Characteristics and sensitivity evaluation of Triassic sandstone reservoir of Tahe oilfields in Tarim basin

The characteristics of the Triassic sandstone reservoir of Tahe oilfields in Tarim basin are studied in terms of tradi- tional and special analysis of drilling cores,and the sensitivi- ty factors of hydrocarbon reservoir in the development process are described.Studies show that the lithologies of Triassic sandstone reservoir of Tahe oilfields consist of coarse-fine grained feldspar-lithic sandstone and lithie ar- kose.with a low content of the interbedded montmorillonites and illites of expansion character and a certain contents of kaolinite and chlorite.The main reservoir spaces are second- ary dissolution pores,interspersed with residual primary pores,The reservoir is of large porosity and high permeabili- ty,of which the Middle Pay Set is the best in the physical properties,the Upper Pay Set takes the second place and the Lower Set the worst.The water (salt)sensibility and alkali sensibility are the two main potential damages in the oilfield, with weak-medium acerbity sensitivity and relatively weak velocity sensitivity.In the sandstones in the whole oilfield, the high content of rock debris and the distinct compacting action result in the line contact,so the reservoir is of thin throat and low-middle permeability.Therefore,the water blocking damage maybe comes into being,resulting from the capillary force,and the flat pore throat structure also brings about a high incidence of all kinds of sensibility damages.