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The viscosity of crude oil plays a pivotal role in the exploration and development of oil fields. The predominant reliance on laboratory measurements, which are constrained by manual expertise, represents a significant limitation in terms of efficiency. Two-dimensional nuclear magnetic resonance (NMR) logging offers a number of advantages over traditional methods. It is capable of providing faster measurement rates, as well as insights into fluid properties, which can facilitate timely adjustments in oil and gas development strategies. This study focuses on the loose sandstone reservoirs with high porosity and permeability containing heavy oil in the Huabei oilfield. Two-dimensional nuclear magnetic resonance (NMR) measurements and analyses were conducted on saturated rocks with different-viscosity crude oils and varying oil saturation levels, in both natural and artificial rock samples. This study elucidates the distribution patterns of different-viscosity crude oils within the two-dimensional NMR spectra. Furthermore, the T1 and T2 peak values of the extracted oil signals were employed to establish a model correlating oil viscosity with NMR parameters. Consequently, a criterion for determining oil viscosity based on two-dimensional NMR was formulated, providing a novel approach for estimating oil viscosity. The application of this technique in the BQ well group of the Huabei oilfield region yielded an average relative error of 15% between the actual oil viscosity and the computed results. Furthermore, the consistency between the oil types and the oil discrimination chart confirms the reliability of the method. The final outcomes meet the precision requirements for practical log interpretation and demonstrate the excellent performance of two-dimensional nuclear magnetic resonance (NMR) logging in calculating oil viscosity. The findings of this study have significant implications for subsequent exploration and development endeavors in the research area’s oilfields.

Irrigation using marginal quality water (brackish, saline, or treated wastewater, with a salinity of 2–8 g L−1) instead of fresh water alters the soil carbon and nitrogen cycle, and thus, soil greenhouse gas emissions. To reveal the responses of soil nitrous oxide (N2O) and carbon dioxide (CO2) emissions and their global warming potentials (GWPs) to irrigation water salinity, a pot experiment was conducted at three levels (2, 5, and 8 g L−1, namely S2, S5, and S8). The results show that the cumulative soil CO2 emissions were reduced with increases in the irrigation water salinity and were 11.6–28.1% lower than those from the fresh water-irrigated treatment (CK). The cumulative N2O emissions from S2 and S8 decreased by 22.7% and 39.6% (p < 0.05), respectively, in comparison to CK, whereas those from S5 increased by 87.7% (p < 0.05). The cumulative GWPs from S2 and S8 were 19.6% and 44.1% lower than those from CK, while those from S5 were significantly higher (p < 0.05). These findings indicate that reducing the salinity of brackish water from 5 to 2 g L−1 before using it for irrigation is a potential strategy to mitigate soil GHGs and solve water resource scarcity. The response of soil greenhouse gas (GHG) emissions to salinity may be significantly different among irrigation water salinity ranges. The results have an important guiding significance for exploring greenhouse gas emission reduction measures, and sustainable utilization models of water and soil resources.