Recovery of impregnated hydrocarbon in drill cuttings using supercritical carbon dioxide

Intuitionistic fuzzy-based entropy weight method-TOPSIS for multi-attribute group decision-making in drilling fluid waste treatment technology selection

Drilling fluid waste is produced by oil and gas industry operations and can potentially cause serious environmental pollution and energy consumption if not properly treated. Currently, there are several treatment methods available for drilling fluid waste such as bioremediation, thermal treatment, solidification/stabilization treatment, electrochemical remediation, physiochemical treatment, and supercritical fluid treatment. However, selecting an adequate method to treat drilling fluid waste is a critical consideration. The objective of this work is to analyze the problem of drilling fluid waste pollution and treatment methods, establish a drilling fluid waste treatment decision index system that takes into account various factors, and apply the intuitionistic fuzzy-based entropy weight method (EWM)-technique for order of preference by similarity to ideal solution (TOPSIS) method to make a multi-attribute group decision on drilling fluid waste treatment methods. The method is then applied to the WBQ004-1-H1 drilling project as an example for comprehensive analysis. The final decision results show that A3 (0.566) > A1 (0.537) > A6 (0.526) > A5 (0.485) > A4 (0.478) > A2 (0.447), so the solidification/stabilization treatment is the most suitable method for this project, providing new insights into selecting drilling fluid waste treatment methods in actual projects.

Physical and chemical characterization of drill cuttings: A review

Drill cuttings comprise a mixture of rocks generated during drilling activities of exploration and production of oil and gas. These residues' properties are variable, depending on several drilling parameters and drilled rock composition. Many scientific studies have been published regarding the characterization of these residues. Articles summarizing these residues' characteristics and toxicity data are poorly explored in the literature. This work reviews the principal methods used to characterize drill cuttings and data about these residues' properties. Some authors have reported the large content of Zn in drill cuttings. These cuttings can be associated with base fluids (as olefins, varying from C11 to C18), and some time crude oil (high range of TPH, unresolved complex mixtures, and PAH compounds). Acute and chronic toxicity tests have shown negative impacts of different types of fluids, the components of these fluids, and cuttings on other marine organisms.

Physical-chemical characterization and leaching studies involving drill cuttings generated in oil and gas pre-salt drilling activities

This work describes characterization and leaching studies of pre-salt drill cuttings from offshore oil and gas exploration in ultradeep waters. The metals Fe, Al, and Ba were present in the highest concentrations in drill cuttings (30000 mg kg^-1, 32600 mg kg^-1, and 33000 mg kg^-1 respectively). The most significant contents of Ba, Al, Fe, Cu, Pb, Mn, Si, and Zn were found in cuttings containing non-aqueous fluids (NADF), but the highest concentrations of Ni and Cr were found in samples containing aqueous fluids (WBDF). The content of total petroleum hydrocarbons (TPHs) in the samples with WBDF fluids ranged from < 5.58 to 15.76 mg Kg^-1 while the TPH content of the samples with NADF ranged from 28.46 to 47.16 mg Kg^-1. Data on the content of unresolved complex mixtures (UCMs) and sheen tests indicated probable contamination of some cutting samples with oil. Most samples showed some degree of contamination by polycyclic aromatic hydrocarbons (PAHs). The metals present in the highest concentrations in saline and aqueous leachates were Si and Ba. The metals Cd, Cu, Ni, and Zn were present in varied concentrations in the saline leachates, and the metals Si, Ba, Cu, and Zn were found in the aqueous leachates.