Determination of Hydraulic Properties of a Large Self-Propped Hydraulic Fracture in the Geothermal Research Borehole Horstberg Z1 in the Northwest German Basin

Table 1

Parameter-values of the Solling and Detfurth sandstone layers. Central depth means depth of the middle of the sandstone layer. Depth means measured depth in the borehole. It differs by less than 1% from true vertical depth.

Parameter	Unit	Solling	Detfurth	Reference
Central depth	m	3660	3785	[7]
Thickness	m	15	5	[7]
Porosity	%	11	8.5	[7]
Permeability	m^2	2·10^-16	3·10^-15	[8]
Temperature	°C	144	148	[8]
Pore pressure	Bar	584	597	[8]
Vertical stress	Bar	860	890	[8]
Minimum horizontal stress	Bar	650	< 680	[8, 9]
Effective min. Hor. Stress	Bar	66	< 83	After [8]