Dai-ichi Kogyo Seiyaku Co., Ltd.

Mineo Sabi

Koji Noda

Yousuke Goi

Kazuhito Jinno

Hiroshi Hotta

Kinya Yokota

Satoshi Hiratsuna

Hiroshi Nishiguchi

To provide an additive for crude oil recovery, used in secondary/tertiary recovery of crude oil, which has high heat resistance and high mechanical shear resistance, of which the viscous property does not degrade even under high-temperature and high-shear conditions; has high pseudoplastic flowability and therefore has a light transfer workload; and is a naturally-derived one and is therefore highly biodegradable and has least adverse impact on environment. An additive for crude oil recovery, which contains cellulose fibers having a number-average fiber diameter of from 2 to 500 nm and a fiber aspect ratio of 50 or more and having a cellulose I-type crystal structure, and, in the cellulose fibers, a hydroxyl group on a surface of the cellulose fibers is preferably chemically modified.

Crude oil recovery additive

To provide an additive for drilling mud, used in drilling for petroleum, natural gas, civil engineering, mines, etc., which has high heat resistance and high mechanical shear resistance, of which the viscous property does not degrade even under high-temperature and high-shear conditions; has high pseudoplastic flowability and therefore secures high flowability during discharging; and is a naturally-derived one and is therefore highly biodegradable and has least adverse impact on environment. An additive for drilling mud, which contains cellulose fibers having a number-average fiber diameter of from 2 to 500 nm and a fiber aspect ratio of 50 or more and having a cellulose I-type crystal structure.

Additive for drilling mud

A process for forming a gel by gelling an aqueous solution of a water-soluble polymer with a chromium compound as a gelling agent, in which a copolymer of acrylamide, 0.5 to 40% by mole of an unsaturated sulfonic acid or its salt, and optionally an unsaturated carboxylic acid or its salt having an intrinsic viscosity of at least 10 in 1N-NaNO.sub.3 at 30.degree. C., is used as the water-soluble polymer, and which is availably applied to improvement of water-oil ratio in oil production and to civil engineering for preventing leakage of underground water. The formed gel is very stable in a water system containing salts in high concentrations at high temperatures.

Process for preparing stable aqueous gel

Growing community of inventors

Kyoto, Japan

Mineo Sabi