Brittleness modeling selects optimum stimulation zone in shaly source rocks in the Whangai Formation, New Zealand
| Autor: | Jesus Pastor Salazar, Fernando Della Pasqua, Luiz Antonio Pierantoni Gamboa, Giovanni Chaves Stael, Claudio Rabe, Raul Correa Rechden Filho |
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| Rok vydání: | 2021 |
| Předmět: |
Total organic carbon
Uniform distribution (continuous) business.industry 020209 energy Fossil fuel Perforation (oil well) Energy Engineering and Power Technology Geology 02 engineering and technology Structural basin Pore water pressure Fuel Technology Brittleness Source rock Geochemistry and Petrology 0202 electrical engineering electronic engineering information engineering Earth and Planetary Sciences (miscellaneous) Petrology business |
| Zdroj: | AAPG Bulletin. 105:329-355 |
| ISSN: | 0149-1423 |
| DOI: | 10.1306/07202018194 |
| Popis: | Within New Zealand, the East Coast Basin represents the primary shale oil and gas play in which the Whangai Formation is widespread. This formation is oil and gas prone and prevalent throughout a large area of the East Coast Basin and is typically composed of the Upper Calcareous, Porangahau, and Rakauroa Members. The primary goal of this study was to develop an integrated methodology to define the best stimulation intervals in the formation. To do this, we evaluated four different definitions of the brittleness index for the Rakauroa Member, the only member drilled in the three study wells. A Python-based automated process was specifically developed for this purpose and uses four indexes: elastic parameters, internal friction coefficient, mineralogy, and total organic carbon content. Through this process, these four indexes were analytically combined to select intervals with the highest brittleness values and identify the optimum stimulation interval and most desirable perforation intervals in the pay zone. Our results show that the Whangai Formation contains 25% clay (and reaching up to 70% clay content in some intervals) and a maximum organic matter content of 2.54%. The geomechanical model indicates a uniform distribution of high pore pressure across the entire reservoir section. The interval between 1497 and 1750 m in the Opoutama-1 well located in the Coastal block presents high combined brittleness indexes, indicating excellent characteristics from a stimulation standpoint. |
| Databáze: | OpenAIRE |
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