Workflow to Utilize Realtime Mechanical Specific Energy in Formation Tops Identification and Drilling Optimization in a Multilayer Heterogenous Mature Oilfield Offshore Abu Dhabi

Abstract

Mechanical specific energy (MSE) curves are modelled from Real-Time (RT) data for daily follow up by Drilling engineers and Operation geologists to identify the efficiency of the drilling process and optimize the surface or downhole parameter to improve the rate of penetration (ROP) and accurately determine the formation tops interfaces. However, the manual process requires some time, resulting in a less efficient decision-making process, as well as drilling optimization and parameters standardization. Therefore, in order to increase the level of automation, monitoring efficiency and to simplify the overall process, a new methodology of selecting formation tops through MSE is proposed by a major offshore operator in UAE, using the benefits of RT data. The applied methodology was to select a sample of 20 wells with 8 ½" mother hole section drilled across the different multi-layered heterogeneous reservoirs including both permeable and impermeable dense sublayers. For the selected wells, the RT recorded drilling parameters, LWD logs and survey stations were used in addition to the directional drilling BHA data such as sensor offset, GR correlation, as well as both expected and actual formation tops and basic mud rheology values. The behavior of MSE across each one of the drilled sublayers was manually compared and tabulated against the actual formation tops to establish comparison values. The model will be loaded and tested using the available Machine Learning Algorithms (MLA) to test the accuracy of the formation tops identified against the standard methodology applied by operation geologists for formation top selection and once the best fit model has been selected, the Operator will proceed to implement the same through RT operations.