초록 ▼

Downhole flow pulsing apparatus comprises a housing (14) for location in a drillstring, the housing (14) defining a throughbore to permit passage of fluid through the housing. A valve (27, 30) is located in the bore and defines a flow passage (29, 31). The valve includes a valve member (27) which is

Downhole flow pulsing apparatus comprises a housing (14) for location in a drillstring, the housing (14) defining a throughbore to permit passage of fluid through the housing. A valve (27, 30) is located in the bore and defines a flow passage (29, 31). The valve includes a valve member (27) which is movable to vary the area of the passage (29, 31) to provide a varying fluid flow therethrough. A fluid actuated positive displacement motor (15, 16) is associated with the valve member (27). In a preferred embodiment, the apparatus is provided in combination with a drill bit (5) and a pressure responsive device, such as a shock-sub (3), which expands or retracts in response to the varying drilling fluid pressure created by the varying flow passage area. The expansion or retraction of the shock-sub (3) provides a percussive effect at the drill bit.

대표청구항 ▼

[ What is claimed is:] [1.]1. Downhole flow pulsing apparatus for providing a percussive effect, the apparatus comprising:a housing for location in a string, the housing defining a throughbore to permit passage of fluid therethrough;a valve located in the bore defining a flow passage and including a

[ What is claimed is:] [1.]1. Downhole flow pulsing apparatus for providing a percussive effect, the apparatus comprising:a housing for location in a string, the housing defining a throughbore to permit passage of fluid therethrough;a valve located in the bore defining a flow passage and including a valve member, the valve member being movable to vary the area of the flow passage to, in use, provide a varying fluid flow therethrough;a fluid actuated positive displacement motor operatively associated with the valve for driving the valve member; anda pressure responsive device which expands or retracts in response to the varying fluid pressure created by the varying fluid flow, the expansion or retraction providing a percussive effect.