US 2001/0033164 A1 · Focused through-casing resistivity measurement

Abstract

A petroleum well (20) for producing petroleum products that incorporates a system adapted to controllably measure a formation resistivity using induction chokes (91-95) to form electrically isolated piping structure sections that can be used as the formation contact electrodes for time-varying current, and methods of producing petroleum products while measuring formation resistivity, are provided by the present invention. The system comprises a first induction choke (91), a second induction choke (92), and a device (50). The first induction choke (91) is located about a piping structure (30) of the well (20). The second induction choke (92) is also located about the piping structure (30) of the well (20), but the first induction choke (91) is distally spaced from the second induction choke (92). The device (50) is located outside of the piping structure (30) and comprises two terminals (71, 72). A first of the terminals (71) extending from the device (50) is electrically connected to the piping structure (30) on one side (81) of the first induction choke (91). A second of the terminals (72) extending from the device (50) is electrically connected to the piping structure (30) on another side (82) of the first induction choke (91), between the first and second induction chokes (91, 92), such that the downhole device (50) is electrically connected across an outside of the first induction choke (91). The system can further comprise other induction chokes (93-95), other terminals (97-99) extending from the device (50), a current sensor (114), a surface power source (54), a power transformer (104), a communications transformer (106), a surface modem (56), a downhole modem (102), a direct current power supply (101), and/or a power amplifier (110, 112). The piping structure can comprise at least a portion of a well casing (30), such that the well casing (30) acts as an electrode for making formation resistivity measurements due to the induction chokes (91-95).

Claims40

Dependent claims

A system for measuring a formation resistivity in a petroleum well, comprising:

a first induction choke located about a piping structure of said well;
a second induction choke located about said piping structure of said well, wherein said first induction choke is distally spaced from said second induction choke;
a device located outside of said piping structure and comprising two terminals,
a first of said terminals extending from said device being electrically connected to said piping structure on one side of said first induction choke, and
a second of said terminals extending from said device being electrically connected to said piping structure on another side of said first induction choke between said first and second induction chokes, such that said downhole device is electrically connected across an outside of said first induction choke.

2 more elements

A petroleum well for producing petroleum products, comprising:

a piping structure of said well extending within a formation;
a first induction choke located downhole about said piping structure;
a second induction choke located downhole about said piping structure, wherein said second induction choke is distally spaced from said first induction choke;
a third induction choke located downhole about said piping structure, wherein said third induction choke is distally spaced from said first and second induction chokes;
a downhole device comprising:
a first device terminal electrically connected to said piping structure on a one side of said first induction choke,
a second device terminal electrically connected to said piping structure on another side of said first induction choke between said first and second induction chokes, such that said downhole device is electrically connected across an outside of said first induction choke,
a first electrode terminal electrically connected to said piping structure between said second and third induction chokes, and
a second electrode terminal electrically connected to said piping structure such that said third induction choke is located between the electrical connection location on said piping structure of said first and second electrode terminals.

6 more elements

A petroleum well for producing petroleum products, comprising:

a well casing extending into a formation;
a power source being adapted to output a time-varying current, and said power source having two power source terminals, a first of said power source terminals being electrically connected to said casing at the surface, and a second of said power source terminals being electrically connected to said formation at the surface;
a surface modem having two surface modem terminals, a first of said surface modem terminals being electrically connected to said casing at the surface, and a second of said surface modem terminals being electrically connected to said formation at the surface;
a first induction choke located downhole about said casing;
a second induction choke located downhole about said casing, wherein said second induction choke is distally spaced from said first induction choke, and wherein said second induction choke is located farther downhole than said first induction choke;
a third induction choke located downhole about said casing, wherein said third induction choke is distally spaced from said first and second induction chokes, and wherein said third induction choke is located farther downhole than said second induction choke;
a downhole device comprising:
a first device terminal electrically connected to said casing on a source-side of said first induction choke,
a second device terminal electrically connected to said casing on another side of said first induction choke between said first and second induction chokes, such that said downhole device is electrically connected across an outside of said first induction choke,
a first electrode terminal electrically connected to said casing between said second and third induction chokes,
a second electrode terminal electrically connected to said casing such that said third induction choke is located between the electrical connection location on said casing of said first and second electrode terminals,
a downhole modem being communicably coupled to said device terminals, such that said downhole modem can send and receive communication signals along said casing via said device terminals, and
a current sensor adapted to measure current flowing through at least one of said first and second electrode terminals, and said current sensor being communicably coupled to said downhole modem, such that said downhole modem is adapted to receive measurement data from said current sensor and transmit said measurement data to said surface modem via said casing.

10 more elements

A method of producing petroleum products from a petroleum well, comprising the steps of:

providing a piping structure of said well;
providing a system for measuring formation resistivity in said well, said system comprising:
a first induction choke located about said piping structure,
a second induction choke located about said piping structure, wherein said first induction choke is distally spaced from said second induction choke, and
a device located outside of said piping structure and comprising two terminals, a first of said terminals extending from said device being electrically connected to said piping structure on one side of said first induction choke, and a second of said terminals extending from said device being electrically connected to said piping structure on another side of said first induction choke between said first and second induction chokes, such that said downhole device is electrically connected across an outside of said first induction choke;
and
measuring the resistivity of a formation with said system while producing petroleum products with said well.

4 more elements

Dependencies are inferred from the claim text.

Focused through-casing resistivity measurement

Life of this patent

Focused through-casing resistivity measurement

Life of this patent

Abstract

Claims40