US4158165A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus and method for determining subsurface formation properties
Assignee: Schlumberger Technology Corp
•
Filing: 1977-06-16
•
Granted: 1979-06-12
•
Expires: 1997-06-16
Abstract
Abstract The disclosure is directed to an apparatus and method for determining the water-filled porosity of formations surrounding a borehole. Alternatively, where porosity is known from other logging information, the disclosed techniques can be utilized for determining the conductivity of the water in formations surrounding a borehole or for determining water saturation. The formations are assumed to comprise a matrix, which may be any subsurface solid material, and fluids contained in the matrix, such as in pore spaces or interstices therein. In accordance with one embodiment, means are provided for deriving a first quantity which is representative of the attenuation of microwave electromagnetic energy propagating between spaced locations in the borehole, the first quantity being, for example, the attenuation constant, α. Means are also provided for deriving a second quantity representative of the relative phase shift of microwave electromagnetic energy propagating between the spaced locations, the second quantity being, for example, the phase constant, β. Further means are provided for deriving a third quantity representative of the conductivity of the water in the formations surrounding the spaced locations. In the preferred form of the invention, the investigated formations are in the invaded zone surrounding the borehole and the conductivity of the water is determinable from the conductivity of the drilling mud being utilized and the nature of the mud filtrate resulting from invasion of the formations by the drilling mud. Means are also provided for generating a fourth quantity which is proportional to the product of the first and second quantities and inversely proportional to the third quantity. The generated fourth quantity is indicative of the water-filled porosity, φ w , of the formations adjacent the region of the spaced locations in the borehole. In alternative forms of the invention, where porosity is known, the conductivity, σ w , or the apparent conductivity, σ w ', of the water in formations surrounding the borehole is determined.
Inventors
- 👤 George R. Coates
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 12:19
CPC Classifications
G; G01; G01V; G01V3/00; G01V3/18; G01V3/30; E; E21; E21B; E21B49/00; Y; Y02; Y02A; Y02A90/00; Y02A90/30
Claims Analysis
Total Claims: 82
Claim 1
Independent Claim
115 words
Apparatus for determining the water-filled porosity of formations surrounding a borehole, comprising: means for deriving a first quantity representative of the attenuation of microwave electromagnetic energy propagating between spaced locations in the borehole; means for deriving a second quantity representative of the relative phase shift of microwave electromagnetic energy propagating between said spaced locations in the borehole; means for deriving a third quantity representative of the conductivity of the water in the formations surrounding said spaced locations; and means for generating a fourth quantity which is proportional to the product of said first and second quantities and inversely proportional to said third quantity; said fourth quantity being indicative of the water-filled porosity of said formations.
Claim 2
Dependent Claim
115 words
Apparatus for determining the water-filled porosity of formations surrounding a borehole, comprising: means for deriving a first quantity representative of the attenuation of microwave electromagnetic energy propagating between spaced locations in the borehole; means for deriving a second quantity representative of the relative phase shift of microwave electromagnetic energy propagating between said spaced locations in the borehole; means for deriving a third quantity representative of the conductivity of the water in the formations surrounding said spaced locations; and means for generating a fourth quantity which is proportional to the product of said first and second quantities and inversely proportional to said third quantity; said fourth quantity being indicative of the water-filled porosity of said formations.
Claim 3
Dependent Claim
27 words
Apparatus as defined by claim 1 wherein said first quantity is the attenuation constant of said microwave electromagnetic energy propagating between said spaced locations in the borehole.
Claim 4
Dependent Claim
27 words
Apparatus as defined by claim 1 wherein said second quantity is the phase constant of said microwave electromagnetic energy propagating between said spaced locations in the borehole.
Claim 5
Dependent Claim
27 words
Apparatus as defined by claim 2 wherein said second quantity is the phase constant of said microwave electromagnetic energy propagating between said spaced locations in the borehole.
Claim 6
Dependent Claim
33 words
Apparatus as defined by claim 1 wherein said borehole is filled with drilling mud and said third quantity is the conductivity of the mud filtrate in the formations invaded by said drilling mud.
Claim 7
Dependent Claim
33 words
Apparatus as defined by claim 4 wherein said borehole is filled with drilling mud and said third quantity is the conductivity of the mud filtrate in the formations invaded by said drilling mud.
Claim 8
Dependent Claim
18 words
Apparatus as defined by claim 1 wherein said microwave electromagnetic energy has a frequency of about 1.1 GHz.
Claim 9
Dependent Claim
18 words
Apparatus as defined by claim 4 wherein said microwave electromagnetic energy has a frequency of about 1.1 GHz.
Claim 10
Dependent Claim
18 words
Apparatus as defined by claim 6 wherein said microwave electromagnetic energy has a frequency of about 1.1 GHz.
Claim 11
Dependent Claim
116 words
Apparatus for determining the conductivity of the water in formations surrounding a borehole, comprising: means for deriving a first quantity representative of the attenuation of microwave electromagnetic energy propagating between spaced locations in the borehole; means for deriving a second quantity representative of the relative phase shift of microwave electromagnetic energy propagating between said spaced locations in the borehole; means for deriving a third quantity representative of the porosity of the formations surrounding said spaced locations; and means for generating a fourth quantity which is proportional to the product of said first and second quantities and inversely proportional to said third quantity; said fourth quantity being indicative of the conductivity of the water in said formations.
Claim 12
Dependent Claim
116 words
Apparatus for determining the conductivity of the water in formations surrounding a borehole, comprising: means for deriving a first quantity representative of the attenuation of microwave electromagnetic energy propagating between spaced locations in the borehole; means for deriving a second quantity representative of the relative phase shift of microwave electromagnetic energy propagating between said spaced locations in the borehole; means for deriving a third quantity representative of the porosity of the formations surrounding said spaced locations; and means for generating a fourth quantity which is proportional to the product of said first and second quantities and inversely proportional to said third quantity; said fourth quantity being indicative of the conductivity of the water in said formations.
Claim 13
Dependent Claim
19 words
Apparatus as defined by claim 10 wherein said third quantity is representative of the water-filled porosity of said formations.
Claim 14
Dependent Claim
35 words
Apparatus as defined by claim 10 wherein said third quantity is representative of the total porosity of said formations and said fourth quantity is indicative of the apparent conductivity of the water in said formations.
Claim 15
Dependent Claim
27 words
Apparatus as defined by claim 10 wherein said first quantity is the attenuation constant of said microwave electromagnetic energy propagating between said spaced locations in the borehole.
Claim 16
Dependent Claim
27 words
Apparatus as defined by claim 10 wherein said second quantity is the phase constant of said microwave electromagnetic energy propagating between said spaced locations in the borehole.
Claim 17
Dependent Claim
27 words
Apparatus as defined by claim 13 wherein said second quantity is the phase constant of said microwave electromagnetic energy propagating between said spaced locations in the borehole.
Claim 18
Dependent Claim
18 words
Apparatus as defined by claim 10 wherein said microwave electromagnetic energy has a frequency of about 1.1 GHz.
Claim 19
Dependent Claim
18 words
Apparatus as defined by claim 15 wherein said microwave electromagnetic energy has a frequency of about 1.1 GHz.
Claim 20
Dependent Claim
124 words
Apparatus for determining the water-filled porosity of formations surrounding a borehole, comprising: means for injecting microwave electromagnetic energy into the formations; means for measuring a first quantity representative of the attenuation of microwave electromagnetic energy propagating between spaced locations in the borehole; means for measuring a second quantity representative of the relative phase shift of microwave electromagnetic energy propagating between said spaced locations in the borehole; means for deriving a third quantity representative of the conductivity of the water in the formations surrounding said spaced locations; and means for generating a fourth quantity which is proportional to the product of said first and second quantities and inversely proportional to said third quantity; said fourth quantity being indicative of the water-filled porosity of said formations.
Claim 21
Dependent Claim
124 words
Apparatus for determining the water-filled porosity of formations surrounding a borehole, comprising: means for injecting microwave electromagnetic energy into the formations; means for measuring a first quantity representative of the attenuation of microwave electromagnetic energy propagating between spaced locations in the borehole; means for measuring a second quantity representative of the relative phase shift of microwave electromagnetic energy propagating between said spaced locations in the borehole; means for deriving a third quantity representative of the conductivity of the water in the formations surrounding said spaced locations; and means for generating a fourth quantity which is proportional to the product of said first and second quantities and inversely proportional to said third quantity; said fourth quantity being indicative of the water-filled porosity of said formations.
Claim 22
Dependent Claim
27 words
Apparatus as defined by claim 18 wherein said first quantity is the attenuation constant of said microwave electromagnetic energy propagating between said space locations in the borehole.
Claim 23
Dependent Claim
27 words
Apparatus as defined by claim 18 wherein said second quantity is the phase constant of said microwave electromagnetic energy propagating between said spaced locations in the borehole.
Claim 24
Dependent Claim
27 words
Apparatus as defined by claim 20 wherein said second quantity is the phase constant of said microwave electromagnetic energy propagating between said spaced locations in the borehole.
Claim 25
Dependent Claim
33 words
Apparatus as defined by claim 18 wherein said borehole is filled with drilling mud and said third quantity is the conductivity of the mud filtrate in the formations invaded by said drilling mud.
Claim 26
Dependent Claim
33 words
Apparatus as defined by claim 21 wherein said borehole is filled with drilling mud and said third quantity is the conductivity of the mud filtrate in the formations invaded by said drilling mud.
Claim 27
Dependent Claim
18 words
Apparatus as defined by claim 18 wherein said microwave electromagnetic energy has a frequency of about 1.1 GHz.
Claim 28
Dependent Claim
18 words
Apparatus as defined by claim 21 wherein said microwave electromagnetic energy has a frequency of about 1.1 GHz.
Claim 29
Dependent Claim
18 words
Apparatus as defined by claim 23 wherein said microwave electromagnetic energy has a frequency of about 1.1 GHz.
Claim 30
Dependent Claim
125 words
Apparatus for determining the conductivity of the water in formations surrounding a borehole, comprising: means for injecting microwave electromagnetic energy into the formations; means for measuring a first quantity representative of the attenuation of microwave electromagnetic energy propagating between spaced locations in the borehole; means for measuring a second quantity representative of the relative phase shift of microwave electromagnetic energy propagating between said spaced locations in the borehole; means for deriving a third quantity representative of the porosity of the formations surrounding said spaced locations; and means for generating a fourth quantity which is proportional to the product of said first and second quantities and inversely proportional to said third quantity; said fourth quantity being indicative of the conductivity of the water in said formations.
Claim 31
Dependent Claim
125 words
Apparatus for determining the conductivity of the water in formations surrounding a borehole, comprising: means for injecting microwave electromagnetic energy into the formations; means for measuring a first quantity representative of the attenuation of microwave electromagnetic energy propagating between spaced locations in the borehole; means for measuring a second quantity representative of the relative phase shift of microwave electromagnetic energy propagating between said spaced locations in the borehole; means for deriving a third quantity representative of the porosity of the formations surrounding said spaced locations; and means for generating a fourth quantity which is proportional to the product of said first and second quantities and inversely proportional to said third quantity; said fourth quantity being indicative of the conductivity of the water in said formations.
Claim 32
Dependent Claim
19 words
Apparatus as defined by claim 27 wherein said third quantity is representative of the water-filled porosity of said formations.
Claim 33
Dependent Claim
35 words
Apparatus as defined by claim 27 wherein said third quantity is representative of the total porosity of said formations and said fourth quantity is indicative of the apparent conductivity of the water in said formations.
Claim 34
Dependent Claim
27 words
Apparatus as defined by claim 27 wherein said first quantity is the attenuation constant of said microwave electromagnetic energy propagating between said spaced locations in the borehole.
Claim 35
Dependent Claim
27 words
Apparatus as defined by claim 27 wherein said second quantity is the phase constant of said microwave electromagnetic energy propagating between said spaced locations in the borehole.
Claim 36
Dependent Claim
27 words
Apparatus as defined by claim 30 wherein said second quantity is the phase constant of said microwave electromagnetic energy propagating between said spaced locations in the borehole.
Claim 37
Dependent Claim
16 words
Apparatus as defined by claim 27 wherein said microwave electromagnetic energy has a frequency of about
Claim 38
Dependent Claim
2 words
1 GHz.
Claim 39
Dependent Claim
2 words
1 GHz.
Claim 40
Dependent Claim
18 words
Apparatus as defined by claim 32 wherein said microwave electromagnetic energy has a frequency of about 1.1 GHz.
Claim 41
Independent Claim
111 words
A method for determining the water-filled porosity of formations surrounding a borehole, comprising the steps of: deriving a first quantity representative of the attenuation of microwave electromagnetic energy propagating between spaced locations in the borehole; deriving a second quantity representative of the relative phase shift of microwave electromagnetic energy propagating between said spaced locations in the borehole; deriving a third quantity representative of the conductivity of the water in the formations surrounding said spaced locations; and generating a fourth quantity which is proportional to the product of said first and second quantities and inversely proportional to said third quantity; said fourth quantity being indicative of the water-filled porosity of said formations.
Claim 42
Independent Claim
111 words
A method for determining the water-filled porosity of formations surrounding a borehole, comprising the steps of: deriving a first quantity representative of the attenuation of microwave electromagnetic energy propagating between spaced locations in the borehole; deriving a second quantity representative of the relative phase shift of microwave electromagnetic energy propagating between said spaced locations in the borehole; deriving a third quantity representative of the conductivity of the water in the formations surrounding said spaced locations; and generating a fourth quantity which is proportional to the product of said first and second quantities and inversely proportional to said third quantity; said fourth quantity being indicative of the water-filled porosity of said formations.
Claim 43
Dependent Claim
28 words
The method as defined by claim 35 wherein said first quantity is the attenuation constant of said microwave electromagnetic energy propagating between said spaced locations in the borehole.
Claim 44
Dependent Claim
28 words
The method as defined by claim 35 wherein said second quantity is the phase constant of said microwave electromagnetic energy propagating between said spaced locations in the borehole.
Claim 45
Dependent Claim
28 words
The method as defined by claim 36 wherein said second quantity is the phase constant of said microwave electromagnetic energy propagating between said spaced locations in the borehole.
Claim 46
Dependent Claim
34 words
The method as defined by claim 35 wherein said borehole is filled with drilling mud and said third quantity is the conductivity of the mud filtrate in the formations invaded by said drilling mud.
Claim 47
Dependent Claim
34 words
The method as defined by claim 38 wherein said borehole is filled with drilling mud and said third quantity is the conductivity of the mud filtrate in the formations invaded by said drilling mud.
Claim 48
Dependent Claim
19 words
The method as defined by claim 35 wherein said microwave electromagnetic energy has a frequency of about 1.1 GHz.
Claim 49
Dependent Claim
19 words
The method as defined by claim 38 wherein said microwave electromagnetic energy has a frequency of about 1.1 GHz.
Claim 50
Dependent Claim
19 words
The method as defined by claim 40 wherein said microwave electromagnetic energy has a frequency of about 1.1 GHz.
Claim 51
Independent Claim
112 words
A method for determining the conductivity of the water in formations surrounding a borehole, comprising the steps of: deriving a first quantity representative of the attenuation of microwave electromagnetic energy propagating between spaced locations in the borehole; deriving a second quantity representative of the relative phase shift of microwave electromagnetic energy propagating between said spaced locations in the borehole; deriving a third quantity representative of the porosity of the formations surrounding said spaced locations; and generating a fourth quantity which is proportional to the product of said first and second quantities and inversely proportional to said third quantity; said fourth quantity being indicative of the conductivity of the water in said formations.
Claim 52
Independent Claim
112 words
A method for determining the conductivity of the water in formations surrounding a borehole, comprising the steps of: deriving a first quantity representative of the attenuation of microwave electromagnetic energy propagating between spaced locations in the borehole; deriving a second quantity representative of the relative phase shift of microwave electromagnetic energy propagating between said spaced locations in the borehole; deriving a third quantity representative of the porosity of the formations surrounding said spaced locations; and generating a fourth quantity which is proportional to the product of said first and second quantities and inversely proportional to said third quantity; said fourth quantity being indicative of the conductivity of the water in said formations.
Claim 53
Dependent Claim
20 words
The method as defined by claim 44 wherein said third quantity is representative of the water-filled porosity of said formations.
Claim 54
Dependent Claim
36 words
The method as defined by claim 44 wherein said third quantity is representative of the total porosity of said formations and said fourth quantity is indicative of the apparent conductivity of the water in said formations.
Claim 55
Dependent Claim
28 words
The method as defined by claim 44 wherein said first quantity is the attenuation constant of said microwave electromagnetic energy propagating between said spaced locations in the borehole.
Claim 56
Dependent Claim
28 words
The method as defined by claim 44 wherein said second quantity is the phase constant of said microwave electromagnetic energy propagating between said spaced locations in the borehole.
Claim 57
Dependent Claim
28 words
The method as defined by claim 47 wherein said second quantity is the phase constant of said microwave electromagnetic energy propagating between said spaced locations in the borehole.
Claim 58
Dependent Claim
19 words
The method as defined by claim 44 wherein said microwave electromagnetic energy has a frequency of about 1.1 GHz.
Claim 59
Dependent Claim
19 words
The method as defined by claim 47 wherein said microwave electromagnetic energy has a frequency of about 1.1 GHz.
Claim 60
Independent Claim
118 words
A method for determining the water-filled porosity of formations surrounding a borehole, comprising the steps of: injecting microwave electromagnetic energy into the formations; measuring a first quantity representative of the attenuation of microwave electromagnetic energy propagating between spaced locations in the borehole; measuring a second quantity representative of the relative phase shift of microwave electromagnetic energy propagating between said spaced locations in the borehole; deriving a third quantity representative of the conductivity of the water in the formations surrounding said spaced locations; and generating a fourth quantity which is proportional to the product of said first and second quantities and inversely proportional to said third quantity; said fourth quantity being indicative of the water-filled porosity of said formations.
Claim 61
Independent Claim
118 words
A method for determining the water-filled porosity of formations surrounding a borehole, comprising the steps of: injecting microwave electromagnetic energy into the formations; measuring a first quantity representative of the attenuation of microwave electromagnetic energy propagating between spaced locations in the borehole; measuring a second quantity representative of the relative phase shift of microwave electromagnetic energy propagating between said spaced locations in the borehole; deriving a third quantity representative of the conductivity of the water in the formations surrounding said spaced locations; and generating a fourth quantity which is proportional to the product of said first and second quantities and inversely proportional to said third quantity; said fourth quantity being indicative of the water-filled porosity of said formations.
Claim 62
Dependent Claim
28 words
The method as defined by claim 52 wherein said first quantity is the attenuation constant of said microwave electromagnetic energy propagating between said spaced locations in the borehole.
Claim 63
Dependent Claim
28 words
The method as defined by claim 52 wherein said second quantity is the phase constant of said microwave electro-magnetic energy propagating between said spaced locations in the borehole.
Claim 64
Dependent Claim
34 words
The method as defined by claim 52 wherein said borehole is filled with drilling mud and said third quantity is the conductivity of the mud filtrate in the formations invaded by said drilling mud.
Claim 65
Dependent Claim
19 words
The method as defined by claim 52 wherein said microwave electromagnetic energy has a frequency of about 1.1 GHz.
Claim 66
Independent Claim
119 words
A method for determining the conductivity of the water in formations surrounding a borehole, comprising the steps of: injecting microwave electromagnetic energy into the formations; measuring a first quantity representative of the attenuation of microwave electromagnetic energy propagating between spaced locations in the borehole; measuring a second quantity representative of the relative phase shift of microwave electromagnetic energy propagating between said spaced locations in the borehole; deriving a third quantity representative of the porosity of the formations surrounding said spaced locations; and generating a fourth quantity which is proportional to the product of said first and second quantities and inversely proportional to said third quantity; said fourth quantity being indicative of the conductivity of the water in said formations.
Claim 67
Independent Claim
119 words
A method for determining the conductivity of the water in formations surrounding a borehole, comprising the steps of: injecting microwave electromagnetic energy into the formations; measuring a first quantity representative of the attenuation of microwave electromagnetic energy propagating between spaced locations in the borehole; measuring a second quantity representative of the relative phase shift of microwave electromagnetic energy propagating between said spaced locations in the borehole; deriving a third quantity representative of the porosity of the formations surrounding said spaced locations; and generating a fourth quantity which is proportional to the product of said first and second quantities and inversely proportional to said third quantity; said fourth quantity being indicative of the conductivity of the water in said formations.
Claim 68
Dependent Claim
20 words
The method as defined by claim 57 wherein said third quantity is representative of the water-filled porosity of said formations.
Claim 69
Dependent Claim
36 words
The method as defined by claim 57 wherein said third quantity is representative of the total porosity of said formations and said fourth quantity is indicative of the apparent conductivity of the water in said formations.
Claim 70
Dependent Claim
28 words
The method as defined by claim 57 wherein said first quantity is the attenuation constant of said microwave electromagnetic energy propagating between said spaced locations in the borehole.
Claim 71
Dependent Claim
28 words
The method as defined by claim 57 wherein said second quantity is the phase constant of said microwave electromagnetic energy propagating between said spaced locations in the borehole.
Claim 72
Dependent Claim
19 words
The method as defined by claim 57 wherein said microwave electromagnetic energy has a frequency of about 1.1 GHz.
Claim 73
Dependent Claim
79 words
Apparatus for determining the water-filled porosity of formations surrounding a particular location in a borehole, comprising: means for deriving the conductivity, σ EMP , of said formations as measured by a microwave electromagnetic propagation logging device; means for deriving the water conductivity, σ w , of said formations; and means for generating a quantity which is substantially proportional to the ratio of σ EMP to σ w , said quantity being indicative of the water-filled porosity of said formations.
Claim 74
Dependent Claim
79 words
Apparatus for determining the water-filled porosity of formations surrounding a particular location in a borehole, comprising: means for deriving the conductivity, σ EMP , of said formations as measured by a microwave electromagnetic propagation logging device; means for deriving the water conductivity, σ w , of said formations; and means for generating a quantity which is substantially proportional to the ratio of σ EMP to σ w , said quantity being indicative of the water-filled porosity of said formations.
Claim 75
Dependent Claim
35 words
Apparatus as defined by claim 63 wherein said borehole is filled with drilling mud and wherein σ w is derived from the conductivity of the mud filtrate in the formations invaded by said drilling mud.
Claim 76
Dependent Claim
83 words
Apparatus for determining the conductivity of the water in formations surrounding a particular location in a borehole, comprising: means for deriving the conductivity, σ EMP , of said formations as measured by a microwave electromagnetic propagation logging device; means for deriving the water-filled porosity, φ w , of said formations; and means for generating a quantity which is substantially proportional to the ratio of σ EMP to φ w , said quantity being indicative of the conductivity of the water in said formations.
Claim 77
Dependent Claim
83 words
Apparatus for determining the conductivity of the water in formations surrounding a particular location in a borehole, comprising: means for deriving the conductivity, σ EMP , of said formations as measured by a microwave electromagnetic propagation logging device; means for deriving the water-filled porosity, φ w , of said formations; and means for generating a quantity which is substantially proportional to the ratio of σ EMP to φ w , said quantity being indicative of the conductivity of the water in said formations.
Claim 78
Dependent Claim
84 words
Apparatus for determining the apparent conductivity of the water in formations surrounding a particular location in a borehole, comprising: means for deriving the conductivity, σ EMP , of said formations as measured by microwave electromagnetic propagation logging device; means for deriving the total porosity, φ t , of said formations; and means for generating a quantity which is substantially proportional to the ratio of σ EMP to φ t ; said quantity being indicative of the apparent conductivity of the water in said formations.
Claim 79
Dependent Claim
84 words
Apparatus for determining the apparent conductivity of the water in formations surrounding a particular location in a borehole, comprising: means for deriving the conductivity, σ EMP , of said formations as measured by microwave electromagnetic propagation logging device; means for deriving the total porosity, φ t , of said formations; and means for generating a quantity which is substantially proportional to the ratio of σ EMP to φ t ; said quantity being indicative of the apparent conductivity of the water in said formations.
Claim 80
Dependent Claim
98 words
Apparatus for determining the water saturation of formations surrounding a particular location in a borehole, comprising: means for deriving the conductivity, σ EMP , of said formations as measured by a microwave electromagnetic propagation logging device; means for deriving the water conductivity, σ w , of said formations; means for deriving the total porosity, σ t , of said formations; and means for generating a quantity which is substantially proportional to σ EMP and substantially inversely proportional to the product of σ w and φ t ; said quantity being indicative of the water saturation of said formations.
Claim 81
Dependent Claim
98 words
Apparatus for determining the water saturation of formations surrounding a particular location in a borehole, comprising: means for deriving the conductivity, σ EMP , of said formations as measured by a microwave electromagnetic propagation logging device; means for deriving the water conductivity, σ w , of said formations; means for deriving the total porosity, σ t , of said formations; and means for generating a quantity which is substantially proportional to σ EMP and substantially inversely proportional to the product of σ w and φ t ; said quantity being indicative of the water saturation of said formations.
Claim 82
Dependent Claim
35 words
Apparatus as defined by claim 67 wherein said borehole is filled with drilling mud and wherein σ w is derived from the conductivity of the mud filtrate in the formations invaded by said drilling mud.
References Cited (Backward Citations)
US3944910A
Cited
US4052662A
Cited
US4012689A
Cited
US4009434A
Cited
US3982176A
Cited
US4063151A
Cited
US4077003A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-06-11 | 1982-12-11 | 1983-06-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-06-11 | 1986-12-11 | 1987-06-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-06-11 | 1990-12-11 | 1991-06-12 | $7700.00 | Window Closed / Lapsed |