Determination of source and breakthrough mechanism of water production in a naturally fractured basement reservoir by analysing water production data

Tóm tắt

Excessive production of water in the naturally fractured basement reservoir has been one of the most intriguing problems in production engineering. Water may appear immediately at early production stage or break through after months on stream. Available methods to determine the source of produced water are entirely based on chloride content. Stiff diagram is one of the well-known graphical methods in place to confirm whether it is formation water by various chemical components. With the Stiff diagram, the operators are able to detect formation water at the early days which apparently assists in quantifying the potential of scale deposit, erosion and so on.

Apart from the water sources, it is crucial to understand the water-out mechanism also via graphical approach. The characteristic trend of water-oil-ratio and its derivative with time in log-log plot indicate a variety of slopes refl ecting different flowing mechanisms and a vast majority of them are attributed to the coning and channelling dependent on the level of pressure depletion and rock fluid interaction. A thorough understanding of the water source and its break-through mechanism is indispensable to production monitoring and optimising well production performance in the long run.