engleski

Risk Planning and Mitigation in Oil Well Fields: Preventing Disasters

Lost circulation presents one of the major risks associated with drilling. The complete prevention of lost circulation is impossible but limiting circulation loss is possible if certain precautions are taken. Industry experience has proved that is often easier and more effective to prevent the occurrence of loss than to attempt to stop or reduce them once they have started. The problem of lost circulation was magnified considerably when operators began drilling deeper and/or depleted formations. A strategy for successful management of lost circulation should include prevenentive (best drilling practices, drilling fluid selection, and wellbore strengthening materials) and remedial measures when lost circulation occures through the use of lost circulation materials. In this paper we present lost circulation zones and causes, potential zones of lost circulation, excessive downhole pressures causes, preventive measures, tools and methods for locating loss zones and determining the severity of loss, lost circulation materials, and recommended treatments.

drilling fluid ; lost circulation ; thief zone ; seepage losses ; LCM ; Equivalent Circulating Density (ECD) ; gunk ; pills ; cross-linked polymers ; wellbore strengthening ; depleted zones

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