Research On The Sedimentary Facies Characteristics Of K Reservoir In Laojunmiao Oil Field

Laojunmiao oilfield is located in the middle of Laojunmiao anticline belt in Jiuquan Basin, which is an asymmetry anticline oilfield with steep northern and slow southern. The K reservoir of Tertiary Oligocene Baiyanghe Formation is an important oil-bearing. After decades of mining, Oilfield has entered the stage of high water containing development. K layer of sedimentary facies and sedimentary facies are no systematic the sedimentary research of K layer is still in a very low level, the sedimentary facies and microfacies of K layer haven't got systematic researched.To improve the precision exploration efforts, Based on the previous research results and exploration data and guided by fundamental sediment logical theory and means, the partition and contrast of K layer, the paper studies sedimentary facies types and distribution of sedimentary facies of The K layer of Tertiary Baiyanghe Formation on the basis of geophysics, geochemistry, basin analysis and ancient landscape restoration。In the partition and contrast of k layer, the two stable distribution mud rock and the mountain-shaped logging feature was marked by layer, the K layer was divided into K3, K2, K1 three small layers as by sedimentary cycle. By the role of thrusting, K layer appeared repeatedly in the part of the wells in the top of Laojunmiao anticline was called 2K,3K.Based on the rock types, sedimentary structures, paleontology signs, sedimentary cycles, lithologic-electrical response characteristics, outcrop, well log data, observation of drilling cores, outcrop, etc. the paper points out that the sedimentary facies in the study area is delta front in the studied area, including the distributary channel deposits, the inter-distrbutary deposits, subaqueous crevasse splay, subaqueous natural levee.The study area belongs to delta front sediment and develops several SE-NW directional underwater distributary channels. The distribution of sand body is controlled by the distribution of sedimentary facies. The sand body is well continued to each other, and widely distributed as sheet sandstone in channel, which is the favorable zone for oil reservoir.