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Deep sandstone reservoirs in the Paleogene Enping Formation of A-Oilfield, Pearl River Mouth Basin, are significant offshore petroleum targets for this basin. Compared with adjacent water zones and shales, the pays are of low resistivity and low contrast (LRLC). Without new unconventional well-logging techniques, conventional well-logging interpretation has encountered difficulties in these LRLC pays. In this article, based on the Simandoux water–oil saturation equation, influence factors of formation resistivity in sandstone LRLC pays are simulated theoretically. Resistivity cutoff is calculated at average reservoir conditions and proved by oil-testing results. It is applied to oil and water in LWD, and the possible genesis of LRLC is discussed. In sandstone LRLC pays, the resistivity of the oil zone is larger than the resistivity cutoff; the resistivity of the water–oil zone approximates the resistivity cutoff and the resistivity of the water zone is lower than this threshold. At average shale volume and porosity of pays in Enping Formation, the resistivity cutoff is referenced at 4.2 Ω·m overall. In sandstone reservoirs, low formation resistivity in the Enping Formation of A-Oilfield might result from high formation water salinity, complicated pore-throat structure, well physical properties, and the presence of conductive and clay minerals. The resistivity cutoff offers important information in real-time tracking of LWD. The proposed method is demonstrated to be beneficial for identifying hydrocarbons and monitoring trajectory in LRLC pays.

Purpose: To clarify the association of serum alpha-fetoprotein (AFP) with inflammatory markers interleukin (IL)-6 and tumor necrosis factor (TNF)-α in patients with chronic hepatitis B (CHB) during the immune-clearance phase in Eastern China., Methods: This research selected 60 CHB patients during the immune clearance phase who tested positive for AFP, including 32 cases treated by non-antiviral therapy (experimental group) and 28 cases treated by antiviral therapy (positive control group). Another 30 cases tested negative for AFP were set as a negative control group. The correlations of serum AFP with IL-6 and TNF-α in patients were analyzed., Results: HBV DNA clearance in patients receiving antiviral therapy, in both the positive or negative control groups, was not significantly related to other clinical data. In the experimental group, a positive correlation of HBV DNA clearance with serum AFP level (r=0.5126, P=0.0027), alanine aminotransferase (r=0.3924, P=0.0263), and total bilirubin (r=0.5126, P=0.0027) was found. The experimental and positive control groups exhibited elevated serum IL-6 and TNF-α contents versus the negative control group (P<0.05). A positive association of AFP with IL-6 and TNF-α was also identified., Conclusion: Serum AFP level is positively related to IL-6 and TNF-α levels in CHB patients during the immune-clearance phase., Competing Interests: None., (AJTR Copyright © 2023.)