标题：STUDY ON EROSION W EAR CHARACTERISTICS AND NON-SMOOTH ABRASION RESISTANCE OF ENVIRONMENT FRIENDLY JET- TYPE HYDRAULIC HAMMER JET ELEMENTS USING IN UNCONVENTIONAL OIL & GAS RESOURCES DEVELOPMENT
摘要：High energy jet hydraulic hammer drilling technology has the characteristics of high impact power, high rock crushing efficiency and long service life. It is especially suitable for drilling in unconventional oil and gas formations (such as shale gas, natural gas hydrate and dry hot rock) with high strength, high hardness, strong abrasiveness and poor drill-ability. It is expected to solve the drilling problems in deep well and even ultra deep well hard rock formations. Meanwhile, due to the high- energy hydraulic driving mode, the technology has the advantages of recycling and environmental protection compared with the conventional drilling technology. Aiming at understanding the erosion and wear failure of jet-type hydraulic hammer jet elements, the computational fluid dynamics method was used to numerically simulate the liquid-solid two-phase flow field in the jet element. The solid particle erosion and wear characteristics of the inner wall surface of the jet element were studied and the anti-wear properties of non-smooth walls was further analyzed. The results show that there is a high-speed jet zone and vortex zone inside the jet element, which drives the solid phase particles to erode the inner wall surface and finally could cause wear. The wear zone is mainly distributed at the positions of the nozzle, cover, wedge, and side wall. Compared with the smooth wall surface, the nonsmooth rough walls can increase wall shear stress and reduce wall vorticity, thus reducing the rate of solid particle erosion wear. When the wall roughness thickness is about 1mm, the wall wear is the lowest. The maximum wear rates of the nozzle, cover, plate, wedge tip, and the side walls were reduced by 76.3%, 58.2%, 52.5%, and 29.6%, respectively. This research can provide reliable theoretical support for efficient and environmental protection drilling under complex geological conditions of unconventional oil and gas resources.
关键词：Unconventional oil and gas resources;environment friendly;jet element;liquid-solid flow;erosion wear;nonsmooth surface;surface roughness
