polymer profile modification

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Polymer Profile Modification

Romashkino Field RussiaMuhammad Noman Khan

[email protected]

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Romashkino Field Field in Tatarstan Russia (Top ten Largest Field in the world) (SPE105199) & (SPE 36212)

70 Km(44 miles)

Structural Height of 50- 60 m(167-197)

Reservoir Depth of 1600 -1800m (5200 to 5900ft)

Devonian Sandstones & Carbonate Rocks

K sandstone layers is 200 to 420mD.

Por is 18.8% to 20.4%.

So= 69.4% to 90.5%.

TATOLPETRO Company to perform Polymer modification treatments of water injectors in

order to produce additional oil.

Pi= 160 to 180 atm (16.2 to 18.2 Mpa).

(1975)Total volume of fluid injected in the program reached

of the total extracted fluid.

19331947 & 48

195419581963 1975

Oil Field Review Russia 2000

4L.L.LU ET AL. Scientific Research

6IOR 1995

7IOR 1995

8IOR 1995

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Representation of Romashkino reservoir

SPE 38464

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Reservoir Properties• The 25° API crude• Original formation pressure: 16.3 - 18.2 MPa; • Saturation pressure: 8.5 - 9.5 MPa; • Original gas-oil ratio: 40 - 65 m /t; • Oil density: 0.858 g/cm ; • Viscosity: 2.6 - 4.5 mPa.s; • Wax content: 3.2%; • Sulfur content: 1.3%; • Tr= 37.8 Centigrade• Original Water saturation : 17%- 21%, 19% in average;• Proven reservoirs of field are 421.22 oil layers are established• The D1 layer , the burial depth ranges from 1650 m to 1850 m.• OOIP= 45 X 10 8 tons• Large area, big formation dip , many oil layers, wide oil water

transition zone • Complicated sedimentary environment

L.L.LU ET AL. Scientific Research

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Divison of Oilfield Development Stages

• We divide the Romashkino oil field development stages in to four stages

a. (1952- 1969) : increasing oil production stageb. (1970-1975) : stable oil Production stagec. (1976-1992) : oil Production decline staged. (Since 1993) : decline slowed down L.L.LU ET AL. Scientific Research

ab

cd

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• Candidate Selection- selection of wells to be treated is performed historical , available reservoir and production data indicating low sweep efficiency

• Wells are gathered in clusters, individual injectivity is known with difficulty

• Treatment Design- treatments generally consist in injection per well of 20 tonnes of special HEC grade at the Conce: of 1% vol., representing 12000bbl.

• Collaboration b/w Total, Tatneft and Baker had designed the Special mobile injection unit

• Treatments last from two to 10 days, before water injection is resumed & after a one day shut-in period.

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Case Histories• Since 1992, by jan 1996, 134 injectors have been

treated with 2795 tonnes of the HHEC grade• Offset producers number 498• The additional oil amounts 4.6 millions bbl,

efficiency of 235 tonnes of oil per tonne of polymer (1650 bbl/t)

• The Treated wells are located at 4 regions of southeastern Romaskhino field

• End of 1992, 30 injectors were treated with 600 tonnes of HEC; 4 year later, the incremental oil is 1.9 millions bbl , eff: of 450 tonnes of oil per tonnes of polymer( 3150 bbl oil/t)

• Selected zone treated during first years of the project & gave results

SPE 36212 & IOR 1995

SPE 36212

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S-Romashkino Case• Zone is formed of 12 IN treated b/w Sep 1992 and july

1993. 35 offset producers are submitted to the influence of these water injection wells

• The perforated layers in these horizons are indicated in Table 1 & some injectivity data in table 2.

• The oil & water production ,WOR,and Cummulative oil (from Jan 1989 to jan 1996) as shown in figures.

• To convert 1 tonnes in to bbl, one has to x the figures by 7 (25 API oil is 0.9 tonne per 1 m cube or 6.3 bbl), 1 tonne of salty water will be estimated to 5 bbl(20% TDS)

• The HEC injection decrease of H20 production by a factor about 2 (from 8300 bwpd to 5000 bwpd), together with an increase of oil production by a factor about 3 (from 3000 bopd to 1000 bopd), decrease water cut by 16 points from 96% -83%.

Changes in fluids prod in jan 94, after 6 to 16 months following the first and last injector treatment, by jan 96 30 to 40 months later, the treatments are still efficient , & come back to base lines.

SPE 36212

FROM 2557 TONNES/TONNE FOR INJECTOR # 1723a to 1 tonne/tonne for # 1840a, about 3 years after the treatments the for S-R 721000 bbl and 398 tonnes of oil per tonne of polymer (2780bbl/t)

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• Injector 1933- the Inj well treated in sept 92, with 13000 bbl of HHEC at 5000mg/l

• Perforated at 5 layer 4 producer whivh are connected to 2, 3 or 4 of them.

• The evaluation for the 4 offset producers of the WOR as function of cumulative oil, 17 months were needed before decrease WOR, Jan 96 the efficiency of treatment terminated.

• WOR evaluation before treatment ( about 10,000 tonnes)

• The eff: is 913 tonnes of oil per tonne of polymer (6400 bbl/t)

SPE 36212

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• Producer # 1826d-the well influence of injector# 1723a, 6 producer

• The injector was treated in sep 92 with 18000bbl of HEC at 6000mg/l

• The 288600 bbl, eff: 2577tonnes of oil per tonnes of polymer (18000bbl/t).

• Increased oil production 2 months following treatment & x by factor 10 four mths later.

• The oil rate went from 2 bopd to 23 bopd, still constant 40 mths later

• The water went from 7 bwpd to less than 1 bwpd, water cut switched from 80% before treatment to 5% since jan 94 until now.

• Producer# 1719a- Jan 96 130850 bbl oil , eff: 1246 tonnes of oil per tonnes of polymer (8700 bb/t)

• Oil Prod increased after 2 mths, 16bopd to 233bopd sixteen mths later

• Water from 1500 to 1000 bwpd, from 99 to 81%SPE 36212

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v

SPE 38464

22IOR 1995

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Important aspects• The HEC increase viscosity when dissolved in more

salty water• When HEC injected it goes to high K. see figure ,

mechanism applied on additional oil obtained from producer #1719a

• Water stopped it will go to low k layer, this mechanism why produce in case of producer# 1826d

• By possible enhance of areal influence of other injectors close to offset producers

• Direct increase of injection rates of untreated injectors belonging to same cluster than treated one.

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Status of Romashkino field• For conductance of geologic and hydrodynamic

modelling we have determined the main principles• -structure by structure modelling of field• -uniform procedure principles for all being

modelled structures• -parallel modelling of main field elements-areas• Based on modelling active development by;• -drilling new wells, sidetracks, double wells,

horizontal wells• -Improvement of WF sytems• -Application of new methods on EOR & stimulationSPE 65190

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Russia Energy data base 2006

Current Status Of Romaskhino field

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• Review of water-control chemical technology• -cover board range of techniques• -organic, inorganic polymer/gels, cements, resins, foams,

emulsion, particulates, emulsion, micro org,infill drilling, pattern flow control horizontal wells

• -MC , the polymer needs to penetrates as far as to low K toto ensure the eff: of oil displacement due to increased viscosity of mobile agent , In PM , Polymer enters as less as to oil prod zones in order not to reduce any wanted oil production due to influx modif: of displacing agent(Water or gas)

• Organic polymers/ gels-can be naturally or synth: produced, natural polymers are biopolymers(xanthane, scleroglucan, curdlan, simusan, succinoglycan produced my micro organ:), cellulose, lignins, guar gums or starch.

• Polymers can be used by own or as gels reaction with cross-linkers

• The use of polymers alone for water control in producing wells isessentially linked to relative k modification technology.

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• The formation of gel with polymer , cross linker leads to increased mechanical , thermal stability, can control gelation reaction

• Crosslinkers are organic( eg: Phenol-aldehyde) inorganic( eg: metal ions)

• Introduce chelates with organic acids, which prevent precipitation of metal NaOH, limit loss of reactive metal through rock adsorption & delay the a reaction with polymer through rupture of metal/ ligand bond with temperatue.

• Cellulose drive; MC, CMC, HEC & CMHEC.

• Cellulose derivatives are reported to make gel with metals or organic cross-linkers

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• HEC used in Romaskhino field , Mw is 1 million, give higest viscosity of the HEC compounds

• This type of polymer is increased viscosity with salinity

• @ 100F, PH = 6.5, f, 20000cp in distilled water, 40000cp with Nacl

• The power granuometery goes from 175 to 425 um with around 60% in the 300 to 350 um range

• @ 100f , pH =6.5 & in 25% Nacl, 2 hrs are needed in bulk to reach constant viscosity , this time doubles at pH =5.

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• The con: of HEC depends

• -salinity of water• -T of water , formation• -injectiviy of treated well• -characteristics of the product• Water in which Hec mixed;• -formation water, waste water, river or lake

waters.• Very from well to another well,• -tonnage of HEC per well: 20 tons(10-30)• -duration of a treatment: 10 days(3-20)• -average q: 300 cube metre per day (180 -

720)

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Conclusion• HEC as profile modif: in Romashkino b/c low T, very

saline, multi-layered, fractured sandstone reservoir, exploited by water flooding for decades.

• Reaching high k zones, face plugging high conductivity fractures, plugs the matrix rocks

• High eff: since 1992, 134 inj . 494 prod,

• Oil amounts 4.6 millions bbl with eff: 240 tonnes of oil per tonne of polymer, the first well treated during first years crossponding to best candaiate for such treatments & gave significant higher eff:

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References1. Loppinet, A., Iakovlev, S., & Glenat, P. (1997, January). Five years of injection

of hydroxyethylcellulose: An ecological pure product for enhanced oil recovery in the field of Romashkino. In Offshore Europe. Society of Petroleum Engineers(38464)

2. Abdulmazitov, R. G., Blinov, A. F., Dikov, V. I., Ibatullin, R. R., Latifullin, F. M., & Khisamov, R. S. (2000, January). Reservoir modeling for giant Romashkino field (problems and solutions). In SPE European Petroleum Conference. Society of Petroleum Engineers( 65190)

3. Lu, Liuli, Zhibin Liu, Haohan Liu, and Yongqin Yan. "Study on Technical Measures of Romashkino Oil Field after Entering Ultra-High Water Cut Stage." Engineering 5, no. 07 (2013): 622.

4. Galeev, R. G., R. Kh Muslimov, R. N. Diyashev, and A. F. Blinov. "40 Years Experience of Romashkino Oil Field Development in Tatarstan: Improvements of Water Flooding." In IOR 1995-8th European Symposium on Improved Oil Recovery. 1995.

5. Glenat, P., Zaborowski, G., & Loppinet, A. (1996, January). Profile Modification in Water Injection Wells by Polymer Treatments. In Abu Dhabi International Petroleum Exhibition and Conference. Society of Petroleum Engineers.(36212)

6. Moussine, Kamil, Nail Gabdelbarievich Ibragimov, and Rais Khisamov. "The optimization of the gas-steam injection using numerical simulation." In SPE Middle East Oil and Gas Show and Conference. Society of Petroleum Engineers, (105199), 2007.

7. Seismicity in the oil Fiels, Report 2000, Schlumberger, VV Adushkin - 1976