Application Of Micro-CT Technology In The Study Of Reservoir Damage

After reforming technique of low permeability sandstone reservoirs, the diffidentcapacity of every Wells reservoir is apparent, the key is not according to the feature of thereservoir itself to make effective testing. For the development of low permeability oil andgas field, reservoir rock porosity and permeability are two important physical parameters.In the traditional geological experimental method, we usually use weighing method and theporosimeter method, to calculate the average value of the samples, whereas the internalpore distribution is uneven, especially for micro pore structure and characteristics, theconventional experimental methods are difficult to obtain.Micro-CT three-dimensional imaging technology, which based on the X-rayattenuation degree of different atomic number of minerals to rebuild a response to the realstructure of the digital core. Micro-CT scanning technique can be used to observe themicroscopic characteristics of the reservoir rock, pore distribution, fluid path simulationand so on, the most important is to assess object the actual core has kept its primitiveness,reflect the status of underground multiphase equilibrium system to maintain its originalnature. Numerical simulation method is proposed, which is an innovation in the field ofpetroleum geology experiment, adding the traditional experimental methods.After knowing the geological feature and reservoir characteristics of low permeabilityin the south region of Sheng-li, using the conventional experimental methods of opticalmicroscope, electron probe combined with technology of microscopic CT3Dreconstruction to analyse the mineral phases in the studied area, the structure of the particlesize, mixed fillings occurrence state and pore space network structure, describes theresearch within the area of three dimensional space of the reservoir rock mineralcomposition, distribution characteristics, rock mineral grains contact relationship, porefilling cement and so on, analyzes the harmful mechanism of low permeability reservoir.Basically achieved the following three innovations: (1) according to the gray-scale difference of CT image, using the routine analysistechnology such as polarized light microscope and electron probe, a corresponding relationmapping of common minerals and pore of electron probe microscopic CT2D slice imageshave been established, discusses using the available micro CT technology to characterizecomposition of the rock.(2) the technology of microscopic CT can be used to observe the structure and spatialdistribution characteristics of single mineral, to analyze the three-dimensional contactionof different mineral relationship types and pore structure characteristics.(3) using microscopic CT technology to extract the micro pore structure, evaluate thepore connectivity, through the microstructure characteristics to evaluate and classify thereservoir of sandstone, discussing the causes of the decreased oil productivity.