Case Stories of Horizontal Wells in Offshore Fluvial Oil Reservoir

Abstract

Fluvial facies reservoirs account for 60% of the reserves in Bohai oilfield. The effective development of such reservoirs plays a very important role in long-term stable production of Bohai oilfield. There are many challenges including: poor reserve, large well spacing, large lateral changes, poor connectivity, heterogeneity, unfavorable viscosity, low structure amplitude and strong bottom water. Horizontal wells are widely used in these reservoirs, especially in the edge or bottom water reservoir and the narrow channel reservoir in Bonan area. Many cases of horizontal wells design, implementation, well pattern optimization and water flooding management were presented to improve the recovery rate of fluvial oil reservoirs. The technique has been widely used in ten fluvial oil fields in Bohai, and has enhanced the recovery rate of by 3% and achieved remarkable technical and economic effects.

Effect of Well Orientation on Oil Recovery from Waterflooding in Shallow Green Reservoirs: A Case Study from Central Africa

“…Grid size (m), 50 × 50 Water saturation (Sw; fraction) 0.2 Porosity (%), 28 Initial oil saturation (Soi; fraction) 0.8 Perm.…”

“…Despite the volume of published literature [26][27][28][29][30][31][32][33][34][35][36][37][38] on the recovery efficiencies of different well types, to the best of our knowledge, there has been no research on the performance of highly deviated wells in the highly heterogeneous shallow reservoirs of the Central African Rift Valley region, which are significantly different from most moderate-depth to deep reservoirs in other parts of world. This is because of (i) the complications associated with drilling along a precise path within an inclined path, (ii) difficulties encountered in preventing sand influx, and (iii) challenges encountered during screen installation for sand production control, which render directional drilling more difficult and time-consuming for complex reservoirs.…”