Small Amount Of Natural Gas Research Articles

Accumulation mechanism and model of coal measure derived oil and gas in the deep reservoir of Huanghua Depression, Bohai Bay Basin, China

Hydrocarbon accumulation in coal measure strata is consist of several types which includes intra-source accumulation and adjusted accumulation, particularly in basins that had experienced multi-stage tectonic activities. The mechanism governing this accumulation is extremely complex. Using the Paleozoic petroleum system in the Huanghua Depression as an example, the mechanism of hydrocarbon accumulation in deep reservoirs can be revealed by means of core observation, geochemistry testing of coal measure source rock, thin section observation, fluid inclusions testing, and profile analysis of typical reservoirs, combined with the burial and thermal history of strata. Based on the regional tectonic, the mechanism of hydrocarbon accumulation in coal measures is defined and the accumulation model was established. The results show that the Paleozoic petroleum system in the Huanghua Depression has three different types of source-reservoir-cap assemblages: under-source, intra-source, and above-source assemblage. Regional tectonic evolution controlled the hydrocarbon generation process of source rocks, showing the hydrocarbon generation characteristics of “oil in the early stage and gas in the late stage.” The Middle Cretaceous is the first of two periods of hydrocarbon accumulation, during which stage occurred in low-maturity oil and a small amount of natural gas were mainly stored in intergranular pores and dissolution pores. The tectonic uplift in the Late Cretaceous caused the destruction of the ancient reservoir. The second accumulation stage occurred in the Middle Paleogene to the present. A large amount of natural gas and high maturity oil were mostly stored in dissolution pores and structural fractures. The hydrocarbon accumulation in Huanghua Depression was simultaneously regulated by reservoir reformation, tectonic activities, and source rock maturation. Based on the foregoing understanding, the hydrocarbon accumulation model of “oil and gas transfer station” in coal measures is put forward, that is, oil and gas are first accumulated in intra-source or near-source reservoirs, and are then adjusted from this “oil and gas transfer station” to other areas as a result of tectonic activity.

Geochemical characteristics and genesis of the Upper Paleozoic natural gas in Longdong area, Ordos Basin, NW China

The Upper Paleozoic gases from the Longdong areas in the Ordos Basin are characterized by low contents of heavy hydrocarbon gases, the mean value of wetness as 2%, relatively heavy δ13C1(δ13C1 value -28.3‰), and large variations in δ13C2 +. The distribution pattern of carbon isotopic sequence of natural gas is mainly characterized by the abnormal light δ13C2 + values and carbon isotopic reversal. According to the organic geochemical characteristics of natural gas and the development of gas-source rocks, the upper Paleozoic natural gas in Longdong area belongs to high mature and over-mature “coal-formed gas”. In theory, only the mixture of highly mature gas with extremely low contents of heavy hydrocarbon gases and a small amount of natural gas with higher contents and lighter carbon isotopic composition of heavy hydrocarbon gases can lead to the occurrence of abnormally light δ13C2 + and the carbon isotope reversal between methane and ethane. The mixed gas is probably derived from the thermal cracking of a small amount of residual soluble organic matter in the gas-source rocks and reservoirs during the initial stage of the uplift movement at the end of Early Cretaceous. Key words: Ethane carbon isotope; Inverted sequence of carbon isotopic composition; Natural gas of high maturity; natural gas genesis; Ordos Basin.

A novel heat-driven thermoacoustic natural gas liquefaction system. Part I: Coupling between refrigerator and linear motor

Nowadays, heat-driven thermoacoustic Stirling refrigerator is of great interest in the world, which utilizes thermoacoustic heat engine to drive thermoacoustic Stirling refrigerator with high reliability and simplicity. This system is suitable for natural gas liquefaction by burning a small amount of natural gas to liquefy the rest. In this paper, a heat-driven thermoacoustic Stirling refrigerator with linear motor phase adjuster is proposed. The linear motor is used to not only provide a suitable acoustic field for the refrigerator to achieve a high performance but also convert the expansion work into electricity. Thus, the system efficiency can be greatly improved. Due to the complicated energy conversion mechanism between heat, acoustic work, cooling power and electric power in the system, here we only try to investigate the coupling relationship between refrigerator and linear motor by adjusting load resistance and equivalent inductance. According to the simulation, optimum results of a cooling power of 463.1 W at 110 K with relative Carnot efficiency of 31.3%, an electric power of 553.7 W and a total exergy efficiency of 53.7% are achieved. Since several refrigerator and motor units are used in this system, this technology may provide a new way for natural gas liquefaction.

일본 난카이 해구 가스하이드레이트 퇴적층으로부터의 가스 시험생산 사례분석

Gas hydrate is a solid substance composed of natural gas constrained in water molecules under low temperature and high pressure conditions. The existence of hydrates has been reported to be world-widely distributed, mainly at permafrost and deep ocean floor. Test productions of small amount of natural gas from the on-shore permafrost have been accomplished in U.S.A and Canada, but, world-first and the only production case from off-shore hydrate bearing sediments was in Nankai trough, Japan. In this study, we introduce key technologies in gas production from hydrates by analyzing the Japanese off-shore gas production project in Nankai trough in terms of depressurization- induced dissociation so as to utilize planned domestic gas production test in Ulleung basin.

Flue Gas Injection Into a Mature SAGD Steam Chamber at the Dover Project (Formerly UTF)

Abstract The Dover Project (formerly the Underground Test Facility) is the world's first field pilot of the Steam Assisted Gravity Drainage (SAGD) process using dual horizontal well pairs to recover bitumen. There have been four phases of SAGD piloting at the Dover site thus far. The Phase B pilot, which consists of three 500 m long horizontal well pairs spaced 70 m laterally apart, has been in continuous operation since early 1993. Phase B reached the peak production rate of 300 m3/d or 100 m3/d per well pair on average in the middle of 1994. After sustaining the peak rate for about two years, the production has been in decline with a steady increase in steam-oil ratio. Research carried out in the past few years suggested that the addition of a suitable amount of non-condensable gases (NCG) would be an effective method to wind-down the steam chamber. It provides an economic means to continue bitumen production by utilizing the large amount of heat stored in the SAGD chamber. Beginning in April 1998, a small amount of natural gas was added continuously to the steam injection. The concentration of NCG has increased steadily in the past 3.5 years. The resulting performance has been better than initially expected. Based on the success of this NCG-steam wind-down strategy, a four-month flue gas injection test was conducted in 2001 to investigate the possibility of using the more cost-effective flue gas, rather than natural gas as an injectant. This paper summarizes the rationale for selecting the NCG-steam wind-down strategy, the field implementation of the flue gas injection test, and the resulting pilot performance. The successful implementation of this technology will have a profound impact on the overall process economics. Introduction The Dover Project is an in situ bitumen recovery facility on the Oil Sands Lease Number 328 located 70 km northwest of the City of Fort McMurray. It was initiated by Alberta Oil Sands Technology and Research Authority (AOSTRA) in 1984 and was ater joined by industry participants to pilot the SAGD processsing dual horizontal wells. The Dover Project Area is located in eight sections of land at the extreme eastern edge of the lease, as shown in Figure 1. To the immediate east of Dover is Petro-Canada's MacKay River Project, which is expected to produce 30,000 BOPD using the SAGD process in 2003. Several papers(1–3) have been published to describe, in detail, the Dover Project from the beginning until mid-1997. The following is a brief summary. FIGURE 1: Dover project area. Available in Full Paper. The first phase of testing, Phase A, involved the drilling of horizontal wells from a limestone tunnel network located about 20 m below the oil sand formation. These well pairs had a horizontal length of about 60 m and were spaced 25 m apart, as shown in Figure 2. They were operated from 1987 to 1991. Encouraged by the results from Phase A, the Project proceeded to the secondphase of piloting in late 1991.

CFD Analysis of NOX Reduction by Domestic Natural Gas Added to Coal Combustion

To date, Israel's electrical energy has been based only on imported fuels. However, with the recently discovered natural gas in the Ashqulon shores, Israel can examine the benefits to its energy resources, environment, and economy of blending its domestic natural gas with imported coal. As for using natural gas, the proposal is to burn it in existing IEC coal-fired boilers in order to significantly reduce NOx emission by reburning. An important aspect is to provide retrofitting in existing IEC boilers by replacing a fraction of the coal by natural gas. This would allow the purchase of coal with a wide range of parameters, which is less expensive. Hence, mixed gas-coal burning would benefit Israel. The authors have made numerical simulations in order to study the optimal conditions of operation and evaluate the economic as well as environmental benefits. Indeed, extensive simulations have shown that there is a significant reduction of NOx emission, as expected, with the addition of relatively small amounts of natural gas. Experiments will now be carried out in a test facility that will provide accurate physicochemical properties of the mixed fuel for more reliable simulations. 19 refs., 6 figs., 1 tab.

Reducing Operating Costs in Stoker Boilers With Natural Gas Cofiring

Natural gas cofiring in stoker boilers is now coming of age and maturing as an off-the-shelf tool to improve the economics of stoker boiler firing. Natural gas cofiring is a technology that blends the most desirable characteristics and capabilities of natural gas with more difficult and problematic solid fuels like coal and wood wastes. Natural gas cofiring involves the use of a very small amount of natural gas, typically less than 10%, firing over stoker grates through special burners. This article seeks to review the five most popular economic drivers related to operating cost reductions available through natural gas cofiring.

Chemical Kinetic Modeling of Hydrogen under Conditions Found in Internal Combustion Engines

A chemical kinetic model is used to study the combustion characteristics of hydrogen under conditions found in internal combustion engines. Laminar flame speeds are predicted under the high-pressure and high-temperature conditions found in a spark-ignition engine. The variation of laminar flame speed with temperature, pressure, and equivalence ratio is examined. The autoignition of hydrogen and hydrogen−natural gas mixtures is also studied under conditions found in a free-piston compression-ignition engine. This engine is expected to exhibit high efficiencies operating on hydrogen. The results suggest that adding small amounts of natural gas to hydrogen will reduce NOx emissions from a free-piston compression-ignition engine. Calculations showed that the predicted NO concentrations correlated well with the maximum temperature in the cycle and that the NO was mostly produced by N2 + O = NO + N.

Influence of Near Burner Combustion Modifications on NOx Formation from an All-Axial Multifuel Burner

Tests were conducted with a naturally staged, axial jet burner firing pulverized coal to evaluate near burner combustion modification alternatives for controlling NOx emissions to ultra low levels in a combustor operating with hot, running slag walls. The study focused on the use of small amounts of natural gas rather than swirl air to aid the stabilization of the axial pulverized coal flames. The relative importance of primary jet velocity and primary air stoichiometyr were determined for these gas stabilized flames. Decreases in primary jet velocity had a dramatic effect on near burner NO production while primary air stoichiometry appeared to have a negligible effect. Another near Burner modification, the use of a vitiated secondary air stream, did not significcantly affect NO levels. Ultra low No levels (below 90 ppmv) were achieved in theis hot-walled combuster by optimizing the performance of the gas stabilized burner in conjunction with staged combustion and reburning.

Role of hydrogen in blast furnaces to improve productivity and decrease coke consumption

The hydrogen contained in blast furnace gases exerts a variety of physical, thermochemical, and kinetic effects as the gases pass through the various zones. The hydrogen is derived from two sources: (1) the dissociation of moisture in the blast air (ambient and injected with hot blast), and (2) the release from partial combustion of supplemental fuels (including moisture in atomizing water, steam, or transport air, if any). With each atom of oxygen (or carbon), the molar amounts of hydrogen released are more than six times higher for natural gas than for coal, and two times higher for natural gas than for oil. Injection of natural gas in a blast furnace is not a new process. Small amounts of natural gas--about 50--80 lb or 1,100--1,700 SCF/ton of hot metal--have been injected in many of the North American blast furnaces since the early 1960s, with excellent operating results. What is new, however, is a batter understanding of how natural gas reacts in the blast furnace and how natural gas and appropriate quantities of oxygen can be used to increase the driving rate or combustion rate of carbon (coke) in the blast furnace without causing hanging furnace and operating problems. The paper discussesmore » the factors limiting blast furnace productivity and how H{sub 2} and O{sub 2} can increase productivity.« less

The formation and control of PCDD/PCDF from RDF-fired combustion systems

During the combustion of municipal solid waste, incomplete destruction of chlorinated hydrocarbons and other precursors in the waste can lead to the formation and emission of polychlorinated dibenzo (p) dioxins and furans (PCDD/PCDF). Since regulations limiting these emissions are expected, the Gas Research Institute has been conducting research to develop advanced combustion systems for municipal solid waste (MSW) incinerators which involve the use of small amounts of natural gas to control PCDD/PCDF emissions and to improve unit operation. Characterization tests have been conducted on both full-scale and small-scale RDF fired combustion systems. The results of these tests have confirmed both furnace and downstream PCDD/PCDF formation and identified the importance of particulate related formation. These new insights into the sources of PCDD/PCDF emissions have lead to the development of advanced combustion control schemes.

Effect of natural gas, C 2H 6 and CO on the homogeneous gas phase reduction of NO x by NH 3

The influence of small amounts of natural gas, C 2H 6 and CO on the homogeneous gas phase reduction of NO x by NH 3 was investigated in air-rich flue gas from an oil-fired boiler (1 MJ s −1) at temperatures from 1100 K to 1350 K. It was found that the addition of natural gas, C 2H 6 and CO to the NH 3 injected into the flue gas decreased the optimum reaction temperature by 150 to 200 K. The maximum removal efficiency of NO x (75%) was not strongly affected by the additives. The effect of the additives on the NO x reduction involves three reactions. 1. (1) The reduction of NO x by NH 3 is accelerated by the additives (natural gas, C 2H 6 and CO). 2. (2) The oxidation of NH 3 to NO x by O 2 present in the flue gas is also accelerated by the additives. 3. (3) The additives are oxidized to CO 2 and H 2O by oxygen. The oxidation of CO, which is also an intermediate step during the oxidation of hydrocarbons, is inhibited by unreacted NH 3.

Natural Gas in Australia and New Guinea

Inflammable natural gas, in amounts exceeding several million cubic feet, has been found in wells drilled at Roma in Queensland. Small amounts of natural gas, accompanying artesian water, are commonly encountered in wells drilled in parts of the Great Artesian basin. According to location two types of gas are encountered in the Great Artesian basin region: (1) an inflammable hydrocarbon gas; and (2) a non-inflammable nitrogen gas, containing no hydrocarbons. The carbon dioxide type of gas is found in parts of New South Wales and Victoria.