Innovative Friction Reducer Provides Improved Performance and Greater Flexibility in Recycling Highly Mineralized Produced Brines

Abstract

Currently, inverse emulsion (water-in-oil) polymers are the most widely applied friction reducers for hydraulic fracturing. While oil-external friction reducers are the industry standard, they are limited by their tolerance to water containing high Total Dissolved Solids (TDS), requiring low TDS in blended waters to achieve adequate friction reduction without the addition of an external surfactant to aid in hydration. To increase operational efficiency and reduce impact on local infrastructure, operators desire to recycle the maximum amount of produced water. To meet this goal, a friction reducer that functions unassisted in high TDS water is needed. This paper describes the use of a Dispersion Polymer Friction Reducer (DPFR) in the Marcellus Shale that addresses this need. A salt-tolerant, water-based friction reducer was developed to allow well operators to reuse high TDS produced waters encountered in the Marcellus Shale. Both lab and field experiments were carried out to assess the effectiveness of the new friction reducer. The data presented in this paper show several advantages of the DPFR: (1) conservation of fresh water sources, (2) greater flexibility in water source options, (3) reduced analytical testing for produced water management, and (4) rapid onset of friction reduction without need for external surfactants. The DPFR provided efficiency improvements to the service company through fewer chemicals required to achieve high pumping rates. The operator benefitted from having greater flexibility in use of produced, recovered and recycled waters. Laboratory flow loop tests indicated that the DPFR would be an effective friction reducer for a wide variety of water types, and this was confirmed by field testing as shown in the treatment plots included in this paper. Minor modifications in material handling procedures were required in the application of the DPFR. This paper details the collaboration between a chemical manufacturer, a service company and an operator which resulted in the successful development, testing and deployment of an innovative technology in the Marcellus Shale. The DPFR technology offers environmental, economic, and operational advantages over the previous inverse-emulsion polymer technology.

A Critical Review of the Risks to Water Resources from Unconventional Shale Gas Development and Hydraulic Fracturing in the United States

“…8 The current upper limit for salinity (for adjusting to friction reducers) in hydraulic fracturing fluids is about 25 000 mg/L, although a salt-tolerant and water-based friction reducer has been developed to enable recycling of even higher saline wastewater for hydraulic fracturing. 146…”

On the cost of electrodialysis for the desalination of high salinity feeds

“…Opinions vary as to the level of total dissolved solids (TDS) that can be tolerated [10] and a complete understanding of issues of chemical compatibility remains elusive [2]. There is evidence that, with improved chemical formulations, high salinity produced waters may be reused without desalination, particularly in the formulation of fluids for slickwater processes [11][12][13][14][15][16] (processes with high volume flow rates to avoid premature settling of sand, which serves to maintain fractures propped open) and to some extent for cross-linked gel fracturing processes [17] (lower volume flow rate processes employing low molecular weight guar gum based gels to ensure proppant remains suspended). However, the increase in chemical costs associated with such formulations not evident.…”