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.