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The separation of the proteins is of great theoretical and practical importance for biotechnological application. Considering the requirement of nondestructive separation, the stimulus-response method is an alternative to the separation of protein. In this work, a cellulose-based composite with CO 2 stimulus-response property is prepared by a simple coprecipitation of poly (N, Nˊ-diethylamino ethyl methacrylate)-co-poly (hydroxyethyl methacrylate) (PDH) and cellulose mixture solution. Subsequently, these composites as the adsorption medium are used to separate the bovine serum albumin (BSA, as the model protein) from solution through stimulus-response course (by CO 2 /N 2 alternation). The results indicate that the ratio of the copolymers/cellulose composite have an obvious effect on the separation of BSA. The average maximum adsorption capacity can get to 562.6 mg/g, and the composites exhibits good adsorption/desorption cycling characteristics. After the composite materials are cycled for three times, the adsorption capacity can still decrease to 300 mg/g. Due to its high adsorption capacity and low preparation cost, the composite is expected to be widely used in industry.

An unified technique with perforation, well test before and after stimulation, ground cross linked acid fracturing, foreign fluid recovery in one down hole pipe string is put forward in a carbonate reservoir, and the pilot test well is well A, located in Erlian Oil Field, Inner Mongolia. The advantage of above mentioned pipe string is that it can complete above four works by sequence just in one pipe string so it can improve work efficiency and reduce reservoir damage in a great deal. What's more, the new developed ground cross linked acid with high viscosity (more than 100 mPa.s), more compatibility, easily controlling of cross linking and gel breaking, etc. is applied so as to get a longer and wider fracture by acid corrosion, which has been verified by field case. Consequently, the post-acid fracturing rate of Well A was as high as 226 m 3 /d with no water. It has a great significance both in improving well performance and reduces cost as well.

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