UNDERBALANCED DRILLING REQUIRES DOWNHOLE PRESSURE MANAGEMENT

Abstract

Controlling downhole-pressure fluctuations while drilling underbalanced reduces formation damage, avoids lost circulation, and minimizes differential sticking. This first of a two-part series describes the dynamic situations occurring within the well bore while drilling underbalanced. The concluding article covers the use of a UBD drilling simulator for the purpose of optimizing well bore hydraulics. The results presented here are those of an ongoing, joint-industry project at RF-Rogaland Research, supported by Norske Shell, Norsk Agip, and Elf Petroleum Norge.