block, referred to as a whipstock, is installed in the borehole such that it deflects the drill bit to the desired direction and inclination (Figure 2.1a). The radius of curva-
ture can be smaller than 150 feet, but the relatively high cost en-
countered during the demonstra-
tion ($1225/ft) may hinder future application.

Modified Petroleum Industry Drilling (MPID)

The basic equipment for this type of directional drilling is essentially the same as would be used for the installation of a vertical well, except this system is modified to use a downhole motor assembly that can be inclined in order to deviate the borehole. The bore-
hole is drilled vertically until it

needs to be deviated to achieve the desired configuration. At this point the downhole motor assem-
bly is inclined, through the use of eccentric stabilizers, to achieve the desired direction and inclina-
tion (Figure 2.1b). While drilling two wells at the demonstration site, the MPID method was further modified to drilling in shallow, unconsolidated sediments.

Utility Industry Compactional Drilling (UICD) (Photo 2.1b)

The basic equipment for this type of directional drilling is essentially the same as would be used for the installation of utility lines or pipe-
lines. The borehole is advanced from inclined platform using hy-
draulic rams and a wedge-shaped bit. When the bit is rotated the