The Study Of Optimization Design Method For The Heavy Oil Reservoir's Rod Pumping System

Nowadays sucker rod pump oil recovery is the most widely used in the domestic heavy oil reservoir. Because the system efficiency is very low generally, the cost of oil production is increased and the economic benefit of crude oil production is decreased. So the study of optimization design for the heavy oil reservoir's rod pumping system can raise the system efficiency, as plays a significant role for developing the heavy oil reservoir.Firstly, on the basis of the fluid thermodynamics and heat transfer theories, applying the theories of mass conservation and energy conservation, the mathematical models for predicting wellbore temperature distributions are established, and the analytical solutions are solved in this paper. Then the viscosity distribution and the wellbore pressure distribution can be calculated. Then considering viscosity-temperature characteristics and regarding system efficiency as the optimal object function under the condition of matching fluid production capacity to lifting capacity, the multiprogramming, that applies several loop variables including swabbing parameters, depth of plunger, working fluid level and so on, is used to study the optimization design method and develop the software of the optimum design for the heavy oil reservoir's rod pumping system. Finally, according to the actual production data of Tahe Oilfield, the parameters were calculated by way of illustration. At the same time, the influential factors, that include water cut, depth of the blending point, amount of blending light oil, heating power and heating depth, of wellbore viscosity distribution are analyzed in order to offer the technical assistance to adopt visbreaking technics for the heavy oil reservoir. The optimal results, which are calculated by the software for five heavy oil wells of Tahe Oilfield, show that the loading and maximum torque calculated whose average relative deviation reaches 10% compared with the site conditions, and the optimal average system efficiency increases 9.6%, and the average daily production per well increases 11.3 cubic meters. It can bring noticeable economic benefits, which illustrates that the optimizing method meets actual demand of heavy oil reservoir, and it has better applied and generalized foreground.