Abstract: The understanding of the distribution of a turbidite reservoir is critical for reserve assessment and oilfield development. The turbidite reservoir at the E₃d^2L Formation of the XX20-2N Oilfield is buried at a depth more than 2000 m below sea level. It is difficult to make clear the distribution pattern of the turbidite reservoir only by seismic information. Regional research reveals that the turbidite reservoir was a lacustrine turbidite caused by the sliding of the deltaic front. We applied all the approaches, such as depositional system study, facies modeling, seismic facies analysis, well testing and DST pressure data, in this study to delineate the boundaries and dimensional features of the turbidite sand reservoir. The results of the study were useful for calculation of the net pay thickness of oil and gas unit and increasing the precision of reserve calculation so as to decrease the risk thereof.