This research seeks to evaluate the critical risks associated with Oil and Gas Construction Projects (O&GCPs) in terms of their level of significance and quantifiable effects on Project Performance (PP) by surveying O&GCPs experts in the USA. A multiphase research methodology was adopted, including Systematic Literature Review (SLR) to identify the key O&GCPs risks; semi-structured interviews to identify PP indicators and establish hypotheses on the effect of O&GCPs risks on PP; surveys to assess the perceived agreement of O&GCPs experts regarding the effects of O&GCPs risks on PP, and to rank the probability and impact of the identified O&GCPs risks; Structural Equation Model (SEM) to quantitatively assess the effects of O&GCPs risks on PP; Fuzzy Set Theory (FST) to assess the level of significance of O&GCPs risks; and interviews to verify the developed assessment models and their outputs. The SLR analysis identified 35 articles on O&GCP risks from 2013 to 2023, revealing 51 risk factors in eight categories based on their sources. The SEM analysis indicated that the oil and gas safety risks category had the strongest direct impact on PP. Furthermore, the FST analysis revealed that non-compliance with PPE emerged as the most significant risk factor across all categories of O&GCP risks. This study enhances knowledge and practice by aiding researchers and practitioners in understanding how key O&GCP risks impact PP. This improved understanding is expected to facilitate the formulation of effective mitigation strategies during the early stages of the projects.