A Novel, Chemistry-Based Approach to Fluid Diversion in Hydrocarbon Based Paraffin Solvent Treatments

Paraffin deposition is a commonly experienced problem throughout the petroleum industry, and especially in certain reservoir fluids found in the Western Canadian Sedimentary Basin (WCSB). As hydrocarbons are produced from the relatively high pressure and temperature found in the reservoir, fluids experience a thermal cooling, as well as significant pressure decreases. These alterations in the fluid thermodynamics can lead to the instability and eventual deposition of paraffins from the hydrocarbon matrix. As production continues, these paraffin deposits can result in significant flow impairment in downhole and surface facilities. Aromatic and aliphatic compounds are commonly used as remediation methods for the dissolution of these paraffins. However, one of the most significant challenges in ensuring an effective remedial treatment is maintaining optimal fluid placement. Given a lack of diversionary placement methods, fluids will preferentially take the path of least resistance. This path does not necessarily coincide with desirable solvent placement for optimum contact with the organic solids. Instead, expensive solvents can be rendered ineffective through a lack of contact. In order to counteract poor fluid placement, a variety of chemical and mechanical diversionary methods have been developed for use in acid or solvent treatments. Mechanical methods rely on tools or packers to force remediation fluids into the desired location. Chemical methods often rely on a viscosification to force remediation fluid from the path of least resistance into the desired areas. To date, the majority of chemical diversion methods have been utilized for acidization treatments, while hydrocarbon based solvents have largely relied on mechanical means of isolation. This paper will provide details on the development, laboratory testing, and case study of a novel chemical system intended to provide diversion for an aliphatic and aromatic based solvent. The use of a delayed viscosifying agent can be custom tailored for each individual wellbore scenario, allowing for optimal fluid placement.