Wellbore Wax Simulation And Thermal Washing Parameters Design Of Hollow Rod In Pumping Well

The reservoirs, well bores and surface gathering lines all may be affected by paraffin deposition during the production process of crude oil.The paraffin deposition on the well bore leads to the conduit blockage of oil flow and further severely interferes with the normal production of oil wells, resulting in the reduction of the oil well production. However, once “paraffin blockage” takes shape, it results in several productive faults such as paraffin jam of sucker-rod pumping system, directly leading to off production of oil well.The main studying contents of this paper can be divided into the following several aspects.Firstly, the wellbore temperature calculation model was established for the normal production of oil well.The relationship between the thickness of the wellbore and the temperature, the parameters of the oil well output and the production time was studied, and the dynamic prediction model of wellbore paraffin wax was established, it can realize the dynamic prediction of the thickness of the wax section of the shaft, the wax section of the wellbore and the most serious of the paraffin section.Secondly, the dynamic prediction model of temperature field in the process of hot washing of hollow rod was established.Based on the dynamic prediction of wellbore temperature field, the relationship between the thickness of the inner tube of the oil pipe, the increase of energy consumption, the process of wax melting, the cost of washing and the thermal washing cycle were studied, and based on the minimum total cost of thermal washing cycle, a model of thermal washing cycle selection was established.Thirdly,considering the influence of the thickness of the oil pipe on the water head loss and the energy consumption of the well flushing pump in the pipeline, the relationship between the cost of washing well and the parameters of thermal washing was studied, and the optimum design model of thermal washing parameters was established.At last,the corresponding software for simulation analysis of wellbore paraffin prediction and thermal washing is programmed applying Visual Basic 6.0.Using the software, the simulation of well bore temperature, formation temperature and the variation of wax precipitation temperature with well depth was realized, and it can predict the thickness of wax, wax precipitation point, the thickest of wax depth.The temperature distribution law of well washing is analyzed, and the simulation and calculation of the oil tube temperature along with the well depth variation law and the theoretical prediction of the wax dissolving time as well as the thermal washing period were realized.Finally, the optimization design of the hot wash parameters, provides a theoretical basis for guidance for field heat wash.