초록 ▼

A method of performing a seismic survey of a hydrocarbon reservoir in the earth formations beneath a body of water includes deploying a seismic cable from a drum carried by a remotely operated vehicle on the seabed. The cable is deployed into a lined trench, which is formed either concurrently with

A method of performing a seismic survey of a hydrocarbon reservoir in the earth formations beneath a body of water includes deploying a seismic cable from a drum carried by a remotely operated vehicle on the seabed. The cable is deployed into a lined trench, which is formed either concurrently with cable deployment or during a previous survey, to ensure good repeatability of successive surveys of the reservoir, in order to enable changes in characteristics of the reservoir, eg due to depletion, to be monitored.

대표청구항 ▼

The invention claimed is: 1. A method of performing a seismic survey of earth formations beneath a body of water, the method comprising the steps of: (a) deploying a seismic cable having a plurality of seismic sensors distributed therealong in close proximity to a locating means at the bottom of th

The invention claimed is: 1. A method of performing a seismic survey of earth formations beneath a body of water, the method comprising the steps of: (a) deploying a seismic cable having a plurality of seismic sensors distributed therealong in close proximity to a locating means at the bottom of the body of water; (b) operating an acoustic source in the body of water to produce seismic signals which enter the formations; and (c) detecting seismic signals which return from the formations with said sensors; wherein the step of deploying the seismic cable comprises deploying the seismic cable from a drum of seismic cable carried by an autonomous or remotely operated vehicle at the bottom of the body of water. 2. A method as claimed in claim 1, wherein the vehicle is towed by a vessel at the surface of the body of water. 3. A method as claimed in claim 1, wherein the vehicle is controlled and/or supplied with electrical power from a vessel or buoy at the surface of the body of water. 4. A method as claimed in claim 1, further including subsequently re-deploying the same or another such seismic cable in close proximity to the same or another such locating means and repeating steps (b), (c) and (d). 5. A method as claimed in claim 1, further including the step of providing the locating means at the bottom of the body of water. 6. A method as claimed in claim 5, wherein the providing step is performed prior to or substantially concurrently with the first performance of step (a). 7. A method as claimed in claim 6, wherein the providing step includes providing locating devices at intervals along the length of the locating means, each locating device serving to uniquely identify a respective point along the length of the locating means. 8. A method as claimed in claim 7, wherein the providing step comprises securing an elongate metallic member to, or at least partly burying the member in, the bottom of the body of water. 9. A method as claimed in claim 5, wherein the providing step comprises forming a trench in the bottom of the body of water, and step (a) comprises laying the seismic cable in the trench. 10. A method as claimed in claim 9, wherein the trench forming step includes lining the trench.