In the near-term, the main business opportunities for Russians may come in the Sakhalin IV lease round area, around the West Schmidt peninsula. There, Arco signed an agreement with Rosneft and SMNG to explore the Astrakhanovskoye structure, northwest of the island in Sakhalin Bay. Arco shot 3D seismic in 1999 and plans to drill one well this year. This is a five-year exploration permit.
Otherwise, the 1995 Sakhalin IV round was unsuccessful, with only Exxon making a serious bid (which was rejected). According to Paul Nixon, Vice President of Texaco Exploration Sakhalin, his company could operate a consortium interested in the acreage, were the lease to be re-tabled. Two potential structures have been mapped in the southern sector, estimated to contain up to 3.3 tcf of gas and 750 million bbl of oil. Nixon also reviewed prospects for other unawarded tracts in his presentation:
- Sakhalin V: This parcel is adjacent to Sakhalin IV. Several large structures have been identified in the south of this acreage, lying north of and on trend with Odoptu and Piltun-Astok. Some attractive features have also been mapped in the undrilled Derugin Basin to the northeast, where Russian geologists estimate reserves potential of 4-8 billion bbl. BP has signed a joint study and bidding agreement with Rosneft/SMNG and may emerge as a bidder for Sakhalin V, Nixon suggested. Other interested parties include ARCO, Elf and Exxon, which have bought seismic data relating to the Schmidt region
- Sakhalin VI: This area is an elongated tract off the island's east coast dipping south from the Kirinskiy block and terminating at Cape Terpeniya. It is located in Pogranichniy Basin, where the Russians put recoverable reserves at a possible 8-12 billion bbl. Large seismically defined structures include the Kerosinskaya and Bogatinskaya anticlines. One dry hole has been drilled, Borisovskaya-1.
A report co-issued by the Department on the Development of Natural Resources Offshore Sakhalin, the Committee for Natural Resources of Sakhalin Oblast, and Dalmorneftegeofizika Trust, also makes observations on three other yet-to-be awarded permit areas:
- Sakhalin VII: This area is southeast of the island. Recoverable reserves here are put at 230 mtoe. East Aniva structural-stratigraphic traps have direct indicators of hydrocarbon accumulations, including typical seismic and geochemical anomalies which may comprise up to 60 bcm and 80 bcm of gas, respectively.
- Sakhalin VIII; Sakhalin IX: The areas are located to the west and south of the island, and may respectively contain 80 mtoe and 120 mtoe. Seismic coverage is thin, but what there is, indicates structural traps with sand resevoirs in Verkhnedui, Kurasi and the lower part of the Maruyam formations. There are also structural-stratigraphic and stratigraphic traps in zones of regional pinching out of the Verkhnedui and Kurasi formations.
However, tenders for these lease areas could be some way off, said Nixon, given Russia's record so far in delaying lease rounds.
As for the areas explored to date, he wrote, "In general, most of the structures identified within the open acreage lie outboard of the contemporaneous paleo-Amur delta front. Many of the prospects probably lie within relatively deeper water depositional systems outboard of the mapped shelf edge(s). Successful exploration here will rely heavily on accurate prediction of the reservoir distribution within these depositional systems and, where present, careful calibration of potential hydrocarbon indicators."
Nixon's presentation concluded: "In offshore Sakhalinellipse all offshore wells to date have targeted the lower Miocene Daginskiy and/or the upper Miocene Nutovskiy reservoirs in large Pliocene anticlines, many of these structures exhibiting excellent direct hydrocarbon indicators.
"It is almost certain that the next structural style to be tested will be older, large Miocene structural drapes over Cretaceous highs. Only when then infrastructure, including pipelines, export terminals and supply bases have been developed, will the basin mature and exploration commence for the higher risk, more subtle traps."
