Wellbore Stability Analysis and Pore Pressure Study in Badri Field Using a Limited Data, Gulf of Suez, Egypt.
the Wellbore stability analysis and stresses definition became a highly recommended especially in the deviated wells, which has impact on the drilling cost, so a good study in the well planning stage will minimize the cost of drilling in total. The leakage of some data is a challenge in this paper. The objectives of this study were firstly to Build a geomechanical model for the Badri field region using data from four offset wells along with structural information and regional experience, secondly utilizing the geomechanical model and perform a wellbore stability analysis for the next development well, thirdly Provide a quantitative risk analysis (QRA) to understand the uncertainty in model parameters and assess the effect on mud weight recommendation results. A geomechanical model was constructed for the badri field based on data from four (4) key offset wells; the model includes the overburden gradient, pore pressure, minimum and maximum horizontal stresses and rock strength. The model was calibrated to drilling experiences, including geomechanical related problems. Based on the field geomechanical model, a wellbore stability analysis was applied on the provided trajectory for the next development well. No safe mud window is predicted for the trajectory, due to the effect of expected depletion in the Kareem and H.Faraun formation, on the minimum horizontal stress. There is uncertainty in model parameters (i.e. expected depletion could be lower or higher, no rock mechanical data to calibrate collapse pressure or stress path parameters). The initial fracture gradient is a conservative estimate (towards lower bound of LOTs), thus the fracture gradient could be higher and a mud window could exist. Additionally, there is lack of UCS calibration data and lack of image data for constraining max stress magnitude and orientation. Because of these limitations, the standard model verification is more difficult. It is recommended to drill with a mud weight of ~10.6ppg and add appropriate bridging/sealing/LCM materials to increase wellbore strength and reduce the possibility of differential sticking in some intervals. It is also highly recommend to run real time WBS monitoring. Monitor model and drilling parameters in real-time using appropriate LWD and SLS logs, and pay close attention to cavings to diagnose failure mechanisms, in order to adjust the mud weight as necessary if problems arise.
AAPG Datapages/Search and Discovery Article #90332 © 2018 AAPG International Conference and Exhibition, Cape Town, South Africa, November 4-11, 2018