Preparation And Performance Evaluation Of A New Low Residue Oil Base Fracturing Fluid

At present,due to the rapid growth of social economy and the continuous loss of non renewable energy,the reserves of conventional oil and gas fields are continuously exploited,which leads to the consumption and use of resources that are easy to exploit and can be exploited.In order to ensure the supply demand,countries around the world gradually turn their attention to unconventional oil and gas reservoirs,such as tight sandstone reservoirs,shale formations,etc.As an important reservoir reconstruction and EOR technology,hydraulic fracturing is often used in guanidine based fracturing system,oil-based fracturing system,viscoelastic surfactant cleaning system and so on.Through the study of various systems,we find that they have their own shortcomings and limitations.In this paper,by analyzing the shortcomings of the above fracturing system,a new main thickening agent is synthesized,and the synthesis process is changed to improve the experimental conversion rate and reduce the reaction time.By optimizing the performance of the main fracturing agent,a new type of low residue oil-based fracturing system is developed.In this paper,two different synthetic heating methods are used to prepare the main agent PE-Fe,and further to prepare oil-based fracturing system.The first method is the conventional heating method,and the second one is the microwave radiation heating method,which aims to shorten the reaction time of the synthesis of the main agent and increase the viscosity ratio.The main step of synthesis is to use DP-4,the intermediate of diethyl phosphate,to react with iron sulfate and alcohol to obtain the target product PE-Fe.In this process,we need to investigate and screen the types and properties of alcohol.Through the orthogonal experiment,we can get the best experimental reaction conditions for the synthesis of the main agent,and finally choose tridecanol as the reaction material.The PE-Fe was applied to the oil-based fracturing system,the formula was:500 mldiesel oil+2%new PE-Fe+3.5%Fe₂?SO₄?₃+1%dihydroxyethylamine+1%Na OH+1%Na Ac,and the new system was compared with the oil-based system of dialkylphosphate,traditional oil-based system and traditional water-bas ed system The performance of the new system was evaluated.The final result of the experiment shows that the viscosity of the new fracturing system is 120.8m Pa·s,it can withstand 135?high temperature,and it has good shearing property.After breaking?the viscosity of breaking fluid is less than 5m Pa·s?,the amount of residue is far less than the other three systems.It has good permeability and flowback,and little formation pollution.The comprehensive evaluation shows that the performance of the new oil-based system conforms to the oilfield construction and has certain application value.