Mud Motor Digital Maintenance with an Industry-Unique PHM Solution

Abstract

The ability to analyze drilling data to obtain continuous monitoring statistics of the drilling process and make prompt decisions are two important elements of a successful drilling operation. A mud motor is one of the important components of the downhole assembly, which enables the drill bit to penetrate the rock during drilling a well. Correctly predicting mud motor failure and the remaining useful life of the components are essential for obtaining drilling efficiency, avoiding costly operational expenses, and achieving timely maintenance. The remaining useful life indicator with low uncertainty identifies the life cycle of mud motors by preventing redundant maintenance and costly drilling operation failures. This paper presents an industry-unique prognostics and health-management (PHM) solution for monitoring and maintaining the mud motor condition. This solution combines three algorithms, including a power section PHM algorithm, lower-end critical connections PHM algorithm, and mud motor degradation algorithm. The workflow solution allows for obtaining valuable information about the mud motor condition at the system and component levels. The power section PHM algorithm, based on a remaining useful life prediction for the mud motor's power section, provides information about the elastomer condition inside of the stator as a percentage of the remaining life cycle. The lower-end critical connections PHM algorithm estimates the remaining useful life of the mud motor's lower-end connections. Both algorithms are component level; i. e., they help to improve managing the life cycle of the appropriate components. The mud motor degradation algorithm is a system-level algorithm. This algorithm uses drilling data to compute the severity of mud motor degradation; thus, identifying possible problems with the mud motor as a complete system. The PHM solution helps to prevent expensive mud motor failure. Furthermore, the solution provides the opportunity to perform additional drilling runs before the motor components must be retired or removed for maintenance. The significant advantage of applying the PHM solution is it only makes use of existing drilling measurements and does not require any special downhole equipment. The mud motor PHM solution is currently in use by one of the biggest oil & gas service company worldwide. In addition to presenting the three algorithms, this paper presents field application case studies that demonstrate the commercial value and efficiency gains achieved by their use. Significant sustainability benefits have been achieved by using the power section and mud motor degradation algorithms due to their assistance in drilling applications.