NOV 12-P-160 mud pump

A mud pump circulates drilling fluid down the drill string and back up the annulus, which is how cuttings leave the hole. The 12-P-160 is a triplex: three pistons driven by one crankshaft. National rates it at 1,600 input horsepower at 120 strokes per minute, with a 12-inch stroke.

This is the usual pump on a land rig in the 1,500 to 2,000 horsepower class, and the rig normally carries two or three of them. The largest standard liner is 7¼ inches. A smaller liner moves less mud and is allowed a higher pressure. The standard fluid end is 5,000 psi. An optional fluid end is 7,500 psi. A well that needs 7,500 psi needs that optional fluid end, even if the power end is stamped 12-P-160.

The stroke is the model. A 14-P-220 is the next size up: 14-inch stroke and 2,200 horsepower. An FB-1600 or FC-1600 is also called a 1,600 horsepower pump, but it is a different frame, with a 7-inch maximum liner and a 4.31 gear ratio instead of the 12-P-160’s 3.439 ratio and 7¼-inch liner. A 12-P-200 kit is an upgrade of an existing 12-P-160. It is not the original rating, and the nameplate should say so.

Read the nameplate for horsepower and fluid-end pressure, and ask whether the power end has been upgraded. The liner in the pump today is a wear part, so it does not tell you which pump you are buying. Ask if the motors, sheave, and charge pump are included. The published weight of 54,700 pounds is the pump without the sheave.