Linbei area was located in the middle of the central uplift zone of Huimin depression. Aiming at the problems of unclear reservoir type, trap scale and reservoir validity of the Jishan sand body in this area, starting from hydrocarbon source conditions, reservoir physical properties, distribution of sedimentary facies and structural features, through the data of drilling and oil testing results, comprehensive application of geological, geochemical analysis and geophysical research means, in depth analysis of hydrocarbon accumulation conditions and main control factors. The results show that: the high⁃quality source rock in the third member of Shahejie formation is the main source of Linbeijishan sand body, and the good configuration of sand bodies in different periods in time and space is the basis for the formation of hydrocarbon accumulation; the relationships between the developed faults and the pathway system of framework sand body in the area provides a good migration channel for oil and gas, which results in the zonal distribution of oil and gas reservoirs along the North⁃South fault steps; The mudstone in the upper part of the third member of Shahejie formation and the thick mudstone at the top of the Jishan sand body are stable, The sand body of each stage are separated by mudstone and pinched out from the east to the west, the high salinity primary CaCl2 water type with good sealing property developed in the third member of Shahejie formation and the lateral sealing of some faults act together to provided good preservation conditions for oil and gas reservoirs.

Aiming at the process on leakage of buried gas pipeline in urban area, and considering gas of different constituents and concentration leakage based under multi building condition, using computational fluid dynamics (CFD) software to establish the three-dimensional physical model of buried pipeline in the leakage process, the environmental wind field and leakage rate into the boundary conditions in the form of user-defined functions were introduced, and the simulation process was divided into steady-state simulation in environmental wind field and transient simulation in leakage. And the leakage process was divided into continuous leakage and leakage after pipe valve closing, and the gas leakage rules were analyzed. The results showed that: It was necessary to simulate the steady state in environmental wind field. There existed three low velocity zones near the flow field and a large velocity gradient on the edge of the building. It showed the following characteristics that the confined leakage of oil layer diffusion, low velocity zone upstream gathering, gas cloud rising, hydrogen sulfide deposition and diffusion and so on in the gas continuous leakage stage. It showed the characteristics of the gas diffusion continuity and dissipation from top to bottom in the valve closed stage. Based on the conditions above, comparing methane, hydrogen sulfide had larger diffusion range, later dissipation time, and greater risk.