Abstract
Operators of horizontal wells that have been completed using massive hydraulic fracturing treatments often encounter an unusual semi-solid. The appearance of this rubbery material in surface equipment and subsurface tubing, anchors, and pumps has been reported with increasing frequency over the past few years. This material can be found as early as just a few weeks or might appear after many years, during either production or workover operations. The material collects in many places, including separators, chokes at the surface, mud anchors, tubing, casing, and on other downhole equipment. Generally, this material is not just a scale, but samples known to the author have appeared to be a combination of many materials that typically include formation fines, crushed fracturing sand, hydrocarbon, metals, and polyacrylamide (possibly from friction reducers used during completion). Attempts to create a solvent to remove this material have been problematic because of the composition of the material itself, which can include varying solids, as well as the very stable nature of the polyacrylamide polymer. Additionally, the placement of an effective cleanup treatment is also challenging because the material could deposit anywhere along laterals, ranging from 4,000 to 10,000 ft of length, and it is not usually known exactly where all the deposits might be located. This paper describes the various forms and components of the solids recovered. Analysis methods used to identify the material and solvents used to dissolve or uncomplex the material are also provided. The remediation treatment placement methods used are illustrated, and available initial post-treatment production results are discussed.
