A new closed loop solution for extracting geothermal energy provides stable, reliable and clean energy for district heating. The solution differs from the conventional open geothermal solutions by being more environment friendly, can be implemented almost anywhere, and has low operational risk and maintenance cost.

The solution is based on an arrangement where one or several horizontal wells are drilled to a suitable depth, normally up to 4 km vertical depth and a similar length horizontal section. The wells are completed with a new patented production string solution, DualVac, which supplies the geothermal energy to the district heating network.

The solution is based on heat exchange between the rock and the circulating water in the well. The water is heated from the rock as it is pumped down the well. The heated water returns to the surface through the inner DualVac pipe with minimal heat loss as the pipe works as a thermoflask.

The closed loop solution avoids requirements for the permeability and porosity of the rock formation. The solution avoids that fluid enter into the formation, i.e. avoid risk of subsurface water pollution, induced seismicity and no need for fracking the formation.

The energy output per well can typically be up to 4 MW. The flow rate can be adjusted to control the temperature and thermal power output. The power output capacity per well depends on various factors, such as the temperature and thermal conductivity of the formation, the temperature of the circulating water and the horizontal well section depth.

Perf, Wash and Cement is an annulus remediation technique implemented when the annulus bond outside a casing string is below an acceptable limit. This technique is about perforating a casing section using a Gun/TCP system, washing the annular space behind casing, removing cement, mud, barite, etc, then placing a new sheath of cement in the annular space and inside the casing. The effect is a rock to rock, cross sectional well barrier across the perforated section.

In Germany, Deutche Erdwarme/Neowells, a Geothermal well operator, needed to do a section well abandonment in the field Graben Neudorf TH1, to establish the well integrity cross barrier, across the 9⅝" liners shoe and provide a base for a subsequent 8 ½" sidetrack window to run a new 7" liner section.

Neither the current 9 ⅝" nor 7" liners on the well were adequately cemented, and both lack any primary annular integrity. Section milling of the 9⅝" casing would have been a high-risk operation, given no annular cement. This operation’s most likely outcome would likely result in the detachment of multiple joints by applying counterclockwise torque at the connections.

Given the low probability of success associated with cement squeezes and section milling, the solution to implement a Perf, Wash & Cement operation was taken. The objective of this lecture will be to share the learnings on how the well integrity was achieved to successfully sidetrack the well.

Fishbones is a patented stimulation technology that enables deep geothermal connectivity across a wide range of rock types without the drawbacks of hydraulic fracturing. With a unique acid and fracking-free approach, we give operators the confidence to access complex reservoirs i.e., delivering increased productivity, even in very deep and tight wells.

Fishbones stimulation systems are open hole liner completions, which are run on a normal reservoir liner string, to connect the well and the reservoir in a single, simple, and efficient operation. Our unique small diameter laterals jet or drill out from the wellbore, penetrating the reservoir exactly where needed. Fishbones has a proven track in increasing productivity in oil and gas wells and injectivity in water injection wells resulting in improved field economics.

As our approach is always tailored and focused on finding solutions to our customer’s challenges by research, development, and innovation, this means our technology can also be applied to any geothermal well. However, wells are drilled in a variety of geological settings, so Fishbones approach is adapted to suit the specific needs of our customer’s well location and reservoir type.

The Iceland Deep Drilling Project (IDDP) is an innovative attempt to unlock the immense energy potential hidden within superhot geothermal resources. Despite the challenges encountered during the drilling of IDDP-1 and IDDP-2, such as extreme heat and corrosiveness, these explorations have provided a platform of learning that is instrumental in the planning and execution of the upcoming IDDP-3 project. The lessons learned through successes and failures, coupled with potential solutions, will help navigate the path ahead. This presentation discusses these critical lessons and their implications, and how they will shape the success and trajectory of the upcoming IDDP-3 project.