Investigation Onto Preparation And Performance Of Special Aluminite For Oilfield Plugging

With the increasing depth of oilfield exploitation,shallow sealing technology is no longer able to meet the current demand for the extraction of Class II and III oil layers.Paying attention to the quality of oilfield sealing construction is the main factor to ensure the success rate of old well sealing.At present,there are still many problems with sealing tools and process construction direction in sealing technology,such as high cost,long milling time,incomplete well flushing process,and inability to inspect the sealing of the pipe string,which continue to limit the development of the petrochemical industry.This article proposes a new oilfield sealing method,which injects high-performance aluminothermic agent into the oil outlet.By utilizing the characteristics of high combustion temperature and long combustion time of aluminothermic agent,the metal powder around the oil outlet melts and the molten product of aluminothermic agent cools together to form a sealing agent that accumulates inside the oil well,achieving its own sealing effect.To explore the feasibility of applying a new type of aluminothermic agent in the field of oilfield sealing,this article studied the new type of aluminothermic agent and its properties for oilfield sealing.Firstly,the components of the oilfield plugging thermit agent were selected（Using nano aluminum powder as the combustible agent,potassium nitrate,ferric oxide,titanium dioxide as the oxidant,and liquid paraffin as the additive）.The B-W method was used in conjunction with the uniform design method to determine the optimal formula as Al:KNO₃:Fe₃O₄:Ti O₂=30%:30%:34%:6%.Due to the high safety performance of the thermit agent,a mixture of copper oxide and aluminum powder with a mass ratio of 7:3 was selected as the excitation agent for igniting the thermit agent.Secondly,the orthogonal experimental method under three factors and three levels was used to analyze the experimental results.Based on the evaluation criteria of combustion speed and temperature,the main factor affecting the performance of aluminothermic agents was determined to be the particle size of aluminum powder,followed by the charge quantity,and the least affected factor was the charge density.Then,the wet granulation method was used to prepare the aluminothermic agent.From the analysis of safety performance,combustion performance,and morphology characterization,it was found that the sensitivity of the oilfield sealing aluminothermic agent is low and requires strong excitation conditions;The combustion temperature is high and the combustion time is long.1 kg of thermite can make the maximum temperature of the inner wall of a 5mm thick iron pipe reach 2689℃,and the maximum temperature of the outer wall of the iron pipe reach1423℃.The combustion duration is about 14 minutes,which is sufficient to meet the requirements of industrial oil field sealing conditions in terms of temperature and time control and sealing performance.Moreover,the thermite is relatively stable in the microscopic state,with a microsphere like structure,and each element conforms to the mixed component ratio,The successful synthesis of oilfield sealing aluminothermal agent.At the same time,simulation testing was conducted on the sealing strength of the three-dimensional pore structure of the oil leakage reservoir simulated by the oil field sealing thermit agent.Through numerical simulation analysis of heat transfer during the oil field sealing process,the melting effect of the oil field sealing thermit agent on the metal powder around the sealing hole was evaluated.The results showed that the simulation results of the thermit agent were good,and the heat transfer process was stable.The solid products formed by the melting metal powder after the combustion of the sealing thermit agent hardened,A system with high sealing strength and dense bonding surface has been formed,which has a good sealing effect.Finally,by comparing the combustion performance and other factors of the existing magnesium and iron based aluminothermic agents for oilfield sealing,it was found that oilfield sealing aluminothermic agents have significant advantages.The new oilfield sealing aluminothermal agent has good combustion and sealing performance,and has advantages such as simple operation process and low cost in oilfield sealing technology.By utilizing its own sealing characteristics,it can be applied in many environments such as crack sealing and casing sealing,providing a new and feasible technical approach for oilfield sealing.Figure[26]Table[27]Reference[103]...