Study On Dissolubility & Application Of Soluble Magnesium Alloy

In recent years,more and more attention has been paid to the development of unconventional energy sources,such as dense gas,dense oil and shale gas.Horizontal well fracturing technology is widely used,and drillable bridge plug,large diameter bridge plug as well as other equipment have been widely employed.However,requirement of the second drill to remove the plugs,which is highly time-,cost-and energy-consuming.Therefore,self-dissolving materials and relevant tools have been becoming the research hotspots.Soluble magnesium alloy(SMA)has low density,good mechanical properties,fast dissolution rate and easy processing performance,which make it useful raw material to fabricate special tools.Research on SMA is started early in Europe and America,and,thereby,a variety of types of soluble fracturing tools have been developed and used in commercial applications.Because of technological monopoly and high price against China,we have to study independent intellectual SMA tools by ourselves.Herein,the chemical composition,mechanical properties and dissolution rates of four types of SMA were tested.Then,one SMA is selected to simulate the dissolution process under production conditions on the basis of results obtained above and production parameters.With the dissolution result,application study of selected SMA is carried out.We successfully design a new SMA bridge plug of novel structure.Systematical evaluation has revealed that the bridge plug is of good bearing capacity and easy releasing operation.There is no significant displacement of the slip when the upper ring is being empty sealed.The anchor force of slip meets the design requirement,and the dissolution performance is good.All indexes reach the design requirement.The new bridge plug has the characteristics of strong versatility,good sealing effect,reliable structure during the service period,controlled dissolution speed,and large internal diameter.Its major technical indexes are not lower than corresponding import.Therefore,this bridge plug will help reduce the production cost,shorten completion job period,and improve safety during production.