Innovative Product Concepts and Drilling Practices Improve Bit and Reamer Performances in Harsh Drilling Environments

Abstract

Hole opening with bit and reamer, continues to receive attention in the drilling industry (Meyer-Heye, et al, 2010), due to the operation's numerous advantages. In comparison to conventional (single diameter) drilling, hole opening bottom hole assemblies (BHAs), are more complicated, in terms of their design and operation. The presence of two cutting tools, bit and reamer, in hole opening BHAs present additional drilling dynamics challenges (Heisig, et al, 1998). As a result of these issues, hole opening applications are commonly plagued by the following shortfalls -shorter BHA runs, excessive vibrations (Fear, et al, 1997), downhole tool failures, poor borehole quality, lower rate of penetration (ROP), and compromised directional performance (Mensa-Wilmot, et al 2014). These challenges, which have drastic negative effects on operational costs, amplify in harsh drilling environments (Mensa-Wilmot, et al, 2001).The above issues must be addressed, to ensure cost trend reversals in hole opening applications. This objective requires solutions that focus on the challenges at their sources of initiation. Most important the solutions must ensure consistent and continuous gains in performance. This paper will present new concepts in hole opening, with regards to project analysis, planning, and execution. The discussions will identify and resolve specific hole opening challenges, with emphasis on harsh environment drilling applications. Field cases with supporting data, highlighting the impact of new solutions on project cost reductions, will also be presented. BackgroundSeveral methods, that use different cutting tools ( Figure 1) and BHAs, currently exist for hole opening operations. The available scenarios have dissimilar attributes, capabilities, and operational efficiencies. Considering the challenges posed by the different options, the bit/reamer strategy (Figure 2) is seen as the most efficient and productive approach. Comparisons and evaluations, upon which these positions are based, have been documented by the industry.

An Experimental Investigation of Drilling Performance Improvement Using Reaming While Drilling

“…Improving the drilling performance has a great contribution to the overall economy of a development project and therefore has been the subject of many studies [2][3][4][5][6][7][8][9]. Reaming While Drilling (RWD) is one of the techniques contributing to the drilling efficiency [10][11].…”

“…• Providing a sufficiently large borehole and more complex completion string access to reservoir has several advantages for exploration and production wells [15]. Despite the advantages, the deployment of two cutting tools (i.e., the pilot bit and reamer) in the bottomhole assembly (BHA) leads to additional drill-string vibrations because the weight and torque will be distributed between the pilot and reamer [10][11][12][13][14][15][16]. Therefore, hole enlargement generally suffers from downhole tool failures, shorter BHA life-time, lower drilling performance, poor borehole quality, and compromised directional efficiency [11].…”