Pressure loss identifying apparatus and method for a drilling mud system

• US 4,430,892 A
• Filed: 11/02/1981
• Issued: 02/14/1984
• Est. Priority Date: 11/02/1981
• Status: Expired due to Fees

• Current Assignee: Allen J. Owings
• Original Assignee: Allen J. Owings
• Inventors: Owings, Allen J.
• Primary Examiner(s): Birmiel, Howard A.
• Application Number:
  US06/317,004
• Time in Patent Office: 834 Days
• Field of Search: 73/151, 73/155, 175/48, 364/422
• US Class Current: 73/152.21
• CPC Class Codes: E21B 21/08 Controlling or monitoring pressure or flow of drilling fluid, e.g. automatic filling of boreholes, automatic control of bottom pressure valve arrangements therefor E21B21/10

Abstract

Methods and means are disclosed for the monitoring of conditions in a mud circulation system as used in the drilling of oil and gas wells, and to quickly detect and indicate pressure failures that may occur in that system to thereby allow for the maximum time and opportunity for remedial action.

Claims

1. In an oilwell drilling mud circulation system having continuing mud returns, a method of identifying system failures, comprising the steps of:

monitoring standpipe pressure, monitoring mud pump speed;

monitoring mud pump flow rate;

monitoring mud return flow rate;

signaling a drill pipe washout if standpipe pressure decreases and mud pump speed, mud pump flow rate and mud return flow rate increase;

signaling a mud pump failure if mud pump speed increases and mud pump flow rate decreases;

signaling a leak in the surface system when standpipe pressure decreases, mud return flow rate decreases, and mud pump flow rate remains constant.

2. In an oilwell drilling mud circulation system having continuing mud returns, apparatus for identifying system failures, which comprises:

means for monitoring standpipe pressure;

means for monitoring mud pump speed;

means for monitoring mud pump flow rate;

means for monitoring mud return flow rate;

means for signaling a drill pipe washout if standpipe pressure decreases and all mud flow rates increase;

means for signaling a pump failure if mud pump speed increases while the mud pump flow rate does not increase;

means signaling a leak in the surface system when standpipe pressure decreases, mud return flow rate decreases, and the mud pump flow rate remains constant.

3. In an oilwell drilling mud circulation system wherein mud circulation is intentionally stopped for pressure testing in a closed system, a method of identifying system failures, comprising the steps of:

monitoring standpipe pressure;

monitoring mud pump flow rates at selected points, monitoring mud return flow rate;

signaling a downhole pressure loss if standpipe pressure decreases and mud pump flow rate measured at the standpipe increases;

signaling a mud pump failure if standpipe pressure decreases and mud pump flow rate measured at the mud pump discharge is nil;

signaling a surface system leak if mud pump flow rate measured at the standpoint is nil and mud pump flow rate measured at the mud pump discharge increases.

4. In an oilwell drilling mud circulation system wherein mud circulation is substantially stopped for pressure testing in a closed system, apparatus for identifying system failures, which comprises:

means for monitoring standpipe pressure;

means for monitoring mud pump flow rates both at the mud pump discharge and on the standpipe;

means for monitoring mud return flow rate;

means for signaling a downhole pressure loss if standpipe pressure decreases and mud pump flow rate measured on the standpipe increases;

means for signaling a mud pump failure if standpipe pressure decreases and mud pump flow rate measured at the pump discharge is nil; and

means for signaling a surface system leak if mud pump flow rate measured on the standpipe is nil but mud pump flow rate measured at the mud pump discharge increases.