PILOT TEST OF CO2 SEQUESTRATION AND ECBM IN JAPAN

Transcription

1 PILOT TEST OF CO2 SEQUESTRATION AND ECBM IN JAPAN Kotaro Ohga 1, Masaji Fujioka 2, Shinji Yamaguchi 3, Miyao Nako 4 1. Hokkaido University,N13 W8, Sapporo, ,JAPAN 2. Japan Coal Energy Center,Mita ,Minato-ku, JAPAN 3. Akita University,Tegatagakuencho 1-1, ,JAPAN 4. General Enviromental Technos Co.,LTD.,Azuchi-cho 1-3-5, Chuou-ku,Osaka,JAPAN Abstract JCOP has been commenced since JFY2002 with full subsidy from Ministry of Economy, Trade and Industry. Yuubari area of Ishikari coal field in Hokkaido was selected as the most suitable pilot test field, because the coal seams of this area are gassy and permeable. The fundamental phase consisting of laboratory experiment and preliminary field experiment has been designed to investigate technical and economical feasibility of storing CO2 in coal seam until end of JFY2006. Injection well (IW-1)was drilled in the end of 2003, production well(pw-1) was drilled in the summer of The distance in the coal seam between the vertical injection well (IW-1) and the deviated production well (PW-1) was about 65m. CO2 injection and CH4 production tests were carried out from the end of this August to the end of H 2 O Injection Pump P PC H 2O Water CH H 2O H 2O 4 September, Fig.1 Outline of Pilot Test of CO2 Injection into Coal Seam in JAPAN From the results, gas and water production rates were observed lower than estimation rates. The gas production rate reached the peak at a few days after CO2 injection. It is seems that this increasing of gas production rate was due to inject CO2. These measurement results were in agreement with calculation results. Keywords; CO2 Sequestration, Coal Seam, ECBM, Simulation Field Test of CO2 Injection Production well (PW-1) was drilled in the summer of The distance in the coal seam between the vertical injection well (IW-1) and the deviated production well (PW-1) was about 65m, as shown in Fig.1. Injection Well The injection system consists of a tank to store liquid carbon dioxide and a couple of pumps to inject the carbon dioxide and vaporizer to vaporize liquid carbon dioxide as shown in Fig. 2. The capacity of the tank is 15kl and designed pressure is 2.45Ppa. The maximum pressure and flow rate of the pump is 18Mpa and 500kg/h, respectively.

2 Production Well Fig.3 shows the PC pump installed on the production well head. Water was produced through the tubing by PC pump and gases moved through the annulus to the surface from the well. Gas production rate, water production rate and concentration of methane and carbon dioxide are measured and recorded. Recorded data was sent to the university by a mobile phone regularly. CO2 Injection System Tank Volume L Vaporizer Injection well Pump 500kg/h2 Valve Fig.2 Injection System Coal seams Fig. 3 Production Well CO2 INJECTION TEST IN 2005 After the improvement of PW-1 and IW-1, production test was carried out from the end of July to December 5th, 2005, for 150 days. About 115 tons of carbon dioxide was injected under the injection pressure 15MPa. Fig.4 shows the results of the production and carbon dioxide injection tests. Blue bar, red bar and green line indicate the water production rate, gas production rate and carbon dioxide injection rate, respectively. The carbon dioxide injection pressure was kept at 15MPa, Fig.4 Results of Injection Tests but the carbon dioxide injection rate increased gradually. The gas production rate increased few days after starting the carbon dioxide injection and the gas production rate reached the maximum rate, which was three times as much as the initial production rate; few days after stopping the carbon dioxide injection, it decreased. The total volume of gas production was about 23300m3 and total volume of water production was about 44.6 m3 during the testing period.

3 NUMERICAL SIMULATION History matching was carried out by using data of injection tests. We used COMET3 as a simulator. Fig.5 shows the grid for numerical simulation. Table 1 shows the values which were used for the numerical simulation md was used as 30 permeability of surrounding of injection well and 1md was used as whole of coal seam. RF carve was used as relative permeability carve. Langmuir values were measured in our laboratory. The carbon dioxide injection pressure and water production rate were input. Gas production rate and carbon dioxide injection rate were calculated. The results of the numerical simulation are shown in Fig.6. Green line indicates calculated injection rate. Red line indicates calculated gas production rate. Calculated results agree approximately with measured results. Fig.7 shows the distribution of carbon PW-1 IW- Fig.5 Grid for Calculation dioxide at the stop of the carbon dioxide injection. Fig.8 shows the distribution of carbon dioxide in the case where gas production was continued for two years after stopping the injection. There is no difference between the distribution of carbon dioxide at the stopping of the injection and two years after the stopping of the injection. Fig.9 shows the results in the case where carbon dioxide injection was continued for two years. Gas production increased gradually. Carbon dioxide concentration became 4% at 330 days after the starting of the injection. After that, carbon dioxide concentration increased gradually. Calculated total carbon dioxide injection volume is about 508,900m3, and total gas production is 244,200m3. Table 1 Model Input Parameters Permeability of Coal Seam 1.0md CH4 Langmuir Volume 28.0 m3 Permeability surrounding 0.13md CH4 Langmuir Pressure KPa injection well CH4 Diffusion Time 18 days CO2 Langmuir Volume 44.0 m3 CO2 Diffusion Time 40 days CO2 Langmuir Volume 972 KPa Relative Permeability RF Porosity of Coal Seam 1.0% Coal Seam Temp. 30 C Initial CH4 Concentration 98% Fracture Width 7.5 mm Initial CO2 Concentration 2%

4 Fig.6 Results of Numerical Simulation Fig. 7 Distribution of Carbon Dioxide At Stopping Injection Fig.8 Distribution of Carbon Dioxide At Two Years after stopping Injection Fig.9 shows the results in the case where carbon dioxide injection was continued for two years.

5 CONCLUSION 1) From the water injection test, the average permeability of coal seam is about 1.0 md. 2) However, very low gas and water production rates were observed at the production tests. Production damages due to plugged perforation holes with fine coal particles might have caused these low production rates. 3) The gas production rate increased gradually after carbon dioxide injection and then it reached the peak. After stopping injection gas production rate decreased to the initial gas production level gradually. It is seems that this increase was due to the carbon dioxide injection. 4) From the numerical calculation, there was no difference between carbon dioxide distribution surrounding the injection well after the stopping the injection and also two years after stopping the injection. 5) If the gas production rate does not improved, it will take about one year for the injected carbon dioxide to reach the production well. REFERENCES (1) M.Fujioka and S.Yamaguchi, Proc. Of 3rd International Workshop on Prospective Roles of CO2 Sequestration in Coal Seam, Sapporo, 2004,85 (2) M.Nako and H.Komaki, Proc. Of 3rd International Workshop on Prospective Roles of CO2 Sequestration in Coal Seam, Sapporo, 2004,13 (3) K.Ohga, Proc.of International Coalbed Methane Conference,Alabama,2005,CD-ROM (4) K.Ohga,M.Fujioka,S.Yamaguchi and M.Nako; Proc.of 2005 ICCS&T, Okinawa (5) K.Ohga,M.Fujioka,S.Yamaguchi and M.Nako; Proc. of International Coalbed Methane Symposium,Alabama,2006 AKNOWLEDGEMENTS This research was a part of the Project of Carbon Dioxide Sequestration Development Technology into the Coal Seams. It was funded by KANSO Technos CO.,LTD and METI( The Ministry of Economy Trade and Industry). We would like to thank to Mr. Soejima for the measurement of field tests and Mr. Honiden for thenumerical calculations...