Rock physics changes due to CO2 injection : the CO2CRC Otway Project

The CO2CRC Otway Project aims to demonstrate that CO2 can be safely stored in a depleted gas field and that an appropriate monitoring strategy can be deployed to verify its containment. The project commenced in 2005, with the baseline 3D seismic collected early in January 2008. CO2 was injected into depleted gas reservoir known as Waarre-C at Naylor field in April 2008. The first monitor survey was recorded in January 2009, shortly after the injection of 35,000 tonnes of CO2. Early predictions in the program suggested that the resulting time-lapse seismic effect will be very subtle because of the reservoir depth, small area, complexity, small amount of CO2/CH4 in 80/20 ratio injected and most of all partial saturation of the reservoir sand. The key challenge than presented to this research was how subtle exactly is the effect going to be? To answer that question I had to develop a workflow that will produce very accurate prediction of the elastic property changes in the reservoir caused by CO2 injection. Then the sensitivity of time-lapse seismic methodology in detecting subtle changes in the reservoir is investigated.The rock physics model I propose uses the “effective” grain bulk modulus (Kgrain) to represent the average mineralogy of the grains. The validity of this approach is confirmed by good agreement achieved between Vpsat core with Vpsat computed from the log data using the “effective” modulus. . The use of “effective” Kgrain was further justified by petrographic analysis. This has increased the modelling precision and changed the predicted time-lapse effect due to CO2 injection from 3% as an average over the reservoir sequence as previously computed to nearly 6%. The significance is that 6% change could be detected with high precision monitoring methodologies. The in-situ saturation type is homogeneous, according to the analysis path assumed in this thesis. If some patchiness exists in the reservoir it will be away from the wells and it would further elevate CO2 related seismic effect.The time-lapse seismic methodology at Otway site utilised very high survey density in order to increase sensitivity. On the negative side, weak sources and the change of the source type between the surveys resulted in non-repeatability greater or of the similar order as the time-lapse signal were expected to be. Hence the interpretation of the time-lapse P-wave seismic data assumed somewhat different path. I used the model-based post-stack seismic acoustic inversion in a similar way that history matching is used in reservoir simulation studies. I performed successive fluid substitutions, followed by the well ties and inversions. The objective was to look into the inversion error. Then the modelled fluid saturation case that result in minimal inversion error reflects the most likely state of the reservoir. Modelling using 35,000 tonnes of CO2/CH4 mix with 35% water saturation and 65% CO2/CH4 mix produced the smallest error when reinstating logs to the 2009 reservoir state.The time-lapse anomaly observed in the data exceeds predictions derived through the rock physics model, seismic modelling and simulation models. This is likely to be the case in general as the effect of CO2 onto a reservoir is difficult to predict. A “conservative” approach may result in an under-prediction of time-lapse seismic effects. Consequently, the predicted and measured seismic effects can be used as the lower and the upper bound of the time-lapse effects at Naylor field, respectively. The method presented here for analysis of a subtle time-lapse signal could be applied to the cases with similar challenges elsewhere

CO2CRC/Otway Project - Influence of Geological and Reservoir Parameters on expected time-lapse seismic signal

In the field of CO2 storage, one important goal is to be able to prove that the injected CO2 is safely stored, and that no leak is occurring. Time-lapse seismic is one of the most powerful tools available for this purpose. However, it is generally used in a qualitative way, to map the injected CO2. Several attempts have been made to use it quantitatively, which are based on the measured time-shifts throughout the seismic volume. Here, we assess the impact of geological and reservoir parameters on the predicted time-lapse signal, which is a first step towards quantification. Uncertainties occur when trying to evaluate the expected timelapse seismic signal. Porosity and permeability are constrained at the wells, but, as is standard in the E&P industry, statistics are used to distribute them throughout the reservoir volume, which is a source of uncertainty. Some reservoir parameters need to be measured, and are poorly constrained for CO2. Our results show that these parameters have an impact on seismic signal prediction, which is not overwhelming (generally below 30%)

Effect of Aeration and Nutrients on Saccharomyces cerevisiae Cultivation using Lignocellulosic Hydrolysate from Empty Fruit Bunch

Indonesia has wide palm oil plantation which produce Empty Fruit Bunch (EFB) waste around 32 million tons per year. EFB is a potential material for bioethanol through pretreatment, saccharification, and fermentation. Fermentation has important role in bioethanol production because this process will convert glucose into ethanol. The most common microorganism used in fermentation process is Saccharomyces cerevisiae. But, the use of S. cerevisiae in bioethanol fermentation using lignocellulosic hydrolysate have a problem that microorganisms cannot grow well. This is due to the presence of inhibitor in the hydrolysate. Solution for this problem is using S. cerevisiae which cultivated on hydrolysate media that will be used in the fermentation (in this case EFB). This research will investigate cultivation of S. cerevisiae on EFB hydrolysate, to obtain the optimum operating conditions such as aeration and nutrients. Fed-batch system is used for cultivation. Optimum condition are determined after analyzing cell number and ethanol yield from dried S. cerevisiae. Optimum condition for cultivation are 1 v/v per min aeration and glucose 5 g/L which produce ethanol yield 24%. We also scale-up the dried yeast into 43.7 g and need a cost Rp 19,958/g which is more expensive than commercial yeast

Integrated rock physics models for improved 4D seismic monitoring of CO2 sequestration in Otway Basin, Australia

We build a detailed rock physics model that links the rock and fluid properties with seismic properties and accounts for variations in reservoir quality, fluid saturations, and seismic resolution. This approach will increase the accuracy of the predicted changes in elastic properties of the reservoir rock by calibration of the down-hole petrophysical log with core sample data and ultrasonic measurements. The results indicate that Vp core saturated provide good agreement with Vp log measurement when the “effective” Kgrain is applied. Results also suggest that “effective” Kgrain may be used to represent the average mineralogy of the grains. A comparative analysis has also been performed incorporating the petrographic descriptions and geochemical analysis. The expected mineralogy derived from “effective” Kgrain and petrographic analyses are very close further confirming the model. This type of detailed rock physics analysis provides the capability to forecast more accurately the changes in the 4D seismic response during long-term CO2 storage at the site, and could be a useful tool for future storage sites with similarly challenging geophysical monitoring objectives

The Importance of Civic Education Learning on Nationalism in the Era of Globalisation

Abstract In this era of globalization, there are negative and positive impacts that can significantly affect the character or identity of Indonesian society, especially the younger generation and the loss of a sense of nationalism or love for the Republic of Indonesia. Therefore, Civic Education is the basis for the younger generation in Indonesia in responding to the negative impacts of globalization. This research uses a library method that is looking for reliable sources such as scientific journals, research articles and descriptive reports that are relevant. The results of this study indicate that the role of Civic Education is very important for the Indonesian state in this era of globalization, which aims to preserve the character or identity of the Indonesian state and be able to compete with foreign cultures. This has proven to be very important for the Indonesian people, such as the Indonesian people being able to think critically, have innovative and creative and of course obey the rules that apply in Indonesia. Therefore, understanding the role of civic education through the education sector requires synergy between all stakeholders. This will be the main capital needed in the current era of globalization. The term globalization is not a new term or a term of the day. Globalization can also be defined as the process of entering into a world that affects all important aspects of human life. Keyword: Civic Education, Nationalism Attitude, Nationalism in the era of globalizatio