Research On Oil/water Layer Identification In Putaohua Reservoirs In Ao 21 Block Of Aonan Oilfield

Ao 21 block of Aonan oilfield is located in the northern part of the Songliao basin in the Central Depression Area, which is in the interface of Daqing-placanticline, Gulong depression and Sanzhao depression. According to the data of well-testing and drilling, the influence of tectonic-litholoy on the block make the oil and water relationship more complex, the oil-water inversion and oil layers with low-resistivity occurred make it difficult to the drill and perforate programming of the block for the future.In response to the complex relationship between oil and water distribution and difficult identification of oil-water layers of Putaohua layer in Ao 21 block, oil and water layers identification technology will be studied. Based on the geological characteristics, data of four characteristics of reservoir and data of drilling log are firstly applied to define the oil and water layers, and then the traditional crossplot method is used. Because of the existence of oil layers with low resistivity, crossplot method cannot meet the requirements of oil and water layers explanation. Therefore, multigroup step discriminant analysis method is applied to establish equations to discriminate oil-water layer, and with the high accuracy of 90%.Based on the well survey, well logging and well testing, the distribution of oil and water is atudied, the boundaries of pure oil area, oil and water area and water area are established and it is conclude that the distribution of sand bodies and faults are the main controlling factor on the oil and gas distribution. At last, the potential blocks for the next exploration and development are predicted. The paper will provide significant references to the efficient development on Ao 21 block.