Probabilistic Analysis of Wellbore Stability During Drilling

A.B., da Sergio; Holzberg, Bruno; Teixeira, Édson; Marcelo, Frydman

doi:10.2523/78179-ms

Cited by 5 publications

(1 citation statement)

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“…For example, as shown in Fig.1, the water depth of the well obo-1 is 1750 m, and TVD is 4500 m, the hole section has density data is 2590~4500 m, the length of hole section without density logging data is 840 m, when the average density of the upper section is 1.8 g/cm 3 , 1.9 g/cm 3 , 2.0 g/cm 3 and 2.1 g/cm 3 , the overburden pressure gradient has obvious change. …”

Section: Improved Methods For Overburden Pressure Gradient Prediction mentioning

confidence: 96%

A New Approach for Casing Program Design with Pressure Uncertainties of Deepwater Exploration Wells

Guan¹,

Ke²,

Lu³

2010

Proceedings of International Oil and Gas Conference and Exhibition in China

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In exploration wells, particularly in deepwater exploration wells, the information regarding formation pressure has many uncertainties because of the lack of seismic data, logging data and daily drilling report. The present casing program design methods based on the deterministic formation pressure data did not take these uncertainties into account and the results could not satisfy field engineering requirements. This paper describes a method based on probabilistic theory for determining the formation pressure profile with credibility, and a new approach for casing program design has been also introduced. As a result, the formation pressure is not a deterministic value but a range with probability information, as the same with the casing set points selection. And then we describe a quantitative risk analysis method for quantitatively analyzing the risk of the casing point selection design. The model includes four sub-models for determining the quantitative risk due to lost circulation, kicking, collapse and sticking. The results can provide valuable information for designers. In one case study, we illustrate how this approach allows us to compute formation pressure profile with credibility and casing set points for a deep well with formation uncertainties. The risk of several casing program of this well has also been discussed finally.

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Section: Improved Methods For Overburden Pressure Gradient Prediction mentioning

confidence: 96%