Research On Intelligent Layered Water Injection Method And Process

Most oil fields in China have entered the stage of high or even ultra-high water cut development.At present,there are serious interlayer contradictions in the oilfield development process,resulting in poor reservoir extraction conditions and high dispersion of remaining oil,making it difficult to tap the potential of remaining oil.Fine water injection is required for each reservoir to ensure the energy of the formation,improve reservoir utilization,and solve the problem of imbalanced injection and production.Although China’s oil fields have entered the stage of intelligent layered water injection,there are still difficult development challenges to overcome,mainly including the following two aspects.The first is insufficient understanding of the variation law of layered water injection flow rate,which leads to injection flow deviating from the target flow rate provided by the reservoir engineering,resulting in poor water injection accuracy,Low testing efficiency and high operating cost;The second issue is the poor stability of the underground equipment of intelligent water injection wells.The underground water injection environment is harsh,and the equipment needs to be frequently adjusted in a narrow space,high temperature and pressure environment for a long time.This can easily lead to the failure of regulating mechanisms such as water nozzles,which can lead to the phenomenon of "disconnection" of underground modules.The reliability of underground equipment cannot be guaranteed,and there is still a lot of work to be done in terms of technology.In response to the insufficient understanding of the flow rate variation law of stratified water injection and the inability to maintain the injection allocation plan for a long time,this article starts with establishing a flow rate variation law model and studies the stable law of flow rate under constant pressure water injection conditions.Under the unstable seepage conditions of infinite formations,based on the continuity equation of weakly compressible liquid unstable seepage,a constant pressure water injection is established as the boundary condition,and the equation is solved using the separation variable method.A layered injection flow rate variation model is established to predict the flow rate,which can predict the flow rate variation trend in advance and make corrections,achieving precise and stable water injection in water injection wells.At the same time,the influence of factors such as formation pressure,formation permeability,and flow coefficient on the stability of flow rate was studied,and the results can guide the on-site stratified flow allocation.In order to improve the reliability of underground equipment in intelligent water injection systems,this article starts from the perspective of optimizing the underground water injection system and uses the principle of water and electricity similarity to establish a parallel model of water injection wells.Through the analysis of fluid loss along the way and water nozzle pressure loss,a comprehensive parallel model of water injection wells is established,which can calculate flow rate,pressure and other numerical values,thus achieving the goal of optimizing underground equipment.And a new type of water injection control hardware system has been established through this model,which can achieve tasks such as remote control,multi-mode wellhead control,and high-precision underground control.In order to further improve the measurement and adjustment accuracy of the new water injection system,this article conducted error analysis on the pressure sensor used in the control system,and found that the sensor cannot meet the requirements of high-precision measurement in practical applications.In order to improve accuracy,this article conducts research on current pressure compensation methods and calibration data processing methods,summarizes compensation methods suitable for oilfield control systems,and completes pressure calibration experiments using high-precision pressure calibration devices.Through analysis,it is found that the accuracy of the sensor can reach 0.05% FS.Based on the theoretical research and hardware system design mentioned above,in order to achieve intelligent and integrated design of the control system,this article ultimately designed a testing software to interact with the hardware control system.The software can also achieve functions such as pressure gauge calibration and characteristic curve drawing,improving the efficiency and accuracy of the oilfield testing and debugging system.