Horizontal Wellbore Placement Can Have a Critical Impact from Economic Success of Hydraulic Fracturing Stimulation

Billy W. McDaniel
Production Enhancement, Halliburton, Duncan, OK

Lateral wellbores have three major differences from vertical wells: Length of wellbore within producing zone; Gravity effects; and Reservoir Compartmentalization effects. If a horizontal wellbore will need hydraulic fracture stimulation, a fourth variable becomes a major factor: Insitu Rock Stress values and their directions!

Prior to the recent surge in drilling of tight gas shale reservoirs, only a small percentage of horizontal completions were known to be hydraulic fracturing candidates before drilling the well. Technology advancements have now broadened our ability to effectively place multiple fractures at preselected locations along a lateral section. In shales, as well as many other low perm oil and gas zones, the degree of fracture stimulation success can make the difference between non-economic and highly profitable wells. Often the difference has been whether or not the wellbore was drilled into a direction that enhances the opportunities for effective fracture stimulation. The natural preferred fracture direction (PFD) is a critical factor, yet can be altered by local formation aberrations, or even by localized reservoir depletion. Some laterals are drilled through multiple fault blocks where the stress field can drastically change from one zone along the lateral to another.

This presentation will focus on understanding the ways that lateral wellbore direction can influence (improve or reduce) the effectiveness of hydraulic fracturing applications. Also it will identify recent new techniques being applied to aid in controlling fracture placements in laterals that are completed open hole, with non-cemented solid liners, or cemented liner completions.

AAPG Search and Discovery Article #90078©2008 AAPG Annual Convention, San Antonio, Texas