Selection of proppant size in frac and pack treatment on unconsolid sandstone reservoir

Key words:  sandstone  frac and pack  proppant  embedment  conductivity  sand invasion

Abstract:

For frac and pack in the unconsolid soft formation，sand production and proppant embedment which have a close relationship with proppant size are the important factors leading to fracturing failure. The experiments were carried out by two new measurement methods for simulating proppant embedment and sand invasion about fracture wall and front end on high permeability reservoirs of Jinxian Oilfield. Under different pressure，the experiments on testing two kinds of simulated formation sand with different grain size were carried out，and the proppant embedment degree in the soft formation, the amount and particle size of sand production, the fracture conductivity after sand invasion were obtained. The results show that the embedment degree increases with the increase of proppant size and decreases with the increase of sand size in the soft formation. The proppant size for frac and pack is about 5-9 times the size of sand. When the proppant size is 6-9 times median size of sand, interior sand bridge can form. When the ratio of proppant for 6-9 times the size of sand and proppant less than 6 times the size of sand is 3 : 1, the combination is appropriate.