The Impact of Ultra Deep Azimuthal Resistivity Technology on ENI Geosteering Workflow Evolution
Authors:   ENI S.p.A, Mele Maurizio , Chinellato Filippo ,   ENI S.p.A, Leone Andrea Leone ,   ENI S.p.A, Borghi Massimiliano ,   ENI S.p.A, Tosi Gianbattista ,   Vår Energi AS, AndersTveit Jørn ,   Vår Energi AS
Published: October 2022

The growth of horizontal drilling has been supported by the manufacturing of increasingly complex technologies, and ultradeep azimuthal resistivity (UDAR) LWD is one the most important step-change in this technological evolution. The increased capability of seeing tens of meters from the wellbore determined the advancement of technical culture and workflows but also boosted the expectations of success for development projects. Today, the amount of data is not yet fully exploited due to a growing distance between the required skills and the interpretation solutions in place. This article focuses on the research of integration effectiveness of tools and expertise within the existing workflows in continuously progressing technical scenarios. Eni has been drilling and geosteering horizontal wells for decades. The successful execution of these projects has been driven by in-house technical skills, the adoption of emerging services, and solutions to improve the look-around and look-ahead capacity. However, the existing geosteering workflows are still limiting the possibility of maximizing the value of acquired information by cutting-edge and constantly evolving technologies. Starting from the analysis of the internal workflows, the limits encountered, in the use of the acquired data, have been examined to imagine further evolution in skills and technology to unveil data application opportunities. UDAR technology has supported complex Eni Geosteering operations since 2013 when it was first tested. The workflow to support operations is divided into three distinct phases: pre-job analysis, real-time execution, and post-job evaluation. The relevant elements of the pre-job analysis stage can be enumerated as follows: knowledge of the geological setting, the choice and quality control of offset wells, handling and simulating complex scenarios, and an efficient data and information transfer with the service company. While drilling, the critical elements are real-time data streaming, data exchange with the service companies, the assessment of distinct UDAR inversions and measurements uncertainties, and straightforward team communication. Real-time interpretation of all the data requires multidomain technical skills and diversified interpretation platforms. Nowadays, what is missing is a complete multi-user geosteering interpretation platform determining the parallel use of different software. The current framework does not guarantee an efficient integration of information and represents an excessive waste of time that can affect the decision-making process. During the post-job stage, the critical points are service company data release and standardization, operator’s capability of data reprocessing, historical data storage, the deployment of innovative solutions developed internally, and the effective data integration in the 3D model update. Nowadays, the depth of detection of UDAR reached tens of meters, with multiple inversion methodologies with 2D/3D resolution capability, becoming a crucial input for operational decision and to 3D reservoir models. The UDAR technology opened new frontiers on look-ahead applications, including vertical wells, and the possibility to integrate surface seismic data to predict formation changes ahead of the bit in real time to make more informed decisions. The rapid technological evolution determined a continuous evolvement of geosteering skills, workflow, and the need for an innovative approach. These advances allowed to maximize data opportunity in user-friendly environments, mandatory to de-risk the operational challenges.