Initial selection and further optimization of drill bits is one of the key factors of an effective drilling process, which is particularly important in high-cost projects. This article presents the incremental changes made to increase the ROP and mechanical efficiency of drill bits while drilling offshore extended-reach drilling (ERD) wells.
With the implementation of the tasks based on a well-by-well analysis of bits, recommendations were developed for optimizing the design of drill bits. These recommendations were based on results of bit simulations in specialized software with correlation of proposed models and actual results. Simultaneous bit optimization was performed in conjunction with other elements of the BHA with the help of an integrated engineering analysis system. The result was the development of new bit designs and sizes designed for drilling specific rock in specific fields.
In addition to the optimization of the drill bits themselves, a refined technological component was introduced: a real-time drillbit optimization system to enhance ROP, decrease bit wear while drilling, and ensure maximum run length via the optimization of drilling parameters.
Application of the proposed technical and technological changes has increased ROP up to two times, and enabled a bit to drill a 4,900-m section in one run with minimum bit wear, leading to a reduction in the cost of the well.
As a result, bits for ERD were optimized for each size, and a drilling parameters map was created. This map was updated based on the result of the construction of each well to ensure maximum efficiency with minimal bit wear during subsequent drilling.
Additionally, one of the most important results was a 6-year record of no NPT associated with the drill bits.
Experience gathered during the development of the bits using advanced modeling applications, together with real-time drilling optimization, will be applied on a nearby offshore field to minimize the time required to reach the optimal ROP.
This article describes the selection, optimization, and continuous improvement of drill bits using the latest techniques and technologies, the use of which occurred gradually during development over several years. The above approaches can be applied to ERD and standard horizontal wells worldwide.