gas hydrate - CCOP

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RESULTS AND DISCUSSION In the following, we present model results for sediments deposited in a typical continental slope setting at a water depth of 1000 m, a bottom water temperature of 2°C and a geothermal gradient of 30°/km (Figure 1). Under these conditions, the hydrate stability zone extends over the upper 410 m of the sediment column (Tishchenko et al., 2005). In the upper sediment column sedimentary organic matter is degraded via microbial sulfate reduction until dissolved sulfate is completely consumed. Microbial degradation of organic matter proceeds in the underlying sediment section and produces dissolved CH 4 and CO 2 . Methane is partly lost by diffusion into the overlying sulfate-bearing pore water where it is consumed via AOM (Luff and Wallmann, 2003; Wallmann et al., 2006). The remaining methane accumulates in the pore fluids until the dissolved methane concentration reaches saturation so that methane hydrates precipitate from solution (Figure 1). Hydrate concentrations increase with sediment depth within the HSZ. However, even at the base of the HSZ, less than 1% of the pore space is occupied by hydrate. It would not be economically feasible to exploit sedimentary hydrate deposits with such low concentrations (Makogon et al., 2005). Figure 1. Model results for organic matter degradation and hydrate formation in slope sediments (w f = 50 cm/kyr, v 0 = 0 cm/yr, POC 0 = 2.0 wt-%). Top row: Temperature (T), pressure (P) and porosity. Second row: Concentrations of dissolved sulphate (SO 4 , note that only the upper 15 m of the sediment column are plotted since sulphate is depleted in deeper sediment layers), concentrations of dissolved inorganic carbon (DIC), dissolved methane (black line) and solubility of pure type-I methane hydrate (blue line). Third row: Rate of methane formation (R M , note the logarithmic scale), concentrations of particulate organic carbon (POC) and gas hydrates (GH, given in % of pore volume filled by hydrate). Hydrate concentrations in sediments increase with sedimentation rate and POC contents (Wallmann et al., 2006). Figure 2 shows that hydrates are only formed at POC concentrations greater than 1 wt-%. The depth-integrated inventory increases almost linearly with the POC concentration in surface sediments. High methane inventories can only be found in rapidly accumulating sediments being extremely rich in organic matter. 14 New Energy Resources in the CCOP Region - Gas Hydrates and Coalbed Methane
Figure 2. Depth-integrated inventory of methane hydrate as a function of sedimentary POC concentrations in the uppermost sediment layer. The depth integration is done over the entire HSZ (0 – 410 m sediment depth) and the inventory is given in kg methane carbon bound in hydrates per depositional area. Simulations were done using the boundary conditions and parameter values specified in Figure 1. Additional model runs were performed to investigate the effect of upward fluid flow on the hydrate inventory. These simulations confirm that the inventory is greatly expanded by upward fluid flow (see also (Buffett and Archer, 2004). With our model and parameter values, the hydrate inventory in sediments with a surface POC concentration of 1.5 wt-% increases from 44 kg C m -2 without fluid flow (v 0 = 0) to 240 kg C m -2 at v 0 = 0.1 cm yr -1 . CONCLUSIONS The new kinetic rate law for organic matter degradation in anoxic marine sediments (Wallmann et al., 2006) applied in this contribution shows that in-situ production of methane within the HSZ usually results in low concentrations of gas hydrates that are only of very little economic significance. In sediments which are not affected by methane inflow from below, significant hydrate concentrations are only obtained at very high sedimentation rates (>50 cm kyr -1 ) and POC concentrations (>2 wt-%). Hydrate inventories are, however, greatly enhanced by upward fluid and gas flow. Economically important hydrate deposits will thus usually be found in areas of active fluid and gas flow. New Energy Resources in the CCOP Region - Gas Hydrates and Coalbed Methane 15
Page 2 and 3: Coordinating Committee for Geoscien
Page 4 and 5: Thematic Session on New Energy Reso
Page 6 and 7: CONTENTS Page OPENING REMARKS……
Page 8 and 9: OPENING REMARKS by Chen Shik Pei Di
Page 10 and 11: WELCOME ADDRESS by Tai-Sup Lee Pres
Page 12 and 13: WELCOME ADDRESS by Keun-Pil Park Di
Page 14 and 15: CONGRATULATORY ADDRESS by David Pri
Page 16 and 17: PART I GAS HYDRATE: EXPLORATION, RE
Page 18 and 19: Partial differential equations for
Page 22 and 23: REFERENCES Berner R. A. (1980) Earl
Page 24 and 25: features of the seabed than those o
Page 26 and 27: secure the stability of the solutio
Page 28 and 29: trends depending on the following f
Page 30 and 31: Organic carbon in sediments is of i
Page 32 and 33: Sedimentological and Geochemical As
Page 34 and 35: Figure 3. Sedimentation rate of the
Page 36 and 37: Marine Gas Hydrate off W. Canada an
Page 38 and 39: Several methods for computing the Q
Page 40 and 41: 0.035 0.03 Amplitude 0.025 0.02 0.0
Page 42 and 43: 60 50 Amplitude 40 30 20 10 0 0 50
Page 44 and 45: REFERENCES Dallimore, S.R. and T.S.
Page 46 and 47: Frequency % 20 16 12 8 HAMA #5, MV=
Page 48 and 49: Figure 3. Experimental procedures f
Page 50 and 51: Figure 7 shows two cases of the com
Page 52 and 53: Seismic Characteristics of Gas Hydr
Page 54 and 55: Purpose The purpose of this paper i
Page 56 and 57: The dissociation zone created by th
Page 58 and 59: hydrate that forms near the wellbor
Page 60 and 61: dissociation, composite thermal con
Page 62 and 63: Figure 9. The Advanced Light Source
Page 64 and 65: Experimental Studies and Developmen
Page 66 and 67: Natural gas hydrate exploitation an
Page 68 and 69: Natural gas Free gas layer Figure 5
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Figure 7. One-dimensional developme
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Temper at ur e 2 1 0 -1 -2 -3 -4
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From the above discussion, the heat
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INTRODUCTION Clathrate hydrates are
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MATHEMATICAL MODEL The mathematical
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Where the hydrate-aqueous radius of
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REFERENCES Brooks, R.H., and A.T. C
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86 New Energy Resources in the CCOP
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In this paper, an overview of the M
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The brief tasks in the Phase I are:
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In "Development of the dissociation
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Figure 5. Preparation equipment. AN
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Other recent research subjects in t
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same crystalline structure directly
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Another important aspect of the pre
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a + CO 2 CH 4 C 2 H 6 b CH 4 in sII
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REFERENCES Collett, T.S. and Kuuskr
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Figure 1. Physiographic and crust m
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Figure 3. Seismic profile showing s
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Figure 7. Distribution of echo char
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Figure 10. Seismic profile and its
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In the early stage of back-arc open
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PART II COALBED METHANE (CBM)
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Supply and demand infrastructure of
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Amisan, Jogyeri, Baegunsa, and Seon
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PROPERTIES OF ANTHRACITE The coals
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Table 4. Average chemical compositi
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CONCLUSIONS 1. Most of the coals em
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INTRODUCTION Coal (total reserves 2
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RESULTS By Government: The outcomes
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The gas composition (12 samples ana
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Table 4. Coal Depth Interval Hole N
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The results of studies made on 11 c
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CONCLUSION CBM is still hoped to be
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The Government of Indonesia through
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The Berau basin is a major coal pro
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PP: CBM - 1 Rambutan (GOI Sponsor)
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Overview of Project for CO 2 Seques
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The organic geochemistry research g
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3.5 25 3.0 20 Ar(%) C O 2(%) 2.5 2
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20 8 10 0 6 δ13C of CO2(‰) -10 -
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Figure 1. Index map of Akabira Coal
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ORIGIN OF AKABIRA CBM In Akabira mi
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gas hydrate - CCOP

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