| 摘要 |
<p>A tubular sand screen (42) is made in one piece entirely of powdered metal slivers (42A) which are molded and sintered to form a metallurgically integral rigid tubular structure. Aggregate metal particles, for example, stainless steel slivers, are bonded together by interatomic diffusion as a result of sintering the compacted slivers under high temperature and pressure conditions. The sintered metal sand screen performs the function of a conventional prepack assembly as well as the screen function. According to one aspect of the invention, the sintered metal screen is subjected to electropolishing to yield an effective porosity of 40-60 mesh, with pores (42B) having an average pore size of 150 microns. Most of the surface irregularities are removed by electropolishing, and very few nucleation sites remain where sand fines in the size range of 74 microns-100 microns can become captured or otherwise lodged to cause plugging of the screen.</p> |
