Technical and Economical Screening of Chemical EOR Methods for the Offshore

Abstract

Enhanced oil recovery (EOR) and maximizing recovery from declining production fields remain a challenge in the offshore industry. The challenge is to find an EOR method that is both technically and economically feasible considering the high capital and operating costs in the offshore environment. The goal of this work was to conduct a simple cost-benefit analysis based on a technical, facility, and economical screening of chemical EOR methods applicable to the offshore. Offshore Newfoundland, Canada is used as a base case as it represents a challenging geographical environment. The reservoir properties are good, based on volumetrics and characteristics, but the fields are located over 300 km offshore in a harsh environment where operational costs are high. A data mining approach was used for the EOR screening process. Data from over one thousand core flooding experiments investigating various chemical EOR methods, including surfactant, polymer, alkaline-surfactant (AS), alkaline-surfactant-polymer (ASP), nanoparticle, and low salinity water injection (LSWI), were collected. Factors with the greatest influence on the performance of a given EOR method were statistically examined and discretized. The ranges of recovery factor, rock type, chemical concentrations, and the most commonly used chemicals are presented in this review paper. Economic factors examined included capital expenditures (CAPEX) and the operating cost of production (OPEX). Benefits are found to be strongly related to oil production and Brent crude oil forecasts. Sensitivity studies of the recovery factor ranges with the different chemical concentrations, net present values (NPV), and the influence of the inflation were all taken into consideration. Two different injection plans were considered: injection from day one of production, and injection after secondary production. The highest CAPEX and OPEX were calculated for the ASP method, whereas LSWI resulted in the lowest. The results indicate that most of the chemical EOR methods could be economically successful, however, the timing of implementation will affect the potential benefits. If high recovery and low chemical concentrations are considered, ASP flooding is the most successful chemical EOR method when injecting from day one. However, if the EOR method starts after a decline in production, surfactant flooding proves more beneficial, regardless of the scenario considered. This paper presents a systematic approach to chemical EOR screening, combining available technical data using a data analytics approach with economic and technical uncertainty.

Evaluation of the Oil Recovery Potential and Cost Implication Analysis of Alternative ASP Formulations for Sandstone and Carbonate Reservoirs

“…The economic evaluation performed is a simple cost-benefit analysis. It is very useful in determining the economic feasibility of a project through comparison of project cost against the benefits gained from the project . This type of economic evaluation is essential since it only deals in monetary terms …”

“…It is very useful in determining the economic feasibility of a project through comparison of project cost against the benefits gained from the project. 40 This type of economic evaluation is essential since it only deals in monetary terms. 41 The objective of this part of the study is to conduct a normalized economic evaluation of the various ASP formulations.…”

A Mechanistic Study of Wettability Alterations in Sandstone by Low Salinity Water Injection (LSWI) and CO2 Low Salinity Water-Alternating-Gas (WAG) Injection

“…However, this carbonic acid dissociates very rapidly at ambient conditions to bicarbonate [54], as shown in reaction (7). The bicarbonate electrolyte in the solution can also form 𝐶𝑂 as shown by reaction (8).…”

“…Another advantage for LSWI is that it can be combined with other EOR methods to further improve oil recovery [4][5][6]. According to economic evaluations on chemical EOR methods by Al-Murayri et al [7] and Muriel et al [8], LSWI and CO2 injection generate the highest net present value (NPV) and both methods are effective in increasing oil recovery. Therefore, a hybrid technique termed CO2 low salinity water-alternating-gas (LSWAG) injection, which combines the EOR effect of both methods, has been developed over the last 15 years.…”

Low Salinity Water Flooding (LSWF), Can We Move Forward? The Economic Case

“…Sadeed et al (2018) found the main parameters when optimizing LSWF economics in a Middle Eastern carbonate reservoir were the number and duration of slugs, degree of dilution, and injection and production rates. Based on technical, facility, and economical challenges, Muriel et al (2020) presented a cost-benefit analysis with a focus on offshore fields. The study compared LSWF with alternative chemical EOR methods, such as surfactant flooding, alkaline-surfactant, polymer flooding, alkaline-surfactantpolymer flooding, and nanoparticle injection in two different scenarios: (1) injection from the first day of production (2) injection after secondary production.…”