Cross-linked gel hydraulic fracturing fluid can induce high damage in the fracture when left for a long period of time. Any residual gel not produced back reduces the conductivity of the fracture and the well productivity, leading to an extended flowback for cleanup operation, which is not cost-effective.The objective of this study is to assess cleanup operation effectiveness by conducting laboratory testing on the flowback fluid samples from hydraulically fractured wells. These development wells are located in a clastic gas field in Saudi Arabia. This Devonian age reservoir has a range of permeability varying tight rocks of 0.1 md that require stimulation to highly prolific rocks with more than a Darcy that produce naturally. The laboratory analysis technique that was used for assessing the cleanup effectiveness is based on determination of the polymer content in the flowback fracturing fluid with a size exclusion chromatography (SEC). This laboratory technique provides the polymer concentration in the return fluid in a series of samples collected throughout the cleanup operation, and based on its results coupled with the production performance, the polymer strength of the residual fracturing fluids can be inferred. This study shows that the SEC technique is effective in qualitatively determining the polymer concentration trend with the flowback time, to assess the residual polymer content. The results are useful in establishing trends for the effective flowback practices based on different reservoir and fracture characteristics, even if fracturing fluids contain breaking agents. Using the laboratory results to optimize these parameters, formation damage can be minimized and well productivity will be ultimately enhanced.This paper summarizes results from the chemical analyses of the flowback fluids from three gas wells that help establish the basis for the flowback cleanup behavior, matched with the reservoir characteristics, fracturing design, fracturing fluid formulations; and concludes with operational recommendations. This study was conducted for the first time in this field with the goal of optimizing flowback duration and cost, and minimizing formation damage; and thereby enhancing well productivity.
