MONITORING WATER FRONT ADVANCE AND BILINEAR FLOW BEHAVIOUR ON PRESSURE TRANSIENT TESTS IN HORIZONTAL WELLS

Transient well testing has been a robust tool for reservoir characterization for a long term because it provides valuable information about dynamic reservoir properties as well as reservoir boundaries. Until recently many horizontal wells have been drilled. As they are a good producer, there has been a little incentive to shut in a horizontal well for pressure transient analysis. Traditional well test analysis for horizontal wells is based on using an analytical model embedding early vertical radial flow followed by a linear flow and late pseudo radial flow regimes. Apparently, most researchers expect early radial and/or linear flow to appear. However, field examples of pressure build up tests for horizontal wells demonstrate a unique bilinear flow behaviour. Also, long pressure build up tests with weeks of shut in‑time conducted in horizontal wells show the influence of nearby water injectors on pressure behaviour. Using new techniques, one can monitor water front movement in a water flooded reservoir over production time. All pressure transient tests prove a dominant behaviour of bilinear flow as well as water front movement. Analysis and interpretation of these field examples are based on few years of production and water injection hsitory, reservoir simulation and well location associated with field geology in order to prove this new interpretation technique. A numerical well testing was also used to demonstrate the applicability of this technique and proved that water front from nearby injectors moved towards producers over production time. This paper presents incorporation of analytical and numerical well testing to identify bilinear flow model and water front movement model. This approach can be used for a better water flooding management in a reservoir in order to avoid early water breakthrough. Also, dominant bilinear flow behaviour on pressure transient data addresses a new analytical model for horizontal wells.