Determination of Hydrocarbon-bearing Property of Deep-water Sandstone by Fluid Pressure Gradient from Seismic Attributes
Chang Deshuang,
Chen Zhigang,
Han Yuchun,
Sun Xing,
Chen Jie,
Zhao Qian,
Zhao Xiaoqing
Issue:
Volume 9, Issue 3, May 2021
Pages:
36-41
Received:
27 April 2021
Accepted:
10 May 2021
Published:
22 July 2021
Abstract: In the same hydrodynamic system, because the densities of oil and gas are smaller than that of water, their pressure gradients are also smaller. Therefore, the pressure gradient can determine fluid properties. Based on seismic data and well logging data, this paper attempts to apply the equivalent medium theory to predict the pressure gradient, and then to identify fluids. Firstly, the upper and lower limits of bulk modulus and shear modulus of rocks can be obtained by using wellbore and well logging interpretation data. Secondly, based on the equivalent medium theory, the fluid velocity (when rock rigidity approaching zero) and the rock matrix velocity (when porosity approaching zero) are predicted. Thirdly, the predicted two types of velocity curves and the original acoustic curves are used for seismic inversion. Finally, according to the inversion results, the formation pressure and pressure gradient can be obtained by using the Fillippone pressure formula, and the hydrocarbon-bearing property of reservoirs can be determined according to the theoretical pressure gradients of different fluids. For offshore deep-water sandstone in an overseas block, when the frequency attributes for hydrocarbon detection cannot reflect hydrocarbons well, the fluid pressure gradient attribute is used to predict hydrocarbons, and the prediction coincidence rate reaches 70%.
Abstract: In the same hydrodynamic system, because the densities of oil and gas are smaller than that of water, their pressure gradients are also smaller. Therefore, the pressure gradient can determine fluid properties. Based on seismic data and well logging data, this paper attempts to apply the equivalent medium theory to predict the pressure gradient, and...
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Research of New Demulsifier in Bohai Oilfield
Ren Yi,
Dai Hongcheng,
Du Dawei,
Cheng Yan,
Zhang Liya
Issue:
Volume 9, Issue 3, May 2021
Pages:
42-45
Received:
7 July 2021
Accepted:
22 July 2021
Published:
2 August 2021
Abstract: The content of asphalt in an EOR oilfield of Bohai is high, reaching more than 30%, and the content of phenol and naphthenic acid is also high, resulting in high acid value of crude oil. The water content is about 85% - 95%, and it is in the later stage of mining. Because hydrophobically associating PAM is used as oil displacement agent in the platform, it is difficult to degrade and seriously affects the demulsifier. The oil-water interfacial film formed by polymer, gum and asphalt is very firm, which increases the difficulty of dehydration. There is no ideal product in the selection and application of reverse demulsifier for heavy crude oil with high content of asphalt, high water content and high acid value. In this experiment, triethanolamine was selected as the starting agent from the aspect of branching and introducing nitrogen element, and water-soluble triblock polyether was synthesized according to the ratio of PO: EO: PO=2:7:6, and then crosslinked with 3% (relative polyether mass) epichlorohydrin. In the process, the crosslinking temperature was 80°C, the reaction time was 5h, and potassium hydroxide solution was used as catalyst. At last, the demulsifier product with good effect of clear water was made, and good effect was obtained in field application.
Abstract: The content of asphalt in an EOR oilfield of Bohai is high, reaching more than 30%, and the content of phenol and naphthenic acid is also high, resulting in high acid value of crude oil. The water content is about 85% - 95%, and it is in the later stage of mining. Because hydrophobically associating PAM is used as oil displacement agent in the plat...
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