Purpose This study aims to solve the premature failure of the rubber stator due to wear, reduce the frictional resistance moment of the screw pump to solve the problem of a model of Daqing oilfield screw pump oil recovery system shutdown after the difficult start. Design/methodology/approach For the first time, the rotor surface of a screw pump was treated with dot-matrix texture to study the effect of dot matrix texture on the tribological performance of the stator-rotor friction subsets of screw pump. Reciprocating friction tests with different texture morphologies (S-shape, double tongue) and angular parameters (0°, 45° and 90°) were conducted at 10% of the texture area and pump silicone grease. Findings When point texture was added to the surface of the rotor sample, the friction coefficient and wear quantity of the sample were lower than those of the surface without texture treatment, and the double tongue 0° combination showed the best tribological properties. At this time, the average coefficient of friction and wear is reduced by 22.8% and 62%, 28.6% and 64.8%. Originality/value The introduction of texture can effectively improve the tribological performance of progressive screw pumps, and this paper provides important theoretical and experimental support for the design of progressive screw pumps in practical applications.

To a great extent, experiment selection of temporary plugging partic1es(TPP) in the temporary plugging techniques (TPT) is blind at present. Based on the investigation of particle migration, deposition and plugging mechanism in the porous media, network model, the inter-connected pore and throat network on the basis of reservoir pore structure, is applied to the optimization of TPP in the TPT. It is shown that the result of simulation has a g(x)d agreement with that of core flooding experiment and can be used to guide the study of core fl{x)Jing experiments. The main advantages of this method arc: 1. the model can be repeatedly used many times and can be used in the simulations of various purposes and aspects; 2. the results are highly comparable by the simulation while much less by the core flooding experiments_

To a great extent, experiment selection of temporary plugging particles(TPP) in the temporary plugging techniques (TPT) is blind at present. Based on the investigation of particle migration, deposition and plugging mechanism in the porous media, network model, the inter-connected pore and throat network on the basis of reservoir pore structure, is applied to the optimization of TPP in the TPT. It is shown that the result of simulation has a good agreement with that of core fiooding experiment and can be used to guide the study of core flooding experiments. The main advantages of this method are:the model can be repeatedly used many times and can be used in the simulations of various purposes and aspects;the results are highly comparable by the simulation while much less by the core flooding experiments. Introduction It's well known that formation damage existing extensively in each phase of field operations is a difficult problem in the petroleum industry, and can not only damage oil and gas resources and considerably reduce the productivity of hydrocarbon reservoirs, but also even kill hydrocarbon reservoirs, and therefore cause a very great waste of manpower, material and financial resources. During the past several decades, beginning with our original consciousness of formation damage problem, unremitting efforts and a great number of researches have been made from the understanding of formation damage mechanism in the past to the controlling and preventing of formation damage by using various methods at present.

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