|
BP: More miscible injectant not economic Company tells AOGCC separation equipment required to produce more MI for enhanced oil recovery without loss of natural gas liquids Kristen Nelson Petroleum News
The Alaska Oil and Gas Conservation Commission has been investigating whether maximizing production of natural gas liquids for shipment down the trans-Alaska oil pipeline, which the commission ordered in Conservation Order 360 in the mid 1990s, is in conflict with the production of miscible injectant, used for enhanced oil production.
Following a 2012 hearing on Prudhoe Bay propane, held after Harold Heinze questioned whether there was waste because propane was not being produced for sale, the commission found that propane was not being wasted, but it understood BP witnesses at that hearing to say that more miscible injectant, MI, was needed and it has been investigating that issue.
One premise of CO 360 was that there was adequate MI for enhanced oil recovery opportunities at the field.
At a Jan. 7 public hearing on the issue, Bruce Laughlin, BP’s Alaska North Slope reservoir management team leader, said in response to a question from commission Chair Cathy Foerster that if BP had more MI there would be opportunities to use it. But, he said, to generate more MI without the loss of natural gas liquids, NGLs, currently sold and shipped with the oil, would require installation of an additional low temperature separator, which he said would be “a very expensive project” and so far it hasn’t been economic. Laughlin said BP can’t justify sacrificing available NGLs to manufacture more MI and while that could change due to new technology or additional opportunities that become available in the future, it wasn’t currently economic.
The 600 million cubic feet plan Foerster asked about a requirement of CO 360 that the Prudhoe Bay operators — at that time BP and ARCO each operated half of the field — report to the commission by Dec. 15, 1995, on plans to provide an annual average volume of 600 million cubic feet per day of MI by the start of 1999.
The order required that if that volume of MI was not available, the operator should present information “to show whether operation of the pool with a lesser availability of MI would be in accordance with good oil field engineering practices and otherwise avoids waste or whether” and if the given implementation date was not practical, what date would be, she said.
Foerster said the commission has checked its files and can’t find the report.
Jeff Leppo, an attorney representing BP at the hearing, told the commission it would take BP some time to respond to the question about the report. He said the company thinks it might have as many as a thousand boxes of materials related to the MI-NGL issues.
More patterns On the issue of volumes of MI and area of coverage, Laughlin said the 1994 field development plan for Prudhoe anticipated that 4 trillion cubic feet of gas would be injected by the end of the Prudhoe Bay miscible gas project in some 200 patterns in the reservoir and the recovery of some 400 million barrels of oil. To date, he told the commission, roughly 3 tcf of gas has been injected not only into Prudhoe miscible gas projects but into all of the surrounding Prudhoe oil field pool. The target, he said, is injection of some 3.9 tcf of MI, touching 320 patterns and recovering more than 450 million barrels.
Foerster asked if there would have been greater recovery had the 600 million cubic feet per day of MI been achieved.
Referring to the CO 360 testimony, Laughlin said the goal then was 420 million to 450 million barrels of recovery and 200 patterns targeted for enhanced oil recovery, while to date 271 patterns have received MI and recovery is projected at more than 450 million barrels.
Forster also asked if BP has revisited the issue of maximizing NGLs vs. maximizing MI and Laughlin said BP looked at it on a regular basis, prompting Foerster to ask for specifics on when those kinds of studies had been done and what the studies indicated.
| 