PGK monthly lecture
Our monthly meeting of Wednesday 16 September will be a ‘hybrid’ event; members can join either physically or online. Our guest speaker is Angela Pascarella (PanTerra Geoconsultants) and she will give a talk about: “Borehole Image Interprtation in Ultradeep Geothermal. A case study of the Dinantian carbonates in the Netherlands”.
17:30-18:00 hrs: Social
18:00-19:00 hrs: Lecture
19:00 hrs: Social
Join us online…
The meeting will be live streamed through MS Teams for members who prefer to join remotely. Click the link below shortly before 18:00 hrs to participate online. Note that you do not need to register. Join Microsoft Teams Meeting
… or physically attend
Those who are willing and able can register to physically attend the event. A larger lecture room at the Haagsche Kluis and a maximum attendance set at 25 participants allow us to keep a safe distance. Rules and guidelines specific to the venue and the event will be explained upon entry and we will keep a record of attendees and their contact details in case a contact inquiry is needed. We count on everyone there to help make this happen in a safe and responsible way. Click here to sign up
By signing up to this event, you acknowledge that…
- … participation is at your own risk
- … you will help prevent contamination by keeping to the rules and guidelines set out by the Dutch authorities, the venue, and the PGK board
- … your attendance requires that you leave your contact details (Email and phone number) in case a contact inquiry is needed
- … you will let us know if you develop symptoms and/or are positively tested for COVID-19 prior to the event or within 14 days after the event
- … the PGK will continue to assess the need to modify or cancel the event in case the situation demands that we do so
Fracture characterization studies for the geothermal industry are assuming an important role since deep and tight reservoirs have been considered for Ultradeep Geothermal (UDG) development. Since tight reservoirs require a connected fracture and or karst network to be able to flow, understanding fractures distribution and characteristics becomes an essential tool for the geothermal exploration and development.
Target of the deep geothermal exploration in the Netherlands are the Dinantian carbonates of the Zeeland Formation, and they have been extensively studied in the UDG Greendeal Project, which was later integrated into SCAN, a government funded program finalized to scope out the potential of geothermal energy in the country. A borehole image-based fracture characterization was carried out by Panterra Geoconsultants as a part of a larger integrated Fracture Characterization study included in this Scan project (Fracture characterization of the Dinantian carbonates in the Dutch Subsurface – Scan report available in NLOG). The borehole image interpretation will be the subject of this discussion.
Fractures in the Zeeland formation
The Dinantian Carbonates of the Zeeland Formation are found in the Netherlands at depths of over 4km, making them the perfect candidate for Ultradeep Geothermal Exploration. Their low porosity and complex diagenetic history make their reservoir quality highly dependent on secondary porosity resulting from karstification, dolomitization and fracturing. Two of the wells penetrating the Dinantian, Luttelgeest-01 and California-GT- 01 were logged with an image log. These logs were analysed to evaluate presence, type distribution and orientations of fractures and their relationship with present day stress and their possible contribution to the flow.
Several fractures were identified in both wells and were classified based on their appearance on the image and their potential to flow. Greater attention was given to continuous and partially continuous conductive (potentially open) fractures and sub-seismic faults that in LTG-01 were often associated to important mud losses during drilling.
Example of continuous conductive fractures, with associated clusters of partially conductive fractures responsible of high-volume mud losses during Drilling: