Method of producing natural gas from a subterranean formation

• US 3,916,993 A
• Filed: 06/24/1974
• Issued: 11/04/1975
• Est. Priority Date: 06/24/1974
• Status: Expired due to Term

• Current Assignee: Marvin Laverne Katz
• Original Assignee: Marvin Laverne Katz
• Inventors: Katz, Marvin LaVerne
• Primary Examiner(s): Novosad, Stephen J.
• Application Number:
  US05/482,074
• Time in Patent Office: 498 Days
• Field of Search: 166/248,302,DIG.1,314,272
• US Class Current: 166/248
• CPC Class Codes: E21B 41/0099 specially adapted for drilling for or production of natural hydrate or clathrate gas reservoirs; Drilling through or monitoring of formations containing gas hydrates or clathrates
• CPC Class Codes: E21B 43/24 using heat, e.g. steam injection
• CPC Class Codes: E21B 43/2401 by means of electricity

Abstract

Method of producing gas from subterranean formations characterized by the steps of drilling and completing a plurality of at least two wells in a subterranean formation that contains at least some of the gas in the form of hydrate; melting the hydrates in the subterranean formation to free natural gas in situ; and producing to the surface natural gas freed by melting the hydrates. Melting of the hydrates includes the step of heating the subterranean formation and the hydrates by passage of a predetermined electrical current from one of the wells to the other. Preferably, the melting of the hydrates also includes the step of simultaneously producing gas to lower the pressure in the subterranean formation below what it would otherwise be and consequently lower the equilibrium temperature at which the hydrates can be melted. Also disclosed are specific apparatus elements and method steps employed in performing this invention in a hydrate-containing subterranean formation.

Claims

1. A METHOD OF PRODUCING GAS FROM AT LEAST ONE SUBTERRANEAN FORMATION COMPRISING THE STEPS OF:

A. DRILLING AT LEAST TWO SPACED APART WELLS FROM THE SURFACE OF THE EARTH INTO A SUBTERRANEAN FORMATION THAT CONTAINS AT LEAST SOME OF THE GAS IN THE FORM OF HYDRATE, B. MELTING SAID HYDRATE IN SAID SUBTERRANEAN FORMATION TO FREE NATURAL GAS IN SITU, SAID MELTING OF SAID HYDRATE INCLUDING THE STEP OF HEATING SAID SUBTERRANEAN FORMATION AND SAID HYDRATE, SAID HEATING BEING EFFECTED BY ELECTRICAL CONDUCTION COMPRISING PASSING FROM ONE OF SAID WELLS TO ANOTHER OF SAID WELLS AN ELECTRICAL CURRENT OF SUFFICIENT MAGNITUDE TO HEAT SAID FORMATION, AND C. PRODUCING GAS TO THE EARTH'"'"''"'"'S SURFACE.

2. The method of claim 1 wherein said melting of said hydrate includes the steps of substantially at the same time:

a. producing gas to the earth'"'"''"'"'s surface from said subterranean formation to lower the pressure in said subterranean formation below what it would normally be;

b. supplying heat to said formation and said hydrate via said electrical conduction to raise the temperature thereof to about the equilibrium temperature at which said hydrate melts; and

c. supplying by said electrical conduction sufficient heat to melt at least part of said hydrate and thereBy free some gas therefrom.

3. The method of claim 1 wherein said subterranean formation initially has essentially no free connate water and said electrical current initially is primarily conducted through adjacent conductive formations to supply heat thereto, said heat being conducted into said subterranean formation containing said hydrate to melt said hydrate and create some free connate water and render said subterranean formation more electrically conductive.

4. The method of claim 1 wherein said subterranean formation initially contains less than the amount of free gas considered to be commercially productive by conventional gas engineering standards.

5. The method of claim 1 wherein said subterranean formation has a low electrical conductivity and said electrical current is primarily conducted through adjacent conductive formations to supply heat thereto, said heat being conducted into said subterranean formation containing said hydrate.