Wells – Processes – Cementing – plugging or consolidating
Patent
1984-10-31
1986-11-04
Guynn, Herbert B.
Wells
Processes
Cementing, plugging or consolidating
166281, 175 72, 252 8551, E21B 33138
Patent
active
046205969
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The invention relates to a method of completing a well after it has been drilled, or of servicing a well by workover operations. More particularly, it relates to a method of completing and workover of a well by contacting a subterranean formation which produces hydrocarbons with aqueous well completion and workover fluids to maintain the hydrocarbons in the producing well formation or formations under control while at the same time inhibiting or preventing damage to the producing formation or formations during the completion or workover operations.
BACKGROUND OF THE INVENTION
After a well has been drilled into the earth's surface, one or more subterranean producing formations may be encountered. It is then desirable to complete the well so as to obtain the maximum hydrocarbon production from such subterranean producing formations, and to complete such well in a manner so that the pressure in the subterranean producing formations is controlled during completion operations, while bridging or sealing off the producing formation to inhibit damage thereto and to minimize fluid loss into the formation which might inhibit or in some cases substantially reduce the production of hydrocarbons from the subterranean producing formation.
Also, it is desirable or necessary after a period of time to perform workover or other service operations on a previously drilled well, and during such workover or service operations, it is desirable to control the pressure in the subterranean producing formation or formations while at the same time bridging or sealing off the formations in a manner so as to minimize particle invasion and fluid loss into the producing formation or formations and thereby reduce if not substantially eliminate damage to the formations.
In addition to the necessary required density characteristics of a workover and completion fluid, it is desirable to seal off or temporarily plug the face of the subterranean producing formation or formations in the well bore so that during the completion and workover operation fluid and solids in the fluid are not lost to the producing formation which might cause damage thereto.
Heretofore various types of workover and completion fluids with components therein of a particle size to bridge and seal off the producing formations have been employed. Workover and completion fluids should have fluid loss (filter loss) control to prevent substantial fluid invasion of the formation. This is achieved by a combination of a fluid loss control agent and a bridging agent.
Various types of soluble or degradable bridging materials are available commercially, and the choice between them depends on reservoir conditions and type of operation. Sized particles of oil-soluble resins or waxes have been used as bridging agents for oil reservoirs. Such particles must be removed by dissolving them in oil when used in dry gas reservoirs or water injection wells. Calcium carbonates were the first degradable bridging particles to be used in workover and completion fluids. On completion of the job, they are removed with acid if necessary. Acidization is an extra operation and additional expense, except in carbonate reservoirs that must be acidized. Furthermore, the acid may dissolve iron on the way down to the acidizing zone and introduce iron compounds into the formation. Then, when the acid is spent, the pH rises, iron hydroxide is precipitated, and formation damage results. All of the carbonate particles may not be contacted by the acid. To avoid this problem, alternate slugs of acid and diverting agent are necessary.
I have found that workover and completion fluids can be formulated utilizing sized particles of a water soluble salt as a bridging agent suspended in a saturated brine solution in which the salt is substantially insoluble. See U.S. Pat. Nos. 4,175,042; 4,186,803; and 4,369,843.
The treating fluid comprises a saturated aqueous saline solution with at least one water soluble salt which is substantially insoluble in the saturated saline solution, the water solu
REFERENCES:
patent: 3675717 (1972-07-01), Goins et al.
patent: 4046197 (1977-09-01), Gruesbeck et al.
patent: 4175042 (1979-11-01), Mondshine
patent: 4186803 (1980-02-01), Mondshine
patent: 4369843 (1983-01-01), Mondshine
Ellis et al, World Oil, Nov., 1981, pp. 75-81.
Mondshine, "Completion Fluid uses Salt for Bridging, Weighting", Oil and Gas Journal, Aug. 22, 1977.
Patton et al, "Well Completions and Workovers: Part 7-Considerations for Selecting Well Servicing Fluids", Petroleum Engineer International, 1980, pp. 50, 52, 56.
Gray et al., Composition and Properties of Oil Well Drilling Fluids, 4th edition, 1980, pp. 497-512, 522-525.
Guynn Herbert B.
House Roy F.
Texas United Chemical Corp.
LandOfFree
Well drilling, workover and completion fluids does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Well drilling, workover and completion fluids, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Well drilling, workover and completion fluids will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-693390