CO2CRC Otway Project

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Thursday 22 September

The Otway Project Stage 2B residual gas saturation test has been successfully completed. After eleven weeks of continuous operations, the remaining formation water was pumped back into the Paaratte, concluding a sequence of five carefully prepared tests; a hydraulic pressure test, tracer tests, thermal test, RST and dissolution test.

Stage 2B had been planned for several years and the complexities, risks and opportunities of the test sequence were well understood. Diligent planning, modelling, drilling, coring and well completion by more than 30 CO2CRC researchers and many helpers paid off with all down hole sensors working perfectly and excellent data collected. The work was conducted without any HSE incidents or accidents.

Otway at Night
Diligent planning has led to a highly successful Stage 2B

Instrumental to the success were leading scientists from Laurence Berkeley National Laboratories (USA), CSIRO and Geoscience Australia and a number researchers and technicians from GA, CSIRO, The University of Melbourne, University of Queensland, The Australian School of Petroleum, LBNL and KIGAM (Korea). The teams on site were working smoothly together.

The project is of global significance and with the amount of data collected there are many months of serious and exciting interpretations ahead of the team.

Read the media release here

Thursday 15 September

Stage 2 experiments at the Otway Project are nearly complete. The most critical part of the experiments was to force CO2 to be permanently stored in the rock pores deep underground (residual gas saturation), by injecting formation water and dissolved CO2. The injection mimics deep geological CO2 storage in the rock formation 1400 metres underground. Despite some technical challenges the injection went very well.

Otway at Night
Operations at the Otway Project ran 24 hours a day during the experiments

The team then injected small amounts of noble gas tracers and a second round of intense sampling was completed. Very good results were obtained during the sampling process - it looks like this part of the work has been highly successful.

Most recently a round of reactive tracers have also been injected with formation water containing dissolved CO2. The next job is to take samples from the formation in the same way as the previous round, giving the team another set of data to evaluate the formation.

Yong-Chan Park
Yong-Chan Park from KIGAM (Korea) at work during the sampling phase

Once these tracer tests are done the final experimental stage will begin. A dissolution test, which will assess how much and how quickly CO2 dissolves into the formation water deep underground, will be the last experiment. Pristine formation water will be reinjected into the formation, dissolving all residually trapped CO2. Samples with the newly dissolved CO2 are then being taken and analysed for the CO2 that was previously residually trapped.

Finally, the remaining formation water on the surface in tanks will be reinjected back into the Paaratte Formation.

Atmospheric monitoring
New atmospheric monitoring equipment is being trialled during the Stage 2 experiments

Cows
Friendly locals

Monday 22 August

Despite some delays (unsurprising for an Australian-first project), the pure CO2 injected earlier has been followed by 450 tonnes of formation water containing 22.5 tonnes of dissolved CO2. This injection has pushed the pure CO2 out into the porous rock, leaving some trapped behind in the tiny pores (this is the permanently stored CO2 we are trying to measure). This has established  ‘residual gas saturation’ - as much CO2 permanently trapped as possible. This part of the experiment mimics how CO2 would be trapped over a much longer period of time as part of a commercial CO2 storage project.

Since the injection the team has been evaluating conditions in the reservoir via pressure measurements and temperature measurements, via a heating/cooling cycle. Another major test sequence begins next week - noble gas tracers will be injected for the second time and samples taken every 90 minutes, 24 hours a day for three days. A busy time for all but by using a range of different methods the CO2 storage capacity of the reservoir can be measured much more accurately. By next week we will have some good pics too - stay tuned!

Injection well

The first stage of CO2 injection has been completed!

Over 4 days, 150 tonnes of pure CO2 (three of the big white tanks) has been injected into the rock 1500 metres underground. This CO2 injection is mimicking  storage of CO2 as part of a CCS project. The next step is to conduct a heating/cooling test, to gather information on how CO2 storage affects the rock properties, before we push the pure CO2 out into the formation with water. Scientists estimate it will only travel about 15 metres into the rock.

As you can see from the frozen pipes in the photo, the CO2 comes out of the tank at -20C. It passes through two vaporisers and a heater to bring it up to about 30C. It is still under enough pressure (5600kPa) to keep it as a fluid when it is injected.

 

Wednesday 6 July

The geochemistry team is now flat out taking samples every two hours, 24 hours a day (it's a tough job but someone's got to do it!). They are using Lawrence Berkeley Laboratory's U-tube system, installed in the well back in February, to take samples from the formation 1400 metres underground. The samples are analysed for Krypton (Kr) and Xenon (Xe), the tracer gases injected on 3 July.  The results will help evaluate how quickly fluids move through the formation.

Geochem Team

 

Tuesday 5 July: The first stage of water production is complete

More than 600 tonnes of water from the Paaratte reservoir are now stored on the surface in our three big tanks.  The team has been monitoring the water quality to follow the transition from drill hole water to pristine formation water. The water will be used to follow the injection of pure carbon dioxide later on - this will push the carbon dioxide out into the rock pores so we can measure residual gas saturation.

One interesting part of the project is the research into microbial activity 1400 metres underground in the formation. Andre Mu from the University of Melbourne and his colleagues took samples during water production to extract DNA and preserve them for microbial culturing. Andre and the team are looking at the kind of bacteria that live at those depths and how they might affect carbon dioxide storage.

Stage 2 experiments at the Otway Project are currently under way.

The experiments are investigating the ways injected carbon dioxide (CO2) is trapped in deep rock formations containing water. Over the next two months a series of extractions and injections of water and CO2 have been designed to evaluate the amount of gas trapped permanently underground through residual gas trapping. More detail on the experiments and residual gas trapping are here: Otway Project Stage 2 fact sheet.

A range of new equipment has been installed at the CRC-2 well.

The first part of the experiment is to produce formation water from the reservoir under study, 1500 metres underground. Three 240,000 litre water tanks will hold the formation water  which will be reinjected as part of the residual gas trapping test.

CO2CRC will use its own supply of natural CO2 from the Buttress gas well to help lift the formation water from the reservoir 1500 metres underground. The pipeline from the Buttress well to CRC-1 has been extended to CRC-2.

The 50 tonne CO2 tank, which will hold pure CO2 for injection, is the most visible piece of equipment. About 150 tonnes of CO2 will be injected into the reservoir to mimic the storage side of a carbon capture and storage (CCS) project.

The new CRC-2 well will be used to both extract and inject  formation water and CO2 for the experiments. It also contains the complex downhole monitoring and sampling instruments that are gathering baseline data and evaluating how much CO2 has been trapped.

CO2CRC Otway Project Open Day

The CO2CRC Otway Project Open Day in March was a success, despite some wet and windy weather. Over 50 local visitors, including students, nearby landowners and interested locals visited the site during the day, to hear about project progress, find out more about carbon capture and storage, and enjoy a free sausage or two. Several tours of the site were run, with the minibus visiting the CRC-1 injection well, Naylor monitoring well and Buttress carbon dioxide production well. The Open Day was a good opportunity for the public to see the project before surface construction work for Stage 2 gets underway.

Open day
Dr Peter Cook updates visitors on Otway Project progress
Open day
Hardy visitors braving the weather
Open day

Liaison officer Josie McInerney (left) discusses the project with visitors

The CO2CRC Otway Project STAGE 2

Stage 2 Installation of monitoring instruments

This video shows the installation of a 28 metre assembly of sophisticated pressure, temperature and sampling instruments at the CO2CRC Otway Project in February 2011 over about an hour.

 

Sandeep & Peter

Final preparations before the instruments are installed downhole

Project aim

The CO2CRC Otway Project is a world-leading international research project investigating the geological storage of carbon dioxide (CO2). In Stage 1, over 65,000 tonnes of carbon dioxide-rich gas was stored in a depleted gas reservoir and comprehensively monitored.

Stage 2 of the project is focussing on CO2 storage in saline formations - deep porous rocks containing formation water. Saline formations are very common worldwide and have the potential to store many years' worth of CO2 emissions.

Key risks for large-scale commercial projects include uncertainties regarding how much CO2 can be stored and how well the CO2 is contained. This project will help reduce these uncertainties and provide the basis for a cost-effective process to evaluate saline formations.

Storing CO2

CO2 is held underground in several ways, known as trapping mechanisms. In Stage 1 the CO2 was stored in a depleted gas reservoir - trapped by a seal rock above the formation and a sealing fault at the side of the formation. This is known as structural trapping.

The first experiment for Stage 2 is designed to test two non-structural trapping mechanisms: residual gas trapping and dissolution trapping. Residual gas trapping and dissolution trapping are important mechanisms in geological storage but have not been demonstrated to the extent of structural trapping - this experiment will provide valuable information on how much CO2 is trapped in this way.

Residual gas trapping occurs when a small amount of CO2 becomes disconnected or 'snaps off' from the CO2 plume as the CO2 moves through the porous rock. The CO2 is stored in the pores in tiny bubbles, trapped by surface tension. The CO2 can't move out of the pore space and remains fixed underground.

Dissolution trapping refers to the portion of CO2 that is dissolved in the formation water. Once the CO2 dissolves, the water becomes denser, sinks towards the bottom of the formation and is more securely stored.

Sandeep & Peter

The experiment

Stage 2 work began with the drilling of a new 1565 metre well, CRC-2, in February 2010.

During the drilling, over 176 metres of rock samples, known as core, were obtained. These samples have been tested extensively to evaluate the amount of storage space in the rock (porosity) and how easily CO2 can move through it (permeability).

Researchers will be able to compare these data with the results of the test injections to fine tune their computer models of storage capacity and security.

To test the trapping capacity of the rocks, the research team will undertake a series of small scale injections into the Paaratte Formation, using a series of instruments installed in the injection well at depths of around 1400 metres. The instruments include temperature and pressure sensors, as well as a system of U-tubes for deep formation sampling, similar to those used in Stage 1.

The aim is to break up the CO2 within the rock pores (residual gas saturation), then remove any remaining mobile CO2. A range of measurement techniques will help evaluate how much CO2 is left behind (permanently stored). By correlating that information with their understanding of the formation rock qualities, the researchers will be able to estimate the storage capacity of the formation using these mechanisms and extend that knowledge through modelling to similar formations.

Experiment plan

The experiment will take about two months and involves a series of extractions and injections.

  1. Before the residual gas test, formation water is extracted from the Paaratte Formation and stored on the surface in tanks. This water will be used for injections later in the experiment. A range of downhole instruments gather baseline data on the water saturated formation. Small quantities of tracer gases are injected in order to track how the CO2 moves through the rock.
  2. A relatively small amount of pure CO2, around 150 tonnes, is injected into the formation. This is mimicking the storage of CO2 as part of a Carbon Capture and Storage (CCS) operation and will fill the rock pores with CO2.
  3. After a period, formation water saturated with CO2 is re-injected to drive the formation to residual gas saturation.
  4. The amount of CO2 trapped is evaluated in a range of ways including water extraction, pressure sensors, tracer concentrations, temperature sensors and borehole logging measurements. By using a variety of testing methods, the experiment will reduce variation in results.


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