Abstract
This paper took extra low permeability reservoirs in Dagang Liujianfang Oilfield as an example and analyzed different types of microscopic pore structures by SEM, casting thin sections fluorescence microscope, and so on. With adoption of rate-controlled mercury penetration, NMR, and some other advanced techniques, based on evaluation parameters, namely, throat radius, volume percentage of mobile fluid, start-up pressure gradient, and clay content, the classification and assessment method of extra low permeability reservoirs was improved and the parameter boundaries of the advantageous reservoirs were established. The physical properties of reservoirs with different depth are different. Clay mineral variation range is 7.0%, and throat radius variation range is 1.81 μm, and start pressure gradient range is 0.23 MPa/m, and movable fluid percentage change range is 17.4%. The class IV reservoirs account for 9.56%, class II reservoirs account for 12.16%, and class III reservoirs account for 78.29%. According to the comparison of different development methods, class II reservoir is most suitable for waterflooding development, and class IV reservoir is most suitable for gas injection development. Taking into account the gas injection in the upper section of the reservoir, the next section of water injection development will achieve the best results.
Highlights
China’s extra low permeability reservoirs occurred with large quantity of geological resources and are generally characterized by poor reservoir properties [1]
The primary task of large scale development of low permeability reservoirs is comprehensive evaluation on reservoirs to determine the characteristics of advantageous reservoirs
Zhengming et al and Zhonghong et al evaluated low permeability reservoir comprehensively by selecting abundance, effective thickness, throat radius, volume percentage of mobile fluid, start-up pressure gradient, and effective driving factors based on the characteristics of low permeability reservoirs [5], and based on optimization, they established a comprehensive reservoir evaluation method for low permeability oil regions by selecting five parameters, namely, throat radius, volume percentage of mobile fluid, start-up pressure gradient, clay content, and crude oil viscosity [6]
Summary
Advantageous Reservoir Characterization Technology in Extra Low Permeability Oil Reservoirs. This paper took extra low permeability reservoirs in Dagang Liujianfang Oilfield as an example and analyzed different types of microscopic pore structures by SEM, casting thin sections fluorescence microscope, and so on. With adoption of rate-controlled mercury penetration, NMR, and some other advanced techniques, based on evaluation parameters, namely, throat radius, volume percentage of mobile fluid, start-up pressure gradient, and clay content, the classification and assessment method of extra low permeability reservoirs was improved and the parameter boundaries of the advantageous reservoirs were established. Clay mineral variation range is 7.0%, and throat radius variation range is 1.81 μm, and start pressure gradient range is 0.23 MPa/m, and movable fluid percentage change range is 17.4%. Taking into account the gas injection in the upper section of the reservoir, the section of water injection development will achieve the best results
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have