Rubiales and Quifa fields are the major oilfield in Colombia; two heavy oil reservoirs (API in the range 11.3° to 14.4°) with unconsolidated sandstone formation with high permeability, however, there is low productivity in vertical and deviated wells, caused by formation damage from drilling fluids, and cased gravel packing completion.

These two formation damages have been mitigated by applying a successful gravel packing technique in both vertical and deviated wells. On June 30, 2014, the oil production rate was 186 thousand BOPD, of which 14.5 thousand BOPD (7%) came from 162 vertical and deviated wells with the successful gravel packing technique.

The successful gravel packing technique consists on first running a standard cemented 7 inches casing and then cutting the casing in the production zone and enlarge the open hole section from 8.5 inches to 13 or 16 inches diameter to remove cement bond overpassing the washout. Finally, the enlarged open hole section is gravel packed with mesh 20-40.

The completion technology purpose is to increase the well productivity, isolating high water saturation intervals on both top and bottom of the oil zone, reducing the skin damage.

Before 2007, 30 wells were completed with conventional cased hole gravel packing. Most of these wells were damaged having to be frequently stimulated with organic treatment; 14 of these wells have been re-completed using gravel packing technique. The results show an increase in the productivity index from 2 to 5 times, compared to conventional completion and showing a maximum increase in total fluid rate from 600 BFPD to 3000 BFPD.

Finally, some examples are presented comparing gravel packing using this technique and the cased hole completion method. Operation procedures, advantages, limitations, and production results are presented in individual well performance comparisons. The successful application of this technology has contributed to increase oil production in Rubiales and Quifa fields development and it has also been extended to others analogues fields.

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