Simulation Analysis on Seepage Variation by Hydraulic Pulse Stimulation Technique in Heterogeneous Reservoir

Hydraulic pulse stimulation technique was an eco-physical method to enhance production and injection capacity in low permeable porous media. The technique had been applied in low permeability and unconventional reservoirs and a combination with other oil recovery enhancement method or formation reconstruction technique had been tried. However, the numerical simulation research on the mechanism of this technique had been mainly focused on homogeneous porous media. A study on the seepage variation in heterogeneous reservoir stimulated hydraulic pulse stimulation technique should be done through fluid solid coupling simulation. Through the establishment of the mathematical and physical model for hydraulic pulse stimulation in heterogeneous reservoir, the properties changes of transverse heterogeneous porous media, vertical heterogeneous porous media and three-dimensional heterogeneous porous media are calculated. It showed that there existed different enhancement extent by hydraulic pulse stimulation under various heterogeneous conditions. It was found that when the permeability difference is smaller in the transverse heterogeneous reservoir or greater in vertical heterogeneous reservoir (reverse rhythm reservoir simulated here), the overall flow capacity (reflected by permeability increase extent) was more obviously enhanced. Taking a three-dimensional heterogeneous physical model (representing the delta front area where a well block was located in a low permeable reservoir) as an example, the stimulation effect on flow was relatively weak in the distributary channel area, and relatively strong in the inter distributary bay area. The greater the permeability difference was, the stronger the stimulation effect was in the inter distributary bay area. With the increase of operating time of hydraulic pulse stimulation technique, the effect in the inter distributary bay became worse, and the effect in the distributary channel became stronger whereas.