Reseach On Chemical-adaptive Temporary-plugging And Diverting Acid Technology In Water-injecting Wells From Chaoyanggou Oil-field

The permeability of Chaoyanggou oil-field, which is a typically hererogeneous oil-field,ranges from few mD to hundreds mD. For prolonged waterflood development, heterogeneitynear water-injecting wells is becoming critical, causing that most water comes into highpermeability zones, less into low permeability zones. In order to improve water injectingprofile, many measures could be made, such as acidification. In conventional acid treatment,most fluid flows into channels with least resistance, where there is maximum injectingcapacity. And then the permeability in less damage zones becomes higher, but the lowpermeability zones which adversely need to be improved, cannot be teated. Heterogeneity ismore obvious, not reaching satisfying effects of acid treatment.Temporary plugging and diverting acid technology is researched to solve the problemsabove, to acidulate low permeability layer. That is, temporary plugging agent is injectedbefore or together with acid. This agent would block off high permeability zones firstly,diverting most follow-up acid into low permeability zones, and then this acid acidulate lowpermeability layer. At last, this agent is dissolved, and has no effect on the high permeabilitylayer, achieving the aim to acidulate reservoir evenly, improving the sweep efficiency of waterand the degree of producing reservoir.In laboratory experiment, assess the solubility in water and acid of three kinds ofmade-up temporary plugging agent from field. Develop formula of new temporary agent,whose size could be adjusted, which has super dispersibility, long suspending time, and highsolubility in water. Develop formula of blocking remover and additives which are applicableto Chaoyanggou oil-field. And then assess compatibility of these two formulae above. At last,assess temporary-plugging and fluid-diverting ability of these four kinds of temporaryplugging agent through indoor core simulation experiment. As the experimental result of thenew temporary agent, plugging rate is38.67%, plugging removal rate is110.34%, andrecovery rate is104.00%in low permeability layer, to the contrary in high permeability layer,plugging rate is90.26%, plugging removal rate is84.65%, and recovery rate is86.15%. Sothe agent developed in this paper can divert fluid well, being applicable to acid treatment.Form the chemical-adaptive temporary-plugging and diverting acid technology, applicable toChaoyanggou oil field. Solve the problem of poor producing in low permeability zones,especially in seriously heterogeneous reservoir.