Geological Characteristics And Dynamic Analysis Of Reservoir Development Of Nanbaxian Oil-gas Field

Nanbaxian oil-gas field is located in the northern margin of the Qaidam Basin. By the 3D seismic, drilling, well logging data, core test data, test and production data, and the oil test, litho-electric experiment and four property relationships study, the logging interpretation template was reestablished, and the fluid types of complex reservoir were identified, the heterogeneity of gas-bearing layers was studied,and the review of the amount of potential resources and optimization of well deployment were adjusted. The main understanding is as follows1、The characteristics of Nanbaxian reservoirs are rich gas and poor oil, the coexistence of shallow gas and the deep gas reservoir, and the oil gas resevior is rich in the middle shallow layer and the distribution is uneven, the blocking and sealing of faults have great effct on the distribution of oil and gas layers, part of fault block shows the characteristics of critical gas reservoirs with oil ring. The plane distribution of oil and gas is strictly controlled by Xian Bei fault(oil/source dredge fault), and the thickness of the fault reservoir becomes thin quickly far away from the fault reservoir with the performance of secondary reservoir.2、The reservoir of N21-N1, E32, E31 is fine sandstone and siltstone overally with high bound water saturation, and part of reservoir shows the feature of low resistivity. The low resistivity gas reseviror can be identified by the CNL-AC, CNL-DEN overlapping method.3、Two sets of relatively stable regional cap are developed,and the lithology is mainly mudstone with thin sandstone regionally.the oil and gas is mainly distributed in three sets of oil group of the N21, N1 and E31 under the two sets of cap rocks. The thin sandstone of the delta front with the effective configuration faults is the main reservoir.4、With the influence of the changing amplitude of fault(east-middle-west) and the contact relationship of the sand and mudstone in the hanging wall and footwall, the oil and gas are mainly distributed in the east and middle of the Xianbei footwall, showing complex water/oil/gas system.5.There are three sets of layer series of development in the Nanbaxian field, the middle-shallow N21, gas reservoir, the middle-shallow N1 gas reservoir and the deep E31 gas reservoir.