During drilling and production operations, referred to as the “upstream” phase of the oil and natural gas industry, water is often found in the same formations as the oil and gas being extracted. This produced water constitutes a significant volume of the produced fluid and has previously been considered as a waste product. Increasingly, however, with local water scarcity and the costs associated with transport, disposal and re-injection, produced water has become a salvageable potable commodity that can be reused to enhance operating economics. Environmental standards, both onshore and offshore, generally dictate the necessary treatment of produced water in order to be discharged or injected back into the formation.
Produced water properties vary widely and contain multiple contaminants that have to be dealt with for reuse, re-injection, or compliant disposal. The fluids contain residual hydrocarbons and high concentrations of suspended solids, organic materials, sulfides, iron, bacteria, silica, boron, and dissolved salts that may cause problems if not addressed.
To facilitate production from onshore shale formations using horizontal drilling techniques, large volumes of wate are injeced under high pressure to fracture the non-porous shale formation. Hydraulic fracturing can utilize as much as 1.2M barrels of water per well. The frac fluid can be a mix of previously-used water, produced water, potable water or groundwater. Once the well is put into production a massive volume of frac fluid flows back to the surface and may be treated for reuse or reinjection or hauled away for disposal.
|Feed Sample||Thincell® 73 gpm||Removal Efficiency||Thincell® 100 gpm||Removal Efficiency|
|Turbidity – NTU||360||0.5||99.8%||1.2||99.7%|
|Total Suspended Solids (TSS) – mg/l||200||<1||99.5%||<1||99.5%|
|Feed Sample||Treated Water PW4||Removal Efficiency|
|Sodium – mg/l||6800||6700|
|Turbidity – NTU||34||5||85.3%|
|Total Suspended Solids (TSS) – mg/l||180||15||91.7%|
|Silica – (mg/l)||24||3||87.5%|
|Feed Sample Nasty #0||Treated Water Nasty #5||Removal Efficiency||Treated Water Nasty #8||Removal Efficiency|
|Sodium – mg/l||2400||2400||2400|
|Turbidity – NTU||31||44||5||83.9%|
|Total Suspended Solids (TSS) – mg/l||185||105||43.2%||18||90.3%|
|Silica – (mg/l)||9.1||4.3||52.7%||0.9||90.1%|
|Feed Sample||Treated Water||Removal Efficiency|
|Turbidity – NTU||370||4.6||98.8%|
|Total Suspended Solids (TSS) – mg/l||7.9||0.5||93.7%|
|Silica – (mg/l)||40||7||82.5%|
Emulsified produced water stabilized with residual polymer and suspended solids leaving oil/water separator.
Emulsified produced water, iron, and suspended solids after oil/water separation.