Multi-media reservoirs depleted by horizontal wells: analysis of pressure behaviours and rate transient accompanied by developing analytical models for flow regimes

摘要

This paper focuses on analysing pressure behaviours and rate transient of multi-porous media formations such as carbonate reservoirs depleted by horizontal wells. Several analytical models (pressure transient and rate transient) have been developed using the well-known dual-porosity models for naturally fractured formations and modified for triple-media formations considering the existence of hydraulic fractures. The solutions of these models demonstrate different flow regimes corresponding to different production times. The study has pointed out that the impact of multi-media on pressure behaviours can be observed at intermediate production time shortly after the production pulse has reached the lower and upper boundaries. While the flow regimes created by multi-media are characterised by two parallel lines on pressure derivative curves. These two lines can be used to identify the type of natural fracture system. It has been found that type-1 NFR is characterised by perfectly parallel lines wherein the vertical distance between these two lines equals the horizontal distance. The study emphasised that rate transient behaviour may not exhibit same flow regimes that could be developed by pressure transient. [Received: July 15, 2016; Accepted: February 1, 2018]