Maximizing Net Pay in Penta-Lateral Well With Advanced Proactive Geosteering and 2D Structural Analysis Using Azimuthal Resistivity Measurements

Abstract

A unique challenge for ongoing Schrader Bluff development is to increase field production with the drilling of a high-angle, multilateral producer. To address the challenge, a project was initiated with the primary goal to safely drill five laterals with a key emphasis on maximizing net sand exposure while balancing the short- and long-term value associated with selecting the appropriate technology. This paper focuses on the technical aspects of the proactive geosteering with azimuthal resistivity measurements and multilayered user-guided inversion used in this project. The prewell study based on multiple offset wells is discussed in detail, followed by presenting the highlights of the real-time drilling/geosteering operations, and concluded with the comprehensive post-well analysis study after all five laterals were drilled. The key effort before the drilling was thorough simulation of various scenarios for several target formations. It allowed the selection of the proper geosteering service level (tools and data inversion methods), providing required resolution capabilities but not exceeding the project budget. Value of inversion on real-time data is demonstrated with several examples accompanied by uncertainty analysis of inversion results. Post-well processing included quantification of the main fault amplitude, in-depth uncertainty analysis, and 3D visualization, as well as geological interpretation using an advanced 3D modeling application. The final position and orientation of the major fault were supported with the results of 2D inversion performed in the vicinity of the fault. The integration between advanced geosteering tools and an active team effort helped achieve this complex penta-lateral well, drilling all legs with excellent directional control with numerous steering adjustments and a final net pay of 20,455 ft out of 28,886 ft drilled, which exceeded the operator’s expectations.