Scholarlink

Abstract <p>This study examines the geomechanical and fault seal characteristics, alongside the stratigraphic and petrophysical properties, of an Offshore Field in the Niger Delta Basin, to evaluate its potential for carbon&#xa0;dioxide sequestration. Lithological analysis identifies two reservoirs (RES A1 and RES A2), separated by a marine shale caprock. Structural analysis reveals a syn-depositional anticline caused by compressional forces, likely influenced by the intrusion of a mobile shale diapir from the deep Offshore Niger Delta Basin, resulting in an asymmetric fold with steep and gentle limbs. Both reservoirs exhibit excellent petrophysical properties, although variations in sand thickness and net-to-gross (<i>NTG</i>) ratios suggest spatial heterogeneity. Geomechanical analysis, based on dynamic and static elastic moduli, indicates that the shale overburden acts as a strong, ductile caprock, capable of maintaining seal integrity during CO<sub>2</sub> injection. At the same time, the reservoirs display lower strength parameters compared to the overburden. Pore pressure increases progressively with depth, reaching a maximum in the basal reservoir. Fault seal analysis reveals the presence of several normal and reverse faults with low shale gouge ratios, suggesting that the fault system is likely non-sealing. However, the absence of intersecting faults within the primary trapping structures supports the viability of the Field for long-term CO<sub>2</sub> storage, provided that injection pressures are carefully regulated to prevent fault reactivation and other leakage risks.</p> Highlights <p><UnorderedList Mark="Bullet"> <ItemContent> <p>Depleted hydrocarbon reservoirs are suitable locations for the safe storage of carbon dioxide owing to their enormous volume and readily available data to characterize such reservoirs.</p> </ItemContent> <ItemContent> <p>The stratigraphy and structural juxtaposition of the Field, Offshore Niger Delta Basin meet the requirements for safe CO<sub>2</sub> storage.</p> </ItemContent> <ItemContent> <p>The petrophysical analysis suggest permissible criteria for CO<sub>2</sub> storage but shale diapir associated with deep Offshore Niger Delta Basin caused lateral discontinuity of the reservoirs within the study area.</p> </ItemContent> <ItemContent> <p>Rock strength properties increase with depth, with shale layers more ductile and less prone to deformation, while the reservoir sandstones have lower elastic properties than the shale overburdens.</p> </ItemContent> <ItemContent> <p>Careful monitoring of injection pressure, well placement, and injection rate is essential to avoid caprock failure and ensure safe long-term storage of CO<sub>2</sub>.</p> </ItemContent> </UnorderedList></p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Evaluation of geomechanical properties for CO2 sequestration in an Offshore Field, Niger Delta Basin, Nigeria

  • 期刊论文

  • 发表日期：

    2026年2月13日

查看全文
  • Johnson Ajidahun,
  • Oladotun Afolabi Oluwajana,
  • Olubusayo Akinyele Olatunji,
  • Yusuf Olanrewaju Odusanwo

摘要

Abstract

This study examines the geomechanical and fault seal characteristics, alongside the stratigraphic and petrophysical properties, of an Offshore Field in the Niger Delta Basin, to evaluate its potential for carbon dioxide sequestration. Lithological analysis identifies two reservoirs (RES A1 and RES A2), separated by a marine shale caprock. Structural analysis reveals a syn-depositional anticline caused by compressional forces, likely influenced by the intrusion of a mobile shale diapir from the deep Offshore Niger Delta Basin, resulting in an asymmetric fold with steep and gentle limbs. Both reservoirs exhibit excellent petrophysical properties, although variations in sand thickness and net-to-gross (NTG) ratios suggest spatial heterogeneity. Geomechanical analysis, based on dynamic and static elastic moduli, indicates that the shale overburden acts as a strong, ductile caprock, capable of maintaining seal integrity during CO2 injection. At the same time, the reservoirs display lower strength parameters compared to the overburden. Pore pressure increases progressively with depth, reaching a maximum in the basal reservoir. Fault seal analysis reveals the presence of several normal and reverse faults with low shale gouge ratios, suggesting that the fault system is likely non-sealing. However, the absence of intersecting faults within the primary trapping structures supports the viability of the Field for long-term CO2 storage, provided that injection pressures are carefully regulated to prevent fault reactivation and other leakage risks.

Highlights

Depleted hydrocarbon reservoirs are suitable locations for the safe storage of carbon dioxide owing to their enormous volume and readily available data to characterize such reservoirs.

The stratigraphy and structural juxtaposition of the Field, Offshore Niger Delta Basin meet the requirements for safe CO2 storage.

The petrophysical analysis suggest permissible criteria for CO2 storage but shale diapir associated with deep Offshore Niger Delta Basin caused lateral discontinuity of the reservoirs within the study area.

Rock strength properties increase with depth, with shale layers more ductile and less prone to deformation, while the reservoir sandstones have lower elastic properties than the shale overburdens.

Careful monitoring of injection pressure, well placement, and injection rate is essential to avoid caprock failure and ensure safe long-term storage of CO2.