US3807501A - Producing oil or gas from formations adjacent salt domes - Google Patents

Abstract

Oil and gas are produced by drilling into a salt dome and washing out a cavity until a boundary line between the salt and the formation is reached. Petroleum then flows into the cavity facilitating production.

Description

United States Patent r191 Kurtis et al.

[451 Apr. 30, 1974 PRODUCING OIL OR GAS FROM FORMATIONS ADJACENT SALT DOMES Inventors: Soma Kurtis, Denver; James H.

Kennedy, Longmont, both of Colo.

Assignee: Marathon Oil Company, Findlay,

Ohio

Filed: Feb. 20, 1973 Appl. No.: 333,606

References Cited UNITED STATES PATENTS 3/1964 Blood 166/308 7/1967 Shock et al. 166/308 10/1967 Jacoby et al 299/4 2/1968 Knutson et al 166/308 1 1/ 1972 Jacoby 299/5 Primary ExaminerJames A. Leppink Attorney, Agent, or Firm-Richard C. Willson, Jr.; Joseph C. Herring; Jack L. Hummel ABSTRACT Oil and gas are produced by drilling into a salt dome and washing out a cavity until a boundary line between the salt and the formation is reached. Petroleum then flows into the cavity facilitating production.

3 Claims, 3 Drawing Figures NJECTED BRINE PRODUCING OIL OR GAS FROM F ORMATIONS ADJACENT SALT DOMES BACKGROUND OF THE INVENTION 1. Field of the Invention Y The present invention relates to the field of wells,

classified in Class 166 of the Classification System of the United States Patent Office.

2. Description of the Prior Art The inventors are aware of no related prior art.

SUMMARY OF THE INVENTION ings, and then proceeding to wash a cavity at the appro-, priate elevation corresponding to the formation, or formations, to be produced, until the boundary line between salt and the formation hasbeen reached. The shape of this cavity is controlled by use of a hydrocarbon or gas cap. The size of the cavity is controlled by the washing rate, brine concentration, and location of fresh water inlet and brine withdrawal.

One, or a multiplicity of cavities, can be developed at a time, given reasonablevertical and horizontal distances of the formations from the bore hole, or by the use of directional drilling in the salt. The present invention is a measured advantage over traditional processes since the size of the exposure to the formation can be increased at will, thus facilitating production. A large cross section of the producing formation can be exposed to the artificial cavity and the actual production casing will sit in clean and open surroundings. Since salt domes are formed by pushing up through surrounding layers, the cavity, when washed out to meet the hydrocarbon containing formation, will be high relative to the overall formation and will thus facilitate production from the formation. Additional brine or water may also be continuously recycled or otherwise introduced into the formation to maintain pressure and hydraulic displacement, thereby further facilitating production. In addition, multiple production casings may be introduced into the salt dome cavity to allow simultaneous production of separated gas and oil. Recycle of brine can eliminate disposal problems. The long settling time provided for oil within the cavity reduces need for settlers and treaters.

Utility of the Invention The present invention is particularly useful in the offshore production of oil and gas from a formation adjacent to a salt dome, but is also useful in on shore operations.

DESCRIPTION OF THE DRAWINGS FIG. 1 shows schematically, an oil and gas-containing formation adjacent to a salt dome. For clarity only a single horizon is shown.

FIG. 2 shows schematically, the cavity washing and production apparatus of the present invention after insertion into the salt dome and after washing of the cavity has been completed.

FIG. 3 shows schematically, the use of multiple production casings for the simultaneous production of separated gas and oil.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples:

EXAMPLE I In FIG. 2, an oil or gas-containing formation 10 is located adjacent to a salt dome 11. Production from the formation can be facilitated by drilling a hole into the salt dome down to the level of the gas/oil-containing formation. The hole is fitted with a casing 12, which is cemented into place and is equipped with washing and production strings 13 and 15. Casing 12 can serve itself as one of these conduits. A cavity 16 is then washed to desired shape and size under controlled conditions, by opening the valves 14 and injecting water through one casing 13 and removal through the other casing 15, or

vice versa, until the boundary line between the formation and the salt dome is reached. Upon completion, oil and gas then flows into the cavity and is removed through casing 12, 13, or 15.

EXAMPLE II In FIG. 3, a cavity is formed in the same manner as in FIG. 2 with the exception that two production casings are introduced into the salt dome cavity instead of one. One production casing 17 is placed toward the top of the cavity, the other production casing 18 is placed toward the bottom, thereby allowing the simultaneous production of separated gas and oil from the cavity.

Modifications of the Invention It should be understood that the invention is susceptible to a wide variety of modifications and variations which will be apparent to a person skilled in the art upon a reading of the present specification. All such variations and modifications are to be taken as being within the spirit of the claims appended hereto.

What is claimed is:

1. In a method for producing oil and gas, the improvement comprising in combination:

a. drilling at least one well into a salt dome communicating with a hydrocarbon-containing formation,

b. washing out a cavity in the salt dome until the boundary line between the salt and the hydrocarbon-containing formation is reached,

0. allowing hydrocarbons from the formation to enter into the created cavity,

d. withdrawing said hydrocarbons from said created cavity through said well.

2. A method of production of oil and gas according to claim 1 wherein a multiplicity of production casings are introduced into said salt dome cavity, said casings terminating at different heights to allow simultaneous production of separated gas and oil.

3. A method of production of oil and gas according to claim 1 wherein additional brine or water is continually introduced into the formation to maintain pressure and hydraulic displacement of the hydrocarbons from the formation.

Claims (3)

1. In a method for producing oil and gas, the improvement comprising in combination: a. drilling at least one well into a salt dome communicating with a hydrocarbon-containing formation, b. washing out a cavity in the salt dome until the boundary line between the salt and the hydrocarbon-containing formation is reached, c. allowing hydrocarbons from the formation to enter into the created cavity, d. withdrawing said hydrocarbons from said created cavity through said well.

2. A method of production of oil and gas according to claim 1 wherein a multiplicity of production casings are introduced into said salt dome cavity, said casings terminating at different heights to allow simultaneous production of separated gas and oil.

3. A method of production of oil and gas according to claim 1 wherein additional brine or water is continually introduced into the formation to maintain pressure and hydraulic displacement of the hydrocarbons from the formation.

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