A New Method To Determine Wettability of Tight Sandstone: Water Imbibition Evaporation Rate Ratio Measurements

With the development of gas exploration techniques, tight sandstone gas reservoirs have become the main source of new natural gas deposits and production in recent years. The wettability of tight sandstone is a very important parameter, affecting the gas-water distribution and movement in the sandstone, which is vital to gas recovery. Generally, the porosity and permeability of tight sandstone are low, with a nonhomogeneous pore structure. Thus, traditional testing methods of wettability on sandstone may not be suitable to treat tight sandstone. This paper proposes a new method of determining the wettability of tight sandstone by measuring the water imbibition evaporation rate ratio. Experimental results showed that the new proposed method could achieve the same results of tight sandstone wettability as the Amott-Harvey method, with a much shorter test duration, cheaper equipment, and improved ease of operation. The results of the new method showed a strong correlation with sandstone composition and structure, and it was more sensitive to small changes in wettability, with higher resolution and accuracy.