Compatibility of Scale Inhibitors and Biocides with Fracturing Fluids. Christy C. Wentworth, Ph.D.

Transcription

1 Compatibility of Scale Inhibitors and Biocides with Fracturing Fluids Christy C. Wentworth, Ph.D.

2 Agenda What Are Fracturing Fluids? Importance of Compatibility Scale Inhibitor and Biocides in Fracturing BWA Water Treatment Solutions BWA Biocide Compatibility with Fracturing Fluids BWA Scale Inhibitor Compatibility with Fracturing Fluids Summary Questions

3 What Are Fracturing Fluids? Fracturing fluid is a combination of water, chemicals, and sand that is injected into a crude oil or natural gas well to reduce friction pressure and create a fracture. Can vary depending on the geological features. On average, frac fluid contains between 98 percent and 99.5 percent water and sand. Between 0.5% and 2% of the fluid is composed of chemical additives:

4 Compatibility of Chemicals with Fracturing Fluids Each component of a fracturing fluid has a specific action: Eliminate MIC, well souring bacteria, and biofilm in the water (biocide) Prevent corrosion of pipes (corrosion inhibitors) Minimizes friction between fluid and pipe (friction reducers) Allow the fractures to continue the flow of oil (proppant) Prevent scale deposits (scale inhibitors) Modify the viscosity of the fracture fluid to required levels (surfactants) Not only does each component need to be compatible with each other, they also need to be compatible with the environment of each frack. Temperature stable ph and TDS of source water Stable activity throughout a frack

5 Scale Inhibitors in Fracturing Challenges Solid deposits that grow over time, blocking and hindering fluid flow through pipelines, valves, pumps etc. with significant reduction in production rates and equipment damages. Ex. calcium carbonate, iron sulfides, barium sulfate and strontium sulfate. SIs and Frack Fluids Crucial to fluid flow assurance SIs are added to oil production systems to delay, reduce and/or prevent scale deposition. Polymers and phosphonates used for scale are easily soluble, thermally stability, and can be efficiently dosed without negatively affecting important fracturing fluid additives.

6 Biocides in Fracturing Challenges Souring from hydrogen sulfide Formation plugging from iron sulfide Microbiologically Induced Corrosion (MIC) Biofilm Harbors bacteria, thick layers, encourage under deposit corrosion Increases pumping resistance Biocides and Frack Fluids Crucial to proper fluid flow and well/pipe integrity Biocides are added to fracturing fluids to either eliminate or control bacteria Oxidizing and non-oxidizing biocides are used topside for source water Preservative non-oxidizing biocides are used to control bacteria over the life of a fracked well

7 BWA Custom Water Treatment Solutions Scale solutions that maintain proper fluid flow and reduce equipment damage costs. Non-oxidizing biocide that removes biofilm, reduce corrosion and improve health & safety. (e.g., H2S)

8 Asset Integrity: Bellacide Product Chemistry Bellacide 300 Phosphonium Chloride with dispersants Biofilm SRBs APBs Removal Compatible with: Friction Reducers H2S Oxygen Halogen NH3 Scavengers Biocides Effective at ph 10 Stable at 80 C

9 Bellacide Friction Reducer Compatibility Marcellus water 0.5 GPT Marcellus water 1.0 GPT Marcellus water 0.5 GPT Marcellus water 1.0 GPT Percent Reduction Control Bellacide 300 Control Bellacide 300 Control Bellacide 300 Control Bellacide 300

10 Bellacide Friction Reducer Compatibility CWS-600 System Friction Reduction Synthetic Brine Biocide Base Fluid Viscosity (cp) ph 0.5GPT - Synthetic Brine GPT 0.10GPT 0.25GPT Synthetic Brine GPT Bellacide 0.35GPT Synthetic Brine The CWS-600 system tested performed well in all tests run on the friction flow loop. Bellacide 300 had NO detrimental effect on the friction reducer efficiency of the CWS-600 slickwater design evaluated Friction Reduction (%) Friction Reducer Control GPT, 0.1GPT, 0.25GPT 0.5GPT, Bellacide Time (seconds)

11 Bellacide Gel System Compatibility DynaFlow-2WR Lot Number Conc. (GPT) Base Gel Visc. 17 Gel-A Gel Adjusted ph HA-1 Hydration Aid Crosslink ph SFT-B Surfactant Crosslink ph HPB-2 High ph Buffer CRL-C Crosslinker BKR-3 Breaker Bio-2 Biocide Bio-1 Biocide Bellacide 300 Biocide 15-BWA NO compatibility issues were seen on the DynaFlow-2WR system with the submitted Bellacide 300.

12 Bellasol Compatibility Matrix Thermal Stability Inhibition Of Product Key statement CaCO3 BaSO4 CaSO4 ºF / C High TDS Tolerance Iron Tolerance Dispersancy Bio-degradable CEFAS Approval Bellasol S16 Cost effective CaCO3; outperforms Phosphonates ** 300 / 150 Yes Bellasol S28 Broad spectrum scale inhibitor ** 300 / 150 Yes Bellasol S30 Superior hydrolytic-stability 400+/200+ Yes Bellasol S50 in class BaSO4 SI Especially in high barium / low ph 400 / 200 Yes Bellasol S60 Bio-degradable ** 300 / 150 Yes Bellasol S65 Bio degradable ** 300 / 150 Yes Bellasol S80 Effective against Silica 400 / 200 Yes * * Activity in mixed scale environments

13 Bellasol Friction Reducer Compatibility Bellasol polymer A was pumped into the blender tank on 3 wells Field water samples analysed for residual scale inhibitor Gradual flowback of Bellasol product Bellasol at 7-13ppm after 12 days Dosage effective under fluctuating field conditions No issues encountered with equipment, and no noticeable scale

14 Summary Because so many components go into fracturing fluids and each composition is dependent upon the geological features of a particular site, it is imperative that every chemical is compatible with each other and the specific environment in which it will be used. Each region and well presents unique challenges and our deep understanding of water chemistry enable us to find the best solution for your frack fluid.

15 THANK YOU! QUESTIONS?