Enhancing Well Construction Efficiency: Diagnostic Analysis to Combat Invisible Lost Time (ILT)

Oil and gas well construction is a high-cost operation. Therefore, drilling operators and service providers have deployed numerous studies and methods to combat and reduce the well construction cost. Traditionally, the focus of the industry has been the reduction of non-productive time (NPT), due to its visible impact and direct consequence on cost. Recently, invisible lost time (ILT) analysis has also been a prominent area of focus in the industry. ILT represents the difference in time between the actual operation duration and the target time or technical limit (TL). It is used to assess the well construction operation's performance in comparison to similar scenarios. This paper will evaluate the application of diagnostic analysis in identifying ILT root causes for the purpose of developing mitigation plans. It will provide a comprehensive review on the utilized diagnostic tools and their impact on ILT reduction, as well as an overview on the dataflow gathered during the well construction process and how it allows key individuals to make informed decisions in efforts to reduce ILT. The subjects reviewed in this paper include the significance and accuracy of ILT detection, the diagnostic tools used in identifying ILT, and how they can be applied to reduce operation cost. The review also highlights the limitation of diagnostic analytics in the detection of ILT.

I. Introduction

The construction of an oil and gas well has proved to be a high-cost operation. In that, the drilling phase incurs the highest cost of any other activity within well construction operations [1]. To meet global energy demands, energy companies are forced to develop and implement technologies that lower the cost of the well construction process. With rising drilling challenges and complexity, companies are utilizing advanced analytics and computing capabilities to reduce the cost per meter drilled. Non-productive time (NPT) is defined as the time when the drilling operation has ceased or there has been a decrease in drilling progression. Traditionally, NPT has been used as the main indicator of efficiency [2]. This is due to its visible impact and direct consequence on cost. However, a new metric has been adapted to investigate the invisible inefficiencies and inconsistencies of the well construction process called invisible lost time (ILT) [3]. ILT represents the difference in time between the productive time (PT) (i.e., the actual operation duration) and the technical limit (TL) (i.e., “the theoretical maximum in safety, efficiency, and production”) [4], [5]. ILT is used to assess whether the well construction operation is performing better or worse than similar scenarios.