Study On Chelate Acidification Of Chang 8 Reservoir In Jiyuan Oilfield

Jiyuan Oilfield is located in the middle of the Ordos Basin,and the Chang 8 member sandstone is a typical low porosity,low permeability to low porosity and low permeability reservoir.The mineralization degree of the reservoir and the content of calcium and magnesium ions are higher,and the mineral acid content of the reservoir is larger.In the process of conventional soil acidification and deodorization,due to the rapid reaction of acid and reservoir minerals in conventional soil acidification system,the effective distance of acid solution is short,and it is easy to form a series of insolub-le precipitates after reaction with reservoir minerals Material,causing new damage to the reservoir,resulting in reduced or even negative effect of acidification.In this paper,based on the study of various acid systems,a new type of sandstone reservoir acidification solution and chelate acid acid system was proposed.Chelate is a special function that relies on a chelating agent that has a good ability to prevent or reduce secondary sedimentation to reduce secondary damage to the new acidification system.In this paper,based on the laboratory experiment and theoretical analysis,this paper puts forward a simple and reliable method for the formation of chelating acid in the Jixuan Oilfield,which is based on the existing geological problems and development status of the reservoirs in the Chang 8 reservoir of Jiyuan Plateau.Acidification technology,including the efficient blocking of the chelate acidification mechanism,chelate acid acid system conventional performance evaluation,chelate acidification influencing factors and chelate acidification technology research.The paper mainly has done the following work:1)According to the data of Jiyuan Oilfield,the lithology and fluid characteristics of Chang 8reservoir in Jiyuan Oilfield are analyzed in depth,and the potential damage factors and sensitivity degree of reservoir are evaluated.2)This paper analyzes the damage range and damage degree of the target reservoir,studies the reservoir damage mechanism of the injection wells,analyzes the water and formation water properties by using the ion chromatograph,the particle size analyzer and the energy dispersive spectrometer,and analyzes the injection wells with the diffractometer and the environmental scanning electron microscope Type and composition,clear acidification blocking plug the target,and then designed to effectively plug the online single step acid system.3)The experiment and design of chelate acid acid system were carried out by acid experiment,corrosion experiment,determination of acid ion in residual acid and so on.The effect of "one" generation "three" was realized.4)Chewing acid acidification process design parameters,including the acid injection rate,acid concentration,injection acid concentration and other parameters of the calculation,optimize the injection of water and acid mixture ratio,clear the various parameters in different environments on the effect of acidification.5)According to the experimental results,a simple and reliable water injection chelate acidification technology.