Abstract

Daqing Oilfield is a continental deposit oilfield with multi-layers. It has entered a high water cut development stage, its tertiary infill wells mainly develop the formations with effective thickness less than 0.5m and a low permeability less than 0.05 Darcy, this kind of layers usually perform a low conductivity. Technically, this formation requires a better completion method. Being previously used on high permeability formation with small aperture and short penetration, the perforating bullet could not meet the completion requirement in such a low permeability formation. At present, new type of perforating bullets are being developed with aperture and penetration of 1.5 fold respectively, but its high perforating energy make a thicker compacted zone around the penetrated channel, this result in a low conductivity.

This paper discusses about this problem, by applying new completion methods to reduce the formation damage in low permeable reservoir. First, the negative pressure perforation method is applied to reduce the stemming; second, a compound high energy perforation method is applied to perform about 10cm length fissures which can penetrates the compacted zone around the channel thus increase the conductivity. Both of the two methods were applied combined on 166 tertiary infill wells in 2011, it increased a fluid productivity to 2.8t/d.m, it was 2.9 folds of the previous perforation. It effectively solved the problem of formation damage caused by deep penetration bullet to highly increase the fluid productivity in low permeable reservoir.

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