La Creciente is a 27,468 hectare block located in the northwest of Colombia, in the Lower Magdalena Valley Basin. Pacific Rubiales holds a 100% participating interest in this E&P contract, awarded by the ANH to Pacific Stratus on August 19, 2004.
During the last quarter of 2006 the LCA-1 well was drilled, resulting in a significant natural gas discovery at prospect A. The production tests yielded an absolute open flow (AOF) of 230 MMcf/d.
Geology
The natural gas structures are represented by faulted blocks which have been defined using 2D and 3D seismic data. Major faults run NW-SE and combined with transverse NE-SW trending faults form the structural styles of the La Creciente area.
The sandstones of the Cienaga de Oro are the main reservoir and consist of a series of superimposed deltaic – shore – shelf deposits distributed irregularly across the area. This irregular distribution of the sandstones compartmentalizes the reservoir along the structural highs. The compartments of the gasiferous sandstones are noticeably evident in the amplitude extraction of the seismic data.
The exploratory plays are similar to that proven on the Ayombe – Guepaje gas field to the northeast of the block. The main play characteristics are:
- Oligocene to Miocene extensional faulted blocks with four-way structural closures involving the Cienaga de Oro Formation.
- Faulted domes and subtle anticlines to the southeast of the block.
- The main source rocks are the Porquero and Cienaga de Oro shales with Kerogen types II and III.
Activities in 2007
As part of the program to define the discovery of the natural gas field, two appraisal wells were drilled during 2007 at Prospect A. The LCA-2 well yielded non-conclusive results and was suspended. The LCA-3 well proved to be successful and was completed as a producer well. In order to understand the drastic stratigraphic changes observed in the LCA-2 well, 140 km2 of 3D seismic and 70 km of 2D seismic were processed and interpreted on prospect A and on prospects D and C, respectively. This information was reprocessed using the latest gas reservoir identification technology such as WEA (Wavelet Energy Absorption), AVO (Amplitude Vs Offset) and pre-stack depth migration (PSDM). Based on the information gathered from the reprocessing and its geological interpretation, prospects C, D, and B were redefined, and new prospects E, F, G, H, I, DW and J1 to J3 were identified.
Also during 2007, an exploratory well was drilled on prospect D, to a total depth of 11,450' (Measured Depth), resulting in another commercial natural gas discovery in the upper sands of the Cienaga de Oro Formation. The production tests yielded a production of 17.85 MMcf/d with a 1/2" choke. With the completion of this well, the company completed the fourth and final exploration phase of its E&P contract, one year ahead of schedule.
Expenditures
In 2007, $71.3 million was spent by Pacific Stratus at La Creciente. These expenditures included the drilling of two appraisal wells at prospect A and the beginning of a third (LCA-4); the drilling of an exploratory well at prospect D, and the acquisition of 2D and 3D seismic. It also included the construction in record time of the surface facilities for the handling and delivery of up to 60 MMcf/d and 10 km of pipeline from the field to the Guepaje-Corozal gas pipeline.
