Prediction of Directional Changes in Well Drilling Based on Formation Rock Strength


To increase oil and gas production deviated wells are drilled where the wellpath changes both in the horizontal and vertical planes. Directional change tolerances are becoming tighter because wells have to be placed with increased accuracy in soft overburden shales and within the reservoirs. Therefore there is a need for planning tools which can predict directional change capabilities of directional tools. Formations which are looked upon as easily steerable from a practical drilling point of view enables the directional driller to obtain rapid directional changes. While less steerable formations gives less directional responds and it is sometimes physically impossible to follow the planned wellpath. The goal of this study was to develop a method to evaluate the possible directional change responses based on formation rock strength. Drilling, log and rock mechanical data was collected in different offshore wells together with the actual directional changes obtained for a different rotary steerable system active steering settings. By correlating the unconfined rock strength, drilling and survey data trends between directional changes of the steerable rotary tools and the formation strengths were seen.

Meeting Name

42nd U.S. Rock Mechanics - 2nd U.S.-Canada Rock Mechanics Symposium (2008: Jun. 29-Jul. 2, San Francisco, CA)


Geosciences and Geological and Petroleum Engineering

Keywords and Phrases

Active Steering; Deviated Wells; Directional Changes; Offshore Wells; Oil And Gas Production; Planning Tools; Rock Mechanical Data; Rock Strength; Rotary Steerable Systems; Rotary Tools; Survey Data; Vertical Plane; Deflected Boreholes; Horizontal Wells; Offshore Drilling; Offshore Oil Wells; Oil Well Production; Oil Wells; Petroleum Industry; Petroleum Reservoir Evaluation; Rock Drilling; Rock Mechanics; Well Drilling

Document Type

Article - Conference proceedings

Document Version


File Type





© 2008 American Society of Mechanical Engineers (ASME), All rights reserved.

Publication Date

01 Jun 2008

This document is currently not available here.