 , radius r p , factor K V , and pressures P 1 and P f .
Claim 63
Independent Claim
168 words
A method of estimating horizontal and/or vertical permeability of a formation traversing a borehole, said method comprising the steps of: drawing fluid from the formation at a first rate Q 1 through a probe having a radius r p for a first time period T 1 ; measuring a pressure P 1 of the fluid substantially at the end of said first time period; allowing the pressure of the fluid in the formation to build-up over a second time period, the pressure measured substantially at the end of said second time period being P f ; estimating a value of formation anisotropy, said anisotropy being the ratio of horizontal permeability k H and vertical permeability k V ; determining a value of factor K V based on said estimated value of formation anisotropy and Table 1; and determining a value of vertical permeability k V based on first rate Q 1 , radius r p , factor K V , and pressures P 1 and P f .
Claim 64
Dependent Claim
28 words
The method of claim 51, said method further comprising the step of: determining a value of horizontal permeability k H based on said estimated value of formation anisotropy.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1993-01-01 | 1993-07-03 | 1994-01-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-01-01 | 1997-07-03 | 1998-01-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-01-01 | 2001-07-03 | 2002-01-02 | $7700.00 | Window Closed / Lapsed |