Research and application on quartz sands with multilayer leather cover in multi-round steam huff-puff wells

The poor effect of sand blocking barrier built by conventional coated sand can not satisfied the request of one-time sand control and multi-round steaming in multi-round steam huff-puff wells in heavy reservoirs. Aiming at the shortage of membranes process and materials for conventional coated sand, a high temperature multilayer cover proppant composed by inner pre-solidification layer, middle solidification layer and external protective coating are developed. At the same time, the dampness and heat evaluation system is established on the basis of bottom-hole temperature, moisture of stimulated well. The high temperature steam aging test has been conducted on the developed high temperature multilayer leather proppant, and then the results were compared with that of the common coat sand. After the four round high temperatures steaming, the bonding strength of proppant and permeability has reached to 7.1 MPa and 87 μm2 respectively, which presented a higher solidification strength and well conductivity performance. The trial tests were launched in 4 wells. The favorable sand control and incremental oil effect have satisfied the demand of one-time sand control and multi-round steaming. The High temperature multilayer cover proppant will be found wide application in the future.