This paper describes the development and testing of a new proppant designed to exhibit a neutrally wet surface. The modified surface does not have a preferential affinity for oil, gas, or water and therefore will not promote the preferential entrapment of any phase within the proppant pack. This proppant technology and the results described in this paper should be useful for completions, production, and the work of reservoir engineers dealing with hydraulically fractured wells, particularly in oil- and condensate-rich reservoirs that are particularly challenged by multiphase flow.
A new proppant technology has been developed whereby a thin chemical coating is permanently applied to the ceramic proppant surface. The coating is very thin, approximately 0.13 µm, or less than 1% of the thickness of the resin on a standard resin-coated proppant grain. The coating is applied to every grain, after the manufacture of the base substrate. It can be applied to any size and type of ceramic proppant, including low-, intermediate-, and high-density ceramic proppant.
The key attribute of the coating is its ability to modify the surface wettability of the proppant grain to a neutral state. Because the coating is applied to every proppant grain, the entire proppant pack exhibits a neutral-wettability surface. When a surface is neutrally wet, the contact angle of the wetting fluid is 90°. For this contact angle, the capillary pressure in the proppant pack is eliminated. A visual test was performed to illustrate the impact of eliminating capillary forces in the presence of the new coating (Fig. 1). Tubes of the 40/80 low-density ceramic (LDC) proppant were assembled with screens at the bottom that would allow water to enter while keeping the proppant in place. When the tube containing uncoated standard proppant was placed in the water, the capillary forces in the proppant pack caused the water to be drawn up into the tube. However, when the same process was repeated with surface-modified proppant, the water level was not drawn up inside the tube....
Novel Proppant Surface Treatment for Enhanced Performance and Improved Cleanup
26 February 2016