The Lons le Saunier applied permit area of 3795 km2, which was granted in July 2007, is centred on the township of Lons le Saunier, situated adjacent to the French-Swiss border.
The Jura Basin is potentially a substantial hydrocarbon province. The permit area covers the central part of the northeast - southwest oriented Basin which is approximately 250km in length with the width varying between 30 and 60 km.
Within the permit area, historical drilling and seismic work mainly completed from the 1950’s through 1980’s has demonstrated that the area contains significant hydrocarbon potential split into three target groups; CBM, conventional gas and conventional oil.
Coal Bed Methane Potential
The Jura Basin overlies a large Carboniferous age sub basin which hosts a substantial tonnage of gassy coal. Previous coal exploration drilling totaled 29 wells for approximately 31,000 metres was completed in the vicinity of the town of Lons le Saunier. An in-situ tonnage of 370 million tonnes of coal over a central area of 32 km2 was estimated by Charbonnages de France.
The lateral extent of the coal measures is undefined, however at Bresse some 70 km south west of Lons le Saunier, an oil exploration well intersected what is believed to be the southern extension of the coal measures. The maximum net coal thickness at Lons le Saunier is approximately 29.1 metres while at Bresse, a net coal thickness of 15 metres has been intersected. To the north and east the coal measures extent has not been defined.
Conventional Gas Potential
The Stephanien coal measures are considered as one of the principal source rocks of the migrated hydrocarbons found in the overlying Middle Triassic sediments.
In addition to the coal exploration wells, the coal measures and the overlying sedimentary sequence have been identified by conventional oil and gas exploration wells as far south as the town of Bresse.
The largest conventional gas field within the permit is located approximately 30 km north east of the township of Lons le Saunier. Five wells were completed at Valempoulières with the Valempoulières-3 well, producing 83.7 million cubic metres (Mm3) or 2.96 billion cubic feet (Bcf) of gas from with initial production of 100,000m3 per day (3.5 million cubic feet). The reservoir was from 860 metres depth and hosted in a five metre thick dolomite unit. The area is considered highly prospective for further discoveries with little exploration work having been completed since the initial discovery in 1961.
Conventional Oil Potential
The presence of oil within the permit area was first encountered in the Lettenkohle and Muschelkalk sediments in the straitigraphic well Reviny in 1943. A further oil occurrence was encountered by the Briod 1 well in the mid 1950’s with further appraisal drilling in the 1980’s however it was never commercialised. The Briod oil zone is between 25 metres and 30 metres thick and located within the fractured dolomite units of the Lettenkohle formation. This is a high priority target for development activities.
|
