Preliminary Study of CO 2 Storage in Coal-Bearing Formation in the Ariake Area, Kyushu, Japan

Transcription

1 Preliminary Study of CO 2 Storage in Coal-Bearing Formation in the Ariake Area, Kyushu, Japan MAGEEP Symposium Oct. 04, 2010, St. Louis Zhenjie CHAI and Sohei SHIMADA Graduate School of Frontier Sciences, The University of Tokyo 1

2 Outline of Presentation 1: Background 2: Simulator development for coal-bearing formation (CBF) 3: Simulator verification 4: CO 2 storage capacity in Ariake CBF 5: Geological model in Ariake area 6: Results 7: Conclusion 2

3 Objectives of cooperative work in CCCU Prof. Jun group :conducting micro analysis approach, chemical reaction minerals (rocks) with CO 2 Shimada group: macroscopic approach, gas adsorption measurement on coal, ECBMR (Enhanced coalbed methane recovery) simulator Cooperation of two groups: CO 2 storage target formation: both rocks and coal Incorporation of micro and macro information on physical and chemical properties 3

4 Background 1) Characteristics of coal seam and saline aquifer as a CO 2 storage formation Coal seam: CBM production, adsorption (storage mechanism), large storage capacity in unit volume, works as a caprock by retarding effect of CO 2 flow, thin formation, Saline aquifer: (mainly) dissolution (storage mechanism), thick formation 2) Some coal-bearing formations(cbf) (sandstone, shale) have similar properties as saline aquifer formation 3) Proposal of CO 2 storage in coal-bearing formation: CO 2 injection into coal seam(s) and storage in it and CBM production, At the same time; CO 2 storage in coal-bearing formation (sandstone, shale) 4

5 Mechanism of CO 2 Storage into DCBF CO 2 storage in CBF and ECBMR Dominant Mechanisms: 1.Sandstone Buoyancy (advection) Dissolution Diffusion 2.Coal Sorption Diffusion CO 2 Adsorption CH 4 Desorption Coal Seam CO 2 CH 4 DSA Formation Red: CO 2 Green: CH 4 Blue: CO 2 +CH 4 +H 2 O+NaCl Buoyancy Dissolution 5

6 Conceptual Structure Conceptual view of simulator Considering the processes of phase changes, thermal equilibrium has been taken into account for accurate computation of thermodynamic properties 6

7 Verification 2 Specification Simulator verification To verify the result of this simulator based on results from other simulators or models. For aquifer, the Test Problems in Pruess, Karsten, Garcia, Julio, Kovscek, Tony, Oldenburg, Curt, Rutqvist, Jonny, Steefel, Carl, et al.(2002). CO 2 -CH 4 mixing CO 2 Mole Fraction Distribution at elevation Z=50m at t=0.5 yrs and t=5 7 yrs

8 Verification 3 Specification Simulator verification For ECBMR, in David H.-S. Law, L.H.G. (Bert) van der Meer, W.D. (Bill) Gunter (2002) Undersaturated single-layer coal seam with 5-spot injectionproduction well pattern. 8

9 Prospective coal basins for CO 2 storage in Kyushu District, Japan coal basins and power stations are located near in this district Coal basins and large CO 2 emission sources 9

10 Location of Ariake area under sea coal seams, geological extension of the former Miike coal mine (largest underground coal mine in Japan), stratigraphy is rather well studied, Sealing performance is unknown mineable coal seams CO 2 storage and CBM production Ariake Area Coal 10

11 Storable CO 2 amount in Ariake area Dissolution CO 2 amount= Ef A h φ Rs CO 2 = 279 x 10 6 ton Ef: sweep efficiency(%), A:area of geological structure(m 2 ), h:average thickness(m), φ:porosity(%),rs CO 2 :solubility of CO 2 (kg/m 3 ) Adsorption CO 2 amount = Ef A h d Ad CO 2 = 31 x 10 6 ton Ef: adsorption efficiency(%) A: area of geological structure(m 2 ), h: average thickness(m), d: density(t/m 3 ) Ad CO 2 : adsorption amount of CO 2 Source : RITE, 2000 The above results are based on the equilibrium state. Dynamic assessment of CO 2 flow is necessary for the stable and safe storage. 11

12 Case Study - Specification Geological model in Ariake area Area Average Depth Overburden Upper Coal Seam Saline Aquifer Lower Coal Seam Underlying 3km 3km m Sandstone Bituminous Sandstone Bituminous Mudstone Ariake sea Production well Injection well 5-spot pattern 12

13 Reservoir Model Geological model in Ariake area Prod Prod Storage target formations 300m Inj 50m 50m 50m 2m 2m 5m 5 Spot Pattern CO 2 injection from lower coal seam (Inj), CBM production from lower and upper coal seams (Prod) No Name Yotsuyama- Katsutate formation Upper coal seam (Daini-Joso) Katsuatate formation Nanaura formation Lower coal seam (Joso) Nanaura- Inari formation Fine-grain sandstone Bituminous Mid-grain sandstone Corsegrain sandstone Bituminous Mudstone Porosity Abs. Perm. [md] / / /0.10 Blue: measured, Red: estimated 13

14 Injection Rate CO 2 injection condition CO 2 injection amount: 80% of dissolbable CO 2 amount in sandstones CO 2 injection rate; Type 1: 5,000 sm 3 /day, with max. BHP constraint (20MPa) Type 2: 20,000 sm 3 /day, with max. BHP constraint (20MPa) Type1 constant injection volume Type2 injection volume decreases gradually due to BHP constraint 14

15 Simulation Result Change of CO 2 storage mode dissolution gas phase adsorption Gas phase decreases and dissolution gas increases after injection stopping. 15

16 Simulation Result Flow-out from upper coal seam About 25% CO 2 flows out from the upper coal seam. (Total injection amount = 60 x 10 6 sm 3 ) 16

17 Simulation Result Flow-out from lower coal seam CO 2 flows back from mudstone to lower coal seam. 17

18 Distribution of gas phase CO 2 concentration 5 years 10 years 50 years coal seam coal seam 120 years 300 years 18

19 Conclusions & Discussions Geological condition of ECBMR project site in Qinshui coal basin fine grain sandstone mudstone Appendix Source: Prof. Qin, Japan CBM Forum, Jan., 2010 Thin coal seam with smaller storage volume, and the sandstone roofs and floors that might be resulted in CO2 diffusion. Roof of the coal seam is mudstone with strongly sealed capability. The coal seam is 4-6 meters in thickness with larger storage volume. floor of the coal seam is mudstone with strongly sealed capability. Optimal CO 2 stored seam in Qinshui basin md (average 0.7 md) Thin coal seams with smaller storage volume, and the limestone and sandstone roofs and/or floors that might be resulted in CO2 diffusion. limestone Al bearing mudstone md (greatly varied) Roof of the coal seam is limestone that might be resulted in strong CO2 diffusion md The coal seam is 2-5 meters in thickness with large storage volume. floor of the coal seam is allite with stronger sealed capability. less than Seam 15 19

20 Conclusion 1: Proposed CO 2 storage in coal-bearing formation (CBF). 2: Simulator for CBF CO 2 storage and ECBMR was developed. 3: CO 2 storage performance was investigated by using the above simulator for Ariake area, Kyushu district, Japan. The results showed the poor sealing performance in this area. 4: There are some sites suitable for CBF CO 2 storage. 5: The developed simulator is a strong tool for the site characterization of CBF CO 2 storage. 20

21 Future work Investigate how geochemical reaction alters geophysical properties. Incorporate the findings into the model. 21

22 Thank you for your kind attention. 22