Method for controlling a producing zone of a well in a geological formation

• US 6,866,098 B1
• Filed: 10/30/2002
• Issued: 03/15/2005
• Est. Priority Date: 02/21/2001
• Status: Expired due to Fees

• Current Assignee: The United States Of America As Represented By The National Aeronautics And Space Administration
• Original Assignee: The United States Of America As Represented By The National Aeronautics And Space Administration
• Inventors: Amini, B. Jon, Byerly, Kent A., Arndt, G. Dickey, Carl, James R.
• Primary Examiner(s): BATES, ZAKIYA W
• Application Number:
  US10/288,799
• Time in Patent Office: 867 Days
• Field of Search: 166/249, 166/250.01, 166/250.03, 166/250.15, 166/250.16, 166/252.4, 175/50, 342/22
• US Class Current: 166/249
• CPC Class Codes: G01S 13/325 using transmission of coded signals, e.g. P.S.K. signals
• CPC Class Codes: G01S 13/885 for ground probing prospecting or detecting using electromagnetic waves G01V3/12
• CPC Class Codes: G01V 3/12 operating with electromagnetic waves operating with millimetre waves G01V8/005
• CPC Class Codes: Y02A 90/30 Assessment of water resources

Abstract

System and methods for transmitting and receiving electromagnetic pulses through a geological formation. A preferably programmable transmitter having an all-digital portion in a preferred embodiment may be operated at frequencies below 1 MHz without loss of target resolution by transmitting and over sampling received long PN codes. A gated and stored portion of the received signal may be correlated with the PN code to determine distances of interfaces within the geological formation, such as the distance of a water interfaces from a wellbore. The received signal is oversampled preferably at rates such as five to fifty times as high as a carrier frequency. In one method of the invention, an oil well with multiple production zones may be kept in production by detecting an approaching water front in one of the production zones and shutting down that particular production zone thereby permitting the remaining production zones to continue operating.

Claims

1. A method for controlling a producing zone in a geological formation of a well having a plurality of producing zones, comprising:

transmitting a plurality of pulses into said geological formation;

receiving one or more reflections from said plurality of pulses when a waterfront is approaching within said producing zone;

detecting said waterfront from said one or more reflections; and

closing down said producing zone.

2. The method of claim 1, further comprising modulating a carrier signal to produce said plurality of pulses at a carrier frequency.

3. The method of claim 1, further comprising selectively controlling said carrier frequency at frequencies below 1 MHz.

4. The method of claim 1, further comprising selecting said reflections from said waterfront by providing a delay.

5. The method of claim 1, further comprising correlating said reflections with a stored signal containing a sequence for said plurality of pulses.

6. The method of claim 1, further comprising positioning an antenna within said well for said transmitting of said plurality of pulses into said geological formation.

7. The method of claim 1, further comprising providing a non-ferrous wellbore tubular to permit said transmitting of said plurality of pulses into said geological formation from within said well.