Taribani Field Unit

The Taribani Field is a large over-pressured oil field covering an area of approximately 80 km2 with productive horizons situated in Miocene and Pliocene age reservoirs that have been deposited in fluvio-deltaic to nearshore marine environments. Reservoir and regional mapping, along with extensive surface geological work undertaken by the Company indicate that the reservoir facies are well developed and, in some cases, their permeability is enhanced by fracture systems associated with regional strike-slip faulting that is found throughout the Upper Kura Basin. These reservoirs are situated at depths of between 2,200 m and 3,500 m.

The Taribani Field was penetrated by forty-one wells during the Soviet era, drilled between 1962 and 1981 and all clustered in the down-dip portion of the field. The Taribani Field has to date produced a total of approximately 550,000 barrels of oil from eight of the forty-one wells. Oil taken by Frontera from the Taribani Field has been tested and found to be 36 degree API with a low sulphur content (0.23 per cent). Frontera believes that the limited production was due to poor historic drilling and completion practices, and a policy decision taken by the government authorities in the 1970s to focus on the development of the Samgori Field, located close to Block 12. Frontera believes that significant reserves from the Taribani Field are commercially recoverable by utilising conventional technologies, and drilling and completion methods. Since acquiring its interest in Block 12 in 1997, Frontera has undertaken detailed field and operational studies at the Taribani Field in order to determine how to bring the field into commercial production.

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Specifically, Frontera has:

  • completed the acquisition, processing and interpretation of a new 3D seismic survey covering 150 km2;
  • digitised and integrated all historical well logs from the Taribani Field;
  • created new time and depth structure maps, as well as new associated sand isopach maps, for twelve productive reservoirs;
  • conducted static and dynamic reservoir engineering studies;
  • conducted fracture and well-bore-hole stability analysis;
  • performed new geologic field work that has enabled the integration of surface observations into the subsurface areas of the Taribani Field; and
  • completed new reservoir engineering studies.

In addition to the geological, geophysical and reservoir engineering studies, many of the existing wells were re-entered and checked for casing integrity, mechanical problems and obstructions, with the intention of using them for future workover or sidetrack operations. Workovers were attempted in seven of these wells with limited success due to the previous Soviet era drilling practices that resulted in skin damage to the well-bores. Detailed core pressure analysis was conducted to prepare for future new well-bore design, mud and completion programmes. Detailed analysis was also undertaken which suggests that the drilling of short radius lateral/horizontal wells are likely to be the key to accessing undamaged portions of the reservoir away from existing well-bores.

Furthermore, in 2000 Frontera drilled, tested and completed the Niko #1 well at the Taribani Field. This well was the first post-Soviet era well drilled into the field using modern drilling practices and provided results that confirmed the effectiveness of modern drilling applications. Specifically, the well provided much needed subsurface information that permitted the Company to calibrate field-wide well logs to conventional core and the reservoirs. It gave critical understanding regarding the fluid properties from the field and established an understanding of the field's depletion drive mechanism.

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Niko #1 also provided important velocity information with which to tie the subsurface information to the 3D seismic survey. This information established that most of the structural potential of the field exists west and approximately 200 metres up-dip of the Niko #1 location. Finally, the results from the well established the deeper  marine intervals (Zones 18 to 25) as being hydrocarbon bearing with the ability to flow at commercial rates. The well flowed at a peak rate of 960 bpd, producing 5,345 barrels during its forty day production test. However, production was suspended as a result of sediment flow believed to be from the open hole and from behind the casing due to a poor cement job and a failed lower packer. Frontera plans to re-enter Niko #1 to drill and complete a horizontal well as part of its planned near term work programme.

Based on its experience with previous production operations, Frontera expects that the previously encountered issues related to the challenges of sediment flow at Niko #1 and other wells in the field can be managed and overcome. Since the completion of drilling and testing operations at the Dino #2 well in August 2006, Frontera has undertaken detailed analysis of the extensive coring, logging and production data obtained from the well, in order to customize new well-completion designs for future wells and prioritize plans for developing four target reservoir horizons; Zones 9, 14, 15, 19. These new engineering designs apply industry-standard solutions to the specific reservoir properties of the Taribani Field, in order to overcome sediment obstruction in future wells and ensure sustainable flow from the field's reservoirs.  Specifically, Frontera plans to implement both horizontal drilling completions and vertical well frac-pac completions in its future drilling plans.

Based on analysis of Zone 9 reservoir data, a new well-completion design for this horizon has been engineered in order to control possible sediment flow during production operations. Analysis of data obtained during coring and logging operations of the Dino #2 well not only revealed a fractured reservoir, but also demonstrated that this reservoir's rock properties are particularly well suited for the artificial inducement of fractures to further enhance permeability. As a result, Frontera has evolved its development well design for Zone 9 from drilling short-reach horizontal wells to conventional vertical wells with the addition of frac-pack completions. These completions will consist of artificially inducing extensive additional fracturing in the reservoir from vertical wells. Sediment control will come from applying packing technology whereby screens are installed and gravel is pumped into the well as a slurry, "packing" it behind the screen at the formation face. The gravel and screen are designed to trap the reservoir formation sediment before it can enter the well and cause obstruction.

In the deeper Zone 14, 15 and 19 objectives of the Taribani Field, analysis has shown that horizontal well completions are likely best suited for these different reservoir types with the application of completion techniques that will likely utilize expandable liners and screens, together with other fit-for-purpose applications, in order to control sediment flow.

To see a schematic of our plans for frac-pac completion at Taribani Field, click here.

To see a schematic of our plans for drilling horizontal wells at Taribani Field, click here.

In addition to the historical subsurface work at the Taribani Field, Frontera also upgraded and installed new production and storage facilities in anticipation of future drilling in the field. Associated railway loading facilities were upgraded at the nearby town of Dedopliskaro (approximately 27 kilometres from the Taribani Field) in anticipation of future production.

2007 Work Program

Based on Frontera's work in the Taribani Field, twelve productive horizons have been identified for potential exploitation and development. Frontera's near term strategy is to focus on establishing commercial production from four of these twelve horizons, beginning with Zone 9. Click here to see a stratigraphic column of the productive intervals at Taribani Field.

Frontera has chosen to initially focus on developing Zone 9 as a consequence of 2006 drilling operations at the Dino #2 in which the well encountered 21 meters of gross pay sands in Zone 9. As expected, the Pliocene age oil-bearing reservoir interval, Zone 9, was encountered from 2,300 meters to 2,311 meters. In addition, a previously unmapped oil bearing reservoir interval was encountered above Zone 9 from 2,275 meters to 2,285 meters. Historically, twelve wells had evidence of oil when perforated in Zone 9, with the best well, #23, exceeding 700 BOPD during initial production. Drilling operations for 2007 are focused on three wells in order to commence development of the Zone 9 horizon in the Taribani Field. The three wells scheduled for operations in 2007 are the Dino #2 (workover/recompletion), T-#45 and Taribani South #1. Click here to see a cross-section of the Taribani Field and Zone 9. 

The Company believes that it can produce approximately 118 million barrels of reserves from Zones 9, 14, 15 and 19 at commercial rates. These reserves have been independently evaluated by Netherland Sewell & Associates Inc. and have been classified as possible (P3) gross (8/8ths) reserves. Netherland Sewell & Associates Inc. has indicated that, provided Frontera can demonstrate the successful application of currently planned conventional horizontal drilling and completion techniques, a significant portion of the P3 reserves in the Taribani Field could be recategorised as probable (P2) reserves and a small portion of the P3 reserves could be recategorised as proved (P1) reserves.

Plans are also underway to continue the assessment of the other eight horizons in the field. Frontera believes that these other horizons will define additional significant recoverable reserves within the field. In addition, the western portion of the field is believed to contain significant potential that has yet to be exploited. No oil-water contacts have been found in the Taribani Field, which indicates that the field limits have yet to be fully determined.

Click here to see a photo gallery of 2005-2007 work program operations

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