Improving the Efficiency of Horizontal Wells in Structural Uncertainty Using a 3D Geological Models

This report is a generalization of practical experience in the area of geosteering for drilling horizontal wells in Western Siberia using 3D geological model.

The main aspect considered is a structural uncertainty, which leads to several equally probable variants of determining the position of the wellbore in the target formation. As a consequence there are significant risks of decrease in drilling efficiency and well deliverability. Cases of geosteering in areas of low geological and geophysical exploration, and lateral reservoir heterogeneity are considered.

To reduce possible risks and to increase reliability of the forecast using geological models the authors recommend the following: deviation measurements with gyroscopes, using seismic interpretation results in geological modelling, using the geosteering technology.

The authors took part in planning and geosteering of more than 150 wells with horizontal tailing-in using live simulation models. By using the author’s approach, collector well drilling efficiency has been increased from 65 to 80% of the wellbore length.