Revised MMS Regulations on Shallow Geohazards in the Gulf of Mexico

Abstract

Abstract This paper discusses safety and technology considerations that form the basis of the new Minerals Management Service (MMS) Notice to Lessees and Operator (NTL) on shallow geohazards in the Gulf of Mexico OCS. The previous NTL addressing shallow hazards requirements was issued in 1983, and contained only minor changes to the original guidelines implemented in 1973. An open industry Gulf of Mexico geophysical/geotechnical forum was established in 1997 and, at its initial meeting, the MMS presented proposed revisions to the existing NTL 83-3. A select committee on Gulf of Mexico site investigation then developed a proposal to incorporate new technology such as high-resolution 3D seismic data reprocessed for shallow hazards assessment. The primary intent of their suggestions was to cover new deepwater geohazard challenges, such as shallow waterflow and gas hydrates, and the improved technology and data now available for their mitigation. The resulting NTL provides a combination performance- and prescriptive-based guidance and standards for shallow hazards surveys. MMS geophysical and geological reviews of plans of exploration, development operations coordination documents, pipeline applications, and applications for permit to drill include precautions on possible, probable, and definite shallow hazards such as pressured gas, faulting, shallow waterflow, and unstable seafloor sediments. The more comprehensive approach of the rewritten NTL will allow the MMS and offshore operators to work together to avoid potential drilling problems and economic loss in the course of exploration and development activities in Gulf of Mexico lease blocks. Introduction The MMS shallow hazards program is designed to ensure that the exploratory, development, production, and transportation operations are conducted with the minimum possible risk to human life and the environment. NTL 98-20, a replacement of NTL 83-3 that merely accommodated changes in the numbering of pertinent federal regulations, specified the required technical standards that have been used to meet this objective in the Gulf of Mexico OCS Region (GOMR). Due to the shifting focus of exploration and development drilling and production in the Gulf of Mexico into deep and ultradeep water and the parallel development of effective new geohazards evaluation techniques, it became imperative that the NTL on Shallow Hazards Requirements be updated to allow for the use of the best available and safest state-of-the-art technology. A draft version of proposed revisions to NTL 83-3 was presented at the initial Gulf of Mexico Geohazards Forum meeting in 1997, and an ad hoc NTL Committee was formed after this meeting with the purpose of providing guidance on the required input for shallow hazards analysis. The objective of both the industry NTL Committee and the MMS was to prepare a world-class document on the nature of shallow hazards on the shelf and in deepwater, data acquisition and processing requirements, and risk assessment and mitigation for use in all Gulf of Mexico OCS oil and gas lease operations. Shallow Hazards Assessment All plans of exploration (POE) and development operations coordination documents (DOCD) that propose seafloor-disturbing activities must include a shallow hazards analysis for each proposed well location and platform site. Additionally, detailed shallow hazards assessments for all proposed pipeline routes are to be included in the pipeline application and the appropriate MMS District Supervisor may also require further shallow hazards evaluation for a specific bottom-founded drilling unit to support a particular application for permit to drill. The objective of shallow hazards assessment is t