Abstract: Apparatus for recovering clean drilling fluid from fluid contaminated with entrained debris comprises an input conduit for the contaminated drilling fluid, the conduit being branched whereby a portion of the contaminated fluid is delivered to a preliminary separation stage and the remainder flows to a main separation stage, each said stage comprising a screen for separating debris from the fluid. The preliminary separation stage comprises a vibrating screen and conveyor means for conveying separated debris into the remainder flow to the main separator stage, thereby increasing the proportion of entrained debris in the remaining fluid.

Abstract: A method of bringing hydrocarbons from a well into production by introducing encapsulated bubbles into the fluid in the production string to reduce the hydrostatic pressure holding the hydrocarbons in the reservoir. For reservoirs where the reservoir pressure has been depleted to the point where the reservoir pressure is not sufficient to push a column of hydrocarbons to the surface at an acceptable rate, encapsulated bubbles can be continuously introduced into the production string at a suitable depth to reduce the pressure required to bring hydrocarbons to the surface and allowing the encapsulated bubbles to be recovered and recycled.

Abstract: In a method and apparatus for screening drilling fluids to remove entrained debris, the fluid is urged upwardly from the lower side to the upper side of an inclined or horizontal mesh screen, so that debris falls from the face of the screen under gravity to be collected and removed, and the clean fluid emerges above the screen. The debris may be removed by a conveyor or by a vibrating mesh surface. The operating life of the screen is thereby extended.

Abstract: A method of bringing hydrocarbons from a well into production by introducing encapsulated bubbles into the fluid in the production string to reduce the hydrostatic pressure holding the hydrocarbons in the reservoir. For reservoirs where the reservoir pressure has been depleted to the point where the reservoir pressure is not sufficient to push a column of hydrocarbons to the surface at an acceptable rate, encapsulated bubbles can be continuously introduced into the production string at a suitable depth to reduce the pressure required to bring hydrocarbons to the surface and allowing the encapsulated bubbles to be recovered and recycled.

Abstract: In a method and apparatus for screening drilling fluids to remove entrained debris, the fluid is urged upwardly from the lower side to the upper side of an inclined or horizontal mesh screen, so that debris falls from the face of the screen under gravity to be collected and removed, and the clean fluid emerges above the screen. The debris may be removed by a conveyor or by a vibrating mesh surface. The operating life of the screen is thereby extended.