Target Sandbody Evaluation Of Carboniferous Kalashayi Formation In Area 6,7,8 Of Tahe Oilfield

Tahe oilfield is located in the junctional of Luntai and Kuqa County in Tarim Basin of Xinjiang. Study area is located in southwest Akekule salient upon the Shaya uplift of the northeast Tarim depression. The well spacing of Carboniferous in Tahe area is large. The sand layer is thin and poor continuity. Existing research on the distribution and evaluation of oil sands is not comprehensive. In order to better provide for the basis of exploration and development in the future, the author carry out the target sandbody evaluation of carboniferous Kalashayi formation in Tahe oilfield.Carboniferous Kalashayi formation in area 6,7,8 of Tahe oilfield is taken as the main research object. With the utilization of drilling, logging and seismic data, the author carry out fine reservoir division of the target well group in study area. On the basis of core observation, logging and seismic facies, with previous research results, the author carry out the research on sedimentary facies, characteristics and diagenesis of reservoir rocks, reservoir pore structure, physical characteristics, reservoir heterogeneity and comprehensive evaluation of oil sand in target well group.Studies have shown that sand-shale segment of carboniferous Kalashayi formation of Tahe oilfield is tidal flat sedimentary with properties of estuary. The types of micro facies are tidal channel, sand flat, sand-mud mixture flat and mudflat. Reservoir lithology is mainly quartz sandstone, feldspar quartz sandstone, lithic quartz sandstone and feldspar lithic sandstone. Diagenesis of reservoir is compaction, cementation dissolution. Pore types of reservoir are mainly secondary pores, including intergranular dissolution pore, matrix dissolution pore and intragranular dissolution pore. Average porosity of Kalashayi formation reservoirs is 10.79%,mainly distributed in the 10-12%. Average permeability is 35.83×10-3μm2 and multi-state distribution of the peak. The effective average porosity is 13.25%. The effective permeability is 50.28 X 10"3μm2. Reservoir types are mainly low-mid porosity and low-high permeability reservoirs. Kalashayi formation reservoirs of study area are mainly typeⅡB better reservoirs, and some typeⅡA good reservoirs. Heterogeneity is strong. Imbalances in the planar distribution and longitudinal direction influenced by reservoir heterogeneity.