Design And Application Of Staged Fracturing Tool For Horizontal Wells In Tight Gas Reservoirs

Sulige gas field is a typical lithologic gas reservoir,of which reservoir distribution is dominated by distribution of sand body and properties.Due to poor physical property and low natural production,reservoir fracturing improvement is strongly required for the field production.Staged fracturing in horizontal wells plays a key role in well stimulation for low pressure,low porosity and low permeability wells in Sulige gas field.To ensure the stimulation effect of staged fracturing,it is especially essential to develop a set of fracturing tools and accompanying tools which are applicable to reservoir characteristics and production requirements of Sulige gas field.This article discusses key achievements via structural design and lab test of isolation packer,sliding sleeve and other downhole fracturing tools.First of all,the hanger packer developed is with advantages of easy-to-set,high bearing pressure,high anchorage load and reliable hydraulic and mechanic releasing system.Secondly,the expandable openhole isolation packer worked out is easy to run and can bear high pressure.The isolation effect is obvious.Thirdly,the ball sliding sleeve and differential pressure sliding sleeve open smoothly in field application.Obvious pressure change indicates sleeve open and pressure is stable.The sleeve keeps in open position after fracturing operation.Fourthly,the low density ball has various properties such as high temperature resistance,high bearing pressure,impact resistance and abrasion resistance.Fifthly,by optimizing horizontal well fracturing tool strings,the single trip multi-stage fracturing string is developed with reasonable structure,stable performance of accompanying tools,handy operation and high operating success ratio.Lastly,staged fracturing tool string and accompanying tools based on 4-¹/₂”base pipe for both gas well and oil well have has been developed.An 8 staged fracturing had been applied successfully in well Su 76-2-8H with this single trip multi-stage fractruing string.It effectively enhances single well productivity.The tools have been spreaded and applied in other 65 wells.The success rate is 100%and effectiveness is 100%in field operation.It shows the reliability of developed tools and significant production enhancement.Achieve large-scale application.As a result,this fracturing tools has good value for extension and large-scale application.