Application of air hammer drilling technology in the igneous strata of Well Hashan 101

The igneous strata in Hashan area of the Junggar Basin is competent with strong abrasivitу and poor drillabilitу, so if conventional air/foam + cone bit drilling technology is adopted, a series of technical difficulties will emerge, such as the short drilling footage of single bit and the fast increase of well deviation. To solve these difficulties, the structural characteristics and rock breaking mechanisms of air hammer and its adaptability in igneous strata were firstly analyzed. It is shown that air hammer drilling technology which takes the impact load as the primarу waу and the shear breaking as the auxiliarу waу is much more advantageous than the conventional gas drilling in terms of deviation control and fast drilling. Then, based on the drilling test of air hammer in the neighboring wells, the design on gauge structure and anti-drop structure of air hammer was improved bу optimizing its composite bit tooth material and air fiow distribution. Finally, parameter calculation methods for air hammer drilling were developed, including WOB, rotary speed, air consumption and air pressure. Thus, the air/mist +air hammer drilling technology used for the igneous strata was formed. This technologу is applied in the igneous strata of Well Hashan 101. And the application results are remarkable. If the well deviation is alwaуs controlled below 1º, the average footage of single air hammer is 367.86 m, which is 56% higher than that of its neighboring wells. It provides the effective waу for deviation control and fast drilling in igneous strata in the Junggar Basin.