This paper contains a summary of the lessons learned in 4 years of experience with using Nitrogen generated on project sitefor as solutions for several different types of operation for optimizing field productivity in offshore and remote location scenarious. Nitrogen is used in many applications in field drilling and production operations such as:
Inductions operations immediately after drilling or well intervention.
As a means of lifting for well testing.
Sand clean up after a fracturing operations.
Removal of solids such as paraffin or hydrates.
Commissioning of valves, pipelines, vessels, production facilities and FPSOs.
Drilling wells in underbalance condition.
All these practices have became cost effective solutions not just to accelerate the processes, but also to provide safe, high efficiency and low logistical requirements operations. The application in offshore scenarious is now becoming essential because effective solutions in such high cost operations can have a major impact on the economics of the projects.
This paper will include some sxamples of typical and some specia lactivities showing comparisons with conventional solutions in order to help decision makers to find out when the use of membrane non cryogenic Nitrogen is the best choice and when a conventional solution is more suitable.
Nitrogen generated in place is just a physical separation by membranes which can be used worldwide with no limitations on climate, geography or accessibility to the location. It is interesting then to share these experiences with other project managers who may think about the solution but donâ??t have parameters available to identify when any given application is appropriate.
The use of non-cryogenic Nitrogen was introduced in the petroleum industry some 40 years ago. It has always been well recognized that in situ generatin is advantageous where logistics issues make it difficult to keep the Nitrogen supply all time it is required for the project. Once determined the maximum SCFM of Nitrogen required has been determined, the NPU - Nitrogen Production Unit (NPU) is chosen and the project has a guarantee of the continuity of its supply with no time limit. Several projects require Nitrogen supply for months, which makes the use of Cryogenic supply problematical even if it is readily available. This kind of project demands Nitrogen generated in situ, not only to avoid logistic issues and high costs, but also from a safety point of view due to the necessity of keeping a stable and continuous supply of Nitrogen at all times.
While the in situ system of generating Nitrogen started gaining acceptance, satisfied customers wanted to make it applicable for more scenarios and operational personnel gained experience in maintenance and control of the NPUs. At the same time engineering personnel were able to generate compact units which are very easy to mob/demob and very quick to rig up/ rig down. These facts made the Nitrogen generated by membranes more and more economic, arriving to the point that nowadays, the use of non-cryogenic Nitrogen is no longer limited to those projects which require high volumes of Nitrogen.
