Experimental Study On Physical Properties Of Loose Sandstone Reservoir Under Different Compaction

As the exploration and exploitation of unconsolidated sandstone reservoir in our country, such as SZ36-1oilfield, QHD32-6oilfield, JZ9-3oilfield, BZ25-1oilfield, reservoirs of this type become even more important in hydrocarbon resources of China, so do the work of detection and description and physical property research on the unconsolidated or weakly consolidated formation.Based on the distinguishing feature of loose sand and artificial cores, the research of particle-size distribution and mineral composition and degree of cementation were discussed combined with authentic samples cored in target block. Then relevant tests of changing physical property under different compaction were carried through different pressure setting parterns. In addition, the experiments of oil-water relative permeability under different confining pressure were also studied.The following results were achieved.(1) The natural reservoir cores and artificial cores have similarities in physical property.Their grain size are mainly in180μm to630μm. Quartz and feldspar are the main mineral composition. The cores are weakly cemented that the cementation factor is between1.3and1.7.(2) The experiment process that cores under different compaction can be simulated by setting the pressure in two ways which only sets up confining pressure or both the confining pressure and internal pressure,and the latter way is more authentic.(3) The porosity and permeability of loose sand cores vary with testing pressure.When the net pressure increase, the porosity and permeability decrease and the latter is more significantly affected. NO clear trend of increasing of permeability when the net pressure descend.(4) As a result of different compaction, the experiments of oil-water relative permeability show that both the irreducible water saturation and irreducible oil saturation increase with the net pressure ascend, the pore space is compressed and the common seepage areas of two phases narrow.Part of the research achievements of this thesis could offer a indoor experimental basis for SZ36-1oilfield and QHD32-6oilfield, and also provides experimental parameters of reservoir physical as well as the technical pamameter, which has a certain theoretical and pratical significance to the development of unconsolidated sandstone reservoir.