Abstract: A well cementing method is described for improving cementing quality by controlling the hydration heat of cement slurry. By controlling the degree and/or rate of hydration heat release from cement slurry, the method improves the hydration heat release during formation of cement with curing of cement slurry, improves the binding quality between the cement and the interfaces, and in turn improves the cementing quality at the open hole section and/or the overlap section. The cementing method improves cementing quality of oil and gas wells and reduces the risk of annular pressure.

Abstract: The present invention provides a SAPO-34 molecular sieve with small crystal size and a hollow structure rapidly synthesized from a waste MTO catalyst and a method for preparation thereof. The method comprises of the following steps: calcining a waste MTO catalyst fine powder; mixing it with an inorganic acid solution to obtain a mixed solution; adding an organic amine and a phosphorus source to the mixed solution, and stirring it to obtain an initial gel mixture for SAPO-34 molecular sieve; crystallizing the initial gel mixture, and then drying the resultant to obtain a raw SAPO-34 molecular sieve powder; and calcining the raw powder obtained to obtain the SAPO-34 molecular sieve with small crystal size and a hollow structure.

Abstract: The present invention provides a long-lifetime SAPO-34 catalyst prepared from waste MTO catalyst as a raw material and a preparation method thereof. The method comprises the following steps: mixing the waste MTO catalyst fine powder with water; adding a phosphoric acid and an organic amine and stirring to obtain an initial gel mixture for SAPO-34 molecular sieve; crystallizing the initial gel mixture and then at least drying it to obtain a raw SAPO-34 molecular sieve powder; calcining the raw molecular sieve powder to obtain a SAPO-34 molecular sieve powder; then mixing it with a binder and a matrix carrier in water with stirring, and then aging it; and molding and then calcining it to obtain the long-lifetime SAPO-34 catalyst. The preparation method of the present invention uses MTO waste catalyst as a raw material to synthesize SAPO-34 molecular sieve in situ within a short time, and to prepare MTO catalysts having a long life and high selectivity for light olefins.