Extending MWD survey interval

27 October 2008 Hi folks,

Since the start of the ongoing discussion on MWD survey accuracy,
another item has cropped up ..

In a series of development wells, an operator has increased the
interval between MWD surveys from once per stand to once per two
stands .. the proviso being that it is in the tangent section and
only after assembly behaviour has been established.

We are now looking at whether we can extend the interval further, at
least to once per 3 stands.

The current situation is that the directional drilling company has
no issue with this, but that the corporate survey policy of this oil
company will not allow it .. one the grounds of being outwith their
required relief well survey policy (absolute uncertainty < 30 m, at
2 standard deviations.

I'd be interested in your experiences (and, preferably, facts)
about :
1. The policies you have encountered / used .. and what they are
based on
2. How they apply to development drilling
3. Anything you did that allowed increased survey frequency

We have identified considerable savings from increasing the survey
interval and would like to learn what you are doing.

Thanks

Dave Taylor
Relentless Pursuit of Perfection Ltd

6 Answer(s)

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