In the northern part of the South China Sea, P oilfield entered the mature stage with a high water cut. As an important contribution to the sustainable development of this field, a horizonal infill campaign targeted the unexploited areas for their valuable remaining oil for improving oil recovery. However, the sparse well control and low-resolution seismic data induced high uncertainties regarding the structural profile, reservoir properties, effective oil column, and remaining reserves with the bottomwater drive in the infill well area. These uncertainties greatly affected the production steering efficiency in the complex reservoirs and well performance, which cannot be effectively addressed by the conventional logging and modeling technologies.
Predrilling modeling results and global successful cases could increase operators the confidence in using the high-definition boundary detection service (HDBDS) for achieving well objectives. Without any artificial assumptions, HDBDS could provide the stochastic resistivity inversion to remotely identify the quantitative subsurface features, including layer numbers, resistivity and anisotropy distribution, thickness, and dip. In the specific operation area, the inversion can detect the reservoir features up to 3 m from the borehole, which could quantitatively reconstruct the subsurface profile to efficiently guide the horizontal geosteering operation for maximum standoff from the water zone. Furthermore, the production steering can be enhanced through optimizing the corresponding water-controlled completion configurations.
During the real-time execution of the horizontal infill wells with an approximate 500- to 600-m section, HDBDS inversion could map the effective boundaries with a distance of up to approximately 3 m, including reservoir top and bottom, water zone top, as well as some interbed boundaries. Combining conventional measurements and HDBDS inversion, the subsurface model was quantitatively reconstructed with the obvious deviations from the original elements. Subsequently, the horizontal wells were precisely controlled for enough oil column, even with a shorter production interval than prognosis in some wells. In the updated reservoir model, the inflow control device (ICD) water-controlled completion configuration was specifically optimized to delay bottomwater breakthrough. As a result, the effective production steering was achieved, with the actual well performance better than expected. Furthermore, the oil trap column and remaining oil reserves could be reassessed to evaluate the production potential and further development direction in this field.
Generally, HDBDS inversion could update the quantitative model to induce the production steering, which was valuable to contribute to the sustainability of this bottomwater field in the deep-development stage.