To reduce the injury caused by hydrogen explosion accident, numerical simulation study is carried out to study the characteristics of hydrogen explosion in confined space under different venting conditions. The results show that in the process of the flame passing through the side vent, the position of the side vent can affect the leading role of the side venting on the flame front distortion. When the flame front is in front of the side vent, the flame is accelerated by the traction of co-flow. When the flame front passes through the side vent, the flame propagation speed under various working conditions is greatly reduced due to the combined action of reflected wave and vertical flow field. When the front of the flame is located behind the side vent, the flame propagation speed fluctuates greatly only when the side vent is 1 m away from the ignition end, and the flame propagation to the end of the pipe is kept at a low speed in other venting conditions. The pressure relief effect of the side vent is positively related to the size of the side vent. When the side vent is located in the middle of the pipe, the pressure relief effect is the best. When the size of the vent is small, the pressure relief effect is greatly affected by the location of the vent. The peak overpressure in h-1-40, h-3-40, h-5-40 decreases by 49.21%, 83.89%% and 78.03%, respectively. With the increase of the size of the side vent, the pressure relief effect of the side vent is almost not affected by its size. The peak overpressure in H-1-80, H-3-80, H-5-80 only decreases by 90.17%, 94.99% and 92.78%, respectively.

To investigate the evolution process of LNG (Liquefied Natural Gas) liquid pool and gas cloud diffusion, the Realizable k-ε model and Eluerian model were used to numerically simulate the liquid phase leakage and diffusion process of LNG storage tanks. The experimental results showed that some LNG flashed and vaporized rapidly to form a combustible cloud during the continuous leakage. The diffusion of the explosive cloud was divided into heavy gas accumulation, entrainment heat transfer, and light gas drift. The vapor cloud gradually separated into two parts from the whole “fan leaf shape”. One part was a heavy gas cloud; the other part was a light gas cloud that spread with the wind in the downwind direction. The change of leakage aperture had a greater impact on the whole spill and dispersion process of the storage tank. The increasing leakage aperture would lead to 10.3 times increase in liquid pool area, 78.5% increase in downwind dispersion of methane concentration at 0.5 LFL, 22.6% increase in crosswind dispersion of methane concentration at 0.5 LFL, and 249% increase in flammable vapor cloud volume. Within the variation range of the leakage aperture, the trend of the gas cloud diffusion remained consistent, but the time for the liquid pool to keep stable and the gas cloud to enter the next diffusion stage was delayed. The low-pressure cavity area within 200 m of the leeward surface of the storage tank would accumulate heavy gas for a long time, forming a local high concentration area, which should be an area of focus for alert prediction.

The objective area in this paper is a complex fault-block reservoir, which is provided by China Petroleum Engineering Design Competition. Reservoir characteristics which comprise of stratigraphic features, vertical changes, and section properties (thickness, percentage sand, and percentage amalgamation) are documented. Through comprehensive analysis on structural architecture and reservoir characteristics, a three-dimensional quantitative reservoir modeling is taken at a regional scale of 69 × 97 × 37 m³ with the application of geostatistics as theoretical guidance. Then, a high-resolution hierarchical reservoir model of this field has been generated with a combination of hierarchical, structural, physical, and well trajectory data. The established three-dimensional geological model integrates all well and structural information, which can provide a basic model for subsequent sedimentary microfacies modeling and property modeling as well. Finally, a series of profiles are built successively, they are three-dimensional fence diagrams, connecting well sections and well group profiles, which can be a valuable tool for reflecting geologic body with great reality and thus achieve reservoir characterization of the complex fault-block reservoir.