NMR And MRI Study On Reservoir Rock And Application To Porous Flow Mechanics And Petroleum Engineering

Using NMR spin echo imaging, spin-density imaging, spin-lattice relaxation time imaging, and single point imaging (SPI), as well as relaxation time spectrum techniques, this thesis established several new methods for measurement the properties of reservoir rock and fluid in-situ. At the same time, the paper studied the mechanisms of multiphase flow and formation damage, as well as the distribution law of producible fluid of low-permeability reservoir by these methods. The main research results are followed:The thesis for the first time established a method, which allows to measure permeability, porosity and pore size distribution of cores simultaneously. From the observation of the pore size distribution by low-field NMR relaxation time spectrometry the mechanisms of pressure dependent porosity and permeability change can be derived. This information cannot be obtained by traditional methods. As the large size pores or fractures contribute significantly to the permeability, their change consequently leads to a large permeability change. The contribution of fractures to permeability is even larger than that of pores. Thus the permeability of the cores with fractures decreased more seriously than that of cores without fractures during formation pressure decrease. Furthermore it did not recover during formation pressure increase. It can be concluded that in fractures mainly plastic deformation takes place, while matrix pores mainly show elastic deformation. Therefore it is very important to keep an appropriate formation fluid pressure during the exploitation of...