Table of Contents
Wellbore Cleaning Solvent P130 ...1
1 Introductory Summary ...1
1.1 Shelf life...1
2 Fluid Design ...2
3 Application ...3
3.1 Formulations and additives...3
3.1.1 DAD PLUS formulations ...3
3.1.2 CLEAN SWEEP PLUS formulations...4
3.2 Limitations...4
4 Field Mixing Procedures ...5
5 Health, Safety and Environmental Considerations ...5
6 Appendix. Organic Deposit Solvency Test Procedures ...6
6.1 Asphaltene solvency...6
6.2 Paraffin solvency...7
List of Figures
Error! No table of figures entries found.List of Tables
Table 1. Physical properties and hazards. ...1Table 2. Solvent toxicity comparison...2
Wellbore Cleaning Solvent P130
1 Introductory Summary
Wellbore cleaning solvent P130 is a nonaromatic solvent for use as an alternative to xylene Solvent A26 or PARAN∗ 121 solvent in solvent washes and wellbore cleaning operations. Its
primary application is for solvent cleaning where the use of A26 and P121 has been restricted or prohibited. P130 readily dissolves or disperses “paraffinic” deposits, heavy residual oil fractions, asphalts and waxes from oil wells.
P130 is a combination of natural extracts that is particularly effective on residual pipe-dope deposits used for wellbore pickling operations prior to gravel packing. It is equally effective on paraffin wax buildups. P130 is applied directly to clean the formation and well equipment. P130 is recommended for applications where environmentally acceptable solvents for organic deposits are desired, replacing the use of Solvent P129. It was developed for use in North Sea operations and exhibits reduced toxicity to marine life. P130 is more biodegradable than P129. P130 does not contain any nonylphenol ethoxylate surfactants (NPEs) and is free of xylene and other low-molecular-weight aromatic tainting chemicals.
Table 1 provides a summary of the physical properties and hazards of P130. Only the principal, immediate hazards are listed in Table 1. Complete information on health hazards, personal protective equipment, handling precautions, environmental hazards and disposal is provided in the Material Safety Data Sheet for P130.
Table 1. Physical properties and hazards. Chemical Code Product Name Form Specific Gravity Health Hazard Physical Hazard Pour Point
(°F [°C]) Flash Point(°F [°C]) Value pH P130 Wellbore Cleaning Solvent P130 Clear liquid at 77°F 0.838 [25°C] Moderate: eyes, skin, inhalation Vapor <-90 [-68] 115 [46] 6.5
1.1 Shelf life
Wellbore Cleaning Solvent P130 can be stored and handled from -50° to 130°F [10° to 54°C]. The shelf life of P130 should be greater than 2 years for unopened containers. Dedicated stainless-steel totes are the preferred containers for storing and transporting P130 to the jobsite. P130 may also be stored in drums. Containers of P130 should be stored away from heat, sparks and flame in a well-ventilated area, out of direct sunlight.
2 Fluid Design
Organic deposits such as heavy crude oil residuals, asphaltic tars, paraffinic waxes and sludge-like materials may form deposits, which can restrict fluid flow in an oil well. The deposits can vary greatly depending on producing conditions and the type of crude oil produced. Mineral deposits and brine can also be found in these sludge-like accumulations. The deposits can reduce production and inhibit the effectiveness of a stimulation treatment. In addition, residual pipe dope, with or without preoperational rust or mill scale, can contribute to damage or poor performance in gravel-packing operations.
P130 is an alternative to the aromatic Solvents A26 and P121. It can be used as a solvent for hydrocarbon deposits such as paraffin, asphaltenes and pipe dope. Its primary application is in solvent cleaning operations where A26 or P121 has been restricted or prohibited. A toxicity comparison of P130 with A26, P121 and P129 is shown in Table 2.
Laboratory testing indicates that P130 can be used to successfully clean up various types of hydrocarbon sludges and pipe-dope fouling. It generally outperforms other commercially available nonaromatic solvent products; however, solvent selection should be determined by comparative solvent tests on representative samples of the deposit to be removed. Laboratory tests have shown that the addition of Mutual Solvent U66 is beneficial for improved organic deposit removal.
Organic deposit solvency test procedures are provided in the Appendix to this section. Table 2. Solvent toxicity comparison.
Regulation/Parameter P121 A26 P129 P130
Mammalian toxicity High High Low Low
Marine algae toxicity (Skeletonema EC50 72 hr)
ND ND ND 22.4 mg/L
EPA/RCRA waste classification F5, D1,
U220 F3, D1, U239 D1 None
CERCLA reportable spill quantity 1000 lbm 1000 lbm Not established Not established
SARA Title 313 listed Yes Yes No No
Flash point (°F [°C]) 39 [4] 84 [29] 117 [47] 115 [46]
Biodegradable (marine) ND ND 19% 44%
Bioaccumulation potential (% log power >3)
100% 100% 100% 100%
Taint list Yes Yes Yes No
3 Application
P130 has a wide variety of applications as a solvent for organic deposits. It can be applied in most equipment and formation cleaning operations where A26 or P121 could be used. Addition of U66 (5% to 7% by volume) has been observed to improve the solvency of P130 for paraffin and other organic deposits. Applicable operations for using P130 include
• circulation cleaning the tubing or annulus with a downhole pump • flushing flowlines or tanks
• cleanup stage or preflush ahead of acid
• preoperational cleaning with or without an acid stage prior to gravel packing (Solvent P130 breaks the viscosity of ClearFRAC∗ fluids and PERMPAC* gravel-pack fluid
solutions. If Solvent P130 is used with ClearFRAC or PERMPAC fluid, a brine spacer must be pumped between the solvent and fluid to ensure that they do not contact each other.)
• formation soaking.
3.1 Formulations and additives
3.1.1 DAD PLUS formulations
P130 can be used to prepare Dowell acid dispersion (DAD) containing up to 20% hydrochloric acid (HCl). Higher concentrations of acid should be avoided. Clay acid and super mud acid should also be avoided. Laboratory tests show that DAD emulsions prepared with P130 are at least as stable as equivalent dispersions using aromatic solvents or P129. The emulsifying agent used for DAD emulsions is U74; however, this product is not approved for use in the North Sea. A substitute emulsifier to replace U74 will be developed.
Corrosion Inhibitor A259 is the inhibitor of choice in the preparation of DAD PLUS solvent with hydrochloric acid (HCl) or DAD PLUS solvent with HCI, and hydrofluoric acid (HF). Other conventional HCl corrosion inhibitors may be used if the dispersions are stable. Corrosion inhibitor requirements are similar to those for conventional DAD using aromatic solvents. Consequently, DAD inhibitor schedules for Corrosion Inhibitor A254 or A260 should be followed for preparing DAD PLUS.
Corrosion Inhibitor A186R is the preferred inhibitor when inhibiting DAD emulsions prepared with 9% Formic Acid L36 or 10% Acetic Acid L400. Other DAD PLUS formulations should not be used without first testing to confirm emulsion stability and corrosion protection.
3.1.2 CLEAN SWEEP
∗PLUS formulations
The original formulations of CLEAN SWEEP I and CLEAN SWEEP II fluids contain aromatic solvents. CLEAN SWEEP I and II fluids are multifunctional solvents designed to solve a variety of formation damage problems affecting the immediate wellbore area.
Similar fluids can be prepared using Solvent P130 instead of the aromatic solvent phases in CLEAN SWEEP I and II fluids. The composition of CLEAN SWEEP PLUS fluid is shown in Table 3.
Table 3. CLEAN SWEEP PLUS composition.
Component Volume (%)
P130 80 L400 10 F3 10 A272 1 The solutions look cloudy when formed but clear upon standing. They can be pumped immediately after mixing.
For corrosion protection against CLEAN SWEEP PLUS fluid corrosion, Corrosion Inhibitor A272 should be used at 1 gal/1000 gal of CLEAN SWEEP PLUS fluid. CLEAN SWEEP fluids do not contain water. In the absence of water, CLEAN SWEEP fluids are not corrosive to steel; however, one of the purposes of using a CLEAN SWEEP fluid is to extract water from the target formation. The fluid becomes chemically reactive to the formation and corrosive to the steel tubulars upon the addition of water from the formation or another source. As a safeguard against corrosion of this kind, Corrosion Inhibitor A272 should be used.
Treatment design recommendations for CLEAN SWEEP PLUS fluid are the same as for conventional CLEAN SWEEP fluid formulations.
3.2 Limitations
P130 is pumpable with standard Schlumberger equipment. Product handling practices are the same as for A26 or P121.
Typical solvent soak or recirculation times may have to be extended to obtain the same cleaning results as with A26 or P121.
P130 has a nominal flash point of 115°F [46°C]. Appropriate fire safety precautions must be observed. The precautions and guidelines outlined in the “On Location Safety Standards No. 4” section in the Safety and Loss Prevention Manual must be followed.
4 Field Mixing Procedures
Treating fluids containing Wellbore Cleaning Solvent P130 are blended at the District bulk loading facility. The solvent gives off fumes that may be irritating if inhaled. Minimum personal protective equipment includes goggles, coveralls, safety boots and oil-resistant gloves. Breathing protection should be worn when large quantities are in use. The following loading sequence is recommended.
1. Mixing must be done in clean, rust-free transport tanks that must be free of water. All hoses, pumps and sumps must be checked to confirm that they are also free of water. 2. Before loading, calculate the volume of additives required.
3. Refer to the “Health, Safety and Environmental Considerations” for recommendations on the handling, storage, transport and field operating procedures for fluids in which P130 is used.
The following mixing guidelines are recommended.
1. To blend the treating solvent with U66, load the required volume of Wellbore Cleaning Solvent P130 to the tank first. Then add the required volume of U66. If additional additives are required, add these specified volumes and mix thoroughly.
2. For detailed mixing procedures for CLEAN SWEEP fluids, consult Section 140.10 of the
Matrix Materials Manual, for the required volumes and mixing procedures. P130 is
substituted for the hydrocarbon solvent specified in the mixing instructions.
3. For detailed mixing procedures for DAD emulsions, consult Section 120.05 of the Matrix
Materials Manual, for the required volumes and mixing procedures. P130 is substituted
for the hydrocarbon solvent specified in the mixing instructions.
5 Health, Safety and Environmental
Considerations
• Dedicated stainless-steel totes are the preferred containers for transporting P130 to the jobsite. If P130 is stored in drums at the warehouse, it is recommended that the P130 be transferred into totes at the District before delivery to the wellsite.
• It is recommended that the blending of all additives required for the treatment be completed at the District. Proper safety precautions should be implemented for handling solvent at the District and jobsite. Minimum personal protective equipment includes goggles, coveralls, safety boots and oil-resistant gloves.
• Care should be taken to avoid spilling chemical products on the ground. Contain spills with dikes, and use an inert absorbent (sand) to soak up the residual material. The collected material should be stored in plastic drums and disposed of according to all applicable regulations.
• Unused P130 may be returned to the District for reuse. If disposal is warranted, incineration is the preferred option. Disposal by incineration must be conducted according to all applicable regulations.
• Treatment lines should be flushed and the waste collected and disposed of by incineration or deep-well injection according to all applicable regulations.
• Empty totes should be returned to the District. Triple rinse empty drums, and send them to an approved drum reconditioner if permitted by the regulations. If reconditioning is not an option, empty drums should be sent to an approved sanitary landfill for disposal. • All flowback operations, including storage, transport and disposal of flowback waste, are
the responsibility of the client. Schlumberger equipment or personnel should not be involved in well flowback operations.
• For offshore treatments using Solvent P130, no offshore discharge is permitted.
6 Appendix. Organic Deposit Solvency Test
Procedures
6.1 Asphaltene solvency
1. Place a weighed amount of crude oil or sludge in a Gooch crucible filled with 100-mesh sand supported by steel wool.
2. Wash the sample with heptane on a suction filter until there is no further incremental weight loss (i.e., <0.1-g change). Remove any residual heptane using air suction, and follow by drying in a 150° to 212°F [65° to 100°C] oven.
3. Place the dried crucible containing the washed sample of asphaltenes into a 100-mL beaker and fill the beaker with 40 mL of P130, A26 or other solvent. Adjust the solvent volume to ensure that the entire sample and its sand support are submerged. Leave the sample static in the solvent for 5 min.
4. Take the crucible with the sample from the solvent and place it on a suction filter. Pour the extraction solvent through the crucible. Follow the solvent with 20 mL of methanol to carefully wash out residual solvent. Continue suctioning until dry and at constant weight (<0.1-g change).
5. Determine the asphaltene weight loss by subtracting the weight measured in step 4 from that in step 2.
6.2 Paraffin solvency
1. Place an aliquot of crude oil or sludge in a centrifuge tube. Wash with acetone, centrifuge and discard the acetone-soluble fraction. Repeat the wash, centrifuge and discard
sequence until the acetone is colorless. Carefully dry any residual acetone with canned or compressed air.
Note:
If the sample has less than 5% asphaltenes, steps 2 and 3 can be skipped.
2. Wash the sample with heptane and centrifuge as in step 1 but save the heptane washes until the heptane is colorless.
3. Evaporate the heptane from the saved washes. Use a hot-water bath for the heat source. 4. Dry the centrifuge tubes containing the resulting paraffin in a 150° to 212°F [65º to
100ºC] oven until there is no further weight loss (<0.1-g change).
5. Fold a 1/2-in. x 1 1/2-in. section of 100-mesh screen into one-thirds lengthwise. Obtain an initial screen weight.
6. Dip the folded screen into the melted paraffin to form an even film on the screen (0.5 to 0.8 g of paraffin). Obtain a total weight of the paraffin film and screen sample.
7. Place the paraffin-coated screen in an 11-dram vial and add 30 mL of P130 or other solvent. Cap the vial and swirl for approximately 10s; then keep the screen sample static for 5 min.
8. Withdraw the paraffin coated screen sample from the solvent and air dry it overnight. Weigh the dried screen sample and determine the solubility of the paraffin.
9. Repeat the preceding steps for each solvent and compare the results.
– Treatment lines should be flushed and the waste collected and disposed of by incineration or deep-well injection according to all applicable regulations.
– Empty totes should be returned to the District. Triple rinse empty drums, and send them to an approved drum reconditioner if permitted by the regulations. If
reconditioning is not an option, empty drums should be sent to an approved sanitary landfill for disposal.
– All flowback operations, including storage, transport and disposal of flowback waste, are the responsibility of the client. Schlumberger equipment or personnel should not be involved in well flowback operations.
