| 摘要 |
<p>This invention is concerned with an apparatus for concentrating a proppant fluid slurry. It has a particular application in connection with oil or gas wells where recovery is improved by causing fractures or cracks in the rock formation in a well to enable the desired product to move more freely. These fractures are created by the high pressure injection of a slurry of fluid such as gelled water, a proppant such as sand, a delayed action gel breaker, a foaming agent, and a gas such as nitrogen. Excess water or other liquid is undesirable in the well but is required because of physical limitations in the pumping equipment. Hence the need for a slurry concentrator between pump and well head. Previous concentrators have been unsuitable because of the difficulties resulting from blockages such as slugs of greatly dewatered sand. A number of inventive features are included in accordance with this invention in its preferred aspect. The concentration is carried out in a casing containing an axial elongated screen. Stationary angled vanes direct the slurry in a helical path in the space between the casing and the elongated tubular screen to avoid the problems of rotating members. The concentrating zone thus provided communicates with a mixing zone where baffles provide restricted flow between the edges of the baffles and the interior of the casing to give a mixing action, disperse slugs of slurry, and to avoid back flow of gas. The baffles are advantageously of resilient material. The mixing zone then leads to a foaming zone, followed by the outlet. It is advantageous to have inlet, concentrating zone, mixing zone, foaming zone and outlet for the foamed slurry in axial alignment and without interruptions so as to give a straight through flow. There are also inventive features contributing to maintenance in that the interior assembly can be removed as one piece upon removal of the inlet end flange and the removal through an assembly flange of a locating member.</p> |
