A New Coated Proppant for Packing Fractures in Oil Reservoirs

Abstract

The method of packing conventional proppant into fractures is used to maintain high liquid permeability. In this study, by coating a hydrophobic material on the surface of a proppant, the layer packed with this coated proppant was endowed with water-plugging and oil-permeability capacities. Moreover, several research experiments were carried out to verify the proposed method: a water plugging capacity (WPC) test of the coated proppant layer, compression and temperature resistance tests of the coated proppant (temperature range from 90 to 210 °C; pressure range from 5.9 to 91.4 MPa), and a 3D test of the oil recovery enhancement. The results show that the proppant coating has good compression resistance, and the proppant begins to break at 27.3 MPa. The upper limit of the temperature resistance of the coating is 170 °C. The WPC of the layer packed with coated proppant was still reliable during fracture, which was enhanced by at least 20% compared with that of the layer packed with a conventional proppant. The fracture packed with the coated proppant had superior working performance compared with that packed with a conventional proppant. It can reduce the flow capacity of the water phase breaking into the dominant flow passage so as to delay the rise in the water production of the oil well and prolong the duration of oil production. In this way, oil recovery could be increased by about 7.7%. In conclusion, the technology proposed in this paper has particular water-plugging and oil-permeating characteristics, with remarkable technical advantages, thus providing a new idea for the development of water control in fracture reservoirs.