Logging Evaluation Method And Main Controlling Factors Of Carbonate Reservoir In The Lower Yingshan Formation Of Tahe Oilfield

The Ordovician Yingshan Formation carbonate reservoir has good exploration potential in Tahe Oilfield,Tarim Basin,China.Since the breakthrough exploration of Tashen 3 Well in 2014,the Yingshan Formation carbonate reservoir has submitted a total of 105.6 million tons of proven oil reserves.However,the reservoir has the characteristics of old age,deep burial,complex diagenesis and structural evolution.It is urgent to establish a matching logging evaluation method for different types of carbonate reservoirs on the basis of revealing the reservoir genesis and clarify the main control factors of reservoir differences,which provide a theoretical basis for the subsequent exploration and development.This paper comprehensively utilizes core and thin section analysis and testing data,combined with conventional logging,imaging logging data,and oil testing data to identify reservoir types,establishes a logging identification chart for carbonate reservoir types in the Ordovician Yingshan Formation of Tahe Oilfield,improves the calculation method for reservoir parameters applicable to the target layer,and finally analyzes and summarizes the differences in reservoir development and its control factors.The results show that the carbonate reservoir space of the Ordovician Yingshan Formation in Tahe Oilfield includes matrix pores,caves,and fractures.On the basis of core calibration logging,combined with conventional logging and imaging logging response characteristics,the reservoir is divided into dissolved pore type,fracture type,fracture-void type,and cave type reservoirs.Summarize the logging response characteristics of various types of reservoirs,establish logging identification charts for different types of carbonate reservoirs,and classify the types of single well reservoirs.Then,it can evaluate the development of reservoir fractures through image logs,and calculate reservoir porosity through conventional log.Above all,it can use Poro Tex technology to calculate reservoir porosity that calibrates the porosity of conventional log calculation to perfect the calculation method of reservoir parameters.Finally,the difference of reservoirs under different fault backgrounds is recognized by using the production test data,combined with conventional log and image logs.The main control factors for the difference of carbonate reservoir in different blocks are clarified from three aspects of lithology,fault and water system.