Study On Comprehensive Log Interpretation Methods In Bayantala Oilfield

Bayantala oilfield in Halaer Basin is a new oil pool found in recent years, and it has potential oil reserves.However, the following probleum exists: complex lithology and pores, and inaccurate calculation of reservoir parameters. Therefore, determinating lithology, calculating reservoir parameters and effective thickness must be studied, and establishing practicable log interpretation methods in the reservoirs is significant for Bayantla oilfiled to develop.In the paper four-property relationship has been established based on analysis of petrophysical property, oil bearing property, lithology, electrical property of reservoirs, and analysis of logging data, core data and thin section data.Then, primary lithology and its log response are summarized.Lithologies in the reservoirs have been classified into 5 kinds with crossplot method.However, the transition-lithology identification with crossplot method can't achive good results.Here, a new pattern recognition method named as Support Vector Machine (SVM) has been introduced.The results show that validity of lithology identification is 94%.To improve calculation accuracy of reservoir parameters, relationship of formation factor( F ) , or saturation exponent( n ) with porosity has been studied and established based on geologic characteristic of Bayantla oilfiled and oil saturation measured by mercury intrusion method, and four-property relationship.Applicable methods to predict oil saturation for Bayantala oilfield have been established after formation factor( F ) , and saturation exponent( n ) are calculated from porosity.On the basis of lithology identification and four-property relationship,the lower limits of reservoir petrophysical property and electrical response have been deduced respectively in Nantun formation and Tongbomiao formation, and effective thickness standards for the reservoirs have been established.