New ideas for shallow gas well control

Journal Article · Sat Jun 01 04:00:00 EDT 1996 · World Oil

OSTI ID:390104

Bourgoyne, A T; Kelly, O A; Sandoz, C L ^[1]

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1. Louisiana State Univ., Baton Rouge, LA (United States)

Flow from an unexpected shallow gas sand is one of the most difficult well control problems faced by oil and gas well operators during drilling operations. Current well control practice for bottom-supported marine rigs usually calls for shutting in the well when a kick is detected, if sufficient casing has been set to keep any flow underground. However, when shallow gas is encountered, casing may not be set deep enough to keep the underground flow from broaching to surface near the platform foundations. Once the flow reaches surface, craters are sometimes formed which can lead to loss of the rig and associated marine structures. This short article overviews an ongoing study by Louisiana State University of the breakdown resistance of shallow marine sediments, using leak-off test data and geotechnical reports provided by Unocal. Such study is important for improving the characterization of shallow marine sediments to allow more reliable shallow casing designs, as the authors will conclude. This study has already proven that sediment failure mechanisms that lead to cratering have been poorly understood. In addition, there has been considerable uncertainty as to the best choices of well design parameters and well control contingency plans that will minimize risks associated with a shallow gas flow.

• OSTI ID: 390104
• Journal Information: World Oil, Journal Name: World Oil Journal Issue: 6 Vol. 217; ISSN 0043-8790; ISSN WOOIAS
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
03 NATURAL GAS
BLOWOUTS
CONTROL
DESIGN
NATURAL GAS WELLS
OFFSHORE SITES
OIL WELLS
SAFETY ENGINEERING
WELL CASINGS