Fighting the Fear: Overcoming Preconceived Notions of Low PolymerCross-Linked Gels and High Viscosity Polyacrylamides in UnconventionalFracturing

摘要

The objective of this paper is to highlight the preconceived notions that both ultra-low polymer cross-linkedgels and high viscosity polyacrylamide fluid systems are difficult to work with or damaging to formations.The paper discusses when such systems are beneficial as well as define some design restrictions.Historicallythese types of fluid systems have fallen into a gray area of technology that have now become accepted bysome operators in the current low-cost market.The fluids technology discussed in this paper have blossomed not solely because of their technologicaladvancement,but also due to the market.Industry downturns have forced operators and service companiesto find more cost-effective means to stimulate the reservoirs in question.This paper examines the useof these new systems in two regions(Williston and DJ Basins),where hundreds of wells have beenpumped with these new systems as well as regained conductivity tests performed in 3rd party labs.We alsocompare production results of thousands of stages pumped with these new systems versus a more traditionalapproach.Over the past decade the DJ Basin has be primarily been stimulated with high-priced low pH zirconateCMHPG fluid systems,as a result of the notion that they leave less residue in the fractures.However,with the very cost sensitive market and the new ultra-low polymer systems testing with higher regainedconductivity than the incumbent system,change was inevitable.In the Williston Basin high rate slickwater jobs have become more commonplace.Hybrid designs havebeen used to increase proppant loadings.However,a new trend to use significantly higher FR concentrationsto achieve a system capable of placing higher proppant concentrations is gaining market share.This leads to the current obstacles for both systems’further use in the field.These obstacles are threefold: 1.The notion that the system is contaminating the proppant pack with residue.Lab testing shows thisnot to be the case.2.Reconditioning field personnel to run the new systems as designed.3.Ensure that these systems are not used in designs that do not fit the operational criteria withoutunderstanding the limitations.The success of all of these items remain attached to the final product,a well producing as much as,ormore,for a lower total cost than the more traditional method.This paper uses data from the lab and field to challenge many of the preconceived notions about whatit takes to successfully place a solid stimulation package.Also,it will address how some of the largestbarriers to new technology are predominantly mental,while the new products are technically sound andeconomically superior.