Research On Adjusting Well Cementing Water Intrusion Cement Slurry System

With the development of domestic exploration and development,most of the oilfields have entered the middle and late stages of development,and more and more wells are being adjusted.Due to the long-term water injection,the formation pressure system is disorderly,the safety pressure window is narrow,the pressure stability and pressure leak are prominent during the cementing process,water channeling and water intrusion frequently occur,seriously affecting the well cementing quality of the adjustment well.In the past,well cementing was adjusted.In order to prevent water channeling and water intrusion,it is necessary to shorten the thickening time of cement slurry,reduce the loss of cement slurry and reduce the volume shrinkage in the process of cement slurry coagulation.Double coagulation slurry,Cement weight loss and other aspects of the start,and its own(microstructure strength)less resistance to water invasion.In this paper,a set of water invasion simulation experiment device was developed.Based on the study of the effect mechanism of water intrusion on the cementing quality and the influence of water intrusion on the properties of cement slurry and its coagulation,a set of evaluation methods to evaluate the resistance to water intrusion of cement slurry Finally,the hydrophobic material X3,which can improve the internal structure of cement slurry,is finally selected to improve the ability of the cement slurry system to resist water invasion in the microstructure and strength,and provides a new theory and method to improve the cementing quality of the adjustment well and technical support.(1)By analyzing the reason of water invasion and seepage flow during cementing and combining with the actual working conditions in underground,a set of cementing water invasion simulation experiment device was developed.This device can simulate cementing slurry in water In addition,the cementing quality and channeling pressure at the second interface of cementing can be measured by measuring the water intrusion,so as to evaluate the water resistance of the cement microstructure and evaluate the water resistance of the cement slurry system Ability to provide a reliable technical means,the device is currently applying for invention patents.(2)The effects of water intrusion on the second interface cementing strength and channeling pressure under different water invasion pressures and different negative pressure difference occurs were simulated by water intrusion simulation experiment device.Combined with the results of environmental scanning electron microscope and X-ray diffractometer.The influence of water intrusion on the microstructure and composition of cement stone was analyzed.The results show that water invasion affects the composition and microstructure of cement stone on the second interface of cementing,And channeling pressure drop important reason.(3)Aiming at the shortcomings of static simulation of water intrusion simulation experiment device,long experimental time and low experimental efficiency,it is not conducive to the rapid evaluation of microstructure strength of cement slurry system against water invasion.A rapid evaluation device of water resistance against invasion of cement microstructure.The device can simulate the erosion of cement slurry by formation water on the second interface of cementing through the perturbation of rotating water flow on cement slurry and can be quickly characterized by measuring the rotational speed of water flow when the microstructure of cement slurry is destroyed to evaluate the anti-water intrusion ability,which will provide a new theoretical support and technical means to improve the adjustment of well cementing slurry formulation adjustment and optimization work efficiency.(4)By optimizing the water intrusion resistant materials and evaluating the water resistance of the materials,it is found that the material X3 solution has the strongest resistance to water intrusion and the engineering performance test of the X3 solution in the slurry of different dosage is preferable,Suitable dosage.Finally,the anti-water intrusion ability of the cement slurry was evaluated by evaluating the water invasion resistance of cement slurry and the water invasion simulation experimental device.The addition of X3 solution to the cement slurry system can significantly improve the water resistance of the cement slurry system.Finally,we successfully developed a set of anti-water intrusion cementing slurry systems that are suitable for well cementing.