Data Analysis for Polymer Flooding That Is Based on a Comprehensive Database

Abstract

Summary It is of major importance to analyze polymer-flooding data because they can be used to obtain screening criteria and identify where and how polymer can be best used to enhance oil recovery. However, recently published screening criteria regarding polymer flooding were based on data collected from the biannual enhanced-oil-recovery (EOR) surveys published by the Oil & Gas Journal. These data recorded valuable information for finished and ongoing polymer flooding worldwide, but they are constrained in two ways. First, they do not include some important information, such as the formation-water salinity, divalent-cation concentration, and polymer type and concentration. Second, the field data do not reflect recent polymer-technology developments that are still in the laboratory-evaluation and pilot-testing stages. To overcome these limitations, a comprehensive data set that provides the overall picture of polymer-flooding research and application is presented in this paper. In total, 865 polymer-flooding projects were considered to construct the data set, including 481 field projects from the Oil & Gas Journal (1974–2012), 329 laboratory experiments (1964–2013), and 70 pilot test projects (1966–2016) recorded in the literature. The laboratory data include porosity, permeability, oil viscosity, polymer molecular weight (MW), polymer viscosity, polymer concentration, polymer-slug size, water salinity, and divalent-cation concentration. All the data reported in this paper showed the experimental conditions that researchers used, which is consistent with the objective of our work. Our purpose is to summarize the data and tell the conditions in which polymer had been tested rather than presenting the screening criteria for polymer-flooding applications. For pilot and field tests, we only select those papers in which a project reaches or exceeds the goal of the project design. Graphical and statistical methods are used to analyze and describe the data set. The distribution of major parameters important to polymer-flooding design is presented with histograms, and the range of all parameters and their statistical values are presented with box plots. The existing data collected in this work have been statistically analyzed, resulting in some generic trends that could aid future readers in the design of a successful polymer-flooding project, such as data pertaining to the formation-water salinity, polymer MW, concentration, and polymer viscosity.