| Ding bian area is located in the northwestern of Shan bei Slope Belt, across Tianhuan Sync in Ordos Basin Jurassic yan’an Formation,as on e of the main oil in this region.chang8reservoir reserves gteatly, but the single well output low and recovery of reservoir is low. reservoir pollution of well drilling and well completion is serious, so protecting reservoir is of great significanceThis thesis takes the sedimentary rocks and the formation geology theories as the foundation, keeps the formation protection technique principles as leading, This paper is based on the reservoir structure and deposit microfacies of Ding bian chang8reservoir.Through observe the core sample, scanning electron microscope,mercury intrusion pore size distribution,to know the lithologic characteristic,reservoir characteristics,pore structure and so on., studies the characteristics and potential damage factors in details with agreat deal of indoor evaluation experiments and related experiments and data. Then points out the reservoir damage mechanism and in the end puts forward the protected measures and suggestions of the formation. The results show this:(1) Chang8of Ding bian is low porosity and low permeability tight sandstone, with complicated porosity structure is bad and diagnoses strength, the clay mineral type and produee variety greatly the fraeture growth, The reservoir rock is mainly feldspar sandstone, the lithic quartz sandstone and quartz sandsrones. The average permeability is2.3×10-3μm2, the average porosity is8.10%. the maximal radiuses of pore throat ranges from0.85um to7.50um. the average is2.92um, the average throat radiuses is0.12um-0.42um, corresponding the maximum interconnected pore throat radiuses is between0.85um-4.3um. In sum, the reservoir is low permeability and low porosity and especially the low porosity and low permeability.(2) Chang8of Ding bian Clay mineral content Kaolinite content for an average of35%, kaolinite in dispersed form distributed in various throat pore, but also to the distributed on the peripheral was the "ring" the kaolinite cementation. Chlorite in the reservoir is also widespread, chlorite in leaves or needles shape distributes in particle or attaches to the surface particles of rock. content of smectite mixed layer is8.25%, an average content of illite is27%,with hairy and coiled sheet, from pore at one end to the other end growth bypass shape,disorderly deposits polymer or sheet cross stack a honeycomb shape, edge growing very finefilaments. Reservoir has high potential damage（3）Through the indoor evaluated experiment and the paper points out that vecocitysensitivity damage is maximum92%,minimum for23%,water sensitivity is54.73%~85.90%and salt sensitivity is43%-88%; in the study area, typically And a weak alkali sensitivesensitivity to maximum damage rate was30.5%, the smallest is18.1%, and the overallperformance is weak sensitivity, it and the reservoir LuNi hardness of mineral less relevant,only partly reflects strong core sensitivity; Sexual weak mainly by the feldspar and stronglyalkaline solution role, reservoir water phase traps and lock water damage is strong, the damagerate is18%~51%, the area of reservoir pore throat radius is average small,stress sensitivity isstrong, damage mechanism is density reservoir, and average radius of pore throat is tiny, tinycracks develop, poreconstriction types is flake, these structures easier to be destroyed.（4）Protection of reservoir fluid are wholly inhibition rate at about45%, API filtrationloss in13ml, surface tension21.5mN/m, break emulsion rate is100.Combined with damagemechanism of reservoir，protecting reservoir perforating system:0.4%BYNTW+0.5%XC+0.2%1#(surfactant)+0.2C%F-5D+5%-20%through testing of the core dynamic damagefilter loss, perforating fluid has good protecting result that core permeability recovered to88.5-93.1%, filtration loss of core ranges from13ml to4.8ml, In contrast, damage ofperforating liquid that is wholly clean salt water used in the oil field is25%~74.5%,filtrationloss of core is7.5~10ml.Perforation is liquid meet protection of reservoir... |
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