G. Alan Petzet
Exploration Editor
Quebec is the site of key Cambro-Ordovician wildcatting and lower gas drilling.
A group of companies is below 7,000 ft at 1 St. Simon, a wildcat in the St. Lawrence Lowlands basin projected to Cambrian Potsdam sand at about 13,800 ft.
The drill site is on part of the ancient Cambro-Ordovician coastline from Newfoundland through Quebec and the eastern U.S. to West Texas (Fig. 1).
Bow Valley Industries Ltd. is operator of the well on a prospect assembled by Exploration Terrenex Ltd. Calgary. The companies say the area south of the St. Lawrence River is a depositional and structural look-alike to Wilburton deep field in the Arkoma basin of eastern Oklahoma, where the gas productive Ordovician carbonate is the Arbuckle.
The main objective of the Bow Valley-Terrenex wildcat is gas in Ordovician Beekmantown dolomite below thrust sheets.
Meanwhile, Exploration Intermont Inc., Montreal, will seek shallower gas on several prospects.
It expects to start in mid-February at eastern Canada's first horizontal drilling project, in vertically fractured Upper-Middle Utica and Lorraine shales.
GEOLOGIC SETTING
Almost all the 200 or so wells drilled in Quebec failed find reservoirs.
Most were drilled into the thrust complex; only a few tested the entire sedimentary sequence (Fig. 2).
"The question in Quebec is not one of source or structure. The problem is reservoir," said Dr. Michael C. Pick, Terrenex president and chief executive officer.
Both the Arkoma and Quebec plays are in autochthonous rocks below Taconic thrust sheets. The rocks were deposited in a low energy environment not conducive to porosity development, but the new well is in an area where karstification may have developed from meteoric water during a major fall in sea level in middle Ordovician time.
The major hydrocarbon deposits along the old shoreline are in the westerly directed embayments such as West Texas and the Arkoma basin, and the St. Lawrence Lowlands basin is such a westerly directed area.
Bow Valley said the well database and old and new seismic were integrated into a regional tectonic model that explains the historically discouraging results and shows the area's remaining prospectivity.
Terrenex holds about 1.8 million acres. Bow Valley will earn a 68% interest in the acreage, Amerada Hess Canada Ltd. 20%, and Intermont 5%.
INTERMONT ACTION
Separately, Intermont is interested in shallower gas production and underground storage ventures in the area, which is at the end of the gas pipeline from western Canada.
Using the Regent 6 rig, it plans to reenter one of four noncommercial wells the provincial energy company Soquip drilled in the 1970s on the Villeroy prospect. It plans to kick off at about 6,500 ft using Sperry Sun short radius technology and drill 1,100-1,500 ft at 90.
The low permeability shales sustained rates of only a few hundred thousand cubic feet of gas a day.
Soquip, which has trucked gas for years from nearby two well St. Flavien gas field, may start a similar operation at Villeroy. St. Flavien was the sole commercial result of an exploration program by Shell Canada Ltd. and Soquip in the late 1960s and early 1970s.
Intermont will move the rig, probably in mid-1992, to the St.-Laurent prospect to drill a 3,200 ft Beekmantown dolomite well in the Becancour industrial park across the river from Trois-Rivieres.
The St.-Laurent and partly submerged St.-Pierre prospects may be important as underground gas storage fields whether they produce or not, said Intermont Pres. Gilbert Beaudoin.
Gaz Metropolitain, Montreal, and Gaz de France, Paris, have developed a gas storage field at Pointe-du-Lac just southwest of Trois-Rivieres. The field produced commercially in 1962-76.
Quebec's industrial gas demand fluctuates greatly within each week as well as seasonally, and the provincial government pays avoided costs of purchased gas for development of storage.
Gas fields generally containing a few billion cubic ft of reserves can be economic because purchasers pay $9/Mcf or more for the gas. The main gas pipeline runs north of the river, with only smaller supply lines on the south bank.
Copyright 1992 Oil & Gas Journal. All Rights Reserved.
