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Abstract: Based on outcrop, core, logging and mud logging data, and modern deposition analog, the sandbodies genetic types and spatial distribution in different facies belts of the shallow water delta in the first Member of Cretaceous Yaojia Formation (K2y1) of Qian'an area in Changling sag of southern Songliao Basin were analyzed, and the sedimentary model of shallow water delta was established according to deposition process. Active channel sandbodies, point bar sandbodies and bifurcation bar sandbodies in distributary channels and complex sandbodies formed the main sandbodies in the delta plain, while terminal distributary channels and mouth bar sandbodies formed the main sandbodies in the delta front. The delta prograded gradually under the construction of river mouth and reconstruction of river erosion, the early delta front evolved into delta plain and was reformed by distributary channels, and new delta fronts were formed at the river mouth ahead constantly. Under the control of the above deposition process, the size of main distributary channels in delta plain-delta front declined, while mouth bars developed increasingly. The sandbodies of different genetic types formed framework of river-dominated shallow water delta. The point bar and active channel sandbodies in main distributary channels of the delta, with the best reservoir quality, are lithologic reservoir targets in future exploration. Key words: Songliao Basin, Cretaceous, Yaojia Formation, shallow water delta, sandbody type, sedimentary model

By using core samples, thin section, scanning electron microscope and rate-controlled mercury penetration data etc, the reservoir characteristics, oil-bearing characteristics and main controlling factors of the tight sandstone oil in Fuyu oil layer of Da'an area, Songliao Basin are studied. The oil-bearing characteristics of Fuyu oil layers in Da'an area are as follows: (1) the extensive and continuous distribution, with “sweet spots” in local areas; (2) low oil abundance, and very complex distribution; (3) oil-bearing grade being oil immersion to oil spot, with very low lower-limit of oil-bearing porosity and permeability; and (4) poor differentiation of oil and water, no uniform oil-water contact. The above oil-bearing characteristics of the tight sandstone in Fuyu oil layers are mainly controlled by the spatial distribution of distributary channel sands, the differences in reservoir physical properties, the structure and size of pores and throats. The boundary of distributary channel sandbody is the boundary of tight sandstone oil distribution. The heterogeneity of tight sandstone oil is controlled by the single distributary channel sandbody and the contact relationship between different stages of distributary channel sandbody. Distribution of “sweet spots” and enrichment of tight sandstone oil are controlled by the differences in physical properties. The differentiation of oil and water in the tight sandstone is controlled by the pore structure and pore size. In-situ oil accumulation is controlled by the nano-pore throat structure system. Key words: tight sandstone oil, reservoir characteristics, tight oil distribution, oil-bearing characteristics, Fuyu oil layer, Songliao Basin

Objective To study the characteristics and advantages of the tight trusteeship mode, and to provide expe-rience and suggestions for promoting the sinking of high-quality medical resources. Methods By literature analysis, the process and characteristics of hospital trusteeship reforms in China were summarized. Based on the “structure-process-results” theory, the tight, semi-tight, and loose trusteeship modes were compared using comparative research methods to summarize the main characteristics and advantages of the tight trusteeship mode. Through analyzing a case of tight trusteeship of a large provincial tertiary public hospital in Shandong Province, the specific practical measures, effectiveness, and existing problems of the tight trusteeship mode were discussed. Results The tight trusteeship mode is usually a comprehensive government trusteeship, where the trustee hospital provides a unified leadership to manage the entrusted hospital as a campus, integrating and homogenizing personnel ma-nagement, financial management, business management, informationization, and other aspects, achieving more stable collaboration and better performance. Conclusion The tight trusteeship mode is more conducive to channeling large public hospitals’ high-quality medical resources including brand, workforce, technology, and information towards primary medical institutions, which is an effective way to promote the expansion and sinking and regional balance of high-quality medical resources in the new era.