Characterization of Stimulation Potential in Jurassic and Carboniferous Shale plays of the Netherlands

This research focuses on the stimulation of shale gas plays of Jurassic Geverik member and Carboniferous Altena formations in the Dutch subsurface. The production of shale gas involves stimulation of the formation by hydraulic fracture treatment. Two typical types of stimulation are used in the industry. The viscous fluid treatment, which consists of small amounts of viscous fluid, high proppant concentrations and volumes and the slick water treatment, which contains large amounts of fluids and low proppant concentrations. Main objective for this study is to determine the best stimulation strategy for shale gas development in onshore Netherlands West Netherlands Basin and the Roer Valley Graben. The first step in the process is a thorough understanding of the shale’s petrophysical attributes. Core and cutting testing determine mechanical properties such as tensile and compressive strength, mineralogical content, Young’s modulus and Poisson’s ratio, hardness and petrophysical properties such as porosity and permeability. Mineralogy plays an important role in controlling shale properties. The more clay particles in the rock the more ductile the rock is. The Carboniferous Geverik member has relatively large amounts of quartz, high values for brittleness, elastic properties and hardness. The Jurassic formations are clay rich, with some intervals with a higher carbonate mineral content, and are typically more ductile, softer and have lower elastic properties. Rock matrix flow and storage capacities are quantified on core samples by the pulse decay method and the GRI method on crushed samples. The experimental study gives a variety of results for the different formations which are partly due to microfractures and large uncertainty caused by poor core quality. Coupling wireline-log information with laboratory measurements of core and cutting samples acquired in this study provides the basis for an artificial neural network. With the use of all the analyses and the neural network the hydraulic-fracture treatment and the completion intervals are selected. Completion intervals are selected on the basis of the brittle zones. The selection of the appropriate stimulation strategy is based on the shale brittleness, geomechanical, and geochemical properties.Section Petroleum EngineeringCivil Engineering and Geoscience