Study On Oil Water Two Phase Flow Characteristics Of Super Hydrophobic Coated Sand

Hydraulic fracturing is one of the most common measures to increase production in oilfield development and the key technology is to form a high fracture conductivity.The main role of proppant is to support the pressure of the cracks,so that it can maintain a high flow conductivity,so the performance of proppant directly affects the quality of fracturing.The performance of proppant can be improved by coating treatment on the surface of fracturing proppant.The surface of the proppant is coated with a layer of super-hydrophobic coating and the seepage characteristics of the fractured oil-water two-phase are different from those of the conventional proppant.In this paper,the hydrophobic mechanism of super-hydrophobic surface and the coating technology of the material surface were summarized and the super-hydrophobic coating was prepared on the surface of the support.Through the sand filling tube displacement experiment and on the basis of experimental results of calculation drawing of oil-water relative permeability curve of super hydrophobic coated sand,found the irreducible water saturation of super hydrophobic coated sand is less than 20% and the residual oil saturation is greater than 25% and the water saturation corresponding to isotonic points was less than 50%.By calculating the ratio of water to oil resistance of super hydrophobic coated sand,it is found that the proppant has the property of preventing water seepage.In this paper,the indoor experiment of superhydrophobic coated sand diversion capacity was carried out and the thermal insulation method of the experimental device was improved according to the API standard and the Chinese standard.Under the same experimental conditions,the super-hydrophobic coated sand and uncoated membrane proppant were tested.The experimental results of the short-term conductivity of the aqueous phase and the oil phase and the oil-water emulsion under different closing pressure conditions show that the conductivity of the super-hydrophobic coated sand is different with uncoated proppant.In this paper,the influence of temperature on the conductivity of proppant was studied.It was found that the long term conductivity of both super-hydrophobic film coated and uncoated proppant was affected by temperature.In this paper,the oil and water relative permeability calculation model considering the capillary force of porous media is modified to meet the experimental conditions of the sand filling pipe.The experimental data of the sand filling pipe are solved.Based on the model calculation results,The relative permeability curves of oil and water under the condition of capillary force show that the capillary force only affects the relative permeability of the non-wetting phase.