Abstract: A composition and a process for treating a subterranean formation are disclosed. The process comprises injecting into the subterranean formation a composition which comprises a polymer, a crosslinking agent, a liquid, optionally a clay, and further optionally a weighting agent wherein the polymer forms a gel in the formation, in the presence of the crosslinking agent.

Abstract: A tie plate with posts is designed for easy insertion of the foot of the rail cooperates with pins through the posts to rigidly affix the rail to the tie plate and to railroad ties or roadbed. The posts may be made of flexible material in which case the rails are snapped into the tie plate. Alternatively the posts may be fabricated from hard plastics, ceramics, or metals, in which case the rails slide into the tie plates. The posts restrain the rail from lifting out of the tie plate or shifting laterally in the tie plate. Pins with fluted, or otherwise textured, surfaces are driven through guiding holes in the posts of the tie plate past the edge of the foot of the rail. The fluted edges of the pin serve to grip the rail. The pins are made of rigid or hard materials so that the pin will provide rigidity to the posts and also slightly deform the edge of the foot of the rail and thereby grip or engage the foot.

Abstract: A composite continuous surface rail is constructed by combining a load-bearing support rail divided into segments to allow for thermal expansion with a continuous surface rail that slideably engages the support rail and spans any number of support rail segments. The continuous top or surface rail includes a running rail and an expansion rail. The expansion rail is provided to absorb thermal expansion of the running rail while continuing to provide a continuous composite rail surface. The surface rail and/or support rail may be electrified. An electrified running rail and expansion rail will provide an electrified composite rail with electrical continuity.

Abstract: A composite continuous surface rail is constructed by combining a load-bearing support rail divided into segments to allow for thermal expansion with a continuous surface rail that slideably engages the support rail and spans any number of support rail segments. The continuous top or surface rail includes a running rail and an expansion rail. The expansion rail is provided to absorb thermal expansion of the running rail while continuing to provide a continuous composite rail surface. The surface rail and/or support rail may be electrified. An electrified running rail and expansion rail will provide an electrified composite rail with electrical continuity.

Abstract: A composite continuous surface rail is constructed by combining a load-bearing support rail divided into segments to allow for thermal expansion with a continuous surface rail that slideably engages the support rail and spans any number of support rail segments. The continuous top or surface rail includes a running rail and an expansion rail. The expansion rail is provided to absorb thermal expansion of the running rail while continuing to provide a continuous composite rail surface. The surface rail and/or support rail may be electrified. An electrified running rail and expansion rail will provide an electrified composite rail with electrical continuity.

Abstract: A composite minimum-joint electrified rail is constructed by combining a non-conductive support rail divided into easily installed segments with a continuous conductive rail that mounts on the support rail and spans any number of support rail segments. The conductive rail may be attached to the non-conductive rail by a tongue and groove arrangement. Multiple conductive rails or strips may be attached to different portions of the same support rail. In addition spring clips are shown for attaching the support rail to railroad ties or roadbed, and fish plates are shown for attaching abutted support rails.

Abstract: A composite minimum-joint electrified rail is constructed by combining a non-conductive support rail divided into easily installed segments with a continuous conductive rail that mounts on the support rail and spans any number of support rail segments. The conductive rail may be attached to the non-conductive rail by a tongue and groove arrangement. Multiple conductive rails or strips may be attached to different portions of the same support rail. In addition spring clips are shown for attaching the support rail to railroad ties or roadbed, and fish plates are shown for attaching abutted support rails.

Abstract: A water permeability contrast correction process to improve the sweep efficiency of waterflooding which involves the sequential injection of (1) an optional aqueous preflush slug to adjust connate water salinity, (2) an aqueous thickened slug comprising a sequestered polyvalent metal cation such as aluminum citrate and a gelable polymeric viscosifier such as polyacrylamide, (3) carbon dioxide to decrease the pH of the polymer slug which triggers the delayed in-situ gelation of said thickened slug to preferentially decrease water permeability in highly permeable thief zones, and (4) an aqueous drive fluid.

Abstract: A water permeability contrast correction process to improve the sweep efficiency of waterflooding in carbonate-bearing strata which involves a sequential injection of (1) an optional aqueous preflush slug to adjust connate water salinity, (2) a slug of aqueous polymer gelable with polyvalent metal cations, such as an polyacrylamide, (3) an acidic aqueous solution effective to dissolve some of the carbonate and at least therefrom polyvalent metal cations specifically calcium or magnesium or both effective to gel said polymer, wherein said aqueous polymer and acidic solution can be injected together in a single slug, followed by (4) an additional aqueous polymer solution injection, wherein the acidic solution provides polyvalent metal cations in-situ for gelation of said polymer slug to preferentially decrease water permeability in highly permeable thief zones, and (5) an aqueous drive fluid.

Abstract: A water permeability contrast correction process to improve the sweep efficiency of waterflooding which involves the sequential injection of (1) an optional aqueous preflush slug to adjust connate water salinity, (2) an aqueous thickened slug comprising a sequestered polyvalent metal cation such as aluminum citrate and a gelable polymeric viscosifier such as polyacrylamide, (3) carbon dioxide to decrease the pH of the polymer slug which triggers the delayed in-situ gelation of said thickened slug to preferentially decrease water permeability in highly permeable thief zones, and (4) an aqueous drive fluid.

Abstract: A water permeability correction process, and composition therefor, to improve the sweep efficiency of waterflooding which involves the sequential injection of (1) an optional aqueous preflush slug to adjust connate water salinity, (2) an aqueous thickened slug comprising a sequestered polyvalent metal cation such as aluminum citrate, a gelable polymeric viscosifier such as polyacrylamide, and a hydrolyzable-pH-adjusting ester effective for delayed decreasing of the pH of the polymer slug which triggers in situ gelation to preferentially decrease water permeability in highly permeable thief zones, and, preferably, (3) an aqueous drive fluid.

Abstract: Selected sulfur-containing compounds function as solution viscosity stabilizers in aqueous compositions comprising acrylamide polymers containing a redox couple or components which can produce a redox couple in the presence of the solution. The aqueous compositions are useful in post-primary oil recovery involving the use of thickened fluids as mobility buffers and mobility control agents.