Look Ahead Advance Formation Evaluation Tool

Abstract

Evaluation which investigates the formation or formation characteristic in advance of the drill-bit before the formation or formation feature of interest has been penetrated or traversed. A closed-loop real-time look-ahead formation evaluation tool which provides acoustic and/or electro-magnetic formation data beyond the drill-bit using a novel angular sensor orientation which also allows for optimized signal propagation and signal returns according to an axial plane and vertical depth.

I claim: 
     
         1 . A look ahead tool comprising a tool body with means for attaching the tool body directly or indirectly to a drill-bit permitting rotation and axial movement along a well passage comprising:
 at least one acoustic source, receiver or transducer directed outwardly of the tool body, wherein the acoustic source and receiver or transducer is received within the tool body in a purpose built housing and oriented at an angle that is within the range of about 0.25° to about 89.5° relative to a longitudinal axis of the tool body to send and receive acoustic waves.   
     
     
         2 . A tool as claimed in  1  wherein an electro-magnetic source and said receiver or integrated transducer send and receive electro-magnetic data to and from the formation ahead of a drill-bit, and said data is processed by said microprocessor. 
     
     
         3 . A tool as claimed in  claim 1  wherein said tool body is configured with a rotary steerable system with a wall contact member at an end. 
     
     
         4 . A tool as claimed in  claim 1  wherein the said tool body includes a downhole wall contact member to form one of a roller reamer, an expandable underreamer, a pressure containment device, and a measurement device. 
     
     
         5 . A tool as claimed in  claim 2 , further comprising communication means for communicating said acoustic data or electro-magnetic and control signals between said tool and a surface decoder. 
     
     
         6 . A tool as claimed in  claim 1  further comprising: a first tool body to investigate a formation ahead of the drill-bit, and a second tool body to stabilize the tool during drilling. 
     
     
         7 . A tool as claimed in  claim 4  further comprising: a microprocessor controller adapted to receive acoustic data and detect a formation or formation feature and control an underreamer in response to acquired acoustic data. 
     
     
         8 . A tool as claimed in  claim 2  further comprising: a microprocessor controller adapted to receive data based on electro-magnetic data and detect a formation or formation feature and control an underreamer.
 A tool as claimed in  claim 1 , wherein said tool body is provided with an internal keyway leading to a source of power communications inside or outside the tool and capable of sending an alert signal to a user. 
 
     
     
         9 . A tool as claimed in  claim 1  further comprising: a plurality of said sources, said receivers or said transducers directed outwardly of said tool body or separately housed and placed along the drill-string in separate tool bodies. 
     
     
         10 . A tool as claimed in  claim 9  wherein the means for attaching the tool body to the support comprises a screw thread on the tool body to engage the drill bit, a directional control system, drill collar, underreamer or roller reamer. 
     
     
         11 . A tool as  claim 9  further comprising: communication means for communicating said acoustic data or electromagnetic and control signals with the microprocessor, and a surface decoder and user interface in real-time to optimize performance. 
     
     
         12 . A tool as claimed in  claim 1  wherein one of another acoustic source and another receiver or transducer is housed in a drill-bit to look ahead and evaluate a formation as yet undrilled. 
     
     
         13 . A tool as  claim 2  further comprising: communication means for communicating said acoustic data or electromagnetic and control signals with the microprocessor, and a surface decoder and user interface in real-time to optimize performance. 
     
     
         14 . A tool as claimed in  claim 1  wherein said source waves are propagated into the housing, into the wellbore, the near and far formation and can be detected as said received acoustic waves. 
     
     
         15 . A tool as claimed in  claim 2  wherein said source waves are propagated into the housing, into the wellbore, the near and far formation and can be detected as said received acoustic waves. 
     
     
         16 . A tool as claimed in  claim 1  wherein the source is located in the drill bit. 
     
     
         17 . A tool as claimed in  claim 4  further comprising: a plurality of said sources, said receivers or said transducers directed outwardly of said tool body or separately housed and placed along the drill-string in separate tool bodies. 
     
     
         18 . A tool as claimed in  claim 1  further comprising: a plurality of said wall contact members separately housed and placed along the drill-string in separate tool bodies.