Drilling efficiency must be improved, in order to drive down operational costs. This requirement must not be viewed in isolation, considering the vast number of activities that determine a drilling program's success. In most instances, discussions relating to drilling efficiency have centered on rate of penetration (ROP)1,2. As a result, ROP is either equated to drilling efficiency, or seen as the parameter that establishes drilling efficiency. These positions, in addition to being flawed, are highly inconsistent with field results. ROP must not be equated to drilling efficiency. Rather, ROP needs to be seen as one of several parameters that influence drilling efficiency.
The industry's most common performance quantifying metrics - cost per foot (CPF), feet per day (FPD), mechanical specific energy (MSE)3,4, etc - are strongly influenced by ROP. These relationships complicated earlier efforts that sought to establish the appropriate dependencies, between drilling efficiency and ROP. To drive down operational costs, while continuing to push drilling activities into harsher and more challenging environments, emphasis must clearly be placed on drilling efficiency. Thus, in order to achieve this goal, drilling efficiency and ROP must both be defined. In addition, the factors influencing ROP and drilling efficiency must be identified. Most importantly, drilling efficiency's different influencing factors5, which include but are not limited to ROP, must always be analyzed based on specific project objectives.
This paper, in addition to addressing the issues listed above, will also establish a clear distinction between drilling efficiency and ROP. In addition the contributions and impact of both ROP and drilling efficiency, as it relates to value creation will be discussed. The positions, to be presented and argued, will be supported with field and operational data.
