Study Of Fractrue Technics For Lava Layer In Daqing Explore Field

Daqing deep volcanic gas reservoir have to be big～frac treatment to producecommercially composition only for it's deeply buried(3500～4500m), hightemperature(130～180℃) and dense structure. Because of Lava layer maturecavern fissure, multiple fractures is ruptured and extended when at reformtreatment. There are three obvious characters: multiple pumps stopping, muchfriction resistance, high leaking-off which add to the fracturing difficulties, so faras to operation failures. Backward in fracturing technique comes to be abottleneck of prospecting and exploitation deep gas reservoir.In this thesis, focus on the fact of Daqing oil field peripheral layer thathaving nature fractures and multi fractures after fracturing, research leaking～offfactor and relevant pressure condition. Therefore, it can chart the pressure fall-offcurves and derivate graphs by establishing the analysis model of fractured tightlayer pressure fall-off curves and utilizing G function. Proceed to the next step;make sure the natural fracture's development degree, open pressure, closepressure and other fracturing parameters. At the same time, an effective methodwill be obtained when pressure fell off. On the basis of this type of reservoiropen fractures mechanism and leaking-off diagnosis achievements, fracturingdesign can be optimized by analyzing in-situ stress section and researching theopen of natural fractures. In the aspect of worksite operation, there are threecharacteristics value of standard fracturing detection parameter interpretation:near well deviation coefficient; pump stopping gradient; leaking-off factor whichaffect the effects of fracturing treatment. Considering the facts of layer differencesuch as near well bore multi fractures; high friction resistance; small differenceof storage separation; micro fracture leaking-off; hole leaking-off and so on. Acalculation for pure pressure with unerring precision and real time fracturing fluid efficiency is invented. A on site operation control technology on worksiteabout dropping filter; septal occluding; altering flow rate and sand rate control isacquired.Because of utilizing of technology supporting measures, the unfavorablefactors of early screen-out of stimulation has been settled satisfactory. Successrate of fracturing has improved from 36.0％in 2002 to 90.9％right now. Thereform scale of single layer is 65 m~3 in average and 116.5m~3 in maximum at 92operation times for 86wells since 2002. The big-frac treatment seldom all overthe world is operated successfully. In these fracturing, there are 14 layers in 13wells have more than 20.0×10~4m~3/d output since fractured. Xu deep 1,Weideep 5 and Xu deep 6 achieve million m~3 of undamped flow rate. It brings ahistorical breakthrough in deliverability of fractured well. This techniqueprovides a technology support for exploiting 100 billions m~3 high qualitiesdiscovered reserve on DaQing oil field.