This page contains a Flash digital edition of a book.
Exploration • Drilling • Field Services


formations. Using 2-BE it was shown that quick and clean resolution of the emulsion occurred. Te new environmental replacement chemistry for 2-BE exhibited the same ability to resolve the emulsion and also contributed to preventing the emulsion from forming in the first place.


10 20 30 40 50 60 70 80 90


0 1 10 100 Days on Production


Fig. 1. Well performance after application of fracture treatments using 2-BE and without using 2-BE.


Te advantage shown by the new chemistry was faster resolution of the emulsion. From this testing it was concluded that a 10 per cent solution of the new replacement chemistry for 2-BE in water could be used to replace the current 2-BE based spearhead. Core flood work proved that when using a mutual solvent pre-flush of the new, environmentally- acceptable chemistry, superior permeability regain was demonstrated compared to a VES system. Field data was gathered from dozens of fracture


treatments on wells that used a 2-BE pre-flush, along with wells that did not use any mutual solvent in the pre-flush. Te gas rates from these two sets of wells were averaged and this data is plotted in Fig. 1. A clear product benefit can be seen when 2-BE was


100 150 200 250 300


50 0 0 20 40 60 80 100 Days on Production


Fig. 2. Well performance after application of fracture treatments using the environmentally acceptabkle mutual solvent compared with 2-BE.


120 140 Env. Acceptable Alternative Average 2-Butoxyethanol Average 1000 10000


Conclusions An environmentally-acceptable replacement chemistry for 2-BE has been identified, tested and


field proven. Te conclusions are: ● Using toxicity, biodegradation and bioaccumulation as the key environmental performance indicators, the alternative chemistry has a superior environmental profile when compared to 2-BE.


● Bottle tests performed in the laboratory show the alternate chemistry to have greater mutual solvency efficacy when compared to 2-BE.


● Core flood experiments showed a greater regain to permeability when using mutual solvent when compared to no mutual solvent.


● Field data summarised from multiple applications showed that production flowback performance of wells where no mutual solvent was applied was half that of wells pre-flushed with 2-BE.


● Field data shows that when the new environmentally-acceptable alternate mutual solvent was applied, the production benefit over that of wells pre-flushed with 2-BE was an incremental 40 per cent. ●


Enter 18 or ✔ at www.engineerlive.com/iog REFERENCES:


Harris O, Wilbur S, George J, and Eisenmann C (1998) Toxicological Profile For 2-Butoxyethanol And 2-Butoxyethanol Acetate. US Department of Health and Human Services Public Health Service Agency for Toxic Substances amd Disease Registry.


Jonathan J Wylde is UK Business Manager, Clariant Oil Services, Dyce, Aberdeen, UK. www.oil.clariant.com 18 www.engineerlive.com With mutual solvent preflush Without Mutual Solvent Preflush


used as a pre-flush additive due to a faster clean-up from the fracture treatment and quicker return to full production. Te cumulative production benefit when using 2-BE after 1000 days of the treatments was over double. Wells without mutual solvent produced 4414 e3


m3 (156 MMscf) while wells that did use mutual solvent produced 9048 e3


(320 MMscf) over the same time period. Fig. 2 shows field data comparing wells


fractured using 2-BE as a pre-flush additive compared to wells fractured with the alternate, environmentally-acceptable chemistry. An even further production benefit was realized when using the environmentally-acceptable chemistry. Te total production for 145 days of wells fractured with 2-BE was 11,287 e3


m3 m3 (399 MMscf) and for wells


that used the environmentally-acceptable alternative was 16,217 e3


(573 MMscf), an increase of approximately 40 per cent. m3


Gas Production (e3


m3


/day)


Gas Production (e3


m3


/day)


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74