Study On Logging Evaluation Of Effective Reservoirs In Fuxian Formation Of TB Region

The Fuxian Formation reservoir in TB area have development river facies sedimentary system,and meandering river sedimentary subfacies system.by now 5 reservoirs have been put into development,and the development effect is good.due to the different deposition of Fuxian Formation reservoir and Yanchang Formation reservoir of delta plain deposition,lead to The results show that the reservoir structure is low,and the well logging data have different characters of logging response,so the interpretation of logging become difficult.in the same time some reservoir is low amplitude structure,oil-water differentiaion is low,the resistance of reservoir is low,and the reservoir is strong concealment.And the formation of local water changes,resulting in a complex relationship between oil and water.In the current exploration and development situation,it is urgent to carry out the second fine interpretation of logging.in order to quickly and accurately evaluate the oil layer,We have carried out stratigraphic comparisons and division in different well areas of oilfields;sedimentary facies and sand body distribution characteristics,Reservoir petrology,pore structure,physical properties,heterogeneity and other characteristics of the study The logging interpretation model is established to determine the lower limit of reservoir physical properties,The effective reservoir logging was identified by using the plate method,the apparent resistivity increasing method,the natural potential ratio and the resistivity intersection method,the acoustic time difference and the resistivity overlap method,For the TB field of efficient development and expansion of exploration and development results to provide strong technical support.Through systematic analysis,the main results are as follows:1.In reservoir character,the sedimentary environment of the study area is relatively stable,and the tectonic characteristics of each layer are developed on the backdrop of the low amplitude west slope.The main developmental meandering river facies sedimentary system is mainly developed.Sandstone and lithofacies developed feldspar sandstone,medium sorting,pore cementation,low surface porosity,pore throat type mainly with small pore throat,pore space mainly include intergranular pore and the intergranular dissolved pore,the intergranular pore is Intergranular hole-based;reservoir throat to shrink is the main type,flake or piece bent is the second.2.The reservoirs of the Fuxian Formation in the TB area are controlled by geological processes such as sedimentation,diagenesis and reservoir formation.reservoir heterogeneity is strong,so that when the oil and gas migrate to fill high permeability reservoir,but the low permeability reservoir with little oil and gas filling,the formation water is residue.3.Standardized the logging curve data and study the four character relationship then we can establish the interpretation parameter model and to confirm of the lower limit of the physical properties.then according to the results of oil test,combined with geological knowledge,we use Graphic method,and the resistance increase rate method,ratio of SP and resistivity intersection method,Acoustic time difference and resistivity overlap method to find the effective reserviors,and establish the regional oil and water layer identification standards.According to the test oil effect,the apparent resistivity increase method is the best method.4.According to the results of the identification standards,we processing and interpretation the logging data the second time,and 96 effective wells are interpreted in the Fuxian Formation in the TB area,add up 441.2 meters,the average single well effective thickness of 4.3 meters,a total of 21 wells to improve the interpretation of 29 layers,the cumulative increase in oil and oil and water layer thickness of 215 meters.