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Title: Borehole failure resulting from formation integrity (leak-off) testing in upper marine sediments offshore

Conference ·
OSTI ID:357830
;  [1]
  1. Louisiana State Univ., Baton Rouge, LA (United States). Petroleum Engineering Dept.

This paper presents results of potential loss of external integrity around casing shoe resulting from leak-off testing (LOT) in upper marine sediments (UMS). Three types of possible failures from LOTs are considered. It is proved that vertical fracture is the most unlikely failure for most UMS. Horizontal fracture can be formed in the plastic zone at a wellbore pressure less than overburden pressure, but it cannot extend beyond the plastic zone until the wellbore pressure exceeds the overburden pressure. An annular channel between cemented casing and rock is the other fracture way in UMS even though the cementing job is perfect. Fracture can be distinguished from LOT curve. Increasing the contact force between cemented casing and rock, such as using expanding cement, will prevent the formation of a harmful channel.

OSTI ID:
357830
Report Number(s):
CONF-980213-; TRN: IM9932%%175
Resource Relation:
Conference: 1998 energy sources technology conference, Houston, TX (United States), Feb 1998; Other Information: PBD: 1998; Related Information: Is Part Of Proceedings of the 1998 ASME energy sources technology conference (ETCE`98); PB: [1170] p.
Country of Publication:
United States
Language:
English