Data Analysis and Updated Screening Criteria for Polymer Flooding Based on Oilfield Data

Abstract

Enhanced-oil-recovery (EOR) screening is considered the first step in evaluating potential EOR techniques for candidate reservoirs. Therefore, as new technologies are developed, it is important to update the screening criteria. Many of the screening criteria regarding polymer flooding that have been described in the literature were based on data collected from EOR surveys of the Oil and Gas Journal. However, the data quality has not been addressed in previous research. The data set originally contained 481 polymer-flooding projects from around the world, and it contained some problems, including outliers and duplicate, inconsistent, and missing data. To ensure the quality of the data set before running analyses, boxplots and crossplots were used to detect and identify data problems. After detecting outliers and deleting duplicate and severely inconsistent data records, only 250 projects remained. Both graphical and statistical methods were used to analyze and describe the results of the data set. Two major sets of information were given after data cleaning: The first was that the majority distribution of each parameter was shown by use of a histogram distribution, and the second was that the range of each parameter and some of its statistical values were presented by use of a boxplot. Finally, the screening criteria are presented on the basis of these statistics and the defined data parameters. The developed criteria were compared with previously published criteria, and their differences were explained. The developed criteria show that a polymer-flooding project can be successfully applied in a reservoir with a temperature of less than 210 F, an oil viscosity up to 5,000 cp, and gravity lower to 12 API.

Review on Polymer Flooding: Rheology, Adsorption, Stability, and Field Applications of Various Polymer Systems

“…12,13 Water cut can be reduced up to 50% and the resistance factor can be increased by 5 to 15% as a result of polymer flooding. 11 China is leading in the implementation of PF projects 14,15 and Daqing oil field of China is the largest oil field in terms of PF project deployment. 16 Up to 2004, there were 31 commercial scale PF projects only in the Daqing field with 2427 injection wells.…”

Historical and recent observations in polymer floods: An update review

“…Among multiple variables evaluated, authors highlight the importance of polymer injection rates on project economics concluding that low polymer injectivity has been overcome using horizontal wells and injecting polymer above the formation fracture pressure. Saleh, Wei and Bai (2014) developed a statistical analysis of 481 polymer floods (303 successful, 65 discouraging and 103 unevaluated projects). The main objective of this study was to update screening criteria for polymer flooding based on field data.…”

Introducing Core-Shell Technology for Conformance Control

“…Some of the wide-range recommendations suggested for polymer flooding were: relative to crude oil, gravity > 15°API, viscosity < 150 mPas (preferably < 100 and > 10), composition not critical; for reservoir, oil saturation > 50%, type of formation (lithology) sandstones preferred (but could be used in carbonates), net thickness not critical, average permeability > 10 mD, depth < 9000 ft (about 2750 m), and temperature < 200°F (about 93°C) to minimize degradation. At the time of writing, Saleh et al (2014) published a paper in which screening criteria for polymer flooding had been readjusted after a thorough revision of the collected data from EOR projects reported in a survey of the Oil and Gas Journal as well as other publications. In contrast with Taber et al's recommendations (1997aTaber et al's recommendations ( , 1997b, authors of this recent study suggest the following: gravity > 12°API, viscosity < 5000 mPas, oil saturation > 21%, temperature < 210°F (about 100°C) and permeability > 0.6 mD (though the permeability of target zones should be higher than 10 mD as Taber et al (1997a) had previously suggested).…”