Oil and Gas Treatments » Paraffin Digester
MICROBIAL CONTROL OF PARAFFIN, SCALE, CORROSION AND EMULSION
Paraffin accumulation, corrosion, scale and emulsion formation have resulted in significant economic losses and reduced profitability for oil producers and operators. Traditional control methods such as hot oiling, chemical treating and scraping have been marginally successful and temporary at best. Often these methods have serious long term effects (especially in the case of hot oiling) on the productive life of the well.
Now there is a bacterial product that offers treatment programs that remove paraffin accumulations, inhibit corrosion or scale formation, and acts as emulsion breakers. This product, PARAFFIN DIGESTER (FORMERLY PARAGONE), is composed of naturally occurring microorganisms suspended in an aqueous solution. PARAFFIN DIGESTER (PD) is non-toxic and non-pathogenic. It will not harm humans, animals or plant life and requires no permits from the Environmental Protection Agency for transportation, use, or disposal.PD is not a solvent and is non-flammable and non-combustible. From a safety standpoint, the advantages over other treatments are obvious.
PD is batch treated and gravity fed or pumped into the well-bore annulus. Usually, little or no modification of wellhead plumbing is required to accommodate the treating equipment. Produced fluids from the storage facilities are not used as a treatment medium.
PARAFFIN REDUCTION IN THE WELL-BORE FLUIDS
Turbulence in the well fluids, created by inflow from the formation and pump action, will disperse PD throughout the well fluids. As the bacteria are dispersed they remove paraffin molecules.
The metabolic processes of the bacteria degrade and resolubilze the paraffin with two beneficial results. First, the petroleum will not reform paraffin deposits at any point in the pumping system, the flow lines, or the storage tanks; and secondly, the viscosity of the fluids can be reduced, which can result in a proportional increase in API gravity.
PARAFFIN REDUCTION IN THE FORMATION
Hot oiling over extended periods of time may reduce a formation's permeability and porosity at or near the well-bore. Because the PD bacteria are able to withstand extremes of pressure and velocity, they can gradually remove paraffin deposits that are partially interfering with the inflow to the well-bore. Eventually, the bacteria will remove the higher molecular weight paraffin's that have melting points above the formation temperature.
In instances where this type of paraffin accumulation is present, some increase in production can be expected, depending on the extent of the paraffin damage and the available production left in the formation. In some cases, this increase has been dramatic.
PARAFFIN IN THE PUMPING AND STORAGE SYSTEMS
PD treatments are designed to provide sufficient volumes of bacteria to clean paraffin from mud anchors, gas anchors, performed nipples, pump valves, sucker rod strings and tubing walls. Eventually the bacteria may colonize in downstream production facilities, cleaning out flow lines and storage tanks. In recorded tests, BS&W or tank bottoms have been dramatically reduced by PD treatments.
Bacteria have proven useful in removing emulsions from production systems.
CORROSION INHIBITING PROCESS
The active organisms secrete and deposit a film of polysaccharide that forms a coating on well components. This coating reduces corrosion as long as the augmentation of the organisms is maintained.
Besides production wells, there are other applications for STRATA products in oil field areas. Disposal and water-flood projects can also be treated for scaling, paraffin and corrosion problems.
TREATMENT FOR YOUR COMPANY
If no chemicals or toxic materials are being injected into the well-bore, treatment can commence immediately. If chemicals or toxic chemicals are in the system or part of the treatment process, this should be discontinued for 7-10 days prior to the PD treatment.
PD treatments are very cost effective when compared to conventional methods. Actual treatment cost depends on several factors including down-hole configuration, oil and water production rate, paraffin and scale deposits. One gallon of PD and one gallon of nutrient water (12 oz of nutrient in 1 gallon of water) will treat 200 gallons of oil sludge or emulsified oily water, if the objective is to recover the oil.
PD degrades and resolubilzers paraffin that accumulates in well-bores, production equipment and tank batteries. The mechanism involves two processes: 1) degradation of the paraffin and 2) surfactant (enzyme catalysts), produced by the bacteria cause the paraffin to become soluble in the oil again.
As stated previously, the PD bacteria produce surfactant s which cause paraffin and other precipitates to go back into solution. They also reduce available oxygen which inhibit reactions such as: Fe, SO3 + O = Fe SO4 (Sulfite to Sulfate). Iron Sulfate is less soluble than iron sulfite. In the case of compounds containing calcium and sodium, the bacteria will use calcium and sodium ions in metabolic reactions. Metabolically produced polysaccharide films coat and prevent nucleation of scale molecules.
The PD bacteria will scavenge the available oxygen thus making it less available for oxidation reactions such as corrosion. In addition the polysaccharide produced through metabolism will coat internal parts, placing a barrier between metal and corrosive elements.
Due to surfactant production and the elimination of free oxygen, emulsions tend to break down or not for form at all.
Due to the technical nature of the product and the application being treated, STRATA will need to work with you before, during and after PD is applied.
TECHNICAL RISK MANAGEMENT
Since 1993, the treatment procedure has been applied to several oil wells in a number of oil fields, with oils of different specifications. There has been no uncontrollable cloning of the bacteria. The cloning of the bacteria on site is controlled through the injection of nutrients to feed the bacteria. Once the flow of nutrients is discontinued, the bacteria disappear completely from the field.
PD is safely injected into the injector wells via the water flood injector wells, without any need for production well shut down. PD creates decreased oil viscosity, decreased cloud point, decreased oil viscosity, decreased pour point and decreased surface tension of oil to the rock grain, improving significantly the recovery ratio of oil. The cost of recovering oil, from wells reaching the end of their life, is a fraction of the traditional method. The Oil recovery ratio is significantly enhanced with PD treatment.
Procedure for Bench Test of Crude Oil with PD
All water used in the test must be tap water and must be dechlorinated prior to use. Do not use distilled water because it will not contain any minerals and will require buffering, as the nutrient will lower the pH below 6.0. In a 1000 ml Erlenmeyer flask add 250 ml of the nutrient/water and 250 ml of the dechlorinated tap water. Place the flask on a heating/stirring stand and set the heating temperature to 38 degrees C. Stir the mixture. Then check the pH of the mixture and if necessary, slowly add sodium hydroxide to raise the pH above 6.0. Shake the PD until it is uniform in appearance, as the product will separate. Add 250 ml of PD to the 1000 ml flask and stir for 45 mnutes at 38 degrees C. Add 250 ml of crude oil into the flask. The crude oil sample needs to be representative of the crude oil in the formation and not a solid piece of paraffin or asphaltene. Seal the flask with a stopper and set the stirring speed as high as possible to maintain even stirring of the fluid. Create and maintain a vortex if possible. Allow to stir for a maximum of 45 mintues or until the PD and crude oil have thoroughly mixed. Turn off stirring action, but leave the heat set at 38 degrees C. Continue the test until there are no more visible changes in the oil sample. You can check this by turning on the stirring action for about 5 mintues and then turing it off, or by shaking the flask by hand. Depending on the original viscosity of the oil, this test usually takes twenty-four to forty-eight hours to complete.
PD WELL TREATMENT PROCEDURE
Preparing PD, Nutrient Water and Flush Water for Treatment
PD is formulated by mxing equal parts PD and Petroleum/Oil Cleaner together prior to use.
Nutrient water is formulated by dissolving 8 oz of dry Nutrient in each gallon of clean fresh water. Dechlorinarte water if necessary. The volume of Nutrient water used equals the volume of PD used in the treatment.
Flush water is formulated by dissolving 12 oz of dry Nutrient in each bbl of clean fresh water. Dechlorinate if necessary. The volume of Flush water varies per well. For water sensitive formations, 2% KCL must be added to all fresh water used in the treatment.
Basic Procedure for Treating a Well Using PD
- Identify candidate well, determine type of problem and outline expected results.
- Prior to treatment, identify any chemical treatments currently being used. Delay treatment with microbes if necessary to allow biocides or acids to clear well bore.
- Place Nutrient water in a clean tank.
- Add PD to the Nutrient water tank. Mix thoroughtly and wait one hour. NOTE: Never add dry Nutrient directly into PD as this may harm the mcirobes.
- Tie into the annulus of the well and pump one bbl of Flush water into the well.
- Then pump the PD/Nutrient water mixture into the well.
- Pump the remaining Flush water into the well.
- Shut the well in for a minimum of 48 hours for basic treatment and a minimum of 7 days for a larger treatment (squeeze).
- Bring well back on line and monitor. Well stroke or pumping frequency may need to be increased due to larger fluid flows after treatment.
- After a well is treated with microbes, it is very important that the Opeator and their presonnel be made aware of the adverse effect any biocides or acids will have on the microbes. It is OK to use a corrosion inhibitor as long as it does not contain any biocide. If a well is truck treated, chemical companies will use a biocide in their treatment unless told otherwise. Many pumpers like to dump an acid soap down the wells. Biocides and acid soaps are not to be used on wells treated with microbes. Treatments can be modified to address specific problems. A basic microbial treatment will last for 30 to 90 days. Squeeze treatments use a large quantity of PD, Nutrient water and Flush water. This type of treatment can last 4 to 6 months. The volume of PD, Nutrient water and Flush water are calculated for each well based on the data provided on Well Evaluation Forms.
PD MICROBIAL TREATMENT CASE HISTORIES
- Location: Colorado, USA
Well Depth: 500-5500
Problems: Paraffin & Scale (CaCo3)
Number of Wells: 13
Historical Problems and Remedies Prior to Microbial Treatment: Every 60 days the wells had to be hot oiled down the tubing and flow lines. Decreased production. Stripping required. Wells have to be pulled every 12 to 18 months.
Average Production Before Microbial Treatment: BOPD 2-3 BWPD 1
Observed Results of Microbial Treatments: Initial Microbial treatment was injected down tubing in September 1993. Since beginning treatment, no hot oiling or butane augmentation has been needed. Oil production has increased up to 50%.
Average Production After Microbial Treatment: BOPD 6-7 BWPD 1 65
Well Depth: 8500
Number of Wells: 5
Historical Problems and Remedies Prior to Microbial Treatment: Paraffin clogging flow lines. Used paraffin solvents. CaCo scale problems. Initial treatment May 1994.
Average Production Before Microbial Treatment: BOPD 8-15 BWPD 3-5
Observed Results of Microbial Treatments: All flow lines were clean within the first three weeks of treatment. Tank bottoms appeared-rolled bottoms-disappeared.
Average Production After Microbial Treatment: BOPD 10-17 BWPD 3-5
- Location: Colorado
Well Depth: 5000
Problems: Paraffin and Scale
Number of Wells: 5
Historical Problems and Remedies Prior to Microbial Treatment: Paraffin build-up required stripping jobs as well as hot oiling. All wells have to be pulled every 12-18 months. CaCo3 scale problems.
Average Production Before Microbial Treatment: BOPD 3-4 BWPD 1
Observed Results of Microbial Treatments: Initial treatment in February 1994. Since beginning treatment, no tank bottoms, no hot oiling, equipment is clean
Average Production After Microbial Treatment: BOPD 5-7 BWPD 1
- Location: Texas/W. Central
Well Depth: 4500-5000
Problems: Heavy Paraffin and Gypsum
Number of Wells: 2
Historical Problems and Remedies Prior to Microbial Treatment: One flowing and one pumping well, each required hot oiling.
Average Production Before Microbial Treatment: BOPD 12 BWPD 28 MCFPD 10
Observed Results of Microbial Treatments: Hot oiling has been eliminated.
Average Production After Microbial Treatment: BOPD 19 BWPD 33 MCFPD 18
- Location: Texas/Palo Pinto Co.
Well Depth: 3920-4230
Problems: Paraffin, Scale & Iron Sulfate
Formation: Marble Falls
Number of Wells: 31
Historical Problems and Remedies Prior to Microbial Treatment: Recent field development with wells having extreme paraffin build ups. Hot oiling and chemical treatments at 30-60 day intervals, to prevent lock ups. Flow lines required hot oiling every 90-120 days.
Observed Results of Microbial Treatments: All 31 wells have been on microbial program for over 3 years. Since the program's initiation, no hot oiling or chemical treatments have been necessary. 30% of the wells showed 10-20% product increase, as well as a 1-2 point rise in API gravity. Tank turndowns were cut by 90%.
- Location: Texas/Jack Wise Co.
Well Depth: 5800-6200
Problems: Heavy Paraffin & Gypsum
Formation: Bend Conglomerate
Number of Wells: 60
Historical Problems and Remedies Prior to Microbial Treatment: Many wells in this area have heavy build up of paraffin and gypsum which requires frequent hot oiling and stripping. Pump changes as frequent as 6 months. Flow line plugging and oil rejection, due to emulsion, was common.
Observed Results of Microbial Treatments: All wells have shown slight to significant production increases. Pump life has at least doubled, many have yet to be pulled since treatment began 3 years ago. Hot oiling of wells and flow lines has been eliminated along with most emulsion problems.
- Location: Texas/Panhandle
Well Depth: 3200
Problems: Paraffin & Iron Sulfide
Formation: Granite Wash
Number of Wells: 12
Historical Problems and Remedies Prior to Microbial Treatment: Heavy paraffin made 2-4 stripping and hot oiling jobs per month necessary in this field.
Average Production Before Microbial Treatment: BOPD 52 BWPD 15 MCFPD 0
Observed Results of Microbial Treatments: In more than 3 years of treatment, none of these wells have been stripped or hot oiled. There has been no "Blue Mud" (iron sulfide emulsion) accumulation that required clean out to date.
Average Production After Microbial Treatment: BOPD 70 BWPD 15 MCFPD 0
- Location: Oklahoma/Texas & Beaver
Well Depth: 5500-5800
Problems: Heavy Paraffin
Number of Wells: 14
Historical Problems and Remedies Prior to Microbial Treatment: All wells had high rates of asphaltine based paraffin accumulations requiring chemical treatment and frequent hot oiling.
Observed Results of Microbial Treatments: After initial treatment, all wells returned to at least normal production with 8 showing increases of 10-300% in oil and gas production. All wells have shown a dramatic decrease in paraffin accumulations.
Average Production After Microbial Treatment: BOPD 19 BWPD 33 MCFPD 18
- Location: Texas/Archer Co.
Well Depth: 3850-90
Problems: Paraffin & high injection pressure
Number of Wells: 9
Historical Problems and Remedies Prior to Microbial Treatment: Water flood with producing wells having moderate paraffin and scale problems. Injection wells had large pressure increases that required frequent acidizing.
Average Production Before Microbial Treatment: BOPD 11 BWPD 520 MCFPD 0
Observed Results of Microbial Treatments: Injection pressures decreased 35%-55% effecting a decrease in electric cost and higher injection rates. Paraffin and scale in production wells has been eliminated.
Average Production After Microbial Treatment: BOPD 23 BWPD 680 MCFPD 0
- Location: Texas/North
Well Depth: 6200-6400
Problems: Paraffin and Corrosion
Number of Wells: 3
Historical Problems and Remedies Prior to Microbial Treatment: All three wells had serious paraffin problems with moderate corrosion. Chemicals were primary remediation with occasional hot oiling.
Average Production Before Microbial Treatment: BOPD 4-5 BWPD 10 MCFPD 20
Observed Results of Microbial Treatments: Due to microbial treatments, alternated with corrosion treatments (which are being phased out), no hot oiling is necessary.
Average Production After Microbial Treatment: BOPD 6-8 BWPD 12 MCFPD 25
- Location: Texas/Ft. Worth Basin
Field: Lost Valley
Well Depth: Withheld
Problems: Paraffin and Emulsion
Formation: Caddo/Marble Falls
Number of Wells: 4 pumping
Historical Problems and Remedies Prior to Microbial Treatment: Moderate paraffin and scale build-ups, serious emulsion causing high rate of tank turndowns. High expense due to chemical and hot oil emulsion breaking. All wells needed hot oiling for reworks and flow line pressure.
Average Production Before Microbial Treatment: BOPD 1 BWPD 10 MCFPD 40
Observed Results of Microbial Treatments: Microbial treatments have eliminated the need for hot oil and chemical emulsion breaking.
Average Production After Microbial Treatment: BOPD 3.5 BWPD 12.5 MCFPD 70
- Location: Texas/Central
Well Depth: 7650-8000
Problems: Extreme Paraffin
Formation: Austin Chalk
Number of Wells: 2
Historical Problems and Remedies Prior to Microbial Treatment: Weekly and bi-weekly hot oiling was necessary to keep the wells in operation.
Average Production Before Microbial Treatment: BOPD 38 & 50 BWPD 28 & 64
Observed Results of Microbial Treatments: All hot oiling has been phased out cutting operating costs significantly.
Average Production After Microbial Treatment: BOPD 42 & 71 BWPD 35 & 82
PD is a very technical product, thus each dosage will depend on the individual project.
Please contact us for the MSDS sheet!