ABSTRACT:

Drilling through the complex overthrust geology associated with the Andes foothills of the Northern Argentina and Southern Bolivia basin presents a number of distinctive challenges. Formations in the upper hole sections are typically hard, abrasive and prone to lost circulation and bit balling. Historically, these intervals are particularly problematic and are responsible for major problems such as low penetration rates, hole deviation and frequent drill string failures. The drilling optimisation service company had extensive local knowledge pertaining to drilling systems and operating practices recommendation in these formations, which is valuable to the company and its customers. While planning several wells in this area, a detailed analysis of drilling performance, mud logging and wireline data from offset wells was conducted. Providing a mechanism to capture and document this understanding of the issues relating to drilling performance improvement, and to aid transfer of these, enabled the company to retain this valuable knowledge within the company and share it with its clients. This analysis helped identify potential problems and led the operators to set objectives for the upper hole sections of achieving the highest penetration rate possible while maintaining a near-vertical wellbore. The Technical Support Group within the drilling optimisation service company performed a number of activities to capture and share knowledge relating to drilling systems selection and drilling performance optimisation. The group's recent work in applying proven knowledge acquisition techniques to the drilling domain has lead to the production of a structured repository for capturing and sharing case-based knowledge related to drilling systems selection and drilling performance optimisation. This Drilling Knowledge Store (DKS) is now being integrated into the OASIS process and provides the vehicle for transfer of lessons learnt from OASIS projects to Hughes Christensen (HCC) and Baker Hughes (BHI). A series of Knowledge Acquisition (KA) exercises focused on capturing knowledge from particular OASIS contracts has been conducted. A key deliverable from such projects is a local best practice document, or ‘knowledge book’, which presents the company's understanding of current best practices for wells drilled in a specific geographical context, and the reasoning underlying those best practices. It was proposed that a similar KA exercise be undertaken with selected engineers in Hughes Christensen's Latin America Region to document the experience and understanding they have gained relating the optimum drilling practices for the Tarija and Tupambi formations. The project aimed to deliver a vehicle that enabled the OASIS engineers in the region and its client to rapidly assimilate much of the experience gained in the specific area by documenting those issues which affect drilling performance in the Tarija and Tupambi formations. This paper describes how proper planning and understanding of the key issues restricting drilling performance lead to the application of improved drilling practices and the identification of the proper technology that resulted in continuous successes on performance improvements and cost savings in a traditionally problematic and high cost drilling area.

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