Padre Island, a long flat land mass stretched along the coast of south Texas, offers an exciting mix of low-cost, low-risk shallow plays and high-impact deep plays, according to Golden Gate Petroleum.
The company is already grossing about 2 million cubic feet of gas and 21 barrels of oil per day from its share of the shallow field developments. But what has the company excited is the potential of its deep plays.
“We have begun drilling high-impact, deep prospects and are close to restarting development of the lower risk, shallow prospects,” Golden Gate executive chairman Sam Russotti said.
“Many of the deeper targets have reserves potential in the 100Bcf-plus range, and with good 3D seismic, and very little deep drilling having been done so far on the island there are plenty of targets to choose from.”
One such target, Plum Deep, has a 2P reserves estimate of 293Bcf with upside potential of 952Bcf.
The onshore Gulf of Mexico explorer said wireline logging has interpreted four potentially gas-bearing zones over a 1000-foot (304.8m) interval in its Kindee ST 212-1 well there.
As operator, the company said it was planning to undertake a testing program to determine the commerciality of each of these zones intersected in the target Plum Deep Prospect.
The well is being sidetracked to enable the cutting of cores in the prospective zones followed by an open hole flow test. Golden Gate said once all the cores have been cut and logs and samples collected, a production liner will be run.
The cores will be subjected to detailed petrophysical and mechanical analysis and the information gathered used to construct a fracture stimulation program that has the “optimum” chances of success, it said.
Golden Gate, which has a 37.5% stake in Kindee ST212-1, said so far, the results have been in-line with its pre-drill expectations.
But whether or not the well is a commercial success, Russotti is confident that a big payoff will some come as six major deep exploration targets have been confirmed with each offering the potential for significant additional reserves and early cash flow.
“The deeper targets along the Gulf Coast have barely been touched – deep drilling will become a lot more important in the region,” he said.
Three Australian juniors that agree with this assessment have begun a deep drilling campaign near the city of Corpus Christi, which lies opposite the northern tip of Padre Island on the other side of Laguna Madre.
On the outskirts of the city is a complex of old giant gas fields named Flour Bluff. The West Flour Bluff field is onshore adjacent to the local Naval Airbase, while East Flour Bluff lies under the waters of the lagoon and Pita Island lies further offshore.
These fields have seen more than 1.3 trillion cubic feet of production from reservoirs at depths shallower than 2400m, but significant reserves remain in between 2700m and 3600m depth.
The field’s developers – private US firm Texas Crude Energy and Australian juniors Victoria Petroleum, Sun Resources and Aurora Oil & Gas – have already drilled several wells with mixed results.
Two potential producing sands proved to be unviable: gas was present in targeted reservoirs but the reservoirs were depressurised to produce. And while the potential of the mid-deep Frio J and upper K sands was proved in both the East and West Flour Bluff fields, the wells delivered poor production performance on initial reservoir completions.
These reservoirs have been shown to be capable of production at rates of 2 to 5 million cubic feet per day. But the well bores are ridged and over-gauge due to formation caving into the borehole, leading to poor cement bonding, casing problems and water migration into hydrocarbon-bearing reservoirs.
But the partners now believe that they and the operator understand the field well enough to be confident of solid results from a new drilling program expected to start in late January.
Victoria Petroleum managing director John Kopcheff said the joint venture was looking to target new sands that had not yet produced at the project and emphasised that Flour Bluff still offered up to 210bcf of potential recoverable gas reserves.
Meanwhile, First Australian Resources is targeting the intra-coastal waterways of south Louisiana.
Working the bayous can be tricky, but FAR likes the region, according to managing director Michael Evans.
“The intracoastal waterways are prolific with hydrocarbons – the geology is identical to the continental shelf of the Gulf of Mexico,” he said.
“But it is more expensive than drilling on land and there is a long lead time to get rigs.”
Drilling in this area is done from barge rigs, which can operate in water 1.5 to 6.5m deep. The barges have to be towed through the intracoastal canals. Then they must be ‘propwashed’ into location – tugboats use their outboards to clear silt so that the barges have adequate clearance.
But the rewards outweigh the logistical problems, and FAR has built a solid base in the bayou country.
“We have a high success rate in Louisiana, but at Lake Long, working with our partners Kriti Exploration and Palace Exploration, we have had a 100% success rate in drilling six wells off barge rigs,” Evans said.
