Bergen, Norway
Bergen, Norway

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Ridyard D.,EMGS Americas | Hesthammer J.,Rocksource
World Oil | Year: 2011

Several oil companies such as ExxonMobil, Statoil and Shell, have been adopting electromagnetic (EM) imaging technology to reduce exploration risk in marine environments. EM data have been shown to be highly accurate in identifying subsurface resistivity variations with the commercial exploration drilling success rate of 50-70% for exploration wells drilled on prospects with a significant EM anomaly, compared to 5-14% for wells drilled on prospects without a significant EM anomaly. EM technology offers several benefits such as it avoids drilling dry wells and another benefit is to drill discoveries on prospects with an EM anomaly. EM surveys can provide useful quantitative information to delineate the reservoir and improve the estimation of fluid type and saturation. The additional value may be created by more accurate knowledge of the value of reserves obtained through integrated analysis of the EM data.


Sperrevik S.,Rocksource | Berry K.,Envision | Cumming D.,Rocksource | Eaton S.,Rocksource | And 5 more authors.
72nd European Association of Geoscientists and Engineers Conference and Exhibition 2010: A New Spring for Geoscience. Incorporating SPE EUROPEC 2010 | Year: 2010

This presentation focuses on how new prospectivity has been identified and developed in a quite mature area on the Norwegian Shelf. The area of interest was recently awarded to PL 559 in the APA 2009 licensing round. It is located at the Nordland Ridge in blocks 6608/10 and 6608/11 just east of several discoveries and fields. The area has previously been part of license PL 128 since 1986, but was stepwise relinquished over the last few years due to disappointing well results where many of the traditional prospects have been proved dry. In the current study the entire area has been interpreted on 3D seismic, which has been tied to nearby wells. Using a new play concept and integrating data we have identified multiple attractive prospects of high commercial value at several different target intervals which have all been proven to contain oil in discovery wells immediately to the west. Studies including pressure evaluation, fault seal studies and migration modeling have been performed to mature and de-risk the prospects. CSEM modeling confirmed that the prospectivity was feasible for de-risking using CSEM technology, and both proprietary CSEM data as well as published material has been used in order to de-risk the prospectivity further. © 2010, European Association of Geoscientists and Engineers.


Hesthammer J.,Rocksource | Hesthammer J.,Entergy | Rykkelid J.I.,Rocksource | Sperrevik S.,Rocksource | And 2 more authors.
First Break | Year: 2011

In the 2009 licensing round for predefined areas on the Norwegian Continental Shelf, three oil companies were awarded stakes in licence PL 559 in the Norwegian Sea. An interesting aspect of this award is that the area had previously been derisked by another oil company using, among other data types, controlled source electromagnetic (CSEM) data. This led to the drilling of a dry well and subsequent relinquishment of the area. The negative result was perceived as a failure of the CSEM technology in terms of being a false positive. However, a preliminary revised interpretation of the area provided an alternative explanation for the dry well, suggesting that the observed EM anomaly was positioned outside the dry well location. After a successful licence application, new CSEM data were acquired. The alternative explanation was strengthened after detailed analyses of the new data provided support for the presence of hydrocarbons as the most likely explanation for the observed CSEM anomaly. The revised interpretation will be tested by the drilling of an exploration well during the autumn of 2011, and the results will be important in order to better understandthe potential of CSEM technology for hydrocarbon exploration. © 2011 EAGE.


Stefatos A.,Rocksource | Hesthammer J.,Rocksource | Sperrevik S.,Rocksource
73rd European Association of Geoscientists and Engineers Conference and Exhibition 2011: Unconventional Resources and the Role of Technology. Incorporating SPE EUROPEC 2011 | Year: 2011

The systematic approach that was followed over a time span of more than 4 years on the NCS and in the Barents Sea in particular, allowed to carry out a detailed prospect analysis in a portfolio setting. The award of highly competitive exploration licenses in the NCS in 2008 proved that the incorporation of the CSEM technology in the pre-application exploration strategy was very successful. Over the second and third quarters of 2011, two exploration wells will be drilled in the PL535 and PL530 licenses in the Barents Sea.


Hesthammer J.,Rocksource | Stefatos A.,Rocksource | Boulaenko M.,Rocksource | Fanavoll S.,EMGS | Danielsen J.,EMGS
Leading Edge (Tulsa, OK) | Year: 2010

During the past several years, we have seen an increasing focus on the use of CSEM technology for hydrocarbon exploration in marine environments and, recently, a number of success stories have been published. The technology has been demonstrated to aid both detection and delineation of hydrocarbon-filled reservoirs. © 2010 Society of Exploration Geophysicists.


Stefatos A.,Rocksource | Hesthammer J.,Rocksource | Boulaenko M.,Rocksource
4th International Conference and Exhibition: New Discoveries through Integration of Geosciences, Saint Petersburg 2010 | Year: 2010

Proper use of CSEM technology requires detailed modeling studies prior to acquisition to ensure that the outcome from subsequent analyses of real data will actually enable the oil companies to change their decisions. Detailed modeling studies from West Africa shows that the reservoir burial depth is the most important systematic factor that affects feasibility. Water depth, transverse resistivity and resistivity contrast of reservoir to the background are also important, but do not exhibit a direct, systematic control on the feasibility and therefore should not be considered as apriory limiting factors to the applicability of the CSEM surveys. Instead, case specific modeling is required to determine the feasibility of the CSEM technology for the particular prospects.

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