I.1. CASE 1: DIADEMA OILFIELD (ARGENTINA)

The study began in January 2006 when 740 GBq of HTO was injected into well I-103, 750 kg of ammonium thiocyanate into well I-124 and 40 L of uranine into well I-125, all of the wells belonging to the Diadema oilfield in the province of Chubut, Argentina. The patterns involved in the operation can be seen in Fig. 52.

The response curves are shown in Fig. 53 where the tracer concentrations are represented in a relative way (activity and mass). The ordinate scale is logarithmic.

О и із

Jgf of

G-119 G-116 G-141

©

G-122

© G-110

FIG. 52. Well pattern in the Diadema oilfield.

The tracers are moving mainly to the south, as can be seen in Fig. 54, where only those wells with a recovery mass or activity of more than 1% are reported.

Breakthrough times were in the range of 48-72 d for HTO, 11-34 d for ammonium thiocyanate and 8-83 d for uranine. Tracer recovery ranged around 0.2-10% for HTO, 15-48% for ammonium thiocyanate and 0.1-50% for uranine for those wells in which tracer was detected.