Preparation and characterization of a self-suspending ultra-low density proppant

A self-suspending ultra-low density proppant (UDP) was developed based on the polymerization of the unsaturated carbon double bond. Its performance was characterized by FT-IR and SEM, and the sphericity and roundness, diameter distribution, density, mechanical properties, the conductivity of the propped fracture, and mass loss of different fluids were measured. The test results indicated that the UDP no longer contained the unsaturated carbon double bond and the polymerization took place in the raw material. The fracture surface of UDP is compact and it is not easy to produce debris after compression failure. The sphericity and roundness of UDP were above 0.9, and the high sphericity and roundness provided high conductivity. The stirring speed has a great influence on the diameter of UDP, and the UDP with different sizes could be used to prop the hydraulic fracture to different widths. The average apparent density of UDP is as low as 1.044 g cm−3, and it can be suspended in the fracturing fluid for a long time. The strain in the UDP is higher than that in the ceramsite and quartz sand, but its crushing ratio is far below theirs; therefore, the conductivity of the fracture propped by UDP was higher than that of quartz sand and ceramsite. The solubility of UDP in kerosene, reservoir water, and hydrochloric acid is below 1%, indicating that the UDP is also suitable for acid fracturing with proppant. All the experimental results proved that the self-suspending ultra-low density proppant has great potential use in hydraulic fracturing and acid fracturing.