Properties Investigation And Application Of Controllable Crosslinking HTGs For Heavy Oil Recovery

Steam breakthrough has a great negative influence on the development of steam flooding in heavy oil reservoirs.As a water shutoff agent,the gel have been widely applied in the field of oil water shutoff.However gel stability restricted their application,especially for steam channeling.The main content of this article is as follows:A novel organic crosslinker and polyacrylamide were synthesized by melamine,formaldehyde and acrylamide,which were characterized by using IR.Polyacrylamide was successfully prepared,and the molecular weight was measured by intrinsic viscosity method and characterized by IR.The effects of polymer concentration,cross-linker concentration,NaCl,temperature,and pH values on the gelation performance were studied in the gelation process.When the polymer concentration is 0.5wt%,the concentration of crosslinker is 80 oC,the crosslinking time 12 h,obtain the gel which strength stage is I,maximum temperature 120 oC.This kind of gel can adapt complex geological environment under well,it have good high temperature resistance,salt tolerance,good stability.This paper presented a high-temperature(200 oC)resistant polymer gel system formulated with partially hydrolyzed polyacrylamide(HPAM),JC-1 and JF-9 mixed crosslinkers.Rheological measurements indicated that the gelation process of the system could be divided into four successive steps: induction,first crosslinking with metal crosslinker,secondary crosslinking with organic crosslinker and stabilization.Effects of various parameters that affect the gelation time and gel strength including the polymer concentration,crosslinker concentration,salinity,pH and the gelation temperature were evaluated.Results showed that the gelation time decreased and gel strength increased with the component concentrations and gelation temperature.Gelant formulated with 0.5 wt% HPAM,0.1 wt% JC-1 and 0.9 wt% JF-9 and treated at 80 oC for 48 h showed sufficient gelation time(4 h),high rigidity(Sydansk code I)and good thermal stability(ageing at 200 oC for 30 days).Morphology observation by scanning electron microscopy(SEM)and atomic force microscopy(AFM)revealed that the gel had compact network microstructure.The thickness of crosslinking points was around 0.5~5.0 nm,and the net mesh width was about 2 ?m.This article has a layered structure of montmorillonite composite with polyacrylamide having good performance,get its complexes and study its gel material application in oil field.XRD and IR confirmed in this paper,the preparation of polymer is MMT/HPAM composites.And means were characterized by a series of gel material.The results show that the gel material has better high temperature performance.After heated 24 hours at 250 oC,it still remains perfect gel performance.Meanwhile,the gel material has good salt tolerance in 2.0 wt% salinity,gel performance will not be affected.Confirmed by SEM,the polymer is from sheet layers into a three-dimensional network structure of the cross-linked gel.Finally,a preliminary field test indicates that this gel technology is feasible in blocking steam breakthrough channeling and has the potential to enhance heavy oil production.The gel system can be stable for 8 month,and increased 1000 tons of oil.