Central Petroleum: drilling of a 700m horizontal wellbore the next step at Surprise 1

Central Petroleum (ASX:CTP) is now planning to conduct a horizontal wellbore test of the Lower Stairway Sandstone in its Surprise-1 well in the Amadeus Basin following the recent positive results from the interpretation of electric logs, cuttings sampling, gas chromatography and coring.

Results indicate a possible gross oil column in the Lower Stairway Sandstone of up to about 17 metres, with permeabilities ranging up to 420 Millidarcys measured in a 9 metre cored zone.

Managing director John Heugh commented, “Movable oil has yet to be proved but the company is optimistic and believes that a horizontal wellbore offers the best possible chance for oil flow to surface by accessing a much longer sandstone section than is possible via a vertical wellbore.”

Smaller hydrocarbon zones up to 1 metre in the Middle Stairway Sandstone and up to 2 metres in the Top Pacoota Sandstone have also been interpreted.

The presence of hydrocarbons and elevated organic material in sections of the Horn Valley Siltstone has also been interpreted and samples taken will be studied for unconventional shale oil/gas potential.

Only the hydrocarbon zones in the Lower Stairway and the Middle Stairway are thought to have flow potential using conventional production techniques.

The Surprise ST-1 well has reached a total depth of 2,732 metres within the Pacoota Sandstone in an 8.5 inch hole size.


Forward Plans

Central will complete a seismic check shot survey over the section from surface to total depth before running 7 inch casing.

The next step will be to mill a window in the casing above the Middle Stairway Sandstone before directionally drilling a 6 inch sidetrack to intersect and drill a horizontal wellbore of up to about 700 metres through the interpreted Lower Stairway oil column.

The horizontal drilling and testing program is expected to begin late this week.


Share Purchase Plan

As a result of the timing of the Surprise-1 operations, Central is considering a further extension of its share purchase plan to eligible shareholders to raise A$5.5 million.

The share purchase plan is currently due to close on 16 December 2011.

Eligible shareholders can purchase shares to a value of $2,500, $5,000, $7,500, $10,000 or $15,000, at an 18% discount to the average closing price of shares in the five days prior to the announcement of the share purchase plan on 15 September 2011.

Originally published at: http://www.proactiveinvestors.com.au/companies/news/23336/central-petroleum-drilling-of-a-700m-horizontal-wellbore-the-next-step-at-surprise-1-23336.html