Research On Imbibition Rules In Fractured Buried Hill Reservoir And The Optimization Of Development Scheme

In the fractured reservoir with low permeability,factures are usually the dominant flowing path,but oil and gas are contained mainly in the matrix.For low-permeability reservoir,the exchange of fluid between fracture and matrix is realized by imbibition,in this way,it does make great sense to study the inherent laws of imbibition in low-permeability fractured reservoir.In this paper,the following achievements have been done with the background information of the reservoir PengLai 9-1:(1)According to the development of factures in the target reservoir,rock samples with different properties are made to meet the demand of flooding test in factures.The results show that viscosity of the fluid in reservoir is the dominant factor which affects the flooding efficiency.(2)A kind of square model is designed to study the exchange laws of fluid between fracture and matrix.Four models with different properties are made with rock samples and then tested to research the factors that influence imbibition.According to the results,higher permeability of matrix and lower viscosity of crude oil lead to higher imbibition efficiency and more contribution of recovered oil from matrix.(3)On the base of rules of similarity,a physical model is made to match the attributes of PengLai 9-1 using the physical simulation technology.(4)Use the physical model to realized simulated development of the target reservoir with different well patterns and then find the best effective pattern.(5)According the test of using hot water as flooding fluid and adding surfactant,viscosity reduction of oil in the vicinity of wellbore is more than that in any other places.Moreover,hot water enhances the phenomenon of water overriding in the main flow line,which lower the sweep efficiency.In the meantime,surfactant makes the flooding in fractures more efficient but weakens the imbibition.