US3815677A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for operating in wells
Assignee: ExxonMobil Upstream Research Co
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Filing: 1972-03-03
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Granted: 1974-06-11
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Expires: 1992-03-03
Abstract
Abstract Primary cement channels formed in the cement surrounding the tubing or pipe strings are located and, thereafter, remedial or repair operations are conducted. In multiple tubingless oil and/or gas wells cement channels formed in the cement are revealed by comparing neutron logs run in each pipe string of the multiply completed well. Comparing each of the neutron logs with an open hole sonic log aids in identifying the cement channels. A series of oriented density log scans of the well bore defines the location and areal extent of the cement channels in more detail. In both single and multiple completions an oriented density log, suitably calibrated to measure apparent density, may be used alone to locate and define channels in the cement. Log interpretations and field examples are presented.
Inventors
- 👤 E Pennebaker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 22:24
CPC Classifications
G; G01; G01V; G01V5/00; G01V5/04; G01V5/08; G01V5/10; E; E21; E21B; E21B47/00; E21B47/005; G01V11/00
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
97 words
A method for locating channels in cement resulting from the incomplete displacement of mud by said cement surrounding at least two pipe strings cemented in a well comprising: running a neutron log in each of said pipe strings while recording each of said logs at the same logging instrument sensitivity and while maintaining the same reference zero for each logging run for detecting said channels in said cement; and comParing said neutron logs with each other to locate departures of said neutron logs from each other, said departures in said logs indicating said channels in said cement.
Claim 2
Independent Claim
97 words
A method for locating channels in cement resulting from the incomplete displacement of mud by said cement surrounding at least two pipe strings cemented in a well comprising: running a neutron log in each of said pipe strings while recording each of said logs at the same logging instrument sensitivity and while maintaining the same reference zero for each logging run for detecting said channels in said cement; and comParing said neutron logs with each other to locate departures of said neutron logs from each other, said departures in said logs indicating said channels in said cement.
Claim 3
Dependent Claim
40 words
A method as recited in claim 1 including running a sonic log in open hole prior to cementing said pipe strings in said well; and comparing said neutron logs with said sonic log to aid in identifying said cement channels.
Claim 4
Independent Claim
86 words
A method for locating channels in cement surrounding at least two pipe strings cemented in a well comprising: running a neutron log in each of said pipe strings; comparing said neutron logs with each other to locate said channels in said cement, the differences in said logs indicating said channels in said cement: obtaining oriented density logs in each of said pipe strings at the same selected depths in said well; and comparing said density logs to determine the location of said channels in said cement.
Claim 5
Independent Claim
86 words
A method for locating channels in cement surrounding at least two pipe strings cemented in a well comprising: running a neutron log in each of said pipe strings; comparing said neutron logs with each other to locate said channels in said cement, the differences in said logs indicating said channels in said cement: obtaining oriented density logs in each of said pipe strings at the same selected depths in said well; and comparing said density logs to determine the location of said channels in said cement.
Claim 6
Dependent Claim
16 words
A method as recited in claim 3 including performing remedial operations including perforating into said channel.
Claim 7
Independent Claim
59 words
A method for operating in a well containing at least two pipe strings cemented therein comprising the steps of: running neutron depth correlation logs in each pipe string; superimposing said neutron logs to the same reference zero; and comparing said superimposed logs for departures of the neutron logs from each other to indicate location of channels in said cement.
Claim 8
Independent Claim
59 words
A method for operating in a well containing at least two pipe strings cemented therein comprising the steps of: running neutron depth correlation logs in each pipe string; superimposing said neutron logs to the same reference zero; and comparing said superimposed logs for departures of the neutron logs from each other to indicate location of channels in said cement.
Claim 9
Dependent Claim
60 words
A method as recited in claim 5, including: running a sonic log in open hole prior to running and cementing said pipe strings in said well; adjusting recording sensitivity of said neutron logs to the same relative sensitivity of said sonic logs; and comparing said superimposed neutron logs and said sonic logs to indicate location of channels in said cement.
Claim 10
Dependent Claim
34 words
A method as recited in claim 6 including making at least one oriented density scan in one of said pipe strings at a selected depth to confirm location of a channel in said cement.
Claim 11
Dependent Claim
35 words
A method as recited in claim 6 including making at least one oriented density scan in each of said pipe strings at the same selected depth to confirm location of a channel in said cement.
Claim 12
Dependent Claim
32 words
A method as recited in claim 8 including perforating from within one of said pipe strings and directing the perforating shots either into or away from a channel located in said cement.
Claim 13
Independent Claim
93 words
A method for operating in a well having at least two pipestrings cemented therein comprising the steps of: running neutron depth correlation logs in each pipe string; comparing said neutron logs for departures from each other to indicate location of channels in said cement; making oriented density scans in each of said pipe strings at the same depth, at which depth a channel in said cement has been indicated by departures in said neutron logs; and then lowering a directional perforating gun in one of said pipe strings and firing said perforating gun.
Claim 14
Independent Claim
93 words
A method for operating in a well having at least two pipestrings cemented therein comprising the steps of: running neutron depth correlation logs in each pipe string; comparing said neutron logs for departures from each other to indicate location of channels in said cement; making oriented density scans in each of said pipe strings at the same depth, at which depth a channel in said cement has been indicated by departures in said neutron logs; and then lowering a directional perforating gun in one of said pipe strings and firing said perforating gun.
Claim 15
Dependent Claim
46 words
A method as recited in claim 10 in which the channel in said cement is located between the wall of the borehole and one of said pipe strings and said perforating gun is lowered in said one pipe string and directed to fire into said channel.
Claim 16
Dependent Claim
47 words
A method as recited in claim 10 in which the channel in said cement is located between the borehole wall and one of said pipe strings and said perforating gun is lowered in the other pipe string and directed to fire away from said one pipe string.
Claim 17
Dependent Claim
52 words
A method as recited in claim 10 in which the channel in said cement is located between the wall of the wellbore and one of said pipe strings and the perforating gun is lowered in said other pipe string and directed to fire as close to said one pipe string as possible.
Claim 18
Independent Claim
63 words
A method for locating mud-filled channels in cement resulting from the incomplete displacement of mud by said cement, said channels surrounding at least one pipe string cemented in a well comprising: scanning the region surrounding said pipe string with a calibrated oriented denSity logging tool; and plotting said density scan, the density variations in said plot providing indications of channels in said cement.
Claim 19
Independent Claim
63 words
A method for locating mud-filled channels in cement resulting from the incomplete displacement of mud by said cement, said channels surrounding at least one pipe string cemented in a well comprising: scanning the region surrounding said pipe string with a calibrated oriented denSity logging tool; and plotting said density scan, the density variations in said plot providing indications of channels in said cement.
Claim 20
Dependent Claim
21 words
A method as recited in claim 14 including performing remedial operations to offset adverse effects of channels existing in said cement.
Claim 21
Independent Claim
96 words
A method for operating in a well in which at least two pipe strings are cemented therein comprising logging said pipe strings to locate channels in the cement surrounding said pipe strings; perforating into a channel in said cement in one pipe string at a selected depth; perforating into said channel in another pipe string at a different selected depth; and pumping cement into said channel to close said channel with the circulation flow path being through the perforations in said one pipe string, through said channel and out the perforations in said other pipe string.
Claim 22
Independent Claim
96 words
A method for operating in a well in which at least two pipe strings are cemented therein comprising logging said pipe strings to locate channels in the cement surrounding said pipe strings; perforating into a channel in said cement in one pipe string at a selected depth; perforating into said channel in another pipe string at a different selected depth; and pumping cement into said channel to close said channel with the circulation flow path being through the perforations in said one pipe string, through said channel and out the perforations in said other pipe string.
Claim 23
Dependent Claim
23 words
A method as recited in claim 16 in which water is circulated through said circulation flow path prior to circulating said cement therethrough.
Claim 24
Independent Claim
85 words
A method for locating mud-filled channels in cement resulting from incomplete displacement of mud by cement, said channels surrounding at least two pipe strings cemented in a well comprising: running a neutron log in each of said pipe strings while recording each of said logs at the same logging instrument sensitivity and while maintaining the same reference zero for each logging run in order to determine the location of said channels in said cement, the differences in said logs indicating said channels in said cement.
Claim 25
Independent Claim
85 words
A method for locating mud-filled channels in cement resulting from incomplete displacement of mud by cement, said channels surrounding at least two pipe strings cemented in a well comprising: running a neutron log in each of said pipe strings while recording each of said logs at the same logging instrument sensitivity and while maintaining the same reference zero for each logging run in order to determine the location of said channels in said cement, the differences in said logs indicating said channels in said cement.
Claim 26
Dependent Claim
18 words
A method as recited in claim 18 in which said logging instrument is centralized during each logging run.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-10 | 1977-12-10 | 1978-06-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-10 | 1981-12-10 | 1982-06-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-10 | 1985-12-10 | 1986-06-11 | $7700.00 | Window Closed / Lapsed |