CA1040094A - Well stimulation - Google Patents
Well stimulationInfo
- Publication number
- CA1040094A CA1040094A CA258,396A CA258396A CA1040094A CA 1040094 A CA1040094 A CA 1040094A CA 258396 A CA258396 A CA 258396A CA 1040094 A CA1040094 A CA 1040094A
- Authority
- CA
- Canada
- Prior art keywords
- agent
- propping agent
- consolidating
- propping
- fracturing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/25—Methods for stimulating production
- E21B43/26—Methods for stimulating production by forming crevices or fractures
- E21B43/261—Separate steps of (1) cementing, plugging or consolidating and (2) fracturing or attacking the formation
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
- C09K8/60—Compositions for stimulating production by acting on the underground formation
- C09K8/62—Compositions for forming crevices or fractures
Abstract
Abstract of the Disclosure A method for stimulating an unconsolidated formation in a well wherein the unconsolidated formation is fractured in the unconsolidated state, i.e., without having had any prior consolidation treatment practiced thereon, the fracturing step employing a propping agent, and con-solidating essentially only a portion of said propping agent in the fractures created by the fracturing step.
The unconsolidated formation remains essentially unconsoli-dated after the method of this invention has been completed.
The unconsolidated formation remains essentially unconsoli-dated after the method of this invention has been completed.
Description
1 Background of the Invention Heretofore it has been taught that in the stimu-lation of an unconsolidated formation in a well the formation should first be consolidated in its entirety for several feet radially around the wellbore and, after this consolidation procedure has been completed, the formation should next be fractured employing a "tackifying" agent in the fracture fluid.
When this process is completed, the formation, as well as all the propping agents in the fractures, have been completely consolidated. This procedure is fully and completely dis-closed in U. S. Patent 3,815,680, issued June 11, 1974.
Summary of the Invention According to this invention an unconsolidated or incompetent formation in a wellbore is stimulated essentially without any consolidation of the formation itself. The method o this invention consolidates only a portion of the propping agent in the fracture itself, the portion of the propping agent consolidated being that portion closest to the wellbore. Thus, in accordance with this methbd and contrary 20 to the prior art, even a substantial portion of the propping agent in the fracture is not consolidated. The consolidation of the propping agent in the fractures in accordance with this invention can be carried out during the latter stages of the fracturing process itself or.even after the fracturing process has been completed.
Accordingly, it is an object of this invention to provide a new and improved method for stimulating an uncon-solidated formation in a wellbore. It is another object by the new and improved method for fracturing an unconsolidated ~4~3(~9114~
1 formation. It is another object to provide a new and im-proved method ~or a combination fracturing and consolidating procedure. Other aspects, objec-ts and advantages of -this in-vention will be apparent to those skilled in the art from this disclosure and the appended claims.
Detailed Description of the Invention ., . . .. . . .. . .. . .. __ _ . _ - The drawing shows a cross section of a wellbore in which the method of this invention is carried out.
More specifically, the drawing shows the earth's surface 1 having a wellbore 2 therein, wellbore 2 having a fracture 3 therein. Conduit means 4 such as drill pipe, tubing and the like is provided for communicating between the earth's surface and the vicinity of the wellbore ad~acent fracture 3.
Packoff means 5 is provided in the annulus between the outside of conduit 1~ and the wall of the wellbore so that fluid under pressure lntro~uced into the wellbore in the vicinity of fracture 3 wlll pass Lnto the fràcture and not back to the earth's surface in such annulus.
~'ormation 6 represents an unconsolidated formation whlch in:itially does not contain any frac-tures like fracture 3.
In accordance with this invention, formation 6 is not treated to consolidate that formation as required by the prior art, but rather is fractured in its original unconsolidated state by passing a conventional fracture fluid through conduit 4 in the direction of arrow 10 so that the fracturing fluid leaving the conduit 4 at its lower end 11 is under sufficient pressure to create a fracture or crack 3 in formation 6.
As is conventional in well fracturing procedures, at least part of the fracturing fluid introduced into the wellbore contains a propping agent. The propping agent is a 39~
1 solid.particulate material that flows into the fracture itself so that the propping agent keeps the fracture open when the pressure on the fracturing fluid in the wellbore is removed and the fracture tends to close again due to its overburden pressure. Any suitable propping agent can be used, for example, gravel, sand, combinations thereof, and the like.
Ordinarily, numerous fractures are formed in a formation when subjected to a fracturing process, but only a single fracture 3 is shown in the drawing for simplicity's sake. However, this invention is applicable to all fractures formed in the uncon-solidated formation 6 whatever their orientation or configura-tion or member may be.
To help stabilize propping agent 12 in fracture 3 so that it will not tend to flow back into the wellbore to any substantla.l. extent, i.n accordance with this invention, a po.rtion of propplng agent 12, which portion is nearest the wellbore wall 2~ l.e., portion 13 in the drawing) is con-solldated thereby leaving formation 6 and the remainder of propp:Lng agent 12 essentially in their original unconsolidated state.
In accordance with this invention, all propping agent 12 in fracture 3 is not consolidated. Only a portion is consolidated. Thus, in the drawing the portion of fracture 3 furthest from the wellbore, i.e., portion 14, is unconsolidated like formation 6 The amount of propping agent consolidated in any given fracture will vary widely depending on the propping agent, the consolida-ting agent, the characteristics of the formation, and the like so that it is impossible to quantify the amount 3 of propping agent that should be consolidated for all cases.
~C~4~4 1 However, a substantial amount, but less than all, of the propping agent in each fracture is consolidated in accordance with this invention. The portion that is consolidated is that portion closest to the wellbore, and generally covers less than 25~ of the propping agent in each frac-ture.
Consolidation of the propping agent can be carried out after the fracturing and propping procedure has been com-pleted. Thus, after propping agent 12 has been inJected into fracture 3, consolidating agent can be injected into conduit L~
and which upon leaving lower end 11 will pass as indicated by arrow 15 preferentially into the more permeable (porous) fracture 3 and penetrate along part of the length o~ fracture 3.
The desired distance o~ penetration can be controlled to be less than the full length of the fracture, for example, the distance represented by zone 13. Thereafter, the con-solldation step is terminated.
Alternatlvely, the consolidation procedure can be carrLed out dur-lng a la~ter part of the ~racturing process.
Tha~ Ls to say the ~ractur:lng ~luid will initially contain no consolldating agent but near the end of -the fracturing process, consolidating agent can be incorporated into the latter part o:~ the portion o~ the fracturing fluid which contains propping agent. This way the consolidating agent passes into fracture 3 in zone 13 along with the latter part o~ the propping agent 12 to give the sarne ultimate results shown in the drawing, i.e., a zone of propping agent near the wellbore that is essentially consolidated while the remainder of the propping agent in the ~ract~re is unconsolidated.
Any con~entional fracturing fluid and consolidating age~rlt can be employed, all being well-lcnown in the art. The g,4 1 "tackifying" agents of U. S. Patent 3,~15,680 can be employed as consolidating agents. In like manner the consolidating materials disclosed in U. S. Patent 3,285,339, issued November 15, 1966, the disclosure of which is incorporated herein by reference, can also be employed as consolidating agents in this invention.
Generally, consolidating agents which are essentially insoluble in the fracturing fluid are employed, although consolidating agents that could be precipitated from the fracturing agent in situ in the fracture could be employed in the method of this invention. It is also preferred, although not required, that the consolidating agent have an affinity for the propping agent.
Generally, the consolidating agent can be selected ~rom a group o~ materials comprising thermosetting resins, thermoplastlc polymers, rubber, wax, simple syrups, combina-tLons of two or more thereof, and the like. Particularly sùltable materials include, wlthout llmitation, phenol formaldehyde resin, ~uran resin, cellulose resin, styrene-butadiene rubber, reclaimed rubber, modified resins, residualhydrocarbon oi:Ls, heavy hydrocarbon oils, and the like.
In some situations wherein a consolidating agent is employed in conjunction with the latter part of the ~rac-turing fluid, the consolidating agent can constitute from about 2 to about 20 weight percent of the total weight of the propping agent which is mixed with the consolidating agent.
Example An unconsolidated formation 6 composed essentially of sand is fractured using a hydrocarbon (diesel oil) 3 fracturing fluid containing gravel as the propping agent.
1 Fracturing fluid is injected into the wellbore until, the pressure exceeds the overburden'pressure above formation 6 at which time fractures such as fracture 3 open and the gravel propping agent flows thereinto. After about three-fourths of the length of such fractures are filled with gravel, consolidating agent is injected along with the last of the propping agent that is to be injected so that a mixture of' consolidating agent and gravel fills up the remaining one-quarter length of the fracture nearest the wellbore. After about six hours, the consolidating agen-t in the fracture has set up so that all the propping agentg both consolidated and unconsolidated, in fracture 3 will resist back flow from fracture 3 into wellbore 2 during the producing life of the well.
Note that formation 6 was not consolidated before frac.turlng and remains essentially unconsolidated except,for poss:lble trace amounts of consolidating agent that may leak ~'rom zone 13 o.~' rracture 3 lnto 1mmediately adjacent areas of the .~ormatlon.
Reasonable variations and modifications are ' possible wLthin the scope of this disclosure without departing f'rom the spirit and scope of this invention.
'
When this process is completed, the formation, as well as all the propping agents in the fractures, have been completely consolidated. This procedure is fully and completely dis-closed in U. S. Patent 3,815,680, issued June 11, 1974.
Summary of the Invention According to this invention an unconsolidated or incompetent formation in a wellbore is stimulated essentially without any consolidation of the formation itself. The method o this invention consolidates only a portion of the propping agent in the fracture itself, the portion of the propping agent consolidated being that portion closest to the wellbore. Thus, in accordance with this methbd and contrary 20 to the prior art, even a substantial portion of the propping agent in the fracture is not consolidated. The consolidation of the propping agent in the fractures in accordance with this invention can be carried out during the latter stages of the fracturing process itself or.even after the fracturing process has been completed.
Accordingly, it is an object of this invention to provide a new and improved method for stimulating an uncon-solidated formation in a wellbore. It is another object by the new and improved method for fracturing an unconsolidated ~4~3(~9114~
1 formation. It is another object to provide a new and im-proved method ~or a combination fracturing and consolidating procedure. Other aspects, objec-ts and advantages of -this in-vention will be apparent to those skilled in the art from this disclosure and the appended claims.
Detailed Description of the Invention ., . . .. . . .. . .. . .. __ _ . _ - The drawing shows a cross section of a wellbore in which the method of this invention is carried out.
More specifically, the drawing shows the earth's surface 1 having a wellbore 2 therein, wellbore 2 having a fracture 3 therein. Conduit means 4 such as drill pipe, tubing and the like is provided for communicating between the earth's surface and the vicinity of the wellbore ad~acent fracture 3.
Packoff means 5 is provided in the annulus between the outside of conduit 1~ and the wall of the wellbore so that fluid under pressure lntro~uced into the wellbore in the vicinity of fracture 3 wlll pass Lnto the fràcture and not back to the earth's surface in such annulus.
~'ormation 6 represents an unconsolidated formation whlch in:itially does not contain any frac-tures like fracture 3.
In accordance with this invention, formation 6 is not treated to consolidate that formation as required by the prior art, but rather is fractured in its original unconsolidated state by passing a conventional fracture fluid through conduit 4 in the direction of arrow 10 so that the fracturing fluid leaving the conduit 4 at its lower end 11 is under sufficient pressure to create a fracture or crack 3 in formation 6.
As is conventional in well fracturing procedures, at least part of the fracturing fluid introduced into the wellbore contains a propping agent. The propping agent is a 39~
1 solid.particulate material that flows into the fracture itself so that the propping agent keeps the fracture open when the pressure on the fracturing fluid in the wellbore is removed and the fracture tends to close again due to its overburden pressure. Any suitable propping agent can be used, for example, gravel, sand, combinations thereof, and the like.
Ordinarily, numerous fractures are formed in a formation when subjected to a fracturing process, but only a single fracture 3 is shown in the drawing for simplicity's sake. However, this invention is applicable to all fractures formed in the uncon-solidated formation 6 whatever their orientation or configura-tion or member may be.
To help stabilize propping agent 12 in fracture 3 so that it will not tend to flow back into the wellbore to any substantla.l. extent, i.n accordance with this invention, a po.rtion of propplng agent 12, which portion is nearest the wellbore wall 2~ l.e., portion 13 in the drawing) is con-solldated thereby leaving formation 6 and the remainder of propp:Lng agent 12 essentially in their original unconsolidated state.
In accordance with this invention, all propping agent 12 in fracture 3 is not consolidated. Only a portion is consolidated. Thus, in the drawing the portion of fracture 3 furthest from the wellbore, i.e., portion 14, is unconsolidated like formation 6 The amount of propping agent consolidated in any given fracture will vary widely depending on the propping agent, the consolida-ting agent, the characteristics of the formation, and the like so that it is impossible to quantify the amount 3 of propping agent that should be consolidated for all cases.
~C~4~4 1 However, a substantial amount, but less than all, of the propping agent in each fracture is consolidated in accordance with this invention. The portion that is consolidated is that portion closest to the wellbore, and generally covers less than 25~ of the propping agent in each frac-ture.
Consolidation of the propping agent can be carried out after the fracturing and propping procedure has been com-pleted. Thus, after propping agent 12 has been inJected into fracture 3, consolidating agent can be injected into conduit L~
and which upon leaving lower end 11 will pass as indicated by arrow 15 preferentially into the more permeable (porous) fracture 3 and penetrate along part of the length o~ fracture 3.
The desired distance o~ penetration can be controlled to be less than the full length of the fracture, for example, the distance represented by zone 13. Thereafter, the con-solldation step is terminated.
Alternatlvely, the consolidation procedure can be carrLed out dur-lng a la~ter part of the ~racturing process.
Tha~ Ls to say the ~ractur:lng ~luid will initially contain no consolldating agent but near the end of -the fracturing process, consolidating agent can be incorporated into the latter part o:~ the portion o~ the fracturing fluid which contains propping agent. This way the consolidating agent passes into fracture 3 in zone 13 along with the latter part o~ the propping agent 12 to give the sarne ultimate results shown in the drawing, i.e., a zone of propping agent near the wellbore that is essentially consolidated while the remainder of the propping agent in the ~ract~re is unconsolidated.
Any con~entional fracturing fluid and consolidating age~rlt can be employed, all being well-lcnown in the art. The g,4 1 "tackifying" agents of U. S. Patent 3,~15,680 can be employed as consolidating agents. In like manner the consolidating materials disclosed in U. S. Patent 3,285,339, issued November 15, 1966, the disclosure of which is incorporated herein by reference, can also be employed as consolidating agents in this invention.
Generally, consolidating agents which are essentially insoluble in the fracturing fluid are employed, although consolidating agents that could be precipitated from the fracturing agent in situ in the fracture could be employed in the method of this invention. It is also preferred, although not required, that the consolidating agent have an affinity for the propping agent.
Generally, the consolidating agent can be selected ~rom a group o~ materials comprising thermosetting resins, thermoplastlc polymers, rubber, wax, simple syrups, combina-tLons of two or more thereof, and the like. Particularly sùltable materials include, wlthout llmitation, phenol formaldehyde resin, ~uran resin, cellulose resin, styrene-butadiene rubber, reclaimed rubber, modified resins, residualhydrocarbon oi:Ls, heavy hydrocarbon oils, and the like.
In some situations wherein a consolidating agent is employed in conjunction with the latter part of the ~rac-turing fluid, the consolidating agent can constitute from about 2 to about 20 weight percent of the total weight of the propping agent which is mixed with the consolidating agent.
Example An unconsolidated formation 6 composed essentially of sand is fractured using a hydrocarbon (diesel oil) 3 fracturing fluid containing gravel as the propping agent.
1 Fracturing fluid is injected into the wellbore until, the pressure exceeds the overburden'pressure above formation 6 at which time fractures such as fracture 3 open and the gravel propping agent flows thereinto. After about three-fourths of the length of such fractures are filled with gravel, consolidating agent is injected along with the last of the propping agent that is to be injected so that a mixture of' consolidating agent and gravel fills up the remaining one-quarter length of the fracture nearest the wellbore. After about six hours, the consolidating agen-t in the fracture has set up so that all the propping agentg both consolidated and unconsolidated, in fracture 3 will resist back flow from fracture 3 into wellbore 2 during the producing life of the well.
Note that formation 6 was not consolidated before frac.turlng and remains essentially unconsolidated except,for poss:lble trace amounts of consolidating agent that may leak ~'rom zone 13 o.~' rracture 3 lnto 1mmediately adjacent areas of the .~ormatlon.
Reasonable variations and modifications are ' possible wLthin the scope of this disclosure without departing f'rom the spirit and scope of this invention.
'
Claims (9)
1. A method for stimulating an unconsolidated forma-tion in a well comprising fracturing said formation without any prior consolidation treatment of said formation, the fracturing fluid used in said fracturing step at least initially containing no consolidating agent, at least a portion of said fracturing fluid containing at least one propping agent, and consolidating only a portion of said propping agent in the fractures created by said fracturing step by maintaining the portion of said fracturing fluid which contains propping agent initially devoid of consolidating agent and incorporating at least one consolidating agent into the latter part of the portion of said fracturing fluid which contains propping agent, said consolidating agent being incorporated in a sufficient portion of said latter part of fracturing fluid essentially to consolidate said propping agent in the fractures near said wellbore, whereby said unconsolidated formation remains essentially unconsolidated.
2. The method of claim 1 wherein a substantial amount, but less than all, of the propping agent in each fracture is consolidated, the portion consolidated being that portion closest to the wellbore.
3. The method of claim 2 wherein less than 25%
of the propping agent in each fracture is consolidated.
of the propping agent in each fracture is consolidated.
4. The method of claim 1 wherein said consolidation of propping agent is carried out after said fracturing and propping procedure is completed.
5. The method of claim 1 wherein said consolidat-ing agent is essentially insoluble in said fracturing fluid and has an affinity for said propping agent.
6. The method of claim 1 wherein said consolidat-ing agent is selected from the group consisting of thermo-setting resin, thermoplastic polymer, rubber, wax, simple syrup and combinations of two or more thereof.
7. The method of claim 1 wherein said consolidat-ing agent is selected from the group consisting of phenol formaldehyde resin, furan resin, cellulose resin, styrene-butadiene rubber, reclaimed rubber, modified resins, residual hydrocarbon oils and heavy hydrocarbon oils.
8. The method of claim 1 wherein said propping agent is sand, gravel, or a combination thereof.
9. The method of claim 1 wherein said consolidating agent is added to a latter part of said fracturing fluid and said consolidating agent constitutes from about 2 weight percent to about 20 weight of the total weight of propping agent to which said consolidating agent is added.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US05/626,245 US4010802A (en) | 1975-10-28 | 1975-10-28 | Well stimulation |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1040094A true CA1040094A (en) | 1978-10-10 |
Family
ID=24509553
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA258,396A Expired CA1040094A (en) | 1975-10-28 | 1976-08-04 | Well stimulation |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US4010802A (en) |
| CA (1) | CA1040094A (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5431225A (en) * | 1994-09-21 | 1995-07-11 | Halliburton Company | Sand control well completion methods for poorly consolidated formations |
| US5787986A (en) * | 1995-03-29 | 1998-08-04 | Halliburton Energy Services, Inc. | Control of particulate flowback in subterranean wells |
| US5775425A (en) * | 1995-03-29 | 1998-07-07 | Halliburton Energy Services, Inc. | Control of fine particulate flowback in subterranean wells |
| US5501274A (en) * | 1995-03-29 | 1996-03-26 | Halliburton Company | Control of particulate flowback in subterranean wells |
| US5960880A (en) * | 1996-08-27 | 1999-10-05 | Halliburton Energy Services, Inc. | Unconsolidated formation stimulation with sand filtration |
| US5791415A (en) * | 1997-03-13 | 1998-08-11 | Halliburton Energy Services, Inc. | Stimulating wells in unconsolidated formations |
| US7845409B2 (en) * | 2005-12-28 | 2010-12-07 | 3M Innovative Properties Company | Low density proppant particles and use thereof |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3695355A (en) * | 1970-01-16 | 1972-10-03 | Exxon Production Research Co | Gravel pack method |
| US3815680A (en) * | 1971-04-09 | 1974-06-11 | Continental Oil Co | Method for fracturing and propping unconsolidated and dilatant subterranean formations |
| US3757862A (en) * | 1972-08-11 | 1973-09-11 | Atlantic Richfield Co | Multilayer propping of fractures |
| US3800847A (en) * | 1973-07-20 | 1974-04-02 | J Rike | Sand consolidation by adhesive agent and particulate pack |
| US3929191A (en) * | 1974-08-15 | 1975-12-30 | Exxon Production Research Co | Method for treating subterranean formations |
-
1975
- 1975-10-28 US US05/626,245 patent/US4010802A/en not_active Expired - Lifetime
-
1976
- 1976-08-04 CA CA258,396A patent/CA1040094A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| US4010802A (en) | 1977-03-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US3815680A (en) | Method for fracturing and propping unconsolidated and dilatant subterranean formations | |
| US3336980A (en) | Sand control in wells | |
| AU662497B2 (en) | Method for controlling solids accompanying hydrocarbon production | |
| CA1152888A (en) | Sand control method employing special hydraulic fracturing technique | |
| US4127173A (en) | Method of gravel packing a well | |
| US4875525A (en) | Consolidated proppant pack for producing formations | |
| US5960880A (en) | Unconsolidated formation stimulation with sand filtration | |
| US3709298A (en) | Sand pack-aided formation sand consolidation | |
| EP0864726B1 (en) | Stimulating wells in unconsolidated formations | |
| US3983941A (en) | Well completion technique for sand control | |
| US5199492A (en) | Sand consolidation methods | |
| US3987850A (en) | Well completion method for controlling sand production | |
| US20020070020A1 (en) | Completing wells in unconsolidated formations | |
| USRE36466E (en) | Sand control without requiring a gravel pack screen | |
| US6273192B1 (en) | Method for strengthening a subterranean formation | |
| US3621915A (en) | Method for forming a consolidated gravel pack in a well borehole | |
| EP0721050A2 (en) | Sand control without requiring a gravel pack screen | |
| CA1040094A (en) | Well stimulation | |
| US3696867A (en) | Resin consolidated sandpack | |
| US4034811A (en) | Method for sealing a permeable subterranean formation | |
| US6155348A (en) | Stimulating unconsolidated producing zones in wells | |
| US3695355A (en) | Gravel pack method | |
| US10641071B2 (en) | Consolidated material to equalize fluid flow into a wellbore | |
| US3088520A (en) | Producing fluid from an unconsolidated subterranean reservoir | |
| US5165475A (en) | Method for the control of solids accomanying hydrocarbon production from subterranean formations |