Further Assessment Proposed For Pétrolia Bourque Project

Pétrolia Inc., the operator of the two horizontal wells drilled on the Bourque property in Quebec, says that it will propose to its partners, Ressources Québec and Tuliq Énergie, that they conduct further assessment of the project.

The Quebec City-based junior said that while it has established the presence of oil and gas in the Forillon formation, the reservoir is tight and will require some additional work to allow economic production.

Last year, the partners completed the re-entry and completion of Bourque No. 1 as well as the drilling of an additional well (Bourque HZ No. 3) on time and within the budget. At the time, downhole recorders were lowered in both wells in order to continue collecting pressure data (DOB, Dec. 29, 2016). The recorders were removed May 17, 2017.

Pétrolia said it will propose the following exploration program:

  • Resume the production test on the Bourque HZ No. 1 R1 well by using a swabbing unit to better quantify reservoir productivity, take a depth sample (PVT) and check the pressure regime;
  • Resume the production test of the Bourque HZ No. 3 well by using a swabbing unit;
  • Re-evaluate the resources by integrating the data of these two wells and 3D seismic data (reprocessed after the initial evaluation by Sproule Associates Ltd.); and,
  • Study the best options for stimulation and completion.

The down-hole recorders at the Bourque site were removed May 17, 2017 and data was transmitted to Petro Management which issued its final report June 19, 2017.

Bourque HZ No. 1 R1

After the recovery of the 181 cubic metres of fluids used during the completion, in the initial production period, gas flow to the surface from the Bourque No. 1 well declined to a flow too small to be measured from the initial 40,400 cubic metres per day. The flow consisted of wet gas in which 120 litres of light oil (43, 57 ° API) was recovered. The well was then closed for a short period for pressure build-up.

Prior to installation of the down-hole recorders, a static pressure gradient survey was performed (with the well closed at the surface) after a 27-hour period of closure and a 2,620 kPa wellhead pressure. The survey showed that the base of the production tubing contained light oil (0.70 kilograms per litre) from the measured depth of 1,625 metres  located near the entrance of the horizontal drain to the measured depth of 1,471 metres (1,439 metres total vertical depth). Pétrolia said this suggests an oil vertical column of 66 metres. The oil column was topped by low pressure wet gas.

After a 24-hour period of closure and a rise of wellhead pressure to 3,128 kPa, the well was put into production on a 6.25 mm (1/4 inch) choke valve for a period of eight hours. During the test period, the gas flow to the surface reached 5,080 cubic metres per day, subsequently decreasing to 1,180 cubic metres per day at the end of the test period.

The well was subsequently left closed for a final pressure buildup with the two down-hole recorders until May 17th, 2017 (3,740 hours). During the recovery of the down-hole recorders, a static pressure gradient survey was performed (with the well closed at the surface). This survey indicated that the production casing was filled with light oil (0.72 kg/l) to a measured depth of 693 metres (686 metres TVD), which corresponds to an oil vertical column of 819 metres. The oil column was topped by low pressure wet gas.

The presence of an oil column that moved up in the tubing to 686 metres TVD indicates that the Forillon formation from Bourque HZ No. 1 R1 is a reservoir containing light oil and associated gas but a  specific depth sampling procedure is required to define if it is light oil or gas condensate, said Pétrolia.

The analysis of the pressure buildup data reveals that the initial reservoir pressure was 9,065 kPa and at the end of the closure period was 8,823 kPa.

A diagnostic derivative analysis of the log-log plot-flow regime identification has been performed on the pressure build-up data and a good match was obtained by applying a horizontal well in a dual porosity reservoir model. The shape of the derivative suggests that the Bourque HZ No. 1 R1 reservoir is formed of mainly tight carbonate-naturally fractured formation-and consists of matrix blocks feeding open fissures, said the company.

Bourque HZ No. 3

More than 88.3 cubic metres of fluid was injected in the Pétrolia Bourque HZ No. 3 well during cleanup operations and 54.4 cubic metres of fluid has been recovered in storage tanks.

On the final day, a one-hour production test with a 6.25 millimetre (1/4 inch) choke valve produced flammable gas with an initial flow of 860 cubic metres per day, decreasing to a flow too small to be measured. After this production period, two recorders were installed down-hole. The presence of a gas/fluid interface was detected at about 935 metres. The well was then closed for a final pressure buildup until May 17, 2017 (representing 3,580 hours).

During the pull out of down-hole recorders, a static pressure survey was performed (with the well closed at the surface). The survey shows that the production tubing is filled with water (1.06 kg/l) up to the measured depth of 536 metres which corresponds to a water vertical column of 762 metre.

The water column is surmounted with non-pressurized gas. Taking into account the open horizontal drain and the water column in the casing, the total volume is estimated at 34.5 cubic metres, which corresponds to the remaining water/brine in the well at the end of the stimulation test. The analysis of pressure buildup data reveals that the initial reservoir pressure of the Bourque HZ No. 3 well is around 8,234 kPa.