A Research On The Mechanism Of Cold Heavy-oil Production And The Simulated Analysis And Optimization Of Cavity Pump

After decades’ exploitation, water-flooding oil field in China has experienced a sharp decrease in output and high water content. Consequently, the economical benefit is getting worse, which can not meet with the economic growth of a nation. However, China takes possession of a large amount of low-grade heavy-oil resources to exploit, featured by higher exploiting cost and lower efficiency if use thermal exploitation as opposed to which, the cold heavy-oil production is a relatively effective technology, but what needs to be further developed is the fitting condition and matching technology of cold heavy-oil technology.In this thesis, the author makes a probe and analysis focused on the current problems of cold heavy-oil production technology. Together with the data of practical production in the oil field and laboratory trial results, the author concludes the main mechanism. Based on this mechanism the exploiting features and main influencing factors of cold heavy-oil production on the heavy oil are analyzed, in which the condition of cement in reservoir stratum is the most important influencing factor. The optimization of completion technique and supplementary technique of cold heavy-oil production includes the perforating technique, the selection of bottom-trip casing, the adaptation analysis of cavity pump, the optimization of sucker, sand washing technology and well-bore viscosity breaking technology. Making the cavity pump applied to the cold heavy-oil production as the object of analysis and optimization. The working mechanism is cleared and the motion rules and equation are worked out by three-dimensional modelings and motion simulations to the cavity pump; through the thermal stress coupled finite element analysis of the cavity pump, the condition of heating and stress is researched, conclusions that leaking and back flow, failures of the rubber stators, decrease of pump’s efficiency are happened during the working process of the cavity pump are made. By the thermal stress coupling under the same boundary conditions with the common cavity pump, the improved program of Even Thickness Progressive Cavity Pump was proposed. The comparative analysis shows that to some extent, the Even Thickness Progressive Cavity Pump can solve the failures of the rubber stators, during the working process and can effectively prevent swelling, uneven thermal dissipation. Viewed from its overall performance, the Even Thickness Progressive Cavity Pump is obviously superior compared to the common ones with same specifications concerning their working properties; the selection principle of cavity pump is formed from angles of the depth, displacement, working pressure and the selection of Rubber Stator of cavity pumps.