A Systematic Approach to Performance Drilling in Hard Rock Environments

Abstract

Abstract The Haynesville shale gas play in North Louisiana poses a number of significant technical challenges. One of the most daunting is penetrating the hard, abrasive Hosston sandstone-shale sequence and hard Knowles limestone in the intermediate section of the overburden. The high strength and interbedded nature of these formations trigger bit and drillstring vibration that can lead to short, slow bit runs and unacceptably high cost per foot. The operator applied a systematic Drilling Efficiency Optimization (DEO) approach encompassing well planning, well execution and post-well analysis to drive performance improvement through these formations. Optimization efforts focused on polycrystalline diamond compact (PDC) bit design, bit hydraulics, positive displacement motor (PDM) selection, soft torque rotary system (STRS) utilization, bottom hole assembly (BHA) design and active management of drilling parameters. Combined, these efforts reduced cost per foot and days per thousand feet by over 50% while drilling approximately 70 wells over a two year period.