Abstract: A method and apparatus for sealing a section of screened well casing, especially useful in soil venting wells. A foamed rubber sleeve surrounding a pipe is caused to collapse when suction is drawn on the annulus between the pipe and sleeve, allowing the pipe and sleeve to be lowered into place. When the annulus is pressurized the sleeve expands out against the screen to seal the contacted portion against the passage of air.

Abstract: A method for selectively treating sections of soil which are more remote from a soil venting well than previously treated soil sections. Air is drawn through a first group of passageways in a well casing during treatment of a particular section of soil. Air is then prevented from passing through the first group of passageways, as by sealing them, and is drawn through a second lower group of passageways. By sequentially following these steps, different sections of soil located farther from the well and deeper than previously treated sections can be selectively treated.

Abstract: Selective permeability reduction is achieved in a heterogeneous treatment zone of a subterranean hydrocarbon-bearing formation by initially placing a nonselective permeability-reducing material in the high and low permeability regions of the treatment zone. Thereafter, a permeability-restoring agent is placed in the regions behind the permeability-reducing material. The agent contacts all of the material in the low permeability region, reacting with it to restore permeability thereto. However, the agent is consumed by reaction before it contacts all of the material in the high permeability region, thereby leaving a sufficient amount of material in the high permeability region to achieve selective permeability reduction therein.

Abstract: A process for retorting oil shale in a vertical retort. Recycle gas containing steam and produced gas is separated from the retort off-gas and used to heat the oil shale. The steam is present in amount by volume of the recycle gas of at least 40% and preferably 70%. The minimum particle size of the oil shale is such that the particles are retained on a screen having 1/4 inch openings. The maximum particle size is such that the particles are capable of passing through a screen having 3 inch openings.

Abstract: A process for preventing, or at least substantially reducing, scaling in an aqueous polymer dilution apparatus by injecting carbon dioxide gas into the solution to maintain the pH of the solution in a range which tends to hold scale forming substances in solution.

Abstract: In this process carbonaceous materials in a wide range of particles size are heat treated in a substantially vertical gravity retort through which heated gasses flow upwardly. The particles are graded by size and fed into the retort with the largest particles being inserted into an upper portion of the retort, and in preferred embodiments, with progressively smaller particles being inserted into progressively lower portions of the retort so that the residence time of each of the particles in the retort is substantially directly proportional to the size and mass of the particles. This process allows high throughput of the material while reducing the amount of entrained small particles which flow up with the heated gas, thus reducing pressure drop in the retort system.

Abstract: Hydrocarbon containing oil shale is processed on the surface of a rabbled rotary hearth by mixing it with a heat exchange medium consisting of heated spent oil shale. Mixing is obtained by feeding the raw shale and the heated spent shale separately, but in proximity to one another, onto the surface of a hearth, and then subjecting both materials to rabbling action. This mixing causes heat from the heated spent shale heat exchange medium to be transferred to the fresh raw shale, which results in the removal of hydrocarbons from the raw shale. In one preferred embodiment, heated spent shale is obtained by removing spent shale from the hearth after processing, mixing it, preferably while it is still hot, with compatible combustible solids, and then introducing oxidizing gases into the mixture. This results in the burning of the combustible solids and any combustible materials remaining in the shale and the heating of the spent shale.

Abstract: The rabbles of this invention have a concave active face. They are used in a system for processing material including, for example, a substantially circular and horizontal floor, and a rabble system disposed above, but adjacent to, said floor. The rabble system urges material on the floor to desired locations, such as discharge openings, in response to relative motion between the floor and the rabble system. The rabble system includes a plurality of rabbles. Substantially each rabble has a body portion which carries a curved or angled surface. This curved or angled surface defines a concave active face. Each rabble also has a leading edge substantially perpendicular to the floor. The concave active face extends from the leading edge and is both substantially parallel to the leading edge and substantially perpendicular to the floor. Said rabbles are preferably oriented in a system with their body portion adjacent their leading edges at an angle in the range of about 0.degree. to about .+-.13.degree.

Abstract: Hydrocarbon mixtures (e.g. "waxy" crude oils) are transported as a slurry by first fractionating the mixture into at least a relatively low pour point fraction and a relatively high pour point fraction. Thereafter, the high pour point fraction is congealed by dispersing it as particles into the bottom of a tower having a continuous stream of water flowing countercurrent to the dispersed fraction and wherein the water in at least the upper portion of the tower is at a temperature sufficient to congeal the dispersed particles. The particles pass upwardly through the tower and through an interface within the tower, the interface being the juncture of water and the low pour point fraction being introduced into the top portion of the tower. A portion of the resulting slurry is withdrawn and transported in a conduit at temperatures below those which bring about solution of the congealed particles in the low pour point fraction.

Abstract: Comminuted solids having a specific gravity greater than 1.0 and having a porosity greater than about 10% are maintained in suspension within a liquid-solids slurry by saturating the pores of the solids with a substance having a specific gravity lower than 1.0.