Study On Wax Deposition Law And Wax Removal And Prevention Technology Of Dongyuemiao Shale Oil Gas Well Barrel

The fluid components of Dongyemiao Shale oil and gas wells are complex,including methane,light oil and hydraulic fracturing rejection fluid,etc.The wax deposition law under the three-phase flow state of oil,gas and water is complex.Therefore,it is of great significance to study the wax deposition law of Dongyuemiao shale oil and gas well barrel,develop efficient paraffin remover,and put forward the technical countermeasures of wellbore wax control and paraffin removal and prevention.In this paper,the composition of well fluid and wax precipitation point of crude oil in Fuye well are tested and analyzed,and the distribution of wellbore temperature and pressure field is analyzed.The wax deposition law of multiphase flow in shale oil gas well barrel is studied by using the self-improved wax deposition multiphase pipe flow simulation experimental device and Aspen HYSYS software.We develope an efficient and safe paraffin remover and carry out dynamic evaluation experiments on the effect of paraffin remover and paraffin inhibitor.The technical countermeasures of wellbore paraffin removal and prevention are put forward.The main achievements and understandings of this paper are as follows:（1）The content of the heavy component C₁₇₊in crude oil of Fuye shale oil and gas well is as high as 20%;The wax precipitation temperature of crude oil under atmospheric pressure is 41°C.When the static melting experiment is carried out,as the temperature of the water bath continues to rise,the wax sample gradually melts and melts into a transparent liquid at 55°C.（2）We carry out the wax deposition multiphase pipe flow simulation experiment and Aspen HYSYS simulation to understand the influence of wellbore temperature,water content rate,flow rate,gas-oil ratio and tubular wall roughness on the wax formation pattern of the wellbore.The study shows that the wax deposition law of the wellbore is mainly influenced by water content,gas-oil ratio,wellbore temperature,flow rate,tubing diameter size and pipe wall roughness.Among them,the influence of flow rate on waxing is more complex:as the flow rate increases,the amount of waxing increases;when the flow rate increases to a certain critical value,the amount of waxing decreases with its increase.（3）Based on the characteristics of wax sample components from Fuye shale oil and gas well,we develope Fuye well paraffin remover and paraffin inhibitor with absolute ethanol,toluene and xylene as main reagent materials.The results of dynamic evaluation experiments on the effect of paraffin remover and paraffin inhibitor show that the paraffin remover and paraffin inhibitor in the flowing state is efficient and safe,which meets the requirements of relevant standards.The effect of anti-wax agent is better with the increase of the volume fraction of anti-wax agent,when the wax removal agent is increased by 5%,the wax removal rate is 91.17%;when the anti-wax agent is increased by 3%,the wax resistance rate is 84.87%.（4）According to the wax deposition law of gas well bore,the technical countermeasures for wax removal and prevention of shale and oil gas wellbore are put forward,such as chemical wax removal,mechanical wax removal,production control,optimization of production string,chemical wax removal and prevention agent injection,etc.