EP 0572055 B1 19970326 - Method for detecting drillstring washouts
Title (en)
Method for detecting drillstring washouts
Title (de)
Verfahren zur Feststellung von Lecks in Bohrgestängen
Title (fr)
Procédé de détection de fuites dans une colonne de forage
Publication
Application
Priority
GB 9211048 A 19920523
Abstract (en)
[origin: EP0572055A1] A method of detecting a drillstring washout during an operation involving the addition or removal of pipes from the drillstring such as back reaming, comprising: a) performing at least one such operation and determining by hydraulic coefficient k from the relationship P = kQ<a>,where Q is the flow rate, P is the standpipe pressure and a is the flow exponent, from each pipe added or removed, so as to derive a series of values indicating the development of k for said operations, and b) on subsequent operations, determining k and comparing the determined values with the series obtained previously, a drillstring washout being detected when the determined value of k falls substantially below the corresponding value of k in the series. The trend in the development of k can be calculated and used to determine if an anomaly exists in the determined value of k. <IMAGE>
IPC 1-7
IPC 8 full level
E21B 21/08 (2006.01); E21B 44/00 (2006.01)
CPC (source: EP US)
E21B 21/08 (2013.01 - EP US); E21B 44/00 (2013.01 - EP)
Designated contracting state (EPC)
DE DK FR NL
DOCDB simple family (publication)
EP 0572055 A1 19931201; EP 0572055 B1 19970326; CA 2095583 A1 19931124; CA 2095583 C 20040810; DE 69309149 D1 19970430; GB 2267300 A 19931201; GB 2267300 B 19950802; GB 9211048 D0 19920708; NO 304710 B1 19990201; NO 931863 D0 19930521; NO 931863 L 19931124
DOCDB simple family (application)
EP 93201208 A 19930427; CA 2095583 A 19930505; DE 69309149 T 19930427; GB 9211048 A 19920523; NO 931863 A 19930521