A Potential Approach to Predict Wax Precipitation from Reservoir Core Analysis

In the context of reducing production costs for the oil industry, this paper aims to suggest a way for predicting wax precipitation at an early stage of the reservoir characterization and production process. In this respect, reservoir core extracts and production oil-saturated fractions have been herein analyzed by high temperature gas chromatography (HTGC) in order to quantify the high molecular weight hydrocarbons (HMWHC) which are at the origin of wax deposits in the tubing and surface facilities. Samples of oils and associated reservoir cores from two adjacent but non-communicating fields are considered in this paper. Wax deposition is documented for Field P but not for Field A. It is demonstrated that the reservoir core extract of Field P is substantially enriched in HMWHC when compared to the produced oil, whereas for Field A, with no production problems, both profiles (oil and reservoir core extracts) are similar and depleted in HMWHC. These results suggest that fields exhibiting a risk of wax precipitation could be identified during the exploration phase as soon as reservoir cores are available. Moreover, it can be envisioned that such additional data provided by the saturates distribution can potentially be used in future thermodynamic models (derived from those currently applied for assessing wax precipitation in pipelines during the transport of produced oil) in order to quantitatively predict, at an early stage of reservoir characterization, paraffins precipitation in reservoirs and tubings during production. The preliminary computed results obtained for the produced oil and the reservoir rock extract of Field P indicate that the temperature of paraffin crystallization onset is significantly under-estimated when using the composition of tank oil (42°C)-heavy paraffins are already deposited. On the other hand, the predictive calculation, using the core extract (52°C) and which can be performed as soon as a core sample is available, will allow us to minimize the risk of paraffin deposition during production and transportation. Corresponding author (I. Kowalewski

A year of lava fountaining at Etna: Volumes from SEVIRI

We present a new method that uses cooling curves, apparent in high temporal resolution thermal data acquired by geostationary sensors, to estimate erupted volumes and mean output rates during short lava fountaining events. The 15 minute temporal resolution of the data allows phases of waxing and peak activity to be identified during short (150-to- 810 minute-long) events. Cooling curves, which decay over 8-to-21 hour-periods following the fountaining event, can also be identified. Application to 19 fountaining events recorded at Etna by MSG’s SEVIRI sensor between 10 January 2011 and 9 January 2012, yields a total erupted dense rock lava volume of 28 106 m3, with a maximum intensity of 227 m3 s 1 being obtained for the 12 August 2011 event. The timeaveraged output over the year was 0.9 m3 s 1, this being the same as the rate that has characterized Etna’s effusive activity for the last 40 years

Quantitative Real-Time Reverse Transcription-PCR Assay for the Expression of Tob mRNA in Human Colorectal Cancer

OBJECTIVE Tob is a member of Tob/BTG antiproliferative family. To date, Tob expression in human carcinoma using clinical specimens has not been studied in depth except for lung carcinoma and thyroid carcinoma. This study is the first to investigate the expression levels of Tob gene in human colorectal cancer tissues, and their corresponding para-cancerous tissues. The correlation of expression of the Tob gene with clinicopathological characteristics of colorectal cancer was also analyzed. METHODS Quantitative real time RT-PCR was used to detect the expression of Tob mRNA in 31 colorectal cancers. RESULTS Compared with normal tissues, up-regulation of Tob mRNA was observed in 31 colorectal cancer tissues (P =0.020). The expression level of Tob at Dukes C + D phase was higher than Dukes A + B phase, and the difference was signifi cant (P < 0.05). However, in this study, it was found that the expression of Tob mRNA was not related with age, gender, and pathological type of colorectal cancer. CONCLUSION The up-regulation of Tob may be closely associated with tumorigenesis of colorectal carcinoma