Seun OlatubiGlobal Petroleum Research Institute (Texas A&M, University )IPEC , Nov 3-5, 2009, Houston, TexasE&P wastesOur objective (s)MethodologyResultsFuture WorkMiscellaneousThis study focused primarily on produced water andspent water based drilling fluids.Reliable forecasts show that continued exploitationof unconventional resources would dramaticallyincrease water based E&P production.Industry disposal and handling costs of water basedwastes are estimated to be about 50 billion dollarsyearly1Large VolumesLow amount of recycle and re-useWater is the new oil: increased competition forfreshwater sources and rising costsIncreased footprint“a typical drilling and completion operation in theMarcellus usesapproximately**4 million gallons of freshwater**; about 100,000 gallons areused for drilling and above 3 million gallons are used for completing astandard 5-10 stage lateral utilizing slick water fracture every 300ft. Inaddition after stimulation about**1.5 million gallons of flow back water**would require disposal”2Re-use aimed primarily for on-site use(s), andpreferably on-site (low foot print)Treatment options that allow the extraction of useable water/effluent from these wastesEvaluation of pre-treatment options to moretertiary treatment options as desalinationCommon step towards re-use for all types of waterbased E&P waste was colloidal filtrationMembranes show superior colloidal and particlefiltration in comparison to other optionsMembranes provide the combination of lowfootprint, waste volume concentration, low energyrequirement and mobilityAdvances in membrane technology has increasedcapabilitiesConcentration polarization/fouling and fluxdeclineLarge volumes of water based wastesproducedOperational challenges and feedcharacteristic challenges.NF (Softening step)RO (Desalination)Oil and suspended solids removalMechanical pre-treatment for NF or ROOptimization for softening process•Oil < 2000 ppm•Salts anddissolved solids•Suspendedsolids•dissolved solids•salinity•concentrated oil•concentratedsuspended solidsWater extractionSolids-free permeateWaste volume concentration andreductionHigh solidsDissolved solidsMostly water•concentrated solids•low waterLow solidsWaterSample uniformity of field samples (produced wateranddrilling fluids)Feed parameter variation (Produced water: oilconcentration, Spent drilling fluids: solidsconcentration)Operational parameter evaluation (CFV, temperatureand pressure)Resistance calculation (results not shown)Fouling mitigation (backflushing) and chemical cleaningCeramic membranePore sizea)0.2 μmb)0.01 μmc)0.005 μmCharacteristicsa)Inert materialb)High temperaturec)High cross flowd)Solvent resistante)High solidsHollow fibre membranePore sizea)0.2 μmb)0.1 μmCharacteristicsa)PVDF materialb)Hydrophobicc)Mediumtemperatured)Low solids**Solids rejection was between 93-99%, solids concen tration was between 16,000-** **25,000 mg/L (mean particle size was between 38-116 microns)** **Turbidity removal was about 99%, from 1857 NTU to l ess than 1.8 NTU.** **Solids concentration was varied from 8.8% - 10.20 % v ol solids, the lower the solids** **the more the flux**Mud weight: 9.7 ppg and 10.8 ppg Solids concentration: (8.8 % (vol),19,000 mg/L) (10.20 % (vol), 31,000 mg/L) pH: 9.5 . Ceramic membrane 0.01 micron pore size**Flux increased with higher temperature and high cro ss flow velocity** **Pressure regimen is very important in prolonging th e onset of fouling** **Solids help reduce the effect of concentration pola rization due to the effect of** **scouring of the membranes Mud weight: 9.7 ppg Solids concentration: 8.8 % (** **vol) , (19,000 mg/L), pH: 9.5**Maximum Flux (GFD)Minimum Flux(GFD)Average Flux(GFD)Permeate Volume(Gal)Temp (C)2018.14 13.89 15.65 1.223830.57 26.31 26.80 2.095251.84 36.10 43.77 3.42CFV (ft/s)6.0412.17 9.2 10.36 0.8110.0830.57 26.31 26.80 2.0916.1270.07 52.13 64.23 5.01TMP (psi)1021.35 30.47 27.85 2.091530.57 26.31 26.80 2.172034.11 27.22 32.38 2.52High SolidsDissolved solids100% volume8.8 – 10.2% solidsby volume(19,000 -32,000mg/L)Concentrated Solids60% volumeSolids freeDissolved solids40% volumeHigh SolidsDissolved solids100% volume8.8 – 10.2% solidsby volume(19,000 -32,000mg/L)**Increased temperature, cross flow velocity and pres sure increased flux** **Pressure regimen was important to reduce the onset of fouling** **Oil concentration as high as 1200 ppm was handled e ffectively using ceramic** **membranes , PVDF could hand less than 300 ppm****Temperature was the most important factor in filtra tion.** **Oil concentration 700 ± 500 ppm, pH 7.3 ±1.5 and sal inity 36,000 ± 5000 TDS mg/L** .Maximum Flux (GFD)Minimum Flux(GFD)Average Flux(GFD)Permeate Volume(Gal)Temp (C)20 58.44 45.45 51.32 3.5238 140.70 100.11 110.06 7.7152 160.04 149.01 152.05 9.64CFV (ft/s)4 68.42 63.10 65.03 4.608 140.70 100.11 110.06 7.7111 164.10 124.8 142.42 9.99TMP (psi)10 68.18 45.45 53.07 3.9315 140.70 100.11 110.06 7.7121 139.93 112.00 100.65 7.88**PVDF membranes showed fluxes 5 times greater than with ceramic and had low** **pressure and energy requirements****PVDF membranes could handle less oil in water befor e fouling** High oil in waterSuspended solidsDissolved saltsLow solids100% volume96-99% oil96-99 % solids5-7% volumeNo oilNo suspendedsolidsDissolved salts80 -90% Volume**Backwash was applied every 40 minutes after the 80 th** **minute at a cross flow velocity of 22 ft/s, the filtration cross flow was 16 ft/s** **By prolonging the onset of flux decline the permeat e was increased by 54% compared to no** **backwash****Backwash was applied every 25 minutes at a cross fl ow velocity of 16 ft/s, the filtration cross** **flow was 10 ft/s****By prolonging the onset of flux decline the permeat e was increased by over 60% of what** **would have obtained without backwash****Backwashing also reduced the total reversible fouli ng from 20% to 6%** **Backwash was applied every 15 minutes at a cross fl ow velocity of 6.5 ft/s, the filtration cross** **flow was 3.8 ft/s. The oil concentration was 500 pp m** **The hydrophobic nature of the PVDF membrane materia l affected the ability to recover the** **flux.****Backwash as high oil concentration would be ineffec tive in hollow fibre membrane filtration** Two cleaning agents were used in our study andmembranes backwashed and not backwashed werealso used in four hour filtration experimentsUsing fouling mitigation techniques and periodicchemical cleaning recovered between 93-99% of themembraneWell designed cleaning regimens are essential formembrane systems and are determined on a caseby case basisMembranes are effective in the colloidal filtration ofwater based E&P wastes to produce re-useableeffluentsMembrane systems operational and feedparameters need to be optimized through empiricalknowledge to optimize filtrationFouling mitigation and cleaning regimens are anintegral part of the membrane systemPretreatment is the key to successful membraneWe are at the field testing stage of a pilot plan for amobile unit for produced water treatment withdifferent sections.**Sample characterization** **Solids**Above 30,000 mg/LLess than 15,000 mg/LBelow 5,000 mg/LPretreatment toreduce solidsCeramic (UF/MF)HF (UF/MF)Below 5,000 mg/LLess than 15,000 mg/LAbove 2,000 ppmLess than 1,500 ppmBelow 300 ppmPretreatment toreduce oilBelow 3,000 ppmLess than 1,500 ppmCeramic (UF/MF)HF (UF/MF)**Oil Concentration** **Salinity**Above 40,000 TDSbelow 40,000 TDSNon- membraneCLASS ICLASS IICLASS IV**TDS (other)**Dissolved solids IDand manufacturer’sspecification aboutmembrane materialand ion(s) reactionUser classificationbased onconcentrationHighMediumLowPretreatmentCLASS ICLASS IICLASS IIIPretreatmentNo pretreatment**Gel/Polymer**Pre treatment toremove gelsCLASS ICLASS IICLASS IIICLASS IV**Miscellaneous V** **I IV** **VI III** **II**Thank youFor more Information:GPRI Websitehttp://www.pe.tamu.edu/gpri-new/home/David Burnett , Director, GPRI.