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Stratigraphic Sequence Analysis of Palaeocene in the X Sag, East China Sea Shelf Basin
Zhongqiang Sun,
Guangao Zhong,
Longlong Liu,
Zhihao Chen,
Wenlong Shen,
Jinliang Zhang
Issue:
Volume 6, Issue 1, June 2022
Pages:
1-13
Received:
16 November 2021
Accepted:
11 December 2021
Published:
8 January 2022
DOI:
10.11648/j.pse.20220601.11
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Abstract: The X sag in the East China Sea Shelf Basin has great exploration potential and rich oil and gas resources, but the exploration degree is low, and the exploration process still faces the key geological problem of inconsistent sequence stratigraphic framework. Therefore, this study is based on regional geology, logging, seismic and analysis data, using well-seismic correlation, spectrum analysis, wavelet transform, relative sea level change analysis and other methods, through the identification of sequence boundaries of seismic and drilling at all levels, supplemented by stratigraphic sequence cycle and relative sea level change analysis. According to different sequence stratigraphic models, the Paleocene stratigraphic division scheme of X sag is determined. The Paleocene strata are divided into five third-order sequences, namely Y Formation, lower L Formation, upper L Formation, lower M Formation and upper M Formation, thirteen fourth-order sequences are further identified, which Y Formation and upper M Formation are divided into transgressive system tract and regressive system tract, the lower L Formation, upper L Formation and lower M Formation are divided into lowstand system tract, transgressive system tract and highstand system tract, and a unified stratigraphic sequence framework of the whole region is established. It provides geological support for the study of sedimentary facies and its development law under the control of Paleocene stratigraphic sequence in X sag, promoting the unification of basic geological understanding of X sag and the selection of favorable areas in the next exploration work.
Abstract: The X sag in the East China Sea Shelf Basin has great exploration potential and rich oil and gas resources, but the exploration degree is low, and the exploration process still faces the key geological problem of inconsistent sequence stratigraphic framework. Therefore, this study is based on regional geology, logging, seismic and analysis data, us...
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Key Factors and Improvement Measures Changing the Gum Content of Stored Fuels
Zubin Zhang,
Ruiyi Gu,
Haiqin Wang,
Xianjie Sun,
Hong Li
Issue:
Volume 6, Issue 1, June 2022
Pages:
14-25
Received:
12 December 2021
Accepted:
30 December 2021
Published:
12 January 2022
DOI:
10.11648/j.pse.20220601.12
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Abstract: This paper reviews the research that has been reported in recent years on the stability of liquid fuels. It has been shown that gum is formed as a byproduct of unstable components, and the existent gum content in fuel increases continuously during storage, resulting in a gradual decline in oil quality. The primary purpose of this study is to evaluate the key factors and improvement measures for reducing the gum content of fuels. The study also presents the oxidation mechanism involved in gum formation and indicates the main parameters and specific storage conditions influencing gum accumulation in fuel. We have found that unsaturated olefins, sulfides, nitrides, metals, oxygen, additives and solar radiation have different impacts on gum formation, among them, unsaturated olefins have the most impact on gum formation. In the report, we have also made recommendations for reducing gum accumulation, such as using fiberglass reinforced plastic (FRP) storage tanks, improving the refining process, and integrating nitrogen content into the gasoline quality standard. Moreover, big data and intelligent analysis methods can also be used to model for the change of existent gum content in various fuels. This model can then be used to predict the maximum allowable retention periods of different fuels.
Abstract: This paper reviews the research that has been reported in recent years on the stability of liquid fuels. It has been shown that gum is formed as a byproduct of unstable components, and the existent gum content in fuel increases continuously during storage, resulting in a gradual decline in oil quality. The primary purpose of this study is to evalua...
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A Critical Appraisal of Thermal Effects on CO2 Entrance Pressure
Abrar Almutairi,
Talal Al-Bazali
Issue:
Volume 6, Issue 1, June 2022
Pages:
26-37
Received:
11 March 2022
Accepted:
28 March 2022
Published:
9 April 2022
DOI:
10.11648/j.pse.20220601.13
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Abstract: The ability of shale to prevent CO2 from passing through is highly related to a surface phenomenon called capillary entry pressure. Namely, in order for CO2 to invade shale pores and establish flow, a threshold capillary pressure must be overcome by CO2. Evaluating the threshold capillary pressure of shale has been of great interest by the oil and gas industry. Most studies relied on measuring the capillary entry “threshold’’ pressure of shale as CO2 flows through it, and converted it to what is referred to as sealing “sequestration’’ capacity. While many scientists and researcher have measured capillary entry pressure of shale as interacts with different non-wetting fluids such as CO2, their studies were done under ambient temperature which did not reflect in situ conditions. In this study, changes in capillary entry pressure of shale when interacting with CO2, under different temperatures (25°C to 250°C), have been investigated. The combined impact of temperature and petrophysical properties of shale (water content, water activity, permeability and porosity) on capillary entry pressure was also addressed. Results showed that capillary entry pressure of shale when interacting with CO2 was highly affected by temperature. Higher temperatures decreased capillary entry pressure of shale. We believe that pore dilation, where pore throat size expands due to the application of heat, may have caused this decrease in capillary entry pressure of shale. However, in some cases higher temperature activated clay swelling that may have caused an apparent decrease in pore throat radii of shale which translated into higher capillary entry pressure of shale. Results also showed that there exists no distinct relationship between petrophysical properties of shale and its measured capillary entry pressure when interacting with CO2 at different temperatures.
Abstract: The ability of shale to prevent CO2 from passing through is highly related to a surface phenomenon called capillary entry pressure. Namely, in order for CO2 to invade shale pores and establish flow, a threshold capillary pressure must be overcome by CO2. Evaluating the threshold capillary pressure of shale has been of great interest by the oil and ...
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Main Controlling Factors of the Flowback Effect for Volumetric Fracturing Horizontal Wells in Shale Oil Reservoir
Meng Feng,
Weihong Xu,
Hui Liu,
Yu Liu,
Zhihao Jiang,
Feipeng Wu
Issue:
Volume 6, Issue 1, June 2022
Pages:
38-46
Received:
15 April 2022
Accepted:
5 May 2022
Published:
12 May 2022
DOI:
10.11648/j.pse.20220601.14
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Abstract: The flowback system after fracturing is a key factor affecting the development effect of shale oil horizontal wells. This paper systematically analyzes the actual data of post-fracturing productivity in the study area, and preliminarily evaluates the main controlling factors and sensitivities that affect the development effect. By means of the reservoir numerical simulation method, the mining field data is fitted, and then the influence rule of the main control factors selected by the systematic simulation calculation on the development effect is calculated. Developed a data mining optimization model for the volume fracturing flowback system in shale oil horizontal wells, and carried out the main controlling factors and sensitivity evaluations that affect the production effect. The results show that the fitting accuracy of the fracturing flowback effect evaluation and prediction model formed in this paper to the actual data of the target area can reach more than 89%; The sensitivity of the main controlling factors affecting the post-fracturing productivity in the study area are: fracturing construction parameters, compressibility parameters, flowback system and geological factors; among them, there is an obvious positive correlation trend between productivity, flowback time and flowback amount, and the cumulative flowback volume has the greatest influence on the flowback system of oil well productivity. The optimization method based on data mining can better guide the optimal design of the fracturing flowback system for shale oil horizontal wells in the target area, and provide support for improving the fracturing production effect of shale oil horizontal wells in the target area.
Abstract: The flowback system after fracturing is a key factor affecting the development effect of shale oil horizontal wells. This paper systematically analyzes the actual data of post-fracturing productivity in the study area, and preliminarily evaluates the main controlling factors and sensitivities that affect the development effect. By means of the rese...
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