Research On Controlling Factors Of The Shanxi Formation Reservoir In North-east Ordos Basin

On the base of abundant groundwork, the petrology feature, regulation of sandstone body spatial distribution and the factors of controlling reservoir characteristic are researched by mass modern testing means, such as microscope flake, EMS, high pressure mercury intrusion, thin section and so on. Many new theories and technological related to sedimentology, petroleum geology, petrology geophysical well-logging are used in the paper.Results indicate that reservoir is mainly quartz sandstone which has high component and texture maturity. And later B phase of diagenesis is established based on diagenesis studied.Primary porosity (primary intergranular and remnant intergranular), corrosion porosity (intergranular dissolution porosity and intragranular dissolution porosity), intercrystal porosity (mainly kaolinite and illite intercrystal porosity ) and induced porosity are most common in Shanxi formation, Of which remnant intergranular and corrosion porosity are main reservoir space in the area.Low porosity and permeability is the main characteristic of shanxi Formation reservoir, porosity is between 12.18-0.07%, average is 5.26%, permeability is between 1605~0.0016x10~-3μn2, average is 6.65x10~-3μm2.The confluent ofporosity and permeability indicates the tendency that permeability is increasing with porosity gradually, But the tendency is different in different porosity distribution range. The different tendency that of permeability changing with porosity imply the factor that controlling porosity and permeability of reservoir is different.The planar distribution feature of porosity and permeability indicates that high porosity and permeability area is consistent with sandstone body stretching of waterway or underwater distributary channel.The reservoir quality is controlled mainly by the sedimentary facies and diagenesis. In the area, the most high quality reservoir should be in underwater distributary channel of delta front the thick sandstone body, which has the highervalues of porosity and permeability and good separation of grain size, diagenesis influencing the values of porosity and permeability of reservoir largely.compacting action is mainly factor which lead to declining of porosity and permeability. Precipitating action of binding material has a dual influence on the values of reservoir, The values of porosity and permeability of reservoir is improved by corrosion.Reservoir is classified as I1 I2 II1 II2 and III types by comprehensive consideration of the relations among reservoir quality, sandstone distribution and gas bearing center. The five types of reservoir are abundant in Shanxi Formation. And II type is mainly distributing in shan23, III type is mainly distributing in shanl.