As a new developing method, fishbone well injection has been used in buried hill reservoirs. Based on numerical simulation, optimization research on the new reservoir developing method, which means fishbone wells injecting water at the bottom and horizontal wells producing oil at the top, is present. Compared with horizontal well injection, the results show that the fishbone well can increase the control area, form planar flooding, and hold the injection water upward slowly and evenly. The reasonable fishbone well parameters, such as branching angle, branch number, and branch length, are obtained. The fishbone well injection provides a new technical method for developing buried hill reservoirs efficiently.

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Due to the sedimentary environment, diagenesis effect, and tectogenesis effect, the geometry form of sandstone shows heterogeneity, which affects the water flooding efficiency, especially in continental sedimentary reservoir. First, according to distribution characters of sandstone, an idealized mode can be obtained. The 2-D and two-phase mathematical mode at certain inlet and outlet pressure was established. By applying discrete and differential numerical methods, the cumulative oil production under two conditions can be calculated. It is higher when the inlet end is wider part of the sandstone. Second, using streamline numerical simulation to build similar injection and production horizontal well model, the authors obtained analog and study sweep efficiency of different displacement directions. Last, by adopting reservoir numerical simulation method, the influence of geometric form of sandstone on water flooding efficiency of well pattern was further studied. The conclusion was drawn that when injector was deployed in narrow part of sandstone and oil well in the wide part, the speed of water flood front was fast, and water breakthrough times were shorter, which led to rapid water cut rises. Under certain bottomhole flowing pressure, formation pressure surrounding injector was a little higher, water injection rate dropped, and cumulative oil production decreased.

The complicated fault-block reservoir is a particular reservoir all over the world, but it is widely distributed in eastern China. Complicated fault-block reservoirs have a particular complex structure and reservoir and fluid feature. So there are different change tendencies of the watercut of single well. Based on the geological character of complicated fault-block reservoir, the authors figure out the factors affecting watercut of single well, mainly including water saturation of producing interval, sealing fault and associated fractures, interlayer heterogeneity, plane heterogeneity, injection/production ratio, and hydrocarbon viscosity. Then by applying a numerical simulation method, an appropriate simulation model of flooding unit is established. The results show that the factors mentioned have a close impact on watercut of single well. But the extent of influence is different.

Tight oil is a new energy in nearly two decades in the world. Due to the increased demand for energy and enhanced environmental protection awareness, tight oil resources gradually attracted the attention of our government. Tight oil reservoirs usually have extremely low permeability and relatively low porosity, so currently tight oil reservoirs that have been put into industry development often has well developed fracture system with massive fracturing. Fracture system generally has the characteristics of anisotropy and pressure-sensitivity. Therefore, tight oil reservoirs development is extremely complicated. The research of percolation mechanism to tight oil reservoirs is necessary. This paper typically researches anisotropic medium in consider with pressure sensitivity in tight oil reservoir. The similarity criterion for physical simulation experiment in tight oil reservoir is obtained by dimensional analysis. Percolation experiments simulated anisotropic fractured tight oil reservoirs are done by new physical experiment method with similar materials. Ffracture deformation can be observed at low pressure or atmospheric pressure. The percolation mechanism and principle in pressure sensitive deformation and anisotropy fracture medium is revealed. A new fracture deformation characteristics model is established, and this model has strong applicability. With tensor theory and coordinate transformation method, full tensor permeability model of anisotropic fracture medium is established. Based on the established mathematical model, the main factors affecting the development of tight oil reservoirs are analyzed. Full tensor permeability is of ‘rotation effect’ with nonlinear deformation of multiple groups of fractures. The rules of numerical calculation and experimental results are consistent. Fracturing parameters, pressure sensitivity, anisotropy have great impact on the permeability in tight oil reservoirs. Research shows that in the exploitation of tight oil reservoirs, fracture development and reservoir reconstruction in tight oil reservoirs play a significant role in the contribution of tight oil production capacity.