Loose Sand and Gravel

The commonest spaces are those among the particles—sand grains and tiny pebbles—of loose, unconsolidated sand and gravel.

最常见的空间是那些由松散的、未固结的砂和砾石组成的颗粒（沙粒和小卵石）之间的空间。

A pile of sand is loose, but it and cement, gravel, water mixture, than the granite also tough.

一堆沙子是松散的，可是它和水泥、石子、水混合后，比花岗岩还坚韧。

For high permeability and loose sand in bohai, these links are composed of wire wrapped screen, gravel packing zone, perf, skin and near wellbore undisturbed formation.

具体到渤海高渗透疏松砂岩，这些环节包括绕丝筛管、砾石充填层、射孔孔眼、压实带及近井原状地层。