Tertiary

Test Your Knowledge

Tertiary: A Defining Era in Oil & Gas Exploration Quiz

Instructions: Choose the best answer for each question.

1. What is the approximate time span of the Tertiary period?

a) 250 million years ago to 65 million years ago b) 65 million years ago to 2.6 million years ago c) 2.6 million years ago to present d) 1 billion years ago to 540 million years ago

2. Which two epochs now encompass what was previously known as the Tertiary period?

a) Paleocene and Eocene b) Paleogene and Neogene c) Oligocene and Miocene d) Pliocene and Pleistocene

3. Why is the Tertiary period important for oil and gas exploration?

a) It was a period of intense volcanic activity, creating abundant geothermal energy. b) It saw the formation of important reservoir rocks and source rocks. c) It was a time of widespread glaciation, leading to the formation of natural gas deposits. d) It was characterized by a lack of tectonic activity, allowing for the undisturbed accumulation of hydrocarbons.

4. Which of the following is NOT a significant geological feature formed during the Tertiary period?

a) Folding and faulting b) Formation of sedimentary basins c) Formation of metamorphic rocks d) Deposition of organic-rich sediments

5. Which of the following is an example of a major oil and gas field located within a Tertiary formation?

a) The Prudhoe Bay field in Alaska b) The Ghawar field in Saudi Arabia c) The North Sea oil and gas fields d) The Bakken shale formation in North Dakota

Tertiary: A Defining Era in Oil & Gas Exploration Exercise

Task:

Imagine you are an oil and gas exploration geologist working in the Gulf of Mexico. You are studying a potential drilling site within a Tertiary formation. Based on your knowledge of the Tertiary period, describe two key geological features that you would look for to indicate a potential oil and gas reservoir. Explain why these features are important for oil and gas accumulation.

Techniques

Tertiary Oil & Gas Exploration: A Deeper Dive

This document expands on the significance of the Tertiary period (now Paleogene and Neogene) in oil and gas exploration, breaking down the topic into key areas.

Chapter 1: Techniques

Seismic surveys form the bedrock of Tertiary exploration. 2D seismic provides a broad overview of subsurface structures, identifying potential basin formations and major geological features. 3D seismic offers significantly higher resolution, allowing for detailed mapping of faults, folds, and reservoir characteristics within the Tertiary strata. The interpretation of seismic data, often aided by advanced processing techniques like pre-stack depth migration, is crucial for identifying potential traps and evaluating reservoir properties. Other techniques include:

• Well Logging: Once a well is drilled, various logging tools provide information on lithology, porosity, permeability, and hydrocarbon saturation, crucial for characterizing reservoirs within Tertiary formations. This includes gamma ray, resistivity, sonic, and nuclear magnetic resonance (NMR) logs.
• Core Analysis: Physical samples (cores) extracted from the wellbore allow for direct measurement of reservoir properties, providing ground-truth data for calibrating seismic and well log interpretations. Detailed analysis of core samples provides information on pore structure, fluid saturation, and rock mechanical properties.
• Mud Logging: During drilling, mud logging provides real-time information on the formation properties encountered, such as gas shows and lithological changes, helping to guide drilling operations and identify potential hydrocarbon zones.

Chapter 2: Models

Geological modeling is essential for understanding the complex interplay of factors that control hydrocarbon accumulation in Tertiary basins. These models integrate data from seismic surveys, well logs, and core analysis to create a three-dimensional representation of the subsurface. Key aspects of Tertiary modeling include:

• Structural Modeling: This involves reconstructing the three-dimensional geometry of faults and folds, crucial for understanding trap formation and hydrocarbon migration pathways.
• Stratigraphic Modeling: This focuses on the depositional history of Tertiary sediments, mapping the distribution of source rocks, reservoir rocks, and seals. This helps identify areas with the highest potential for hydrocarbon accumulation.
• Petrophysical Modeling: This uses well log data to predict reservoir properties throughout the basin, estimating porosity, permeability, and hydrocarbon saturation in unsampled areas.
• Dynamic Modeling: This simulates the flow of hydrocarbons within the reservoir, considering factors such as pressure, temperature, and fluid properties. This helps predict reservoir performance and optimize production strategies.

Chapter 3: Software

Several software packages are used extensively in Tertiary oil and gas exploration:

• Seismic Interpretation Software: Petrel (Schlumberger), Kingdom (IHS Markit), and SeisSpace (CGG) are widely used for interpreting seismic data, building geological models, and visualizing subsurface features.
• Well Log Analysis Software: IP (Interactive Petrophysics), Techlog (Schlumberger), and PowerLog (Halliburton) are used for analyzing well log data, calculating reservoir properties, and integrating with geological models.
• Geostatistical Software: GSLIB, Leapfrog Geo, and SGeMS are used for geostatistical analysis and uncertainty quantification in reservoir modeling.
• Reservoir Simulation Software: Eclipse (Schlumberger), CMG (Computer Modelling Group), and STARS (Schlumberger) are used for dynamic reservoir simulation and production forecasting.

Chapter 4: Best Practices

Effective Tertiary exploration requires adherence to best practices that optimize resource allocation and reduce risk:

• Integrated Approach: Combining data from different sources (seismic, wells, geological data) is crucial for building robust geological models and reducing uncertainties.
• Data Quality Control: Ensuring high-quality data is essential for accurate interpretations and reliable predictions.
• Uncertainty Quantification: Acknowledging and quantifying uncertainties associated with geological models and predictions is vital for informed decision-making.
• Environmental Considerations: Minimizing environmental impact during exploration and production is paramount, adhering to strict regulations and best practices.
• Collaboration and Knowledge Sharing: Effective teamwork and collaboration among geologists, geophysicists, engineers, and other specialists are critical for successful exploration projects.

Chapter 5: Case Studies

Several case studies illustrate the successful application of these techniques and models in Tertiary plays:

• North Sea Brent Field: This field, located in the UK sector of the North Sea, exemplifies the successful application of 3D seismic imaging and detailed reservoir modeling for maximizing hydrocarbon recovery from complex Tertiary structures.
• Gulf of Mexico Deepwater Plays: Exploration in the deepwater Gulf of Mexico highlights the importance of advanced seismic imaging techniques and dynamic modeling in understanding the complex geology and fluid flow in these challenging environments.
• Persian Gulf Giant Fields: The development of supergiant fields in the Zagros Fold Belt demonstrates the effectiveness of integrated geological and geophysical studies in identifying and developing prolific Tertiary reservoirs. These case studies demonstrate how different techniques are applied and the critical role of data integration in unlocking the potential of Tertiary plays. Specific details of each case study would require a more extensive analysis.