EMPIRICAL ANALYSIS OF LATERAL SPACING UNCERTAINTY IN NORTH AMERICA DUE TO MWD SURVEY ERROR

Lateral spacing in unconventional plays can have a significant impact in the economics of field development (Bharali et al., 2014; Lalehrokh & Bouma, 2014). This spacing is most often verified using magnetic measurement while drilling (MWD) instruments. In well spacing studies, the distance between two laterals is typically assumed to be precise, however, MWD may have large uncertainties associated with their bottom hole locations (Williamson, 2000; Grindrod et al., 2016). Standard error models were built primarily using data from major service providers' offshore operations and assume a level of accuracy that may not reflect current practices for onshore drilling in North America (Love, 2019). This study better quantifies the positional uncertainties of MWD surveys in long laterals and uses those uncertainties to estimate well spacing uncertainty.

More than 35,000 MWD bit runs across more than 9,000 laterals wellbores in major basins across North America have been analyzed for survey errors. The observed errors are then tested in magnitude and distribution against assumptions of industry standard models. An empirical MWD error model for North America is generated, and additional area-specific analysis is performed for the Bakken, DenverJulesburg, Eagle Ford, Marcellus/Utica, Permian/Delaware and Western Canada. The wellbore trajectories were analyzed to produce a prototypical wellplan for each basin studied, as well as an overall "North America" wellplan. Positional uncertainty calculations were performed for each wellplan using several industry standard positional uncertainty models as well as the empirical models based on real MWD data. Using the combined covariance method of wellbore separation, the uncertainty in lateral spacing is estimated for each wellplan at landing point, mid-lateral, and the toe.

Learn more about us: https://www.helmerichpayne.com/resources/technical-publications/empirical-analysis-of-lateral-spacing-uncertainty-in-north-america-due-to-mwd-survey-error or you can reach out to us directly here: https://www.helmerichpayne.com/contact.