EOS - In the Analysis of Force Balance Conditions for the Formation of Deep Basin Gas

2013 ◽  
Vol 734-737 ◽  
pp. 1179-1182
Author(s):  
Liang Tong Fu ◽  
Tai Liang Fan ◽  
Ren Li Qi ◽  
Zi Qiang Cao
Keyword(s):  
Natural Gas ◽  
Material Balance ◽  
Force Balance ◽  
Gas Reservoirs ◽  
Deep Basin ◽  
Unconventional Gas ◽  
Gas Accumulation ◽  
Unconventional Natural Gas ◽  
Temperature And Pressure ◽  
The Relationship

Deep basin gas, which is trapped deep in a basin, is a kind of unconventional natural gas. It is also one of the important unconventional gas resources. In the previous studies of the mechanism of deep basin gas accumulation, force balance and material balance are considered as essential conditions for the formation of deep basin gas reservoirs. However, the gravity of natural gas is not fully taken into account in the analysis of force balance. In this dissertation, the density of natural gas under the condition of underground temperature and pressure is calculated by using the EOS. The result shows that the density of natural gas cannot be neglected and the PR EOS is applicable to the analysis of the relationship between the volume of natural gas and the condition of underground temperature and pressure.

Current Situation of Tight Sand Gas in China

2011 ◽  
Vol 361-363 ◽  
pp. 85-89
Author(s):  
Shi Zhen Li ◽  
De Wu Qiao
Keyword(s):  
Natural Gas ◽  
Energy Resources ◽  
Huge Amount ◽  
Gas Reservoirs ◽  
Gas Reservoir ◽  
Unconventional Gas ◽  
Unconventional Natural Gas ◽  
The World ◽  
Porosity And Permeability ◽  
Tight Sand Gas

Unconventional natural gas because of a huge amount of resources has been received extensive attention in the world. Based on the present technology in China, tight sand gas as one type of unconventional gas, has become the most realistic energy resources, and has reached a certain development scale. Low porosity and permeability of tight sand gas reservoirs are widely distributed in China's major basins, the proved reserves of tight sand gas reservoirs in the proportion of reserves increases significantly year by year. Tight sand gas exploration in unconventional natural gas is most realistic, the concept of tight sand gas, reservoir characteristics, formation mechanism of unconventional tight sand gas, distribution in China are reviewed in the essay, exploration direction and some suggestions are pointed out at the end.

scholarly journals Dynamic Material Balance Method for Estimating Gas in Place of Abnormally High-Pressure Gas Reservoirs

Lithosphere ◽  
2021 ◽  
Vol 2021 (Special 1) ◽  
Author(s):  
Lixia Zhang ◽  
Yingxu He ◽  
Chunqiu Guo ◽  
Yang Yu
Keyword(s):  
High Pressure ◽  
Material Balance ◽  
Balance Method ◽  
Production Data ◽  
Reservoir Pressure ◽  
Material Balance Equation ◽  
Gas Reservoirs ◽  
Gas Reservoir ◽  
Material Balance Method ◽  
The Relationship

Abstract Determination of gas in place (GIP) is among the hotspot issues in the field of oil/gas reservoir engineering. The conventional material balance method and other relevant approaches have found widespread application in estimating GIP of a gas reservoir or well-controlled gas reserves, but they are normally not cost-effective. To calculate GIP of abnormally pressured gas reservoirs economically and accurately, this paper deduces an iteration method for GIP estimation from production data, taking into consideration the pore shrinkage of reservoir rock and the volume expansion of irreducible water, and presents a strategy for selecting an initial iteration value of GIP. The approach, termed DMBM-APGR (dynamic material balance method for abnormally pressured gas reservoirs) here, is based on two equations: dynamic material balance equation and static material balance equation for overpressured gas reservoirs. The former delineates the relationship between the quasipressure at bottomhole pressure and the one at average reservoir pressure, and the latter reflects the relationship between average reservoir pressure and cumulative gas production, both of which are rigidly demonstrated in the paper using the basic theory of gas flow through porous media and material balance principle. The method proves effective with several numerical cases under various production schedules and a field case under a variable rate/variable pressure schedule, and the calculation error of GIP does not go beyond 5% provided that the production data are credible. DMBM-APGR goes for gas reservoirs with abnormally high pressure as well as those with normal pressure in virtue of its strict theoretical foundation, which not only considers the compressibilities of rock and bound water, but also reckons with the changes in production rate and variations of gas properties as functions of pressure. The method may serve as a valuable and reliable tool in determining gas reserves.

Subsidy analysis and development trend forecast of China's unconventional natural gas under the new unconventional gas subsidy policy

Energy Policy ◽  
2021 ◽  
Vol 153 ◽  
pp. 112253
Author(s):  
Jianye Liu ◽  
Zuxin Li ◽  
Xuqiang Duan ◽  
Dongkun Luo ◽  
Xu Zhao ◽  
...  
Keyword(s):  
Natural Gas ◽  
Development Trend ◽  
Unconventional Gas ◽  
Subsidy Policy ◽  
Unconventional Natural Gas

Fluid saturation evolution with imbibition in unconventional natural gas reservoirs

2018 ◽  
Vol 6 (4) ◽  
pp. T849-T859
Author(s):  
Mianmo Meng ◽  
Hongkui Ge ◽  
Yinghao Shen ◽  
Wenming Ji ◽  
Fei Ren
Keyword(s):  
Natural Gas ◽  
Volcanic Rock ◽  
Gas Reservoirs ◽  
Free Gas ◽  
Gas Saturation ◽  
Liquid Saturation ◽  
Fluid Saturation ◽  
Unconventional Natural Gas ◽  
Trapped Gas ◽  
Natural Gas Reservoirs

Hydraulic fracturing plays an important role in developing unconventional natural gas. The large amount of fracturing fluid retention becomes a significant phenomenon in gas fields. Much research has been carried out to explain this mechanism. Imbibition is regarded as one of the important factors and has been investigated extensively. However, the saturation evolution of different types of fluids (liquid, free gas, and trapped gas) has been less researched during imbibition. A porosity experiment combined with an imbibition experiment was conducted to research the fluids-saturation evolution. There are three types of experimental rocks: tight sand, volcanic rock, and shale. The free-gas saturation decreases with the increasing liquid saturation in all samples. However, the sum of these two types of saturation is approximately 100% during imbibition in tight sand. This indicates that the pore space is almost totally filled by liquid and free gas. The sum of these two types of saturation is less than 100% during imbibition in volcanic rock. This indicates that there is trapped gas by liquid. Trapped-gas saturation increases at the early period and decreases at the late period. The sum of these two types of saturation greatly exceeds 100% during imbibition and increases with the imbibition time in shale rocks. This means that there is large amount of extra imbibition liquid. At the same time, the free-gas saturation fluctuates with the increasing liquid saturation. Based on the above results, it can be concluded that tight sand reservoirs have nearly no trapped gas and extra imbibition liquid, volcanic reservoirs have trapped gas and a little extra imbibition liquid, and shale reservoirs have some trapped gas and a large amount of extra imbibition liquid. This research contributes to understanding the fluid saturation evolution during hydraulic fracturing in unconventional natural gas reservoirs.

Environmental and Economic Significance and Feasibility Analysis of Tight Sand Gas Reservoir in China

2013 ◽  
Vol 734-737 ◽  
pp. 320-325
Author(s):  
Jian Guo Wang ◽  
Long Chen ◽  
Hai Jie Zhang ◽  
Tao Han
Keyword(s):  
Natural Gas ◽  
Rapid Development ◽  
Economic Feasibility ◽  
Coal Bed ◽  
Gas Reservoirs ◽  
Unconventional Gas ◽  
Well Completion ◽  
Economic Significance ◽  
The Rich ◽  
Tight Sand Gas

Currently, with a sharp increase in demand for natural gas and a strict energy supply circumstances, the development of tight sand gas becomes a pressing need for the rapid development of Chinas society and economy. At the end of 2010, the reserves and annual production of tight sand gas in China accounted for 39.2 percent and 24.6 percent of national natural gas, respectively, and the proportions are expected to increase. Compared with other unconventional gas such as shale gas and coal bed methane, the techniques of tight sand gas are relatively mature and development costs of it are relatively low. So tight sand gas should be considered in priority in the exploration and exploitation of unconventional gas in China. The total reserves of tight sand gas in China are 12 trillion cubic meters. Tight sand gas in China possesses the rich reserves and enormous potential to develop, which can ease the current shortage of energy. Besides, China has mastered a series of key techniques such as the well drilling and completion protection supporting technique; well completion and staged fracturing technique of horizontal well, which guarantees the technical feasibility of the development of tight sand gas reservoirs. From the perspective of market, social and environmental meaning, reserves, technique and economic feasibility, this paper presents a systematical analysis about the importance of developing tight sand gas in China.

Study on filtration patterns of supercritical CO2fracturing in unconventional natural gas reservoirs

2017 ◽  
Vol 7 (6) ◽  
pp. 1126-1140 ◽  
Author(s):  
Jintang Wang ◽  
Baojiang Sun ◽  
Zhiyuan Wang ◽  
Jianbo Zhang
Keyword(s):  
Natural Gas ◽  
Gas Reservoirs ◽  
Unconventional Natural Gas ◽  
Natural Gas Reservoirs

scholarly journals Flowing material balance method with adsorbed phase volumes for unconventional gas reservoirs

2019 ◽  
Vol 38 (2) ◽  
pp. 519-532
Author(s):  
Guofeng Han ◽  
Min Liu ◽  
Qi Li
Keyword(s):  
Coalbed Methane ◽  
Gas Adsorption ◽  
Material Balance ◽  
Balance Method ◽  
Gas Reservoirs ◽  
Unconventional Gas ◽  
Adsorbed Phase ◽  
Unconventional Gas Reservoirs ◽  
Flowing Material ◽  
Material Balance Method

This paper presents an improved flowing material balance method for unconventional gas reservoirs. The flowing material balance method is widely used to estimate geological reserves. However, in the case of the unconventional gas reservoirs, such as coalbed methane reservoirs and shale gas reservoirs, the conventional method is inapplicable due to the gas adsorption on the organic pore surface. In this study, a material balance equation considering adsorption phase volume is presented and a new total compressibility is defined. A pseudo-gas reservoir is simulated and the results were compared with the existing formulations. The results show that the proposed formulation can accurately get the geological reserves of adsorbed gas reservoirs. Furthermore, the results also show that the volume of the adsorbed phase has a significant influence on the analysis, and it can only be ignored when the Langmuir volume is negligible.

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