scholarly journals Porosity and Water Saturation Estimation for Shale Reservoirs: An Example from Goldwyer Formation Shale, Canning Basin, Western Australia

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6294
Author(s):  
Muhammad Atif Iqbal ◽  
Reza Rezaee
Keyword(s):  
Organic Carbon ◽  
Total Organic Carbon ◽  
Western Australia ◽  
Water Saturation ◽  
Clay Content ◽  
Total Porosity ◽  
Gas Content ◽  
Accurate Estimation ◽  
Canning Basin ◽  
Shale Reservoirs

Porosity and water saturation are the most critical and fundamental parameters for accurate estimation of gas content in the shale reservoirs. However, their determination is very challenging due to the direct influence of kerogen and clay content on the logging tools. The porosity and water saturation over or underestimate the reserves if the corrections for kerogen and clay content are not applied. Moreover, it is very difficult to determine the formation water resistivity (Rw) and Archie parameters for shale reservoirs. In this study, the current equations for porosity and water saturation are modified based on kerogen and clay content calibrations. The porosity in shale is composed of kerogen and matrix porosities. The kerogen response for the density porosity log is calibrated based on core-based derived kerogen volume. The kerogen porosity is computed by a mass-balance relation between the original total organic carbon (TOCo) and kerogen maturity derived by the percentage of convertible organic carbon (Cc) and the transformation ratio (TR). Whereas, the water saturation is determined by applying kerogen and shale volume corrections on the Rt. The modified Archie equation is derived to compute the water saturation of the shale reservoir. This equation is independent of Rw and Archie parameters. The introduced porosity and water saturation equations are successfully applied for the Ordovician Goldwyer formation shale from Canning Basin, Western Australia. The results indicate that based on the proposed equations, the total porosity ranges from 5% to 10% and the water saturation ranges from 35% to 80%. Whereas, the porosity and water saturation were overestimated by the conventional equations. The results were well-correlated with the core-based porosity and water saturation. Moreover, it is also revealed that the porosity and water saturation of Goldwyer Formation shale are subjected to the specific rock type with heterogeneity in total organic carbon total clay contents. The introduced porosity and water saturation can be helpful for accurate reserve estimations for shale reservoirs.

Sweet-spot mapping of the Goldwyer Formation through formation evaluation and property modelling in the Canning Basin, Barbwire Terrace case study

2017 ◽  
Vol 57 (2) ◽  
pp. 692
Author(s):  
Munther Alshakhs ◽  
Reza Rezaee
Keyword(s):  
Organic Carbon ◽  
Total Organic Carbon ◽  
Source Rock ◽  
Water Saturation ◽  
Total Porosity ◽  
Resource Assessment ◽  
Estimation Methods ◽  
Sweet Spot ◽  
Canning Basin ◽  
Hydrocarbon Resource

The Goldwyer Formation of the Canning Basin has been regarded as a highly prospective shale petroleum play. This study assesses the potential prospectivity of this source rock as an unconventional hydrocarbon resource via property modelling. Considering the sparsity of wells penetrating the Middle Ordovician Goldwyer across the vast under-explored area of the Canning Basin, a basin-wide study of the source rock is not justified. Due to a higher well density, assessment of the Goldwyer Formation within the Barbwire Terrace, a sub-division of the Canning Basin, is carried out instead. This assessment includes the estimation of key shale play properties, such as, total organic carbon, total porosity, water saturation, and brittleness. Each property was estimated from available well wireline log data by testing multiple estimation methods. Total organic carbon values were derived from multiple regressions of different well data. A simplified Archie’s equation was used to estimate water saturation. Density porosity method was used for total porosity estimations. Sonic data along with density were utilised to estimate the brittleness index. Each property was then modelled across the Barbwire Terrace, which provided geostatistical estimates on the propagation of each parameter. In order to generate sweet spot maps, averaged maps of the properties were combined in a weighted manner. In the model, the Goldwyer Formation was divided into three layers based on dominant lithology. The uppermost shale dominated layer was predicted by the model to be the most prospective stratigraphic zone. The sweet spot maps highlight the southern flanks of the northern and western part of the Barbwire Terrace as the highest prospective geographic locations. This approach attempts to simplify the complexity of unconventional resource assessment, and has provided a single product evaluating the prospectivity of the Goldwyer as a hydrocarbon resource.

scholarly journals Impact of Geological Factors on Marine Shale Gas Enrichment and Reserve Estimation: A Case Study of Jiaoshiba Area in Fuling Gas Field

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Siyu Yu ◽  
Xixin Wang ◽  
Shaohua Li ◽  
Yuming Liu ◽  
Liming Xiao ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Total Organic Carbon ◽  
Shale Gas ◽  
Gas Content ◽  
Accurate Estimation ◽  
Gas Field ◽  
Adsorbed Gas ◽  
Marine Shale ◽  
Geological Factors ◽  
The Impact

Geological factors are key elements to control shale gas enrichment and influence the accurate estimation of shale gas reserve. However, the impact of the main geological factors, such as porosity, mineralogy, and organic matter, on marine shale gas enrichment and reserve calculation has not yet been fully clarified. Herein, we measured gas adsorption, porosity, mineralogical composition, and total organic carbon content of the marine shale samples from the Jiaoshiba area of Fuling gas field in Sichuan Basin, South China, and investigate the relationships between the geological factors and the adsorbed gas content. The results show that adsorbed gas content is positively correlated with total organic carbon and porosity; the larger specific surface area of samples with more clay minerals essentially contributes to shale gas enrichment. Additionally, the sealing of faults imposes a significant impact on shale gas accumulation. The probability volume method was applied to calculate the shale gas reserve. The reserves of P90 (the most pessimistic reserve), P50 (the most likely reserve), and P10 (the most optimistic reserve) were calculated, respectively, which provides useful information to reduce the risk in shale gas development.

scholarly journals Total Organic Carbon Assessment in Soils Cultivated with Agave tequilana Weber in Jalisco, Mexico

2020 ◽  
Vol 13 (1) ◽  
pp. 208
Author(s):  
Celia De La Mora-Orozco ◽  
José G. Flores-Garnica ◽  
Lucia M. Vega-Ramírez ◽  
Irma J. González-Acuña ◽  
Juan Nápoles-Armenta ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Total Organic Carbon ◽  
Management Practices ◽  
Water Saturation ◽  
Management Strategies ◽  
Information Criterion ◽  
Agave Tequilana ◽  
Tukey Test ◽  
Significant Difference ◽  
Agriculture Management

The Agave tequilana Weber is an important commercial crop in the State of Jalisco, Mexico. However, the agave cultivation generates significant soil loss. For that reason, knowledge about the implementation of the agriculture management practices, such as manure application and the combination of inorganic fertilizers and manure, are relevant. The objective of this research was to determine the effect of agricultural management practices on the total organic carbon (TOC) in the soil in three study locations: Arandas, Tepatitlán, and Acatic in the Altos Sur region of Jalisco. A random sampling was carried out in each study location, 12 samples were obtained for each location at 0–30 cm deep, and a total of 36 samples were analyzed. The evaluated parameters were the potential hydrogen (pH), electrical conductivity (EC), bulk density (BD), soil-water saturation (SWS), total nitrogen (TN), and total organic carbon (TOC). Basic statistics and correlations between parameters were generated. In addition, to estimate TOC from a multivariate analysis, models were developed based on the lowest Akaike information criterion (AIC) and of the classification and regression trees (CART). ANOVA and Tukey test were determined. Results demonstrated a significant difference in the TOC percentages between the study locations. The Tukey test showed that there is no difference in TOC content between the Tepatitlán and Arandas sites, but there is a difference between these two sites and the Acatic. The latter resulted with the lowest values of TOC. Long-term studies are recommended to develop crop management strategies.

Two effective methods for calculating water saturations in shale-gas reservoirs

Geophysics ◽  
2017 ◽  
Vol 82 (3) ◽  
pp. D187-D197 ◽  
Author(s):  
Jingling Xu ◽  
Lei Xu ◽  
Yuxing Qin
Keyword(s):  
Shale Gas ◽  
Water Saturation ◽  
Critical Issue ◽  
Petroleum Exploration ◽  
Gas Content ◽  
Gas Reservoirs ◽  
Gas Saturation ◽  
Shale Gas Reservoirs ◽  
Shale Reservoirs ◽  
Southeastern Sichuan Basin

Water saturation is one of the most important parameters in petroleum exploration and development. However, its calculation has been limited by the insufficient logging data required by a new technique that further influences the calculation of the free gas content. The accuracy of water saturation estimates is also a critical issue because it controls whether or not we can obtain an accurate gas saturation estimate. Organic matter plays an important role in shale-gas reservoirs, and the total organic carbon (TOC) indirectly controls the gas content and gas saturation. Hence, water saturation is influenced by inorganic and organic components. After analyzing the relationship among TOC, core water saturation, and conventional gas saturation, considering the influence of TOC on gas saturation in organic-rich shale reservoirs, we developed two new methods to improve the accuracy of water saturation estimates: the revised water saturation-TOC method and the water saturation separation method, in which Archie water saturation, modified total shale water saturation, and TOC are integrated. According to case studies of Longmaxi-Wufeng shale, southeastern Sichuan Basin, China, the water saturation results from these two methods in shale reservoirs with different lithologies are consistent with those from core analysis. We concluded that these two methods can be evaluated quickly and they effectively evaluate the water saturation of shale reservoirs.

scholarly journals Geological models and controlling factors of gas content in marine–terrigenous shale in the Southern Qinshui Basin, China

2018 ◽  
Vol 37 (1) ◽  
pp. 375-393 ◽  
Author(s):  
Xiaowei Hou ◽  
Yanming Zhu ◽  
Zhenfei Jiang ◽  
Haitao Gao
Keyword(s):  
Organic Carbon ◽  
Total Organic Carbon ◽  
Carbon Content ◽  
Adsorption Capacity ◽  
Total Organic Carbon Content ◽  
Gas Content ◽  
Organic Carbon Content ◽  
Isothermal Adsorption ◽  
Free Gas ◽  
Adsorbed Gas

Geological prediction models for gas content in marine–terrigenous shale under the effects of reservoir characteristics and in situ geological conditions, were established using methane isothermal adsorption, high temperature/pressure methane isothermal adsorption, total organic carbon, X-ray diffraction, mercury porosimetry, porosity in net confining stress, and field desorption methods. Results indicated that the adsorption capacity of marine–terrigenous shale has a linearly positive correlation with total organic carbon content and maturity. Clay and quartz minerals are the two main components of inorganic minerals in marine–terrigenous shale, with an average content of 54.3% and 36.9%, respectively. Adsorption capacity of marine–terrigenous shale is slightly positive correlated with clay content, while it exponentially decreases with increasing quartz content. The effects of in situ temperature and reservoir pressure on adsorption capacity in marine–terrigenous shale are also significant. The adsorption capacity of marine–terrigenous shale shows a clear decreasing trend as temperature increases, while it increases with increasing reservoir pressure. The porosity of marine–terrigenous shale is characterized by highly stress-sensitive, decreasing exponentially with increasing effective stress, which results in a more complex occurrence of free gas in deep shale reservoirs. In addition, gas saturation for the shale samples was calculated based on the results of field desorption, after which geological prediction models of total gas, adsorbed gas, and free gas were established while considering the coupled effects. Adsorbed gas, free gas, and total gas content all initially increase as burial depth increases, and then eventually decrease. Adsorbed gas content and free gas content have a positive correlation with total organic carbon content and porosity, indicating that the total gas content at different burial depths is mainly controlled by the total organic carbon content and porosity.

scholarly journals Investigating Influential Factors of the Gas Absorption Capacity in Shale Reservoirs Using Integrated Petrophysical, Mineralogical and Geochemical Experiments: A Case Study

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3078 ◽  
Author(s):  
Zhuoying Fan ◽  
Jiagen Hou ◽  
Xinmin Ge ◽  
Peiqiang Zhao ◽  
Jianyu Liu
Keyword(s):  
Shale Gas ◽  
Total Porosity ◽  
Organic Content ◽  
Absorption Capacity ◽  
Influential Factors ◽  
Gas Absorption ◽  
Gas Content ◽  
Adsorbed Gas ◽  
Shale Reservoirs ◽  
Gas Volume

Estimating in situ gas content is very important for the effective exploration of shale gas reservoirs. However, it is difficult to choose the sensitive geological and geophysical parameters during the modeling process, since the controlling factors for the abundance of gas volumes are often unknown and hard to determine. Integrated interdisciplinary experiments (involving petrophysical, mineralogical, geochemical and petrological aspects) were conducted to search for the influential factors of the adsorbed gas volume in marine gas shale reservoirs. The results showed that in shale reservoirs with high maturity and high organic content that the adsorbed gas volume increases, with an increase in the contents of organic matter and quartz, but with a decrease in clay volume. The relationship between the adsorbed gas content and the total porosity is unclear, but a strong relationship between the proportions of different pores is observed. In general, the larger the percentage of micropores, the higher the adsorbed gas content. The result is illuminating, since it may help us to choose suitable parameters for the estimation of shale gas content.

scholarly journals Shale favorable area optimization in coal-bearing series: A case study from the Shanxi Formation in Northern Ordos Basin, China

2017 ◽  
Vol 36 (5) ◽  
pp. 1295-1309 ◽  
Author(s):  
Wei Guo ◽  
Weijun Shen ◽  
Shangwen Zhou ◽  
Huaqing Xue ◽  
Dexun Liu ◽  
...  
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Total Organic Carbon ◽  
Shale Gas ◽  
Ordos Basin ◽  
Sedimentary Facies ◽  
Gas Content ◽  
Burial Depth ◽  
Organic Carbon Content ◽  
River Channels

Shales in the Well district of Yu 106 of the Shanxi Formation in the Eastern Ordos Basin is deposited in the swamp between delta plains, distributary river channels, natural levee, the far end of crevasse splay, and depression environments. According to organic geochemistry, reservoir physical property, gas bearing capacity, lithology experimental analysis, combined with the data of drilling, logging, testing and sedimentary facies, the reservoir conditions of shale gas and the distribution of an advantageous area in Shanxi Formation have been conducted. The results show that the total organic carbon content of the Shanxi Formation is relatively high, with an average content value of 5.28% in the segment 2 and 3.02% in segment 1, and the organic matter is mainly kerogen type II2 and III. The maturity of organic matter is high with 1.89% as the average value of Ro which indicates the superior condition for gas generation of this reservoir. The porosity of shales is 1.7% on average, and the average permeability is 0.0415 × 10−3 µm2. The cumulative thickness is relatively large, with an average of 75 m. Brittle mineral and clay content in shales are 49.9% and 50.1%, respectively, but the burial depth of shale is less than 3000 m. The testing gas content is relatively high (0.64 × 104 m3/d), which shows a great potential in commercial development. The total organic carbon of the segment 2 is higher than that of the segment 1, and it is also better than segment 1 in terms of gas content. Based on the thickness of shale and the distribution of sedimentary facies, it is predicted that the advantageous area of shale gas in the segment 2 is distributed in a striped zone along the northeast and the northsouth direction, which is controlled by the swamp microfacies between distributary river channels.

Physico-chemical and hydrological properties of soilless substrates

2021 ◽  
Vol 42 (3) ◽  
pp. 700-704
Author(s):  
Anbarasu Mariyappillai ◽  
◽  
Gurusamy Arumugam ◽  
Keyword(s):  
Organic Carbon ◽  
Total Organic Carbon ◽  
Natural Fiber ◽  
Particle Density ◽  
Colorimetric Method ◽  
Chemical Properties ◽  
Maximum Level ◽  
Total Porosity ◽  
Physico Chemical ◽  
And Chemical Properties

Aim: To evaluate the physico-chemical and hydrological characteristics of cocopith, perlite, vermicullite, vermicompost, sand, rice husk, paddy straw, saw dust and rock wool for using them as substrates for soilless agriculture. Methodology: The soilless substrates were initially evaluated for pH and EC, and then estimated for total organic carbon by dry combustion method, total nitrogen by Kjeldahl digestion method, potassium by atomic absorption and phosphorus by colorimetric method. The hydrological properties of substrates were estimated by Keen - Rackzowski box method. Results: The desirable level of physical properties of bulk density (0.47 gm cm-3), particle density (0.63 gm cm-3), total porosity (75.81%) and chemical properties of pH (6.23), EC (5.02 dS m-1), total organic carbon (36.39 %), and other properties were noticed under cocopith. The maximum level of water holding capacity (769.30 %) and volume of expansion (185.78 %) was registered by cocopith. Interpretation: Cocopith has favourable hydrological properties with desirable level of physical and chemical properties, which makes it the best medium for soilless agriculture. Coconut fiber is a characteristic natural fiber from the external husk of coconut and its extraction process also without polluting nature.

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