Quest for a Pragmatic Drilling Fluid Performance Index—Key to Improving Fluid Performance and Optimising Quality Well Delivery Economics

摘要

Over the years there have been numerous attempts at establishing a key performance-measuring index (KPI) that would allow comparisons to be drawn with drilling activities in different locations. In the case of drilling fluids no model has gained any universal acceptance and measuring performance in this activity has typically been left to the ‘easy to acquire’ cost/m or cost/m3 per interval drilled on a campaign well basis within a specific field. Drilling fluids cost across the oil industry range between 5-25% of the well construction costs. If we continue with the traditional cost focused indices then at the low end of this range there is no visible incentive to reduce costs and hence no drive to measure nor improve performance in many of our locations. The real drivers to improve performance lie with the impact on the overall well performance and field development economics in terms of Non Productive Time (NPT) and deferred or impaired production and these can be significant. A pragmatic approach is being developed within Petroleum Development Oman (PDO) that embraces the importance of NPT data as a measure of drilling performance and addresses the issues of production performance of the well to identify well improvement opportunities. This paper reviews the existing mud performance parameters and their drawbacks, presents a practical prediction technique for drilling mud cost based on existing offset field/well data which is less complex than the typical functional drilling cost models (Kaiser 2007) and describes how to integrate mud-related cost factors into a simple Mud Quality Index (MQI) equation. The underlying assumptions and limitations of the new KPI will also be discussed to determine any further improvements deemed necessary. Using real data from some PDO fields, MQI data was generated for a group of wells and compared to the old mud cost matrix data to show the disparity in the wells performance ranking based on the different KPIs. The KPI tool is expected to facilitate drilling fluids planning, design and management decision-making on the capital- intensive exploration, deep appraisal and development drilling projects when fully deployed.