A plugging agent with temperature-resistant, salt-resistant and high-expansion for plugging large fractures and a preparation method thereof of the present disclosure are provided, the plugging agent system consists of the following components: main agent: 6%10%, cross-linking agent: 0.6%1%, initiator: 0.006%0.01%, additive: 6%14%, and the rest being water; the preparation method includes the following steps: adding montmorillonite to water to prepare a montmorillonite dispersion system; adding the main agent, the cross-linking agent and the initiator to the montmorillonite dispersion system to prepare a main agent solution; putting the main agent solution into an oven with a temperature range with 9020 C. for 948 h to obtain gelation, the adhesive strength of the agent system can reach grade H, with 5080 expansion multiple, good strength after being expanded and good water plugging effect under the condition of a temperature of 140 C. and 250,000 degree of mineralization.

The present disclosure relates to a high-temperature retarder suitable for oil and gas well cementation, a preparation method thereof and a cementing slurry.

A sol is provided for the production of inorganic fibres comprising precursors for aluminium oxide, silicon oxide, strontium oxide, wherein the precursors are present in proportions suitable to yield inorganic fibres having a composition comprising: 70Al.sub.2O.sub.380 wt %; 10SiO.sub.220 wt %; 10SrO20 wt % wherein the sum of Al.sub.2O.sub.3, SiO.sub.2 and SrO is at least 95 wt %.

The disclosure relates to embodiments of a thixotropic, non-cementitious, thermal grout and applications or methods of use of the grout related to horizontal directional drilling, trenchless technology, trenching, and installation of pipe, conduits, ducts, utility lines, and other product lines which may, e.g., be in trenches, underground, or under obstacles, such as a body of water or roadways.

The present disclosure relates to a high-temperature retarder suitable for oil and gas well cementation, a preparation method thereof and a cementing slurry.

A sol is provided for the production of inorganic fibres comprising precursors for aluminium oxide, silicon oxide, strontium oxide, wherein the precursors are present in proportions suitable to yield inorganic fibres having a composition comprising:70Al.sub.2O.sub.380 wt %; 10SiO.sub.220 wt %; 10SrO20 wt % wherein the sum of Al.sub.2O.sub.3, SiO.sub.2 and SrO is at least 95 wt %.

An unfired, refractory molded body (1), especially a plate, especially for thermal insulation of molten metal and/or an ingot solidifying from molten metal, that includes a binding agent matrix (2) of a set binder and aggregate grains (3) of biogenic silicic acid, preferably of rice husk ash, which are incorporated into the binding agent matrix (2), wherein the binding agent matrix (2) consists of silica gel, as well as a process for its production and its usage.

The present invention is directed to a reinforced building block made of autoclaved aerated concrete (AAC) comprising rebars formed essentially from A) at least one fibrous carrier and B) and a hardened composition formed from B1) at least one epoxy compound and B2) at least one diamine and/or polyamine in a stoichiometric ratio of the epoxy compound B1) to the diamine and/or polyamine component B2) of 0.8:1 to 2:1, as matrix material, and C) optionally further auxiliaries and additives and to methods of production thereof.

The invention provides a high temperature resistant Portland cement slurry and a production method thereof. The high temperature resistant Portland cement slurry comprises the following components by weight: 100 parts of an oil well Portland cement, 60-85 parts of a high temperature reinforcing material, 68-80 parts of fresh water, 1-200 parts of a density adjuster, 0.1-1.5 parts of a suspension stabilizer, 0.8-1.5 parts of a dispersant, 3-4 parts of a fluid loss agent, 0-3 parts of a retarder and 0.2-0.8 part of a defoamer. The high temperature resistant Portland cement slurry has a good sedimentation stability at normal temperature, and develops strength rapidly at a low temperature. The compressive strength is up to 40 MPa or more at a high temperature of 350 C., and the long-term high-temperature compressive strength develops stably without degradation. Therefore, it can meet the requirements for field application in heavy oil thermal recovery wells, reaching the level of Grade G Portland cement for cementing oil and gas wells.

A refractory object may include a Cr.sub.2O.sub.3 content of at least about 80 wt. % of a total weight of the refractory object, an Al.sub.2O.sub.3 content of at least about 0.7 wt. % and not greater than about 10.0 wt. % of the total weight of the refractory object, a SiO.sub.2 content of at least about 0.3 wt. % and not greater than about 5.0 wt. % of the total weight of the refractory object and a TiO.sub.2 content of at least about 1.0 wt. % and not greater than about 5.6 wt. % TiO.sub.2 of the total weight of the refractory object. The refractory object may further include an MOR of at least about 37 MPa as measured at 1200 C.