A Review of Seismic-While-Drilling (SWD) Techniques: A Journey From 1986 to 2005

摘要

Seismic While Drilling (SWD) specifically encompasses theseismic techniques operated while the drillstring is lowered inthe borehole, during effective drilling, during maneuvers orwhile connecting drill pipes. This paper provides a State of theArt review on both old and newer SWD techniques used bythe Industry. In the past 21 years (1986-2006), the Drill-bitSWD technique practiced by the industry utilizes the acousticenergy radiated by the Tri-Cone bit to provide vital real timeinformation during drilling by providing time-to-depth andlook-ahead informationAnother emerging technique which is being used mainly bySchlumberger since 2000 is Vertical Seismic Profile WhileDrilling (VSP-WD), which consists in recording the seismicsignal generated by a surface seismic source on seismicsensors integrated inside the downhole Borehole Assembly(BHA). Two efficient wireline VSP which could beassimilated to SWD techniques and which are not be discussedin this paper are the technique of Tube Logging Conveying orTough Logging Condition (TLC), in particular the TLC-VSPand the standard wireline logging technique of IntermediateVSP.Recently introduced Swept impulse hydraulic tool iscapable of generating a broadband seismic signal at the bitwhile drilling. This tool overcomes the limitations of drill-bitseismic particularly in soft formations and in inclined holes byallowing seismic operations with PDC bit. Operatingprinciples, seismic processing and results of a fielddemonstration of seismic profiling while drilling in a shallowwell are described in this paper. The two major issues thatneed to be understood in order to make these seismicmeasurements with precision and reliability are also raised inthis paper.This paper aims to give a present day picture of the SWDtechniques. Data acquisition and sensor deployment strategiesare discussed in some detail. The benefits of SWD aredemonstrated by means of several field examples, showinghow the data can be used to reduce drilling costs, predictdrilling hazards and improve efficiency of drilling operationson a real time basis. The operating domain of SWD techniqueis identified along with the current limitations. Futuredevelopment directions are also proposed.