Reservoir Characteristics of the Lower Silurian Longmaxi Shale in Zhaotong Region, Southern China

Abstract

The lower Silurian Longmaxi Formation hosts a highly productive shale gas play in the Zhaotong region of southern China. According to core observation, X-ray diffraction analyses, and scanning electron microscopy (SEM) observations, the shale comprises primarily quartz, carbonate minerals, and clay minerals, with minor amounts of plagioclase, K-feldspar, and pyrite. The clay mineral content ranges from 15.0% to 46.1%, with an average of 29.3% in the Zhaotong region. Organic geochemical analyses show that the Longmaxi Formation has good potential for shale gas resources by calculating total organic carbon, vitrinite reflectance, and gas content. Scanning electron microscope images demonstrate that reservoir pore types in the Longmaxi shale include organic pores, interparticle pores, intercrystalline pores, intraparticle pores, and fractures. Reservoir distribution is controlled by lithofacies, mineral composition, and geochemical factors. In addition, we investigated the relationships between reservoir parameters and production from 15 individual wells in the Zhaotong region by correlation coefficients. As a result, the brittleness index, total organic carbon (TOC), porosity, and gas content were used to define high-quality reservoirs in the Longmaxi shale. Based on these criteria, we mapped the thickness and distribution of high-quality reservoirs in the Longmaxi Formation and selected highlighted several key sites for future exploration and development.

Advances on the Mechanism of Reservoir Forming and Gas Accumulation of the Longmaxi Formation Shale in Sichuan Basin, China

“…Exploration in the basin has greatly promoted the development of shale gas in China. Several commercial shale gas fields, including Fuling, Weirong, Changning, Zhaotong, and Taiyang, have been established and contribute significantly to increasing natural gas production in China. − …”

Poços horizontais e fraturamento hidráulico na formação Irati, Bacia do Paraná. Uma análise à luz da experiência dos países produtores

“…Irati. Assim, alicerçado em revisão bibliográfica de outros documentos que tratam de temática similar, é possível identificar alguns parâmetros geológicos, mineralógicos e geoquímicos e que necessitam ser avaliados, quando se trata de comparações desta ordem, como: idade geológica, ambiente deposicional, área (em km²), profundidade (m), espessura média da camada de interesse (m), litologia, mineralogia, COT médio (%), para que se estabeleça uma analogia minimamente segura (ANDREWS, 2013) Fonte: Elaborado pelo autor a partir de Aboarrage e Lopes (1986), Alexander (2015), Alsalem et al (2016), Araújo et al (2000), Askenazi et al (2013), Cardneaux (2021), Chong et al 24 (2010, apud Euzen, 2011, Dong et al (2018), Ferri et al (2014, Hall et al (2011), Hentz e Ruppel (2011), Li et al (2016), Liu et al (2021), Luo et al (2020), Ramos e Formoso (1975), Rezaee et al (2015), Rocha (2016), Sales e Sosa (2013), Silva (2007), Tassinari et al (2021) e Wilson (2019.…”