| Popis: |
With the development of oil drilling in depth, the strata are more ancient and abrasive. The Rate of Penetration (ROP) is low in conventional drilling methods, and Positive Displacement Motor (PDM) matching PDC bits is often used to improve it. However, the application of excessive Weight on Bit (WOB) would easily lead to PDM brake, over-standard well inclination, bit wearing aggravation and other bad phenomena. Moreover, the ROP improving effect is limited. As a result, a hydraulic jet impact tool was designed to use in conjunction with the PDC bit to integrate the advantages of vibration shock and rotary cutting in rock breaking process. The impact tool exerts dynamic load on the bit, which improves the rock breaking state at the well bottom and optimize the bit’s rock breaking efficiency as a result. Rock breaking mechanism of the PDC bit assisted by impact tool was analyzed, structure and working principle of the impact tool was introduced, and influence of tool structural parameters was analyzed based on indoor tests. Finally, field applications were carried out using the impact tool and PDC bits in the HY-4 wells of Saudi Aramco block and PX-3 wells in China. The ROP improving effects were 61.8% and 95% higher than that of the adjacent wells respectively. Application and analysis result proves the ROP improving effect of the impact tool combining the PDC bit in hard and abrasive strata. |
