Maximizing Extended Reach Drilling Efficiency with Unconventional Thinking

Abstract This case study outlines how drilling times and costs were reduced for an oilsands steam-assisted gravity drainage (SAGD) operation. It describes the primary challenges encountered when attempting to streamline the drilling process and how generally accepted solutions to these problems are not necessarily the best ones. The evidence presented demonstrates how unconventional approaches to drilling optimization resulted in substantial reductions in the time and cost while also improving wellbore placement, quality, and repeatability. The primary challenges identified when attempting to reduce drilling times were as follows: Ineffective hole cleaning while increasing the drilling rate of penetration (ROP). Increased downhole tool damage resulting from excessive torsional and axial shocks, stresses, and abrasion. The inability to directionally place the wellbore as required while maintaining a high ROP. The challenge was to adjust drilling parameters and bottomhole assembly (BHA) designs to reduce drilling times and costs without sacrificing wellbore quality or BHA reliability. Through careful modelling, adjustment, and measurement over the course of an 11-month optimization program, drilling costs were reduced by 25% per well and the below rotary table time was reduced by 28%. The primary discovery from this process was that, contrary to traditional understanding, increasing drilling ROP and rotary speed can actually result in improved BHA reliability, directional wellbore placement, hole cleaning, borehole condition, and liner run times. The key to realizing these improvements is careful BHA design and drilling parameter refinement to ensure that the entire drilling operation is optimized to be fit-for-purpose for fast, efficient, and reliable drilling. This paper discusses how using a conservative approach might be detrimental to drilling efficiency and that what is perceived as aggressive drilling practices could actually be beneficial when there is an intimate knowledge and understanding of the drilling environment. As a result of this mindset shift, tens of millions of USD per year in drilling cost savings have been realized.