State-of-the-Art Review of Lost Circulation Materials and Treatments – Part II: Probability and Cost Analyses

Abstract

Lost circulation is a major problem in drilling operations. As the drilling environment is getting more complicated nowadays, the problem of lost circulation can lead to a significant additional non-productive time (NPT). The objective of this work is to provide in-depth insights into probability and cost analyses of the current lost circulation materials and treatments used around the world. This is the second part (Part 2) of the state-of-the-art lost circulation materials and treatment, the other part (Part 1) focuses on the trends and uses. Lost circulation data of more than 2000 wells drilled worldwide were gathered from many sources such as daily drilling reports, final well reports, technical reports, petroleum literature, etc. The treatment data were classified based on the type of loss as treatments for partial, severe, and complete loss. Descriptive data analytics and visualization tools were used to analyze the data. A dashboard was created to help to analyze the data. The results of this work revealed that there are simply two criteria to be used in the decision-making process to choose the best lost circulation treatment. The first one is that the treatment has to have a high probability of success, and the other criterion is that the treatment has to have a relatively reasonable cost based on the type of loss. In different words, optimization has to be conducted to choose treatments based on the type of loss. However, some treatments with a high probability of success may have a low number of usage which might be the reason behind the high probability of success. Thus, careful attention should be given for the number of uses of each treatment when calculating the probability. On the other hand, some treatments have a low probability of success and high cost, which indicates that the high cost does not always correlate with a high probability of success. In addition, the type of loss will play a major rule in selecting the treatments since some treatments are too expensive to be applied for partial loss as an example, and usually, other options are available. In short, this study will provide clear insights into the cost and probability of the state-of-the-art lost circulation treatments and materials used in the oil and gas industry. The recommendations provided by this study can be utilized to make better future decisions to treat lost circulation.