Preparation and application of a novel phenolic resin dispersed particle gel for in-depth profile control in low permeability reservoirs

Phenolic resin dispersed particle gel (PDPG) was successfully prepared from bulk gel by a mechanical shearing method. The effects of bulk gel strength, shearing time, shearing rate, and bulk gel-water ratio on the PDPG particles were systematically analyzed. The morphological results showed that the PDPG particles have a round shape with nano-size to micron-size distribution. The shearing rate is one of the most critical factors in the preparation, while the shearing time and bulk gel strength are secondary factors in preparing the PDPG particles. In addition, the bulk gel-water mixing ratio has a slight impact on the prepared PDPG particles. The PDPG particles had a good shearing resistance and expansion capacity which enhances their application performance in oilfields. Sand pack flowing experiments indicated that PDPG particles can easily enter the in-depth formations and effectively plug high permeability channels. The higher the formation permeability ratio of sand packs, the better the profile improvement rate. By retention or adsorption in large permeability zones, trapping and bridging across pore throats or large channels, the prepared PDPG particles can effectively improve the formation profile and divert the following water into low permeability zones, and then the oil is enhanced. The injection of PDPG particles was first successfully applied to Changqing Oilfield in China which provided a reference to control water production in other similar low permeability mature oilfields.