US 6,681,859 B2 · Downhole oil and gas well heating system and method

Abstract

A down hole heating system for use with oil and gas wells which exhibit less than optimally achievable flow rates because of high oil viscosity and/or blockage by paraffin (or similar meltable petroleum byproducts). The heating unit the present invention includes shielding to prevent physical damage and shortages to electrical connections within the heating unit while down hole (a previously unrecognized source of system failures in prior art systems). The over-all heating system also includes heat retaining components to focus and contain heat in the production zone to promote flow to, and not just within, the production tubing.

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Drawings

Claims3

Dependent claims

An apparatus for heating a segment of oil and gas well bores and surrounding strata comprising:

an electrical resistance heating rod;
electrical cable for carrying electrical current from an electrical current source outside of the well bore to said electrical resistance heating rod when positioned inside of said well bore;
an electrical lead having first and second lead ends, said first lead end being connected to said electrical cable, and said second lead end being attached to said heating rod;
a protective block in which is embedded the respective portions of said electrical lead and said heating rod as connect one to the other, said protective block being constructed of a moldable material which, when cured, is substantially impervious to pressure and chemical permeation and oil and gas well bore bottom pressures and environments;
a metallic encasement member encasing said protective block and sealingly welded to form a substantially impervious enclosure with said block and said embedded portion of said heating rod therein, except that said metallic encasement admits said electrical lead there into for attachment with said electrical lead;
a perforated production tubing segment, a proximal perforated production tubing segment end of which is reversibly engageable to a distal terminus of oil or gas well production tubing string and a distal perforated production tubing segment end of which is engageable with said metallic encasement member;
and
a heating rod support frame which extends from said metallic encasement means opposite its engagement with said perforated production tubing segment and in which a portion of said heating rod is supported.

5 more elements

A method for enhancing production from an oil and gas well comprising the steps of:

selecting an apparatus for heating a segment of oil and gas well bores and surrounding strata, said apparatus comprising:
an electrical resistance heating rod;
electrical cable for carrying electrical current from an electrical current source outside of the well bore to said electrical resistance heating rod when positioned inside of said well bore;
an electrical lead having first and second lead ends, said first lead end being connected to said electrical cable, and said second lead end being attached to said heating rod;
a protective block in which is embedded the respective portions of said electrical lead and said heating rod as connect one to the other, said protective block being constructed of a moldable material which, when cured, is substantially impervious to pressure and chemical permeation and oil and gas well bore bottom pressures and environments;
a metallic encasement member encasing said protective block and sealingly welded to form a substantially impervious enclosure with said block and said embedded portion of said heating rod therein, except that said metallic encasement admits said electrical lead there into for attachment with said electrical lead;
a perforated production tubing segment, a proximal perforated production tubing segment end of which is reversibly engageable to a distal terminus of oil or gas well production tubing string and a distal perforated production tubing segment end of which is engageable with said metallic encasement member;
and
a heating rod support frame which extends from said metallic encasement means opposite its engagement with said perforated production tubing segment and in which a portion of said heating rod is supported;
positioning said heating rod adjacent to a production zone in an oil or gas well bore, production from which zone is believed to be impeded by viscous materials;
and
attaching an electrical current source to said electrical cable;
and
actuating said electrical current source to heat said heating rod to heat and thereby heat said visous materials in said production zone for reducing viscosity of said viscous materials for, in turn, producing said viscous materials.

11 more elements

Dependencies are inferred from the claim text.

Description1,914 words

Summary924 words

#1. Field of the Invention

#The present invention relates to systems and methods for producing or delivering heat at or near the down hole end of production tubing of a producing oil or gas well for improving production therefrom.

#2. Background Information

Brief description of the drawings2 figures

#FIG. 1 is an elevational view of a producing oil well with the components of the present down hole heating system installed.

#FIG. 2 is an elevational, sagittal cross section view of the heating unit of the present invention.

Detailed description951 words

#Referring to FIG. 1, the complete down hole heating system of the present invention is generally identified by the reference numeral 10. System 10 includes production tubing 12 (the length of which depends, of course, on the depth of the well), a heat insulating packer 14, perforated tubing 16, a stainless steel tubing collar 18, and a heating unit 20.

#Referring in combination to FIGS. 1 and 2, heating unit 20 includes electrical resistance type heater rods 26, the electrical current for which is supplied by cables 22 which run down the exterior of production tubing 12 and connect to leads 24 at the upper end of heating unit 20.

#Heat insulating packer 14 and stainless steel collars 18 are includes in their stated form for “containing” the heat from heating unit 20 within the desired zone to the greatest practical degree. Were it not for these components, the heat from heating unit 20 would (like the heat from conventional down hole heater units) convect and conduct upward in the well bore and through the production tubing, thereby essentially directing much of the heat away from the area which it is most needed—the production zone.

Facts

Application

10/037,754Filed 22 Oct 2001

Published

US 2003/0075330 A124 Apr 2003

Granted

27 Jan 2004

Term ended

14 Feb 2022

Estimated · how

20 years from earliest known nonprovisional domestic filing plus recorded patent term adjustment, including 115 days of adjustment. Maintenance-fee lapses, terminal disclaimers and statutory extensions have not been checked. The continuity chain may be incomplete; this is not an enforceability determination.

Classification2 codes

E21B 36/04
Heating, cooling or insulating arrangements for boreholes or wells, e.g. for use in permafrost zones: using electrical heaters
E21B
Earth or rock drilling

Downhole oil and gas well heating system and method

Life of this patent

Downhole oil and gas well heating system and method

Life of this patent

Life of this patent

Abstract

Drawings

Drawings

Claims3

Description1,914 words

Drawings

Classification2 codes

Life of this patent

Description1,914 words