Study Of Reservoir Heterogeneity Of Chang6₃ Reservoir In Huaqing Area Of Ordos Basin

The reservoir of the Chang 63 layer in the Huaqing area is the semi deep lake and deep lake and delta sedimentary environment,mainly for the delta sedimentary system.The permeability is mainly distributed in the range of 0.0225 to 1.382 m D and the porosity is distributed in the range of 5.6% to 16.1%.The reservoir heterogeneity can be analysed by the use of drilling,logging, mud logging data.The coefficient of variationonrush coefficient and the average difference of the Chang 63 reservoir layer in the Huaqing area are respectively 0.93,5.36,118. The number of wells whose coefficient of variation of the permeability of the Chang 63 reservoir in the Huaqing area are greater than 0.7 is 102.The interlayer reservoir properties vary widely.There are 102 wells whose reservoir permeability ratiosare greater than 6,on the whole the difference of vertical permeability is particularly large and the phenomenon of single onrush is very common. The number of the wells whose mutation coefficient of the reservoir permeability are greater than 3 is 100,accounting for the 98%; There are 2 wells whose onrush coefficient are between 2 to 3, only accounting for the 2%. The sedimentary rhythm characteristics of the Chang 63 layer in the Huaqing area include positive rhythm, negative rhythm, positive and negative complex rhythms and positive complex rhythm. The pore types of the Chang 63 reservoir in the Huaqing area are mainly the intergranular pore belonging to small-pore fine throat and fine-pore micro level throat and the average throat radius is 0.55μm. The pore structure is poor and the small pore and micro fine roared thin pore throat are mainly developed. The uniformity of pores and throats isrelatively poor.To make a long story short,the reservoir of the Chang 63 in the Huaqing area is the strong heterogeneous reservoir.