Pilots to Determine if Passive Seismic Technologies Can Aid in Solving Field and Exploration Challenges in Carbonates

Abstract

In the Middle East where giant billion barrel oil fields exist and there is the potential to find additional reserves, efforts to pilot advanced geophysical technologies to overcome carbonate challenges are often under consideration. Passive seismic technologies are a new source of information that has the potential to add value in helping overcome field and exploration challenges. Some passive seismic methods are now considered proven technologies in clastic rocks, such as hydro-frac monitoring and microseismic. There are other passive seismic methods which are still considered to be in a research stage. Whether a method will perform the same in a carbonate environment as in the clastic environment is also an important consideration when considering a new technology project in carbonates. When a challenge presents itself and a potential new technology is identified to overcome the challenge it is common practice to first conduct a small pilot. Field and Exploration challenges or problems that the passive seismic technologies have the potential to overcome include among other things, monitoring the impact of faults and fractures on flood front advance, identification of thin thief zones, sweep efficiency and by-passed reserves, water fingering and in exploration the direct detection of hydrocarbons to identify new reserves. Progress in advancing the microseismic technologies suggests that these technologies are not without limitations and should not be treated as a “silver-bullet”. The results of pilots suggest that passive seismic results should be treated like an additional seismic attribute to be integrated with other reservoir characterization and exploration information. The proper matching of passive seismic with other appropriate technologies, such as seismic or VSP images can help overcome limitations and improve interpretation reliability. How to properly pilot a new technology is not always as straight forward and easy as one might think. Difficulties in surface conditions, well integrity, equipment availability and the proper situation to demonstrate value from the passive seismic information often lead to inconclusive results and can make it difficult to get approvals to proceed with yet another redesigned pilot. The following paper documents some of the positive and negative lessons learned from passive seismic pilots.