Ni Guanhua

Impact of the geological structure on pulsating hydraulic fracturing

In order to study the impact of the geological structure on pulsating hydraulic fracturing (PHF), the industrial experiments of PHF were carried out in the tectonic zone and the non-tectonic zone, and then, the differences of PHF process and effect were analyzed. The results show that the fault structure brings out a weak surface in the area of PHF, easily inducing the seam crack extension to the fault, and pulsating water constantly moves to the direction of fault. Pulsating injection time and injection quantity of PHF in the tectonic zone are significantly larger than that in the non-tectonic zone, producing large water blocking effect to gas drainage and hindering gas migration dynamics. There is a natural relief area existing in the fault so that the pulsating pressure of PHF cannot be increased, reducing the effect of PHF. Geological structure reduces the increment of the stable gas concentration and improves the initial gas concentration before and after PHF.