Pacific Rubiales Touts 'Exploratory Success' in CPE-6 Block

Pacific Rubiales announced new exploratory success at its Guairuro-2 well, located in the CPE-6 Block, Llanos Basin, Colombia. This well is the second stratigraphic well drilled in the CPE-6 Block and is the second of six wells to be drilled in the block during 2010, pursuant to the Company's minimum exploration commitment.

Ronald Pantin, CEO of the Company commented, "This second successful well in this block paves the way to a region that has shown to be very prospective and that holds the key to potentially large discoveries in the Los Llanos Basin."

The Guairuro-2 stratigraphic well, more than 4 km southeast of Guairuro-1, reached a total depth of 3,309 feet measured depth (MD) or 2,297 feet true vertical depth below sea level (TVDSS), finding the top of the C7 interval of the Carbonera Formation at 3,112 feet MD or 2,300 feet TVDSS, the top of the basal sandstones at 3,196 feet measured depth (MD) or 2,384 feet TVDSS, and the top of the Paleozoic Basement at 3,246 feet MD or 2,434 feet TVDSS.

The well was drilled with a 6 1/8" slim design and was continuously cored along the main exploratory objectives, the Carbonera C7 interval and the Basal Sandstones, obtaining a core recovery of 153 feet (75.4%) for a total cored section of 203 feet. The Company is now preparing the well to perform pressure tests on 42 levels and five fluid samples from C-7 to the Basal Sandstones. The resulting data will be used to complete the geological evaluation of the C7 interval and the Basal Sandstones (Mirador Formation).

The petrophysical analysis of the well indicates a net pay zone of 31.5 feet with porosities varying from 25% to 30%. The well showed two differentiated oil bearing intervals: from 3,080 feet MD, or 2,268 feet TVDSS, to 3,131 feet MD, or 2,319 TVDSS; and from 3,163 feet MD, or 2,351 feet TVDSS, to 3,220 feet MD, or 2,406 feet TVDSS, for a total gross oil column of 81,5 feet at the well.

Like the Guairuro-1 well, the Guairuro-2 showed oil-impregnated cores in all sands from Carbonera C-7 down to 3,223 feet MD within the Basal Sandstone unit. However, in the Guairuro-2, the sands at top of the C-7 interval showed a net pay zone up to 14 feet. The results of Guairuro-2 confirmed the extension of oil bearing sandstones in Mirador Formation and in the C-7 Unit of Carbonera Formation 4.3 km to the south of Guairuro-1 well and 7 km to the east of the area where the SM-5 and Los Kioskos wells were drilled. The findings of the Guairuro-2 well. along with wells Guairuro-1, Los Kioskos-1, Manacacias-1, Manacacias-2 and SM-5, confirm the presence of a stratigraphic trap for the Guairuro prospect, that can extend further south and consequently be much larger than was previously assumed.

Stratigraphic Play

In the eastern and Southeastern Llanos Basin, the Basal Paleogene clastics play includes all pools and prospects hosted in sandstones of the Eocene Mirador Formation to the Oligocene-Early Miocene Carbonera Formation. In the northern reaches of the CPE-6 Block, the main plays occur within continental basal sandstones deposited transgressively on the post-Cretaceous foredeep unconformity, and within fluvial to shoreline sandy deposits.

The stratigraphic play that the Company is investigating is related to the sandstones of Early Paleogene age deposited in the apex of a incised valley and that is geographically located in the north part of the CPE-6 Block. The geometry of this incised valley is quite irregular and its dimensions are enormous. The incision extends 30 to 40 km to the south of the north boundary of the CPE-6 Block and 25 to 30 km wide in its middle part. The 6 wells drilled till now (Manacacias-1 & 2, Los Kioskos, SM-5 and Guairuro 1 & 2), are all located in the deepest and thickest part of this incised valley and notwithstanding the fact that the Company has not identified any structural closure, all these wells exhibit hydrocarbon bearing sandstones with thicknesses from 20 to 40 feet, thereby substantiating the stratigraphic character of the hydrocarbons accumulations.

In the CPE-6 Block area, complex geological relationships created a variety of stratigraphic traps where petroleum accumulations can occur in: a) the basal fluvial Mirador Formation along channelized incisions capping the Paleozoic units located below the unconformity, and sealed with localized transgressive shale units; b) onlaps and up-dip pinch-outs of the Mirador Formation against the underlying unconformity and capped by the basal shale C-8 unit of the Carbonera Formation; c) onlaps and up-dip pinch-outs of the C-7 unit of the Carbonera Formation against the underlying unconformity or Mirador Formation and capped by the basal shales of the C-6 unit of the same formation; and d) up-dip truncation of the basal units below converging unconformities capped by marine shales of overlying sequences. Since the Mirador-Lower Carbonera sequence were deposited in a transgressive cycle (retrograding clastic facies), these assemblages of stratigraphic traps could repeat up-dip in a shingled fashion making a broader stratigraphic trap that can cover a much larger acreage. The fact that, from the 31.5 feet of hydrocarbon-bearing sandstones that the Guairuro-2 well exhibits, almost half are within the overlying C-7 sandstones, is an indicator of either connections across faults from the basal fluvial-sandstones to the coastal sandstones of C-7, or the "touch-down" of prograding and downlapping parasequences of Carbonera C-7 on top of the basal Mirador sandstones. In any case, what is important is that the C-7 sandstones, at the location of the Guairuro-2 well, may be taking over the basal sandstones on their role of carrier beds for hydrocarbon and may have become the units that might serve as the conduit for the advance of the hydrocarbons more to the south of the basin and consequently extending the stratigraphic trap to the southern reaches of the incised valley.

Despite the fact that exploration for hydrocarbons in this part of the basin is still in its earliest stages, the Company firmly believes that the type of stratigraphic play traps explained above dominates this part of the Llanos Basin for unconventional heavy oil accumulations. The Company is therefore confident that there is great potential for resources yet to be discovered and will be redirecting its stratigraphic drilling campaign in its pursuit.

The CPE-6 Block is a Technical Evaluation Agreement (TEA) awarded to the Company in 2008 by the Colombian National Hydrocarbon Agency (ANH), in which Meta Petroleum Ltd. (a wholly-owned subsidiary of the Company) is the operator and holds a 50% working interest; Talisman Energy Inc. holds the remaining 50%.


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