Integrated Surveillance Enhancing Quality of Decisions and Reservoir Description in the Harding Field

Abstract

Summary A key factor in managing mature fields is to establish adequate surveillance in each phase of their life. The complexity increases when the field is developed with horizontal wells. Differences in data quality and resolution should be taken into consideration when planning such surveillance. Current uncertainties in Harding field relate to unreliable well conformance data using conventional production logs (PL) and assumptions in the reservoir description, which are subseismic resolution. We describe the learning from a horizontal well in Harding, where appropriate surveillance enhanced reservoir understanding and quality of decision making. Based on the initial understanding from the reservoir model, an insert string well work option was proposed to reduce water cut. Historically in this field, conventional PLs provided unreliable well conformance data in horizontal multiphase flow. To improve the characterization at the well scale, an array PL was deployed for the first time on this field. The flowing results revealed that the insert string solution was inappropriate and would result in lost oil production. The shut-in data identified crossflow between two zones separated by a shale section. In the initial model, this shale was mapped only at local level. Post surveillance, it was remapped on seismic as an extensive baffle having an impact on an area with more mobile oil to recover. There is a potential upside with a new infill target being identified toward the toe of this well. Most of the initial decisions about the insert string were based on seismic and modeling work. The new array PL data brought additional information into the model, increasing confidence in the results. Data resolution at the well level matters and this highlights the need to take more PL measurements to calibrate the seismic response and improve the reservoir model.