Statoil has drilled an average of 30 technical sidetracks yearly since 2000, and a significant portion of the total drilling and well technology costs is related to these operations. A twoyear project was initiated in 2004 to investigate the causes for the technical sidetracks. The project’s main objective is to reduce drilling cost related to technical sidetracks. One of the main activities in the project is the detailed post-event analyses to capture the root causes of the technical sidetracks. The analysis process includes, amongst other factors, interpretation of time based drilling and formation evaluation (FE) data. This activity was conducted throughout 2005 and is still ongoing. A total of 24 detailed analyses have been concluded with a direct cause and a corresponding root cause. The three major findings from these analyses were: 1) Little consistency between reasons for sidetrack reported in daily drilling reports compared with root causes found from the detailed analyses. 2) Marked reduction in formation related causes. 3) Operational practice accounts for 10 of the 24 technical sidetrack root causes. The majority of the technical sidetracks, according to the daily drilling report system, is due to formation related problems. However, the findings from the detailed analyses conclude that operational practice constitutes the major root cause. The picture is somewhat more differentiated, since the complex nature of some incidents results in several root cause related to both downhole mechanisms and operational practice. These observations enforce an increased focus on the operational practice, I.e. how to conduct specific drilling operations and also how to handle drilling challenges. This paper presents why this knowledge is of great value during both planning and operations phase. Furthermore, it concludes that this type of detailed analysis significantly accelerates the learning outcome with regards to drilling operation challenges and the diagnosis of these, thus promoting a more proactive working methodology throughout the organization.
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