gas hydrate - CCOP

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Purpose The purpose of this paper is to summarize the studies conducted at the Lawrence Berkeley National Laboratory (LBNL), Berkeley, USA, in support of gas production from natural gas hydrates in geological media. These studies include numerical analyses of the gas production potential of the various classes of hydrate deposits, and laboratory investigations to determine important parameters and relationships describing the kinetic, hydraulic and thermal behavior of hydrate-bearing sediments. Finally, the LBNL studies in support of field tests of gas production from hydrates are briefly discussed. NUMERICAL STUDIES The Numerical Simulator The numerical studies were conducted using the TOUGH-Fx/HYDRATE simulator (Moridis et al., 2005a), which can simulate the non-isothermal hydration reaction, phase behavior and flow of fluids and heat in natural CH 4 -hydrate deposits. It includes both equilibrium and a kinetic model of hydrate dissociation, and accounts for heat and up to four mass components (i.e., water, CH 4 , hydrate, and water-soluble inhibitors such as salts or alcohols) which are partitioned among four possible phases: gas, aqueous, ice, and hydrate. A total of 13 states (phase combinations) can be described, involving any combination of hydrate dissociation mechanisms. Case 1: Gas Production from Class 1W Deposits Class 1 appears to be a promising target for gas production because the thermodynamic proximity to the hydration equilibrium requires only small changes in P and T to induce dissociation (Moridis and Collett, 2003; Moridis et al., 2005b). Additionally, the existence of a free gas zone can guarantees gas production even when the hydrate contribution is small. The Class 1W deposit in Case 1 involves a 15m-thick HBL, in which the hydrate saturation S H = 0.7 and the aqueous saturation S A = 0.3. The HBL is underlain by a 15m-thick zone of mobile gas and water. The reservoir radius is R max = 567.5 m and its intrinsic permeability k = 10 -12 m 2 (=1 Darcy). At the bottom of the HBL, the initial P = 1.067x10 7 Pa and T = 286.65 K, and the P and T distributions in the profile follow the hydrostatic and geothermal gradients, respectively. Gas is produced by depressurization through a heated well at the center of the reservoir at a rate of Q = 0.82 ST m 3 /s. To describe gas production from Class 1 hydrates, we employ the concepts of Rate Replenishment Ratio (RRR, defined as the fraction of the gas production rate Q P that is replenished by CH 4 from hydrate dissociation) and Volume Replenishment Ratio (VRR, i.e., the fraction of the cumulative produced CH 4 volume V P that has been replenished by CH 4 from hydrates), as proposed by Moridis et al. (2005b). The evolutions of the volumetric rate of CH 4 release from the hydrate (Q R ) and of the corresponding Q P are shown in Figure 1a. We identify four stages (Figure 1b). Stage I correspond to dissociation from two zones: the initial horizontal hydrate interface and a cylindrical interface around the well. A second horizontal hydrate interface evolves at the top of the hydrate interval. Additionally, a hydrate channeling system begins to evolve. This is composed of narrow conductive channels alternating with impermeable high-S H bands that advance into the body of the hydrate in a ‘wormhole-like” manner aligned with the general direction of flow. This is a consequence of the hydrate lensing process caused by capillary pressure (Moridis et al., 2005b), and provides access to the hydrate interior. 54 New Energy Resources in the CCOP Region - Gas Hydrates and Coalbed Methane
In Stage II, dissociation is at its maximum and occurs along the two horizontal interfaces (upper and lower) and the cylindrical interface, while the hydrate channels are fully developed. The end of Stage II is marked by a precipitous drop in RRR caused by the “sealing” of the entire bottom (horizontal) boundary by an impermeable hydrate lens of a very high S H , in which S A and S G fall below their irreducible levels. In Phase III, only the cylindrical and the upper horizontal interfaces are active dissociation fronts. (c) Figure 1. (a) Evolution of Q R (A) and Q P (B), (b) the corresponding RRR (C) during production from the Class 1W deposit; (c) evolution of V R (A), V P (B) and the corresponding VRR (C) (Moridis et al., 2005b). New Energy Resources in the CCOP Region - Gas Hydrates and Coalbed Methane 55
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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 20 and 21: RESULTS AND DISCUSSION In the follo
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 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
Page 70 and 71: Figure 7. One-dimensional developme
Page 72 and 73: Temper at ur e 2 1 0 -1 -2 -3 -4
Page 74 and 75: From the above discussion, the heat
Page 76 and 77: INTRODUCTION Clathrate hydrates are
Page 78 and 79: MATHEMATICAL MODEL The mathematical
Page 80 and 81: Where the hydrate-aqueous radius of
Page 82 and 83: REFERENCES Brooks, R.H., and A.T. C
Page 84 and 85: 86 New Energy Resources in the CCOP
Page 86 and 87: In this paper, an overview of the M
Page 88 and 89: The brief tasks in the Phase I are:
Page 90 and 91: In "Development of the dissociation
Page 92 and 93: Figure 5. Preparation equipment. AN
Page 94 and 95: Other recent research subjects in t
Page 96 and 97: same crystalline structure directly
Page 98 and 99: Another important aspect of the pre
Page 100 and 101: a + CO 2 CH 4 C 2 H 6 b CH 4 in sII
Page 102 and 103: REFERENCES Collett, T.S. and Kuuskr
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Figure 1. Physiographic and crust m
Page 106 and 107:
Figure 3. Seismic profile showing s
Page 108 and 109:
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)
Page 116 and 117:
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
Page 148 and 149:
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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