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Production Asset of the Month

Steam food screening from the Petroleum Engineering Handbook 23

Table 15.1—SEOR Project screening criteria Pilot

Reference Ref. 18 Ref. 19 Ref. 20 Ref. 21 Ref. 22

Depth, ft <3000<2500<3000 >20 >400 2700' h

Net thickness, , ft >20 >30>30 >20>10 30’–75’ f

Porosity, >0.2>0.3>0.3 >0.2 0.34

S

Oil saturation, >0.5 >0.4 0.82 o x >0.1 0.15–0.22 >0.0>0.08 0.28 f S o

Oil gravity, API 10–34 8 –40 12–15<25<36 13°–21° k

Permeability, , md >250>1000>1000 3,500 fooding or cyclic steam injection, known µ,

Oil Viscosity, cp <15,000200–1000<1000 >20 100–1900 as the Huff and Puff method, have been hk/ µ, /

Transmissibility, md-ft cp>5>50 >84 onshore.

Initial pressure, psia <1500 1228

Few, to date have tried to take the

Pattern size, acre <10 = 5 technology offshore, with the com- 18. Hayes, H.J. et al. 1984. Enhanced Oil Recovery. Washington, DC: National Petroleum Council, Industry and Advisory to the U.S.

Department of the Interior.

mon assumption being that the density 19. Iyoho, A.W. 1978. Selecting Enhanced Oil Recovery Processes. World Oil (November): 61.

of wells required and the heat loss as 20. Ali, S.M.F. 1974. Current Status of Steam Injection As a Heavy Oil Recovery Method. J Can Pet Technol 13 (1). PETSOC-74-01-06. injected steam travels down the well into 21. Venkatesh, E.S., Venkatesh, V.E., and Menzie, D.E. 1998. PDS Data Base Aids Selection of EOR Method. Oil & Gas J. 82 (23): 63-66.

22. Chu, C. 1985. State-of-the-Art Review of Steam?ood Field Projects. J Pet Technol 37 (10): 1887-1902. SPE-11733-PA. reservoirs would be too great. 23. Donaldson, A.B. and Donaldson, J.E. 1997. Dimensional Analysis of the Criteria for Steam Injection. Presented at the SPE Western

However, a UK company is now

Regional Meeting, Long Beach, California, 25-27 June 1997. SPE-38303-MS.

proposing to use steam food for a feld

Source: The Steam Oil Production Co.

in the UK North Sea, which, if success- ful, could pave the way to develop other he says. “Chevron predicts 50-80% Brown says. The frm expected they similar felds in the basin. [recovery factor using steam food]. Based wouldn’t get better than 50% steam qual- on modelling, we are looking at around ity, by the time it reached the reservoir,

A Pilot reservoir 60%, achieving about 150 MMbbl from 90% quality, 1500psi

The Steam Oil Production Co. has production from Pilot.” steam injected at the surface. its eyes on the Pilot feld, in Promote But, after winning the license

Not so deep concerns

License P2244 in Blocks 21/27a and and undertaking heat loss

One of the key criteria for a 28/2a in the central North Sea, also con- modeling using a CMG Stars steam food project is depth. taining the Pilot South and Harbour (both simulator, they received some

If a reservoir is too shallow, it discovered by Fina in 1989 in excellent welcome results. could result in steam blowouts, quality and permeability Tay Sandstone “The results were surpris- but if it is too deep, heat loss in reservoir) felds and the Pilot Southeast ing,” says Greg Harding, the

Steve Brown the well will reduce the quality prospect. The license has been appraised frm’s technical director. “We of the steam too much. Going by Fina, Venture Production and then were only losing 5% of steam too deep will also, in combination with

EnQuest. quality in the model. We thought there the steam, push the limits of comple-

Together, the three discovered felds must be some mistake, so we looked tion components, Brown says. As a contain 272 MMbbl proven plus prob- around for other information on heat result, typically, the depth limit is given able oil in place at 12-18°API and 160- loss and realized a key factor is the rate at around 3000ft, sometimes a little 900cp reservoir viscosity, and around at which steam is injected. Because the deeper, he says. 3.5-6 Darcies permeability, according temperature of the steam is set by pres- to Steam Oil. But, while a horizontal “At 3000ft, typically the reservoir is sure, that keeps it constant. So you get a appraisal well in the most viscous region at 1300psi,” Brown says. “At broadly consistent loss of heat, fowed at just under 2000 b/d from a that pressure the steam tem- regardless of the rate you are 600-700m-long well, the recovery factor, perature will be about 300°C injecting down the well.” with long horizontal wells and water or 600°F. There are a range of The key to injecting at a injection, would be about 13%, leading components available at that high rate, and an enabler for to an uneconomic project. temperature, but you have to be this technology offshore, is

Steam Oil thinks better rates could be very careful about selection. If being able to drill high density achieved using steam food. The com- you go to 5000ft, we are talking horizontal wells, Brown says. pany was set up in early 2014, aiming to 340°C and you start to run out On Pilot, you would need 400

Greg Harding initiate the frst offshore steam food in of completion components.” conventional wells. Using long

Europe. But, there is some hope here, horizontal wells, 100m apart,

Steam Oil founder and CEO Stephen as the industry has been developing com- with alternating injection and production

Brown says steam injection in the North ponents for use on steam assisted gravity wells, you need 40, he says. “Those two

Sea actually isn’t as unfeasible as it might drainage (SAGD) wells in Alberta and for things opened up this possibility.” sound. geothermal wells.

Shopping for kit “What attracted us to steam food was “When we frst applied for the license

The Steam Oil Production Co. has the potential for higher recovery factors,” we expected depth to be a big issue,” oedigital.com December 2015 | OE 43 042_OE1215_ProdOps1_EOR.indd 43 11/20/15 5:43 PM