| 摘要 |
<p>An apparatus, for use in conjunction with a testing string having a central flow passage therethrough and located in a fluid filled bore of an oil well extending from the earth's surface to an underground formation, comprising: normally closed valve means, in the lower portion of the testing string and controlling fluid communication through the central flow passage of the testing string, for selectively opening the central flow passage after the testing string has been lowered into the well bore to the underground formation; and, normally open valve means in the testing string adjacent the normally closed valve means and controlling fluid communication through the central flow passage of the testing string when the normally closed valve means is in the open position, for moving to a closed position prior to the opening of the normally closed valve means responsive to weight in the testing string, and for moving to an open position subsequent to the opening to the normally closed valve means responsive to fluid pressure increases in the well bore.</p> |
