Case History of a Horizontal Well Using a High-Angle Pilot Hole

Abstract

Petro-Hunt Corporation drilled a horizontal well in the Austin Chaikin Gonzales County, Texas. A high-angle pilot hole was used to determine a target interval and horizontal borehole orientation, while satisfying a variety of operational and geological considerations. The well was directionally drilled to an angle of 44° and intermediate casing was set. The pilot hole was then drilled at the same angle through the target formation and evaluated using openhole logs, including a circumferential acoustic imaging device. After evaluation, the pilothole was plugged back, and the horizontal borehole was kicked off and drilled to a horizontal displacement of 3, 578 ft. This method allowed the entire target formation to be evaluated prior to committing the wellbore to a particular interval, while avoiding potential operational problems associated with a vertical pilot hole. The acoustic imaging log allowed the operator to select the optimum Stratigraphic interval in which to locate the horizontal borehole, and confirmed the proper borehole orientation. The well was successfully completed on schedule and within budget. The planning and drilling of the well is reviewed, with emphasis placed on operational and geological considerations and the evaluation of the pilot hole.

Applying Short-Radius Horizontal Drilling to a Deep, Hot Reservoir in the Mubarek Field

“…An oil based mud of weight 9.5 ppg would be used and the system would be treated with a blended finely ground cellulose fibre LCM prior to entering the Ilam/Mishrif reservoir in order to minimise any losses. After setting a 7" liner in the top of the Thamama the well would be circulated 3 ARTlaJLATED SHORT RADIUS TOOlS to a water based drilling fluid and built to horizontal using adjustable articulated short radius tools.…”