The Hontomín Technology Development Plant is located in northern Spain, 30 km from the city of Burgos. The site includes one injection well and one observation well, both of them located at a depth close to 1,580 m. Both deep wells are fully instrumented and further monitoring capacities include a shallower hydrogeological monitoring network, and a set of tools in surface, as 30 microseismic control stations. The carbonate reservoir is in a dome-like structure with a low primary porosity in the rock matrix and fluid transmissivity mainly through the fracture network, expanding the scope of R&D activities on CO2 storage in comparison of traditional porous media. The Hontomín site offers high flexibility of CO2 injection conditions being prepared for CO2 injection in the liquid, gas and supercritical phases and thus is ideal for experimentation of different injection strategies. Its CO2 injection plant includes three cryogenic injection pumps allowing injection rates between 0.5 and 2 kg/s and pressures up to 120 barg and three cryogenic CO2 tanks of 50 ton capacity. The installation is complete with a gasifier to adjust the CO2 temperature and a water injection plant, which plays a crucial role in the pressure control during injection and other operative phases. The water injection plant includes a ceramic plunger pump capable of 120 bar pressure and 300 l/min brine flow injection, a 25,000 l capacity deposit for water mixture preparations and four 2,500 m3 deposits for water storage besides the necessary water treatment equipment. The 1,580 m deep injection and observation wells are equipped with instrumentation ensuring the continuous monitoring of injection (WHP/T, BHP/T, distributed temperature along the injection tubing and RTD, inter alia), geochemistry (deep sample for fluids) and observation (pressure/temperature and RTD) parameters and a wide range of surface monitoring techniques are applied on site for assessment of the injected CO2 behaviour. The injection well (H-I) and the deep monitoring well (H-A) have been fully instrumented with a U-tube fluid sampler, P/T sensors, DTS, ERT electrodes and an array of retrievable hydrophones. All these data, plus the information collected at existing monitoring devices in shallow aquifers (hydrogeological and hydrogeochemical network of shallow aquifers) and in surface (30 micro-seismic control stations), are collected and managed at the control room, where access can be provided for dealing with an specific research purpose on CO2 storage.
Experiences on CO2 storage, excluding EOR activities, are mainly related to clastic reservoirs with high porosity and permeability values. Several monitoring activities have been adapted from the oil and gas industry. However, injection in a fractured carbonate reservoir will allow working in non-ideal conditions, thus leading to find solutions that CO2 storage development may find during its implementation at demo or commercial scale, in a controlled area. Extensive site characterization data has been acquired during the past years, and baseline values can be used to compare them with the activities to be performed in the facility. HontomínTDP is the only large scale pilot for CO2 storage in operation in Europe and has been recognized by the European Parliament as a key test facility (E.P. Resolution 2014)
HontomínTDP has been in the commissioning phase, limited CO2 injection has taken place until the end of 2014. The works at Hontomín will aim to improve storage monitoring techniques and methodologies.
Key issues can be tested such as: