Changes

==Circulating system==

==Circulating system==

[[file:land-rigs_fig2.png|thumb|{{figure number|2}}Circulating system of a rig. From Whittaker.<ref name=pt03r50>Whittaker, A., ed., 1985, Field geologists training guide: Boston, MA, IHRDC, 291 p.</ref>]]

[[file:land-rigs_fig2.png|thumb|300px|{{figure number|2}}Circulating system of a rig. From Whittaker.<ref name=pt03r50>Whittaker, A., ed., 1985, Field geologists training guide: Boston, MA, IHRDC, 291 p.</ref>]]

Circulation of [[drilling fluid]] (mud) serves several functions on a rig, including cooling the bit, providing hole stability, and aiding in formation evaluation.  

Circulation of [[drilling fluid]] (mud) serves several functions on a rig, including cooling the bit, providing hole stability, and aiding in formation evaluation.