Abstract A mud saver valve assembly is connected between the lower end of the kelly and uppermost joint of drill pipe, the assembly including a downwardly opening spring loaded poppet valve and an upwardly opening ball check valve. The downstream face of the poppet is shielded from line pressure by a sealed air chamber at atmospheric pressure in such a manner that the resultant force of downstream pressure on the poppet tends to open the poppet. Before adding another joint to the drill string the mud pump is shut down and the pressure gage checked to make sure there is no pressure in the drill string, any pressure in the drill string being transmitted through the ball check valve. If there is pressure it is bled off through a bleed off valve, if possible. With pressure down, the connection between the mud saver valve assembly and drill string is broken and a connection is made between the mud saver valve assembly and a joint of pipe in the mouse hole. No mud escapes from the kelly since the hydrostatic head of mud in the kelly is not sufficient to open the poppet valve in the mud saver valve assembly. The added joint of pipe is connected to the drill string still in the hole and the mud pump is turned on, automatically opening the poppet valve to restore circulation. The new joint is checked for leaks and if okay the drill string is lowered and drilling resumed. Since the downstream side of the poppet is shielded from mud pressure the pressure drop across the valve need not equal the spring force to hold the valve open, whereby pump horsepower is not wasted and whereby rapid valve erosion is eliminated. If on opening the bleeder valve, drill string pressure is not relieved, it is possible to close the blow out preventers and reverse circulate to kill the pressure in the formation, the poppet valve being full open under well pressure thereabove in the kelly transmitted by the ball check valve, the atmosphereic chamber below the poppet enabling the poppet to stay open when there is well pressure in the kelly sufficient to overcome the spring bias tending to close the poppet.
Inventors
👤 M Litchfield
👤 F Scott
Bibliographic Details
Application Number—
JurisdictionUS
Data Sourcegoogle_patents
Last Synchronized2026-10-31 03:50
CPC Classifications
E; E21; E21B; E21B21/00; E21B21/10; E21B21/106
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
185 words
In the method of adding a joint to a rotary drill string suspended in a well bore from a kelly connected by a mud line to a mud pump with gage means indicating the pressure at the pump output, in which method after the mud pump is shut down, the gage is then read to see if the drill string pressure communicated through the kelly has fallen sufficiently for it to be safe to disconnect the kelly from the drill string preparatory to inserting a new joint of pipe, the improvement comprising: placing a downwardly opening, upwardly closing spring loaded poppet type mud saver valve in the connection between the kelly and drill string to retain mud in the kelly when the pump has been shut down and the connection between the kelly and drill string broken, and prior to breaking said connection by-passing said poppet valve to effect immediate full equalization of pressure between the drill string and drill pipe whereby when said gage is read immediately after shutting down the pumps prior to breaking the connection it will indicate true drill string pressure.
Claim 2
Dependent Claim
185 words
In the method of adding a joint to a rotary drill string suspended in a well bore from a kelly connected by a mud line to a mud pump with gage means indicating the pressure at the pump output, in which method after the mud pump is shut down, the gage is then read to see if the drill string pressure communicated through the kelly has fallen sufficiently for it to be safe to disconnect the kelly from the drill string preparatory to inserting a new joint of pipe, the improvement comprising: placing a downwardly opening, upwardly closing spring loaded poppet type mud saver valve in the connection between the kelly and drill string to retain mud in the kelly when the pump has been shut down and the connection between the kelly and drill string broken, and prior to breaking said connection by-passing said poppet valve to effect immediate full equalization of pressure between the drill string and drill pipe whereby when said gage is read immediately after shutting down the pumps prior to breaking the connection it will indicate true drill string pressure.
Claim 3
Dependent Claim
144 words
Method according to claim 1 including after the step of reading the gage and before breaking the kelly to drill string connection the following steps performed, e.g. when the gage reading indicates excessive pressure in the drill string: closing off the upper end of the annulus between the drill string and the upper end of the well bore, introducing the pressure drilling fluid into said annulus adjacent the upper end thereof but below the point where the annulus is closed off as aforesaid, and shielding an area of the lower side of the poppet from drill string pressure sufficient for the valve to open due to said equalization of the dril1 string and kelly pressures when said drilling fluid is introduced into said annulus and flows down the annulus and back up the drill string into and out of the kelly through said poppet.