A method for forming spheroidal particles including inducing flow of a slurry of particles and a reactant through one or more orifices, detaching an amount of the slurry from the slurry flow following exit from the one or more orifices, the detached amount forming a slurry body, forming the slurry body into a spheroidal shape, contacting the spheroidally shaped slurry body with a coagulation solution to form a stabilized spheroidal particle and drying and/or sintering the stabilized spheroidal particle.

A ball sealer for hydrocarbon resource recovery, comprising: a generally spherical entire structure including at least two layers of a spherical core and a surface resin layer covering the spherical core, of which at least the surface resin layer comprises a polyglycolic acid resin; and having a diameter of at least about 25 mm (1 inch). The ball sealer is produced through a process comprising the steps of: disposing a spherical core by a support pin at a substantially central position within a mold cavity, injecting a surface resin comprising a polyglycolic acid resin into the cavity surrounding the spherical core, causing the support pin to retreat up to a wall surface of mold cavity in synchronism with a completion of the injection of the surface resin, and then hardening the surface resin. As a result, it is possible to produce a large-diameter ball sealer suitable for use in the hydraulic fracturing process (hydraulic fracturing) widely used for recovery of hydrocarbon resources by using a polyglycolic acid resin which is a biodegradable resin having good mechanical strengths and a good size designability at least as a surface-forming resin, through relatively simple steps and with good dimensional accuracy.

The invention relates to a heating device (1) which is designed to heat a packaging film in a deep drawing process, over the course of which the heated packaging film is molded into the cavity of a deep drawing mold. The surface region of the heating device (1) which is brought into contact with the film section to be molded into the cavity has at least one depression (50), the opening area (40) of which equals 40 to 95% of the opening area (40) of the cavity. The invention also relates to a deep drawing device comprising the aforementioned heating device (1).

A method for producing a portion unit with at least one filled receiving chamber surrounded by a film, comprising the steps of a) transporting a first film in the direction of a heating device; b) bringing the first film into contact with a surface of the heating device; c) heating the first film by means of the heating device; d) breaking the contact between the first film and the heating device; e) molding the first heated film into the cavities of a thermoforming mold, thereby forming a receiving container with at least one receiving chamber; f) filling the at least one receiving chamber; g) optionally closing and separating the filled receiving containers, thereby forming the portion unit, wherein the region on the surface of the heating device that is brought into contact with the film has at least one depression and, in step b), the at least one depression is covered by the subregions of the first film that are molded into the cavity of the thermoforming mold in step e).