Abstract: A user-friendly reverse circulation float equipment tool and process permit the application of reverse circulation cementing in shallow or deeper wells, without having to use an inner string. The reverse circulation float equipment tool can have: an upper section with a ball-activated upper valve, a lower section with a ball-activated lower valve, and an intermediate ball chamber between the upper and lower sections to contain the ball in a reverse mode. The reverse circulation float equipment tool and process allow circulation in the normal and reverse circulation modes while running the casing and during hole conditioning. After the reverse circulation job, the convenient reverse circulation float equipment tool and process allow closing of the bottom of the casing to prevent U-tubing of the cement slurry.

Abstract: The present invention relates to tools and methods for stabilizing incompetent or otherwise unstable subterranean zones or formations penetrated by a well bore during drilling. The methods basically comprise drilling the well bore through an enlarged portion of an unstable subterranean zone or formation when it is encountered, pumping a hardenable cementitious material through the well stabilization tool while moving the tool through the enlarged portion of the well bore whereby the enlarged portion is filled with the hardenable cementitious material, allowing the cementitious material to harden and then drilling the well bore through the hardened cementitious material.

Abstract: The present invention relates to tools and methods for stabilizing incompetent or otherwise unstable subterranean zones or formations penetrated by a well bore during drilling. The methods basically comprise drilling the well bore through an unstable subterranean zone or formation when it is encountered, pumping a fluid through a well stabilization tool while moving the tool through the portion of the well bore in the unstable zone or formation whereby fluid jets formed by the well stabilization tool enlarge the diameter of the well bore by fluid jet erosion, pumping a hardenable cementitious material through the well stabilization tool while moving the tool through the enlarged portion of the well bore whereby the enlarged portion is filled with the hardenable cementitious material, allowing the cementitious material to harden and then drilling the well bore through the hardened cementitious material.

Abstract: Methods of measuring the erodability of drilling fluid deposits and the shear stress required to remove drilling fluid deposits formed on the walls of a well bore are provided. The methods basically include introducing a drilling fluid into a test apparatus which simulates a permeable section of a well bore. Drilling fluid deposits are caused to be formed on the walls of the permeable section, and the drilling fluid is circulated through the permeable section at progressively increasing flow rates to determine the pressure drop below which no appreciable erosion of the drilling fluid deposits takes place which corresponds to the minimum shear stress required to erode the deposits. The erodability of the drilling fluid which is inversely proportioned to the minimum shear stress can also be determined. Apparatus for carrying out the methods is also provided.

Abstract: A method and apparatus for indicating the position of a cement wiper plug in a wellbore during liner or casing cementing operations. The arrival of the cement wiper plug at a shearable, temporary restriction means in a pipe string is sensed by an increase in pipe string pressure at the surface. Using the knowledge of the location of this shearable, temporary restriction means, a determination of whether or not it is desirable to displace the cement wiper plug to a landing assembly at the bottom of the pipe string can be made. A predetermined amount of displacing fluid, sufficient to either completely or partially displace the cement wiper plug to the landing assembly, can then be introduced into the pipe string.

Abstract: A spacer composition for use in borehole cementing operations is disclosed which has excellent high temperature stability and compatability with cement slurries and drilling fluids. The spacer composition comprises a single phase water base system containing stabilized attapulgite clay.

Abstract: A spacer composition for use in borehole cementing operations is disclosed which has excellent high temperature stability and compatability with cement slurries and drilling fluids. The spacer composition comprises a single phase water base system containing stabilized attapulgite clay.