ISO 19901-10:2021 pdf download – Petroleum and natural gas industries — Specific requirements for offshore structures — Part 10: Marine geophysical investigations.
5  Objectives, planning, and quality management 5.1 General 5.1.1  Objectives and project specifications The general objective of a marine geophysical investigation is to provide information about the seafloor and sub-seafloor that is relevant to the design, placement, installation, operation, assessment/re- assessment, and decommissioning of offshore structures. This includes the assessment of geohazards over the lifetime of the development. This document considers the upper portion of a hydrocarbon well as an offshore structure, and therefore covers the requirements for characterising ground conditions and identifying geohazards that can be encountered by the drilling operation and the installation, use and decommissioning of wells. The depth of interest for a marine geophysical investigation for a hydrocarbon well is typically (as appropriate) — in the case of a targeted hydrocarbon reservoir shallower than 1 000 m below the seafloor, to a depth just above the reservoir, or — for deeper reservoirs, at least 200 m below the preferred setting depth of the first pressure- containment casing string or 1 000 m below the seafloor, whatever is greater. Marine geophysical investigations for pre-drilling well-sites focus on possible gas in the sub-seafloor overlying the reservoir that can pose a threat to the drilling operation. The investigations described here are not concerned with the reservoir that is targeted by the drilling operation. Where relevant, project specifications should refer to methods described in this document. Any references to methods should be accompanied by method-specific information, as applicable. If method-specific information is contained neither in the project specification nor in this document, then contractor’s practice applies.
5.1.2 Georeferencing and GIS Marine geophysical investigation data shall be georeferenced using a coordinate reference system (CRS). Full specifications of the CRS shall be delivered with the metadata; without this CRS reference the description of position is ambiguous. Results from marine geophysical investigations can, with advantage, be presented in a GIS-compatible format. Additional guidance is given in Clause 6 and in A.5.1.2, which contains details of the IOGP’s SSDM as one option for data presentation. 5.1.3 Ground model A ground model is constructed from a database of any valid input data. It can take different forms and, in the strictest sense, can be of any complexity. For example, when based on bathymetric data, it can take the form of a terrain and geomorphological model; or when based on geological data, it can take the form of a geological model. A geological model can include structural, stratigraphic or lithological components typically interpreted from seismic reflection data verified by ground-truthing. If soil-type and soil-strength data are included (see ISO 19901-8), it can be a soil model or a geotechnical model.