Facilities at RCSG
World-class combination of equipment for well technology research
An overview of the facilities at RCSG
A drilling rig is permanently installed above a 387m deep well that is completely cemented. Experiments can be executed in the well, e.g. by installation of a casing string in the well.
Shallow test well
In addition to the 387m deep test well, the center also has a shallow well of approximately 12 m deep inside the building. This is sufficiently deep to allow a single piece of casing to be completely installed in the well. An ideal testing environment is therefore available before going to the larger scale rig and/or field application. A wellhead can be placed on top of the well enabling to put pressure on the system. The overhead cranes present in this hall facilitate the installation of the casings or tools in the well, in order to carry out experiments safely, quickly and effectively. Logging tools have recently been tested in the well and also various cement and plug testing has been undertaken.
400T hydrostatic press and 300T mechanical press
The 400T hydrostatic press and 300T mechanical press can be used to support experiments requiring large mechanical force or loads, for example mimicking formation load, placement forces or hydrostatic load. Downhole conditions can be simulated by adding heaters to the components. The presses are characterized by a simple setup to apply force on tools and materials, e.g. to test mechanical loading of casing materials. The 400T setup is able to test larger samples. Samples are automatically handled to ensure safe (hands off) installation of materials, casings, tools etc. Fluids (mud) can also be taken into account for testing. The press is simple to handle, which makes it perfect for quick preparation tests.
The “High Internal Pressure Equipment “, or HIPE, is a 6 meter high pressure vessel specifically designed for strength testing casing and tubing. The size allows long sections of these casings or tubes. both burst and collapse tests can be performed with operating pressures of up to 1000 bar (14,504 psi). This type of test is for example relevant for the strength testing of casings made from new materials,. also, pressure testing of sensors etc. can be performed.
The equipment present here enables the researcher to simulate the conditions for drilling in the subsurface. This mainly concerns the simulation of the high pressure that prevails in the subsurface. A drill bit is placed in the pressure vessel that can drill a rock sample that is placed in the pressure bombe. This vessel is connected to the mud pumps in the basement which deliver the fluid pressure for the drilling experiments. The mud with cuttings are transported to the shaker, similar to the ones operated in the field, where the cuttings and the liquid are separated 9similar to field operations). During drilling, a vertical load is applied to the drill head, which can reach up to 50 tons (hence the name). Because these are high pressure experiments, there are high safety standards when performing the experiments. For example, the operator space is protected with extremely thick safety glass. The RCSG uses rock samples from stock or has samples made from cement that can be used for the drilling experiments.
At the RCSG we have large scale flow loops to support research aiming at flow optimization for production and drilling. For the geothermal and district heat sector it is essential to reduce the pump energy for circulation as much as possible. RCSG is supporting a consortium of partners from the district heat sector and academia to investigate environmental friendly drag reducing molecules in the DRAGLOW project. Progress and results of the first phase are shared on the 14th of April 2022, please see more details here.
Cutting flowloop. This flow loop has been developed to investigate the behavior of “cuttings”, the rock and sediments that are released during drilling as grains or small chips. These cuttings need to be removed from the hole in order to prevent the well from clogging up during drilling. This hole cleaning is generally performed by pumping fluid in the well that transports the cuttings to surface. This is a crucial part of the drilling process and can be particularly cumbersome in horizontal wells. The installed tube on the flow loop is transparent, which makes it possible to monitor the flow and transport behavior with cameras. With the tube, which can be arranged horizontally, vertically from an angle, a casing bore is simulated during drilling or production. For example, a rotating drill string can be installed in the pipe to facilitate the situation in the field. It is important to understand the behavior of the cuttings and fines because they can have an impact on the mechanical performance of the drill string and bit and can also have a detrimental effect by wear on the well materials.
ESP flowloop. Geothermal wells in the Netherlands use downhole pumps (Electrical Submersible Pumps) to produce the hot water from the wells. A dedicated set-up is currently being build at RCSG for use on the cutting flowloop frame that enables the investigation of the performance of these ESP’s, as this is critical for the success of geothermal projects.
Narrow annuli flowloop. It is expected that more and more geothermal wells will be drilled with one or more horizontal legs. Wells with horizontal legs are able to deliver more water to a particular geothermal installation at one surface location. This potential increase of power output per surface location will become essential for the built environment where surface area for developemnt of infrastructure is scarce. The horizontal flow loop helps to identify the ideal conditions for cuttings transport from horizontal wells and therefore for the execution of horizontal wells.
Multiphase flow loop. The Multiphase Flow Loop was originally designed and installed to investigate the behavior of mixtures of water, oil and gas. Storage vessels are in place where the liquids can be stored, after which they are mixed into a stream. The flow behavior can be examined in the loop that has a horizontal section that can also put under an angle. For example, you see a viewing window in which you can monitor with a camera. We are currently investigating whether the loop can be put back into operation, for example to investigate scaling, i.e. the precipitation of minerals from the liquid. This is sometimes an operational problem in geothermal installations. It could also be investigated in the future whether experiments can be performed with CO2 or CO2-rich mixtures, relevant for CO2 storage.
Rotary Expansion Test facility
De Rotary Expansion Test Facility, of afgekort RETF.htm, is in staat om op casings over de gehele lengte krachten uit te oefenen, al dan niet in combinatie met torsie. Dit kan van belang zijn om de sterkte van materialen te testen tijdens installatie of tijdens het gebruik, waarbij de krachten in de ondergrond worden gesimuleerd. Als er nieuwe materialen op de markt komen, bijvoorbeeld composiet casings, biedt de RETF goede mogelijkheden om de sterkte hiervan te bepalen.