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The development of anti-rhythmic carbonate reservoirs in the Middle East often encounters challenges such as water hold-up and reverse coning during the water injection process, leading to premature water breakthrough and various water-out issues. The unclear understanding of these phenomena, attributed to strong reservoir heterogeneity, results in a relatively low recovery degree in water injection development. This paper investigates the mechanisms behind water hold-up and reverse coning phenomena, offering detailed solutions. Numerical models of the oil reservoirs were developed, and an extensive study of influencing factors, including reservoir types, Kv/Kh, water injection pressure differential, wettability, and perforation position, was conducted to unveil the underlying mechanisms. Key findings indicate that the water hold-up phenomenon is influenced by capillary force barriers due to wettability and high-perm streaks, while the reverse coning phenomenon depends on the combined forces of gravity, capillary force and downward production differential among which downward production differential is the dominant factor compared to capillary force and gravity. The study also proposes a differential perforation principle tailored to different water-out types to enhance vertical sweep efficiency. The differential perforation principle is as follows: the optimal perforation position is at top layer and the optimal perforation length approximately accounts for 1/4 of the total oil layer thickness for water-out in bottom; the avoidance perforation height in top accounts for 1/6 of the total oil layer thickness and the optimal perforation length approximately accounts for 1/2 of the total oil layer thickness for water-out in top; the avoidance perforation height in top and bottom accounts for 1/5 and 2/5 of the total oil layer thickness respectively for water-out in both top and bottom.

Fly ash (FA) and slag could improve the performance of glazed hollow bead (GHB) thermal insulation mortar, but little research touched on how the FA and slag affect its performance and optimize its component contents. In this study, an experimental and statistical investigation is conducted to analyze the influences of FA and slag variables on the performance of GHB mortar based on the response surface methodology (RSM). The predicted model was proved statistically significant in terms of the fluidity, compressive strength, flexural strength, and thermal conductivity. Then, the validated model was used to identify the critical parameters and discuss their mechanisms of action. It can be found that (i) FA plays a significant role in fluidity and compressive and flexural strength owing to its morphological and physical filler effects; (ii) slag has an obvious influence on compressive strength and thermal conductivity due to its microaggregate effect. Finally, optimization design was conducted using the desirability approach of RSM to give the optimal component of 20.73% FA and 21.49% slag. The predicted combination was validated by confirmatory tests within an error of 1.52%. This study provides a feasible and effective solution for optimizing GHB thermal insulation mortar to achieve higher performance.

Various types of protected areas (PAs) are important for biodiversity conservation and essential for the 2050 Vision for Biodiversity. Rapid urban expansion affects the effectiveness of PAs in many ways. However, we still lack a clear understanding of the spatial relationship between urban expansion and different types of PAs in China during the last 30 years. Here, we analyzed the spatiotemporal changes in such relationship based on the boundaries of 2622 terrestrial PAs, as well as local Moran's and the Kruskal-Wallis H test during the period of 1992–2020 at the national, regional and provincial scales. The results showed that the number of PA threaten by urban expansion at the national scale fluctuated over time (10 to 80), while the median of the nearest distances between PAs and urban built-up areas decreased from 80.4 km to 2.6 km. At the regional scale, the PAs in east China were more affected by urban expansion than the ones in west China, with higher number of threatened PAs and closer distance between PAs and urban built-up areas. More importantly, non-national PAs were more severely affected by urban expansion than national PAs, and the proportion of threatened non-national PAs is 92.5% in 2020. Thus, future planning and management should place more attention to the non-national PAs that are severely affected by urban expansion. We investigate spatial relation between urban expansion and 2622 protected areas in China. Rapid urban expansion in recent years has posed a serious threat to PAs. Non-national PAs are more severely threatened than the national PAs. [ABSTRACT FROM AUTHOR]