US3811509A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Well drilling method
Assignee: Cities Service Oil Co
•
Filing: 1972-08-31
•
Granted: 1974-05-21
•
Expires: 1992-08-31
Abstract
Abstract A method is disclosed for reducing drilling torque and preventing sticking of drilling pipe when a permeable formation such as sand is penetrated during the drilling of a well. The reduction in drilling pipe torque which results is particularly advantageous in the drilling of deviated holes. A slug of gel slurry is deposited in the hole after the permeable formation has been entered, and the slug is then squeezed at a calculated pressure which causes liquid from the slurry to migrate from the hole into the formation. However, the bulk of the gel is filtered out by the formation at or near the wall of the hole, and is thus laid down as a packed cake with the formation itself serving as the matrix on which the cake forms. The squeeze is carried out at a pressure which is substantially greater than the hydrostatic pressure at the point being squeezed and at least equals the greatest pressure which is expected to exist later on at the side of the squeeze after drilling has proceeded to a greater depth. The resulting gel cake is dense enough to seal the wall of the hole and thereby substantially negates loss of fluid from the drilling mud into the formation. Preventing loss of fluid into the formation by means of the gel cake also provides the additional advantage of curtailing inward growth of the hole wall by build-up of drill cuttings thereon. Circulation of drilling mud remains adequate and provides good lubrication between the pipe and the wall of the hole even during sharply deviated drilling. As drilling continues, the integrity of the gel cake is not detrimentally affected by further elevation of pressure where the cake resides in the hole since the squeeze pressure for the formation thereof was at least as great as will later exist at that point from use of higher density drilling mud, greater casing pressure, etc.
Inventors
- 👤 F Priebe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 13:25
CPC Classifications
E; E21; E21B; E21B21/00; E21B21/003; E21B33/00; E21B33/10; E21B33/13; E21B33/138
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
25 words
A process as in claim 1 wherein the observed total reduction in mud volume is within the range of about 20 to about 100 barrels.
Claim 2
Dependent Claim
214 words
In an open hole well drilling operation wherein a drill pipe having a drilling bit at the lower end is lubricated by circulation of drilling mud from the bottom to the top of the hole during drilling, the method of treating the hole and thus reducing drilling torque requirements and preventing sticking of the drilling pipe when drilling through a permeable formation, said method comprising spotting a slug of gel slurry in the hole and then squeezing the slug of gel slurry by pumping a drilling fluid into the hole above the spotted slug at a pressure which is at least about as great as the maximum pressure which will exist in the section of the hole thus treated during subsequent drilling of the hole to a greater depth until a significant reduction in the volume of the drilling mud is observed wherein: a. the slug of gel is discharged from the drilling bit and is thus spotted in the hole, b. the drilling bit is in a raised position above the slug after the slug has been spotted in the hole, and c. drilling mud is then circulated and the pumping pressure thereof is increased and maintained at the increased pressure until a significant reduction in volume of the drilling mud is observed.
Claim 3
Dependent Claim
160 words
In an open hole drilling operation wherein a drill pipe having a drilling bit at the lower end is lubricated by a circulation of drilling mud from the bottom To the top of the hole during drilling, the method of treating the hole and thus reducing drilling torque requirements and preventing sticking of the drilling pipe when drilling through a permeable formation, said method comprising squeezing a slug of gel slurry against a section of the hole wall adjacent to the permeable formation, thereafter drilling beyond the section of the formation thus treated, thereafter squeezing a second slug of gel slurry into at least one other section of the formation at a different interval of depth, and thereafter drilling beyond the section of the formation thus treated, wherein the second slug of gel slurry which is squeezed into the formation subsequent to squeezing of a previous slug is squeezed at a lower pressure than was exerted on the previous slug.
Claim 4
Dependent Claim
246 words
In an open and deviated hole rotary drilling operation wherein a drill pipe having a drilling bit at the lower end is lubricated by circulation of a drilling mud from the bottom to the top of the hole during drilling and wherein the hole deviates or is not vertical through a permeable formation; the process of treating the hole and thus reducing drilling torque requirements and preventing sticking of the drill pipe when the drill pipe is rotated within the permeable formation or withdrawn through the permeable formation; wherein the process of treatment comprises: a. interrupting rotary drilling with the drill pipe and bit, b. placing a slug of gel slurry into contact with the permeable formation, c. placing a fluid into the drill hole above the slug of gel slurry, d. applying sufficient pressure to the fluid above the gel slurry such that the gel slurry exerts a pressure against the permeable formation at least as great as the maximum pressure which will at any time be exerted by any fluid during the drilling of the well, but any such pressure of the drilling fluid and the gel slurry against any formation that is contacted by either such fluid or gel slurry must be less than the fracturing pressure of that formation, e. maintaining the pressure on the fluid of (d) until the pressure can be substantially maintained without substantial additional application of pressure, and f. resuming rotary drilling with the drill pipe and bit.
Claim 5
Dependent Claim
14 words
The process of claim 5 wherein the fluid of (c) is a gel slurry.
Claim 6
Dependent Claim
15 words
The process of claim 5 wherein the gel slurry is free from a propping agent.
Claim 7
Dependent Claim
78 words
The process of claim 5 wherein the pressure of (c) is maintained on the fluid by: aa. allowing the pressure to drop by a measurable increment to a lower pressure, bb. thereupon pumping additional of the fluid into the drill hole to restore the original pressure, and cc. repeating steps (aa) and (bb) until not more than five barrels of fluid are required to restore the pressure of (c) after not less than 15 minutes after step (aa).
Claim 8
Dependent Claim
15 words
The process of claim 8 wherein the gel slurry is free from a propping agent.
Claim 9
Dependent Claim
23 words
The process of claim 8 wherein the permeable formation comprises sand and wherein the drill hole is drilled from an offshore drilling platform.
Claim 10
Dependent Claim
47 words
The process of claim 8 wherein, subsequent to treatment additional drill hole is drilled and the steps of (a), (b), (c), (d), and (e) are repeated to treat the drill hole not previously treated, but at a pressure lower than the pressure applied in the first treatment.
Claim 11
Dependent Claim
207 words
The process of claim 5, wherein, following step (a): w. the gel slurry of step (b) is placed into contact with the permeable formation by injecting sufficient fresh gel slurry into the bottom of the drill hole through the drill pipe and drilling bit such that the gel slurry will extend to the top of a permeable formation to be treated when the drill pipe and drill bit is withdrawn to above the top of the permeable formation to be treated, x. the drill pipe and drill bit is withdrawn to above the top of the formation to be treated, y. the fluid of step (c) is the drilling mud and is placed into the drill hole abOve the slug of gel slurry by upward movement of the gel slurry injected in step (x), and z. the supplying and maintaining the pressure on the fluid of steps (d) and (e) is by circulating the drilling mud above the gel slurry through the drill pipe and drilling bit under back pressure at incrementally increasing pressures until the pressure of steps (d) and (e) is reached and not more than five barrels of fluid is lost in less than 15 minutes at the pressure of steps (d) and (e).
Claim 12
Dependent Claim
15 words
The process of claim 12 wherein the gel slurry is free from a propping agent.
Claim 13
Dependent Claim
23 words
The process of claim 12 wherein the permeable formation comprises sand and wherein the drill hole is drilled from an offshore drilling platform.
Claim 14
Dependent Claim
47 words
The process of claim 12 wherein, subsequent to treatment additional drill hole is drilled and the steps of (a), (b), (c), (d), and (e) are repeated to treat the drill hole not previously treated, but at a pressure lower than the pressure applied in the first treatment.
Claim 15
Dependent Claim
23 words
The process of claim 5 wherein the permeable formation comprises sand and wherein the drill hole is drilled from an offshore drilling platform.
Claim 16
Dependent Claim
47 words
The process of claim 5 wherein, subsequent to treatment additional drill hole is drilled and the steps of (a), (b), (c), (d), and (e) are repeated to treat the drill hole not previously treated, but at a pressure lower than the pressure applied in the first treatment.
Claim 17
Dependent Claim
25 words
The process of claim 5 wherein the gel slurry comprises a gel agent selected from bentonite, diatomaceous earth, drilling mud polymers, starch and mixtures thereof.
Claim 18
Dependent Claim
15 words
The process of of claim 18 wherein the gel slurry comprises bentonite dispersed in water.
Claim 19
Dependent Claim
29 words
The process of claim 19 wherein the content of gel agent in the slurry is within the range of about 20 to about 40 pounds per barrel of slurry.
Claim 20
Dependent Claim
14 words
The process of claim 20 wherein the gel slurry further comprises a plugging agent.
Claim 21
Dependent Claim
26 words
The process of claim 21 wherein the content of plugging agent is within the range of about 5 to about 10 pounds per barrel of slurry.
Claim 22
Dependent Claim
12 words
The process of claim 22 wherein the plugging agent is pulverized nutshells.
Claim 23
Dependent Claim
30 words
The process of claim 5 wherein the pressure is maintained until a cake of gel forms on the wall of the drill hole in the region of the permeable formation.
Claim 24
Dependent Claim
22 words
The process of claim 5 wherein the slug of gel slurry is spotted over a substantially elongated interval of the drill hole.
Claim 25
Dependent Claim
29 words
The process of claim 5 wherein at least 2 slugs of gel slurry are spotted at different intervals of depth in the hole and the intervals overlap one another.
References Cited (Backward Citations)
US2943680A
Cited
US3028913A
Cited
US2990016A
Cited
US3208523A
Cited
US3228469A
Cited
US3496902A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-05-20 | 1977-11-19 | 1978-05-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-20 | 1981-11-19 | 1982-05-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-20 | 1985-11-19 | 1986-05-21 | $7700.00 | Window Closed / Lapsed |