Optimization of Drilling Well Stage Using a Pressure Profile 3D Model in Cantarell Field, Gulf of Mexico

Abstract

To execute the drilling well plan in Cantarell field, located in the Gulf of Mexico, Petroleos Mexicanos (PEMEX) is implementing a methodology to get a better control during the drilling stage. This methodology uses the conventional available information and a new pressure profile 3D Model. This model has been generated from available information, such as: logs, geologic/geophysics information, pressure values, and drilling mud weight. The methodology is being implemented and adjusted successfully as follow: construction of new wells by recommending casing setting depth after an abnormal pressure zone, determining an operational window for drilling fluids, identification of transitional pressure zones, analysis of the expected dynamic pressures, and recognition of zones with potential torque and drag problems. Introduction The prospect generation and production maintenance plans of Cantarell, the largest offshore production field in the world located in the south part of the Gulf of Mexico, need a better performance in well construction stage compared to the current operational status. For this reason, a multidisciplinary working team is implementing a different approach in the drilling planning process that uses a new Pressure Profile 3D Model. To complete a single well, three drilling phases are required: surface, intermediate, and production. Drilling operations during construction of the intermediate hole have to deal with the following conditions: presence of an abnormal pressure zone from Miocene-Oligocene to Eocene, critical casing setting depth just after this abnormal pressure zone has been left and a subnormal pressure zone appears, total and partial lost circulation in Eocene-Paleocene, hydraulic performance, and lost circulation during cementing jobs. The pressure profile 3D model was obtained processing logs in conjunction with data from vertical or nearly vertical wells distributed over the field; for instance, resistivity, travel time, density, neutron-porosity, and gamma-ray response. Pore pressure and fracture gradient for these wells were estimated using the most common methods and also innovative methods, then the 3D Model was generated with additional information such as: the most accurate horizons, formation tops, stacking velocities, and local structural geology. Model calibration was done considering drilling events, drilling fluids density, and static measured pressures. The main applications of the 3D Model here described are the following: starting point to recommend casing setting depth for the critical stage, establishing an operational window for the drilling fluids, recognition of the transitional formation pressure zones, analysis of the expected dynamic pressures during drilling and casing cementing, and recognition of zones with potential torque and drag problems. It is being showed that using this methodology, this 3D Model in combination with conventional available information works in a more effective way than usual because the working team has a systematic and effective control in all the monitored parameters. Area of interest Location The Cantarell and Sihil fields are located in the Gulf of Mexico approximately 80 Km Northwest from Ciudad del Carmen, Mexico, on a 120 Km[2] area with approximately 60 meters of water depth. The Cantarell field produces out of five blocks: Akal, Nohoch, Kutz, Chac and Sihil. The oil industry development has focused in the allocthonous Akal block because of its great dimension, but the new drilling plan is giving some importance to recently discovered Sihil field in the autochthonous block.