Development of a well impermaint model for predicting clogging of geothermal injection zones

Publieke samenvatting / Public summary

Geothermal energy (Figure 1) has a high potential for environmentally-sustainable energy generation, because of its high surplus heat availability. The Dutch Masterplan Geothermie2 sets firm ambitions for the growth of geothermal energy to attain around 50 PJ (175 doublets) in 2030 and 200+ PJ (700+ doublets) in 2050. To achieve the CO2 reduction goal, 5% of the 930 PJ of heat production by 2030 and 23% of the 870 PJ by 2050 must be produced by the geothermal energy sector1. In Dimoprec we direct attention to the following points as stated in the Master Plan:
1) cost-effective projects,
2) safe & effective operational activities,
3) strong societal support (public acceptance).
In Dimoprec, we focus on regular techno-environmental problems. The chemistry of geochemical fluids comprises various types of minerals and gases, causing scaling and clogging of the geothermal system. The resulting reduced injection and production rates, lead to higher pumping costs and by that higher energy requirement, i.e., CO2 emission; this can be a showstopper3. We develop a scaling prediction tool and a set-up to detect and manage the degree of reduction in mineralization under prevailing conditio

The general aim is to accelerate energy efficient geothermal development. Through knowledge development, we minimize operational risks and prolong the lifespan of geothermal systems, reduce operational costs with environmental-societal risk minimization and improve subsurface integrity. Our focus is to develop a tool for clogging and mineralisation prediction, tested with a newly developed scaling skid in the field.
Geothermal energy replaces hot water production by fossil fuels. A well that produces 200 m3/hr of water, using a temperature drop of 40 °C , produces ca. 9 MW energy. Deducting the peripheral energy of pumps, etc., gives an effective result of at least 4.5 MW. So, it plays a key role in CO2-emission free energy production, over at least 30 years. The above goals are under ideal economic and technical conditions without decline in reservoir and well performance. Here, a major issue is clogging through mineralization of the geothermal system.
Our geo-systematic predictive model improves the sustainability and provides long-term reliable operational solutions. Our newly-developed scaling skid gives predictive insights and allows to test the verified model outcome.

Korte omschrijving
The overall goal of the project is to realize a cost-effective and socially accepted decision-making framework for sustainable geothermal heat extraction; i.e., the perception of geo-stewardship. Considered are the technology, the geo-effects, and the robustness of the tool within the techno-environmental framework.
The guidelines to solve the clogging-mineralization issue will be established for geo-environmental situations (>1500 m).Optimized operational conditions will be demonstrated in candidate Dutch geothermal reservoirs. The predictive full-field model will be validated using field data from three doublets. So, this cooperation includes the share and use of industrial and academic expertise to develop and apply our generic geothermal tool for the relevant industry and other stake holders, checking high temperature-pressure-chemical interactions under in-situ conditions. Furthermore we develop and build a field tool (scaling skid) for on-site scaling testing. The tool compares changes in system parameters, to the model outcome. The study focuses on TRL 4 to 6, to improve the value chain of the concept preceding a prototype field demonstration in Dutch geothermal wells.

Climate mitigation is based on 1. CO2 reduction through sustainable energy production; 2. energy savings; and 3. CO2 capturing. Our project covers the first two as part of the energy transition’. DIMOPREC focuses on cost reduction, subsurface de-risking and on affordable and sustainable heat supply. We develop a tool and procedure to detect, control and avoid clogging and poor reservoir/well performance. We develop guidelines to deal with the chemical complexity, i.e.:
1. Improvement of geochemical model predictions by decreasing the uncertainty by incorporating effective geo-chemistry information.
2. Development of a tool and a field-scale predictive clogging model and delineating a safe window to facilitate management of operational and environmental risks.
3. Cost effective geothermal projects by reduction of clogging, i.e.:
• Limited consumption of costly and environmentally-questionable inhibitors.
• Improving well performance, both injectivity and productivity, inducing higher production rates.
• Geothermal fluid circulation cost (OPEX) reduction, (15-25%) of the total cost