From 3200’ to TD of 3899’ a pump and dump system was used, maintaining a 10.5 ppg equivalent mud density, by monitoring ECD with PWD instrumentation and vortex mixing 16.0 ppg waterbase mud “on the fly” with seawater. 这段话里的pump and dump process 什么意思呢？这是关于钻井的一篇文章。
另外，To avoid nonproductive time encountered on the 1997 well, the operator designed a casing program for the next well to include riser less drilling of the shallow gas hazard using the pump and dump process. 这段话里也出现了这个短语，请专家帮忙解释一下，多谢了。
