The Measurement of Shale Gas Content

2013 ◽  
Vol 288 ◽  
pp. 333-337 ◽  
Author(s):  
Ya Li Jiang ◽  
Hua Qing Xue ◽  
Hong Yan Wang ◽  
Hong Lin Liu ◽  
Gang Yan
Keyword(s):  
Shale Gas ◽  
Sichuan Basin ◽  
Initial Rate ◽  
Direct Method ◽  
Test Procedure ◽  
Mathematic Model ◽  
Gas Content ◽  
Average Value ◽  
Exploration And Production ◽  
Lost Time

The gas content is critical parameter in the shale gas exploration and production. The direct method was used to determine the shale gas content and the apparatus were made by ourselves. It were described the gas content test procedure, mathematic model and data processing in the paper. The adsorb gas and residue gas can be directly obtain from test, and the lost gas was estimated by the initial rate of adsorb gas. The shale gas contents from Sichuan basin are from 1.15 to 1.84 m3/ton, the average value is 1.64 m3/ton. Lost gas is the major gas in the shale and increasing with the lost time. Consequently, the shale should be sealed in the canister as soon as possible to decrease the lost time during the test. It also can enhance the accuracy of gas content. There are a great member of nano-pore and fracture in the organic matter, so that more TOC of shale are more gas content.

scholarly journals Coupling between Source Rock and Reservoir of Shale Gas in Wufeng-Longmaxi Formation in Sichuan Basin, South China

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2679
Author(s):  
Yuying Zhang ◽  
Shu Jiang ◽  
Zhiliang He ◽  
Yuchao Li ◽  
Dianshi Xiao ◽  
...  
Keyword(s):  
Source Rock ◽  
Shale Gas ◽  
Sichuan Basin ◽  
Gas Content ◽  
Potential Zone ◽  
Hydrocarbon Generation ◽  
Gas Generation ◽  
Longmaxi Formation ◽  
Siliceous Shale ◽  
Organic Pores

In order to analyze the main factors controlling shale gas accumulation and to predict the potential zone for shale gas exploration, the heterogeneous characteristics of the source rock and reservoir of the Wufeng-Longmaxi Formation in Sichuan Basin were discussed in detail, based on the data of petrology, sedimentology, reservoir physical properties and gas content. On this basis, the effect of coupling between source rock and reservoir on shale gas generation and reservation has been analyzed. The Wufeng-Longmaxi Formation black shale in the Sichuan Basin has been divided into 5 types of lithofacies, i.e., carbonaceous siliceous shale, carbonaceous argillaceous shale, composite shale, silty shale, and argillaceous shale, and 4 types of sedimentary microfacies, i.e., carbonaceous siliceous deep shelf, carbonaceous argillaceous deep shelf, silty argillaceous shallow shelf, and argillaceous shallow shelf. The total organic carbon (TOC) content ranged from 0.5% to 6.0% (mean 2.54%), which gradually decreased vertically from the bottom to the top and was controlled by the oxygen content of the bottom water. Most of the organic matter was sapropel in a high-over thermal maturity. The shale reservoir of Wufeng-Longmaxi Formation was characterized by low porosity and low permeability. Pore types were mainly <10 nm organic pores, especially in the lower member of the Longmaxi Formation. The size of organic pores increased sharply in the upper member of the Longmaxi Formation. The volumes of methane adsorption were between 1.431 m3/t and 3.719 m3/t, and the total gas contents were between 0.44 m3/t and 5.19 m3/t, both of which gradually decreased from the bottom upwards. Shale with a high TOC content in the carbonaceous siliceous/argillaceous deep shelf is considered to have significant potential for hydrocarbon generation and storage capacity for gas preservation, providing favorable conditions of the source rock and reservoir for shale gas.

scholarly journals Classification and Evaluation on Shale Gas Reservoir for Wufeng-Longmaxi Formation in Chuannan Area, Sichuan Basin

Lithosphere ◽  
2021 ◽  
Vol 2021 (Special 1) ◽  
Author(s):  
Jianlin Guo ◽  
Chengye Jia ◽  
Dongbo He ◽  
Fankun Meng
Keyword(s):  
Shale Gas ◽  
Sichuan Basin ◽  
Gas Content ◽  
Brittleness Index ◽  
Type I ◽  
Gas Reservoir ◽  
Longmaxi Formation ◽  
Positive Correlation ◽  
Gas Saturation ◽  
Shale Gas Reservoir

Abstract Based on the comprehensive statistic and analysis on some representative geological and physical data, the classification criteria on net pay for shale gas reservoir of the Wufeng-Longmaxi formation in Shunan area, Sichuan Basin, are proposed, which include porosity (φ), gas saturation (Sg), density of rock (DEN), brittleness index (BI), and gas content (Vt). When the porosity, gas saturation, brittleness index, and gas content are larger than 3%, 30%, 40%, and 1 m3/t, respectively, and the density of rock is lower than 2.7 g/cm3, then this formation can be seen as the net pay. The application of two key parameters, gas content and brittleness index, could reflect the reservoir resource basis and fracability, respectively. The gas content has a positive correlation with porosity and total organic volume, and the brittleness index has a positive correlation with siliceous and carbonate content. According to the range of these two parameters, the net pay can be classified into three types. For type I, the gas content and brittleness index are larger than 4 m3/t and 50%, respectively. For type II, either the gas content or the brittleness index is lower than 4 m3/t and 50%. For type III, the gas content should be larger than 1 m3/t and lower than 4 m3/t, and the brittleness index is between 40% and 50%. The field application case indicates that the Wufeng formation and low member of the Longmaxi formation have good quality and mainly consist of type I and II formations. In addition, it is found that there is a positive correlation between the penetration ratio for type I formation and the testing production and estimate ultimate recovery (EUR). While this ratio is larger than 50%, the testing production rate and EUR will be over 15×104 m3/d and 8000×104 m3 with a probability of 92%, which meet the requirement of exploitation with reasonable economic benefits.

scholarly journals Differences of Main Enrichment Factors of S1l11-1 Sublayer Shale Gas in Southern Sichuan Basin

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5472
Author(s):  
Xuewen Shi ◽  
Chao Luo ◽  
Gaohui Cao ◽  
Yifan He ◽  
Yi Li ◽  
...  
Keyword(s):  
Shale Gas ◽  
Sichuan Basin ◽  
Mineral Content ◽  
Enrichment Factors ◽  
Gas Content ◽  
Longmaxi Formation ◽  
The Difference ◽  
Organic Porosity ◽  
Gas Bearing ◽  
Organic Pores

In this study, shale cores from 20 wells in the S1l11-1 sublayer of Longmaxi Formation buried in shallow shale (<3500 m) and deep shale (>3500 m) in the southern Sichuan Basin, China were collected to compare their pore structures and gas-bearing properties using multiple experiments. Results showed that the deep layer has relatively lower brittle mineral content, which is disadvantageous in terms of the higher requirements it imposes on hydraulic fracturing. Results also showed that the most important factor controlling the differential enrichment of S1l11-1 shale gas in southern Sichuan Basin is porosity. Moreover, the porosity composition of shallow shale and deep shale has significant differences: the porosity of shallow shale is dominated by organic pores, while for deep shale, both organic and inorganic pores are important. The inorganic pores provide significant storage space for free gas in deep shale; their contribution warrants more attention. We also found that the difference in organic porosity of the shallow and deep shale samples resulted from large differences in pore development ability, while the highest inorganic porosity was concentrated near the optimal mineral composition when the content of quartz plus feldspar plus pyrite was about 70%. This study revealed the primary factor controlling the difference in gas content between shallow and deep shale and detailed the characteristics of microscopic pore structure, providing a basis for the exploration and development of deep shale gas in the Wufeng-Longmaxi Formation in the southern Sichuan Basin.

scholarly journals Review of Well Logs and Petrophysical Approaches for Shale Gas in Sichuan Basin, China

2015 ◽  
Vol 8 (1) ◽  
pp. 316-324 ◽  
Author(s):  
Yuanzhong Zhang ◽  
Sicheng Jin ◽  
Hao Jiang ◽  
Yuwei Wang ◽  
Pengyu Jia
Keyword(s):  
Shale Gas ◽  
Sichuan Basin ◽  
Development Trend ◽  
Development Stage ◽  
In Situ Stress ◽  
Gas Production ◽  
Well Logs ◽  
Petroleum Engineering ◽  
Gas Content ◽  
Horizontal Drilling

China has vast reserves of shale gas. Currently, shale gas is one of the focuses of the unconventional reservoir. Well logs play an import role in shale gas production, and it is the bridge connecting geology, geophysics and petroleum engineering. In the exploration stage, well logs are used to identify lithology, evaluate the parameters of mineral types and compositions, total organic carbon (TOC), porosity, permeability, gas content, and the potential resources quantity. In the development stage, well logs offer various parameters of geological and engineering for horizontal drilling and production, evaluate the mechanical properties and calculate the magnitude and orientation of the in-situ stress for hydraulic fracturing stimulation. We reviewed current well logs for shale gas in China and discussed the development trend in the paper. A case history in Sichuan Basin presented to analyze the logs response characteristics and parameters calculation for a shale gas well. The difficulty and the future attention focus are also discussed.

Evaluation of shale gas potential of Cambrian Jiulaodong Formation in Wei-201 well block in Sichuan Basin, China

2016 ◽  
Vol 4 (2) ◽  
pp. T123-T140 ◽  
Author(s):  
Julius Kwame Borkloe ◽  
Renfang Pan ◽  
Jineng Jin ◽  
Emmanuel Kwesi Nyantakyi ◽  
Jianghui Meng
Keyword(s):  
Organic Carbon ◽  
Carbon Content ◽  
Shale Gas ◽  
Sichuan Basin ◽  
Gas Storage ◽  
Source Rocks ◽  
Gas Content ◽  
Brittleness Index ◽  
Organic Carbon Content ◽  
Gas Potential

The Cambrian Jiulaodong Formation of the Wei-201 well block in the Sichuan Basin was investigated for shale gas potential. In the subsurface, the thermally mature formation attained a stable thickness of 234 m encompassing an area of approximately [Formula: see text] and representing a potential gas resource. The total gas content measurements from canistered samples was more than the estimated total gas storage capacity of the free gas, absorbed gas, and gas dissolved in water and in oil. The canister gas content ranged between 0.971 and [Formula: see text] and averaged [Formula: see text]. The average estimated gas in place was 2.5 billion cubic meters for the formation in the Weiyuan area. Reflectance measurements for thermal maturity range between 2.60% and 3.06% and average 2.84%. The results of our total organic carbon content (TOC) content analysis conducted on the core shale samples indicate that the TOC content of the formation ranges from 0.87% to 3.57% and averages 2.2%. The mineral composition of marine mudstone formation of the Jiulaodong shale is relatively consistent. Brittle mineral content increases with organic carbon content and is approximately 32%–43%, of which quartz content is 29%–40% with a very low amount of clay mineral as the mixed layer. The amount of illite-smectite ranges from 0% to 1% and the brittleness index range from 37% to 62% and average 57.1%. The Cambrian Jiulaodong Formation ha very good petroleum-source rock potential due to its average TOC content of greater than 2%, average canister gas content of [Formula: see text], good type I kerogen, high maturity with average 2.84% of source rocks that are characterized by a fairly high abundance of organic matter increasing from top to bottom and a large thickness of 234 m. Natural fractures, cracks, and pores developed in the Jiulaodong Formation also provide space for shale gas storage, and its average brittleness index is greater than 57%, which is good for fracability.

Shale Gas-in-Place Calculation from Sichuan Basin, China

2013 ◽  
Vol 803 ◽  
pp. 342-346
Author(s):  
Hua Qing Xue ◽  
Hong Ling Liu ◽  
Gang Yan ◽  
Wei Guo
Keyword(s):  
Shale Gas ◽  
Sichuan Basin ◽  
Water Saturation ◽  
Organic Content ◽  
Gas Content ◽  
High Porosity ◽  
Formation Pressure ◽  
Free Gas ◽  
Gas Accumulation ◽  
Content Measurement

The methods of shale gas content measurement and shale Gas-in-place calculation are introduced in detail. The shale gas content is form 1.05 to 1.84 m3/t. From Gas-in-place calculation the adsorption gas content is a little more than free gas content. The advantage of shale gas accumulation areas are high formation pressure, low water saturation, high porosity and high total organic content. There are some discrepancy between shale gas content testing and gas in place calculation and three reasons may cause this phenomenon.

Geomechanical Characterisation and Modelling Help to Unlock Shale Gas Reservoirs in the Southern Sichuan Basin

2013 ◽  
Author(s):  
Roger Yuan ◽  
Fa Dwan ◽  
Navpreet Singh ◽  
Liang Jin ◽  
Danny Soo ◽  
...  
Keyword(s):  
Shale Gas ◽  
Sichuan Basin ◽  
Gas Reservoirs ◽  
Shale Gas Reservoirs
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