The Development And Application Research Of Oxidative Cross-linking Curing Agent For Asphaltic Heavy Oil

Sinopec was disturbed by Bitumen risk at Kazhdumi strata during the well drillingprocess in Iran Yada Oilfield. The bitumen driven into the wellbore might lead to stickingeven ending the drilling. Several technical measures which would prevent or dispose thebitumen risk presented by the field engineers turned out unsatisfied. Study on the curingtechnology and exploit a good quality curing agent of heavy oil which can block bitumenreservoir pore, prevent the bitumen driven into the wellbore and cut the source of drillingfluid pollution was one of the effective measures to control the bitumen risk fundamentally.In this paper, the basic properties of Iran heavy oil were firstly measured and then thesimulation oil was determined in which the optimal curing agents were screened out byevaluation of softening point. Next, the optimal conditions were obtained and inspected anda series of evaluations were conducted for the optimal curing agents. Finally, the field testwas carried out in Iran Yada Oilfield F17well and good curing effect was achieved.YHJ-5,YHJ-7and YHJ-8which have better curing effect were screened out byevaluation of softening point and the softening point of heavy oil increased20-40℃aftercuring. The curing effect would be better when YHJ-5accounted for20%of heavy oil, thereaction temperature was120℃and the reaction time was4h or at110℃,4h and YHJ-8accounted for20%of heavy oil in the heavy oil-oxidant system. Also the curing effectwould be improved when additives joined even at the condition of less curing agent dosageand within a shorter reaction time. The curing effect of YHJ-5was not so good for its quickdecomposition while YHJ-8still kept good performance in the alkaline drilling fluidenvironment. With a strong acidity, YHJ-8aqueous solution should not be used in stratawhile YHJ-5and YHJ-7who had a weaker acidity might be ok for their little corrosion to the rock of strata. However, YHJ-5and YHJ-7had varying degrees of corrosion to drillingtools. In general, YHJ-5had more serious corrosion in liquid phase while the gas phasecorrosion was more serious for YHJ-7. The curing effect would be good at120℃,4h,5MPaand YHJ-7accounted for20%of heavy oil. It would be better with additives and pluggingslurry joined and the softening point of heavy oil increased65℃after curing. The adhesionrate of cured heavy oil was less than10%. It was able to meet the demand of less than5%inthe drilling fluid system. The cured heavy oil had a certain strength which had acompressive strength of1.85MPa with a softening point of121℃.The field test was carriedout in F17well and the bitumen curing agent accounted for20%of solidifying slurry.Thepolluted fluid decreased from1.88m3/h to0.36m3/h and the gas logging abnormal valuereduced from1.28min/h to0.66min/h after curing. The returned bitumen appearedagglomeration phenomenon.Good curing effect was achieved when the new technology ofbitumen curing applied in F17well for the first time.