ABSTRACT:

Many wells in the Deepwater Gulf of Mexico are drilled through highly depleted reservoirs. Challenges executing wells in these narrow drilling margin environments include – 1) impairment of drilling operations due to mud losses while drilling & 2) inadequate cement coverage across stacked depleted reservoirs requiring remediation work. Industry experience demonstrates that events related to losses can be mitigated through proactive implementation of wellbore strengthening (WBS) techniques. This paper discusses recent Shell applications of WBS with a focus on Deepwater Gulf of Mexico (GoM). We discuss the design and operationalization of these methods to minimize non-productive time (NPT). In our first example well, lost circulation material (LCM) was added to the drilling mud and a static squeeze was performed across highly depleted sands (?P ~4500 psi). In contrast to previous wells with similar depletion, this well was drilled and cemented with relatively lower NPT. In other wells drilled through reservoir with similar depletion levels, only carefully sized background LCM was used. The results of these wells have been integrated with industry learnings and Shell multidisciplinary expertise to devise a recommended operational workflow for WBS application in the GoM.

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