Improvement Processes for Coalbed Natural Gas Completion and Stimulation

Olsen, T.N.; Brenize, Galen; Frenzel, Taryn

doi:10.2118/84122-ms

Cited by 36 publications

(11 citation statements)

References 17 publications

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“…It is worth noting that the δ 13 C 1 value of biogenic gas produced by CO 2 reduction is related to the δ 13 C 1 value of the CO 2 matrix and formation water. Compared to biogenic gas, thermogenic gas demonstrates the following characteristics: (1) heavy hydrocarbons are generally found in high/medium volatile bituminous coals and other 3 Geofluids higher-rank coals; (2) the 12 C- 12 C bond in the gas molecule breaks more frequently than the 12 C- 13 C bond as the degree of coalification increases, which causes the enrichment of heavy isotope 13 C in CH 4 and C 2 H 6 during the generation of thermogenic gas; and (3) thermogenic gas is comparatively rich in deuterium with the increase of coalification [31]. 1, the occurrence of CBM in coal reservoirs is mainly comprised of the free state, the adsorbed state, and the water-soluble state [26].…”

Section: Basic Characteristics Of Fluids In Coal Reservoirsmentioning

confidence: 99%

“…Coal is one of the most widely available energy sources with a huge world consumption, which is formed from the remains of ancient organisms through deep burial and coalification under the conditions of incredible heat and pressure (Figure 1(a)) [1][2][3]. It is estimated that the global methane reserves in coal seams can be up to 269 × 10 12 m 3 , which constrains production safety in coal mines and contributes significantly to greenhouse gas emissions [4]. From the last century, United States, Canada, and Australia have carried out extensive exploration and commercial exploitation of the CBM resource in multiple coal-bearing basins, such as San Juan Basin, Black Warrior Basin, Bowen Basin, and Surat Basin [5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

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Fluid Performance in Coal Reservoirs: A Comprehensive Review

Gao

Liu

et al. 2021

Geofluids

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The fluids in coal reservoirs mainly consist of different gases and liquids, which show different physical properties, occurrence behaviors, and transport characteristics in the pore-fracture system of coal. In this study, the basic characteristics of fluids in coal reservoirs are firstly reviewed, consisting of coalbed methane (CBM) components and physical properties of CBM/coalbed water. The complex pore-fracture system mainly provides the enrichment space and flow path for fluids, which have been qualitatively and quantitatively characterized by various methods in recent years. Subsequently, this study has summarized CBM adsorption/desorption behaviors and models, the CBM diffusion-seepage process and models, and gas-water two-phase flow characteristics of coal reservoirs. Reviewed studies also include the effects of internal factors (such as coal metamorphism, petrographic constituents, macroscopic types, and pore structure) and external factors (such as pressure, temperature, and moisture content) on CBM adsorption/desorption and diffusion behaviors, and the relationship between three main effects (effective stress, gas slippage effect, and coal matrix shrinkage effect) and the CBM seepage process. Moreover, we also discuss in depth the implication of fluid occurrence and transport characteristics in coal reservoirs for CBM production. This review is aimed at proposing some potential research directions in future studies, which mainly includes the control mechanism of the microscopic dynamics of fluids on CBM enrichment/storage; enhancing CBM desorption/seepage rate; and the synergistic effect of multiple spaces, multilevel flow fields, and multiphase flow in coal reservoirs. From this review, we have a deeper understanding of the occurrence and transport characteristics of fluids in pore-fracture structures of coal and the implication of fluid performance for CBM production. The findings of this study can help towards a better understanding of gas-water production principles in coal reservoirs and enhancing CBM recovery.

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Section: Basic Characteristics Of Fluids In Coal Reservoirsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Fluid Performance in Coal Reservoirs: A Comprehensive Review

Gao

Liu

et al. 2021

Geofluids

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“…To increase methane gas production at CBM play, there are 2 common methods which are (Fekete, 2010;Holdicth, 1993;Olsen, 2003;Leschyshyn, 2005):…”

Section: Cbm Production Mechanismsmentioning

confidence: 99%

Indonesia’s Unconventional Resources, Modified Resource Triangle, and a Typical Example of Stimulation of Coalbed Methane Reservoir

Rachmat¹,

Pramana²,

Ayu³

2012

MAS

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Indonesia has been producing oil since 19th century and started producing 2 types of Unconventional Resources (UR) which are heavy oil since 1958 and Coal Bed Methane (CBM) since this year (2012). The concept of resource triangle was introduced by Masters and Gray in 1979 to describe the huge reserves of UR and its difficulty to be produced. A modified version had been done with a scale to exactly describe the amount of oil or gas reserve of UR. It is then linked with the stimulation techniques needed to produce them. To recover the heavy oil, thermal stimulation or recovery technique is needed to reduce its very high viscosity. Similarly, Coal Bed Methane (CBM) is also categorized as unconventional reservoirs (UR) because of its low permeability and can only be produced economically at commercial flow rates with special recovery processes or well-stimulation treatment. This paper will give a comparison study of producing CBM with and without hydraulic fracturing, a type of well-stimulation technology. The optimization procedure to select the type of water frac fluid and propping agent size and type that technically and economically suitable for CBM reservoir. The process was done using fracturing simulator and reservoir simulator for dual porosity system (CMG GEM). Fracturing simulator predicted the amount of fluid and propping agent and the resulting fracturing conductivity. Afterwards, the post-fracturing results will then be transferred to CMG-GEM, by which, using Warren and Root equation, the gas production profile is predicted and compared with its pre-fracturing results. From this study, optimum hydraulic fracture treatments is found by having the connected permeability around 5-10 Darcy. This can be accomplished by pumping enough volumes of proppant at low concentrations (6 ppa) into the fracture using less expensive fluids and distribute it uniformly.

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“…Barrier treatments are smaller, more precise and designed to maximise damage over a smaller created fracture area (e.g., an efficient fracture for production, Figures 15a and 15b, as opposed to more effective fracturing for barrier placement, Figures 15c and 15d) (Olsen et al, 2003); thus, more detail is required to design, execute, evaluate, and verify a barrier placement than a production well fracturing treatment.…”

Section: Summary Of Design and Workflows For Barrier Placementmentioning

confidence: 99%

“…(a) Efficient production well frac in low permeability, low anisotropy coal interval; this would be non-ideal for barrier placement (b) Efficient production well frac in high permeability, high anisotropy coal interval; this would be non-ideal for barrier placement (c) Moderately inefficient production well frac in low to moderate permeability, low to moderate anisotropy coal interval; this is more effective for barrier placement (d) Highly inefficient production well frac in moderate to high permeability, moderate to low anisotropy coal interval but ideal for barrier placement Figure 15: Models depicting efficient and inefficient hydraulic fractures for production contrasting inefficient and efficient fracturing for barrier placement (after Olsen et al, 2003) 56 …”

Section: Summary Of Design and Workflows For Barrier Placementmentioning

confidence: 99%

Modifying subterranean fluid flow patterns using barriers to improve pre-drainage in coal mining

Johnson¹,

Raymond²

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Gas drainage has been performed in advance of coal mining for commercial production of gas and to reduce levels of gas to safe or regulatory levels required for coal mining. Inadequate pre-drainage can lead to higher levels of gas than may be adequately managed by ventilation systems, potential pressure scenarios, or even outbursts, any of which can affect mine safety and economics. Thus, it may be desirable to more rapidly depressurise the coal seam based on mine safety and production scheduling, currently requiring either stimulation of the coal or additional drilling of pre-drainage wells and potentially jeopardising project economics.

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Improvement Processes for Coalbed Natural Gas Completion and Stimulation

Abstract: TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractDrilling activity to access natural gas production from

Cited by 36 publications

References 17 publications

Fluid Performance in Coal Reservoirs: A Comprehensive Review

Fluid Performance in Coal Reservoirs: A Comprehensive Review

Indonesia’s Unconventional Resources, Modified Resource Triangle, and a Typical Example of Stimulation of Coalbed Methane Reservoir

Modifying subterranean fluid flow patterns using barriers to improve pre-drainage in coal mining

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