Research And Application Of Low Damaged Fracturing Fluid System In Chanqing Oil And Gas Field

The Changqing gas ifeld reservoir properties have characteristics as strong heterogeneity, lowformation pressure. As well II, well III increase gradually, the active major conventional guar gumfractuirng fluid shows low flowback rate, large formation damage. And the well production raisedififcult atfer fracturing. A new guar gum thickener is developed with a certain anti-swellingproperties, reduce interfacial tension capacity in low concentration. Form a new guar gumfracturing fluid system with the cross-linking agent and other additives with low pressure damagecrack, which can be adapted to Changqing gas field.Use guar gum as raw mateiral, C^H33Br as hydrophobic reagent to prepare hydrophobicassociation guar gum. With the apparent viscosity of the hydrophobic modified guar glue solutionas the evaluation index, optimal dosage of NaOH, dosage of hydrophobic monomer CI6H’”Br，reaction temperature and reaction time on the process conditions. The expeirmental results showedthat the optimal expeirmental conditions as follows: the molar ratio of NaOH, CibHB.^r, Guargum is0.506:0,05:1? the reaction temperature is60BC, reaction time is8h. The modified guargum solution has a substantial increase in stability, anti-bacteiral properties have also beenimproved greatly. The guar gum has been modified by orthogonal experiment on the use ofsemi-dry carboxymethyl process. The optimal experimental conditions as follows: reactiontemperature80reaction time4h, the ratio of sodium chloroacetate and guar gum is0-6:1，andat pH ofS. The modified guar gum has less residue, and good water solubility.Explored the water treatment of guar gum fractuirng fluid, the expeirmental results show that:the ZnCh as a catalyst and the H7O2with dosage1%(mass fraction30%) make the COD value ofwater samples from the oirginal55894.4mg/L drop to5395.8mg f L, and achieved good results.Developed a new guar gum fractuirng fluid system for ifeld applications, the surface-active guargum fractuirng fluid system showed a low interfacial tension table without adding cleanup additive, clay stabilizers，fungicides and other additives, which also have a low interfacial tensiontable, good anti-swelling, corrosion resistance, temperature resistance, anti-shear, fast brokenplastic and other properties, signiifcantly reducing the fractuirng time and work intensity. In thefield test of28wells, the surface-active guar gum fractuirng fluid system showed stableperformance, and had a better oil and gas production.