Using Reservoir Petrography to Find Geothermal Sweet Spots in the Triassic Bunter, West Netherlands Basin

Summary A data inventory of petrographic and diagenetic features of 23 wells from the West Netherlands Basin (WNB), based on a combination of existing reports and new data of 6 wells, was used to review the reasons for the variations in reservoir quality. This study shows that there is no single factor responsible for the variations in reservoir but a multitude of factors, and a number of reservoir risks exists. All factors have in common that they are governed in first instance by detrital composition and by texture, which is a function of provenance and depositional environment. Other than previously thought, not only extrabasinal but also intrabasinal grains are important to consider in order to understand the diagenesis of the sandstones. The reservoir quality was then modified to a strongly varying degree by diagenesis. This implies that a systematic mapping of sediment facies in combination with information on the paleo burial depth could allow to help finding sweet spots in the WNB Bunter.