The Niger Delta Basin has been a focal point for hydrocarbon exploration for more than eight decades. This prolific petroleum field, located on the continental margin inof the Gulf of Guinea (Fig. 1A), is recognized as Africa’s leading oil province (Short & Stauble, 1967; Avbovbo, 1978; Doust & Omatsola, 1990; Kulke, 1995). The Tertiary section of the Niger Delta is divided into three formations—Akata, Agbada, and Benin—based on sand-shale ratios, which are well- documented in the literature (Short & Stauble, 1967; Avbovbo, 1978; Doust & Omatsola, 1990).
The Tertiary Niger Delta (Akata-Agbada) province was formed at a rift triple junction related to the opening of the southern Atlantic, starting in the Late Jurassic and continuing into the Cretaceous (Michele et al., 1999). Deposition of the Agbada Formation, the primary petroleum-bearing unit, began in the Eocene and continues to the present. This formation comprises paralic siliciclastic layers more than 3700 meters thick, representing the deltaic portion of the sequence (Avbovbo, 1978). The grain size of the reservoir sandstone varies significantly, with fluvial sandstones being coarser than their delta front counterparts; point bars fine upward,; and barrier bars exhibiting the best grain sorting. Much of this sandstone is nearly unconsolidated, with minor argillosilicic cement (Kulke, 1995).
The Niger Delta Basin is a highly prospective hydrocarbon province covering approximately 300,000 km² (Kogbe, 2019). It features a complex sedimentary succession with numerous potential reservoirs, source rocks, and seals, which are critical components of the petroleum system (Kogbe, 2019; Akpan & Essien, 2018). The basin's petroleum system predominantly consists of the Tertiary Akata-Agbada Formation, the primary source rock for hydrocarbons in the region (Akpan & Essien, 2018; Kogbe, 2019). The Agbada Formation, a paralic sequence of sandstones, shales, and coals, is among the most important lithostratigraphic units in the Niger Delta Basin (Emery & Myers, 2016; Ojo et al., 2018). This sequence is characterized by a complex interplay of sedimentary processes, resulting in diverse depositional environments and facies associations (Kogbe, 2019; Ojo et al., 2018).
Previous studies have highlighted the significant hydrocarbon potential within the basin's sedimentary succession (Adegoke et al., 2020; Osterloff et al., 2020; Maju-Oyovwikowhe & Lucas, 2019; Ukwuedojor & Maju-Oyovwikowhe, 2019). However, exploration and production in the Niger Delta Basin have been limited by complex structural and stratigraphic settings, reservoir heterogeneity, and high drilling costs (Akpan & Essien, 2018; Osterloff et al., 2020).
Recent studies have emphasized an integrated approach that combines core and well data with sedimentological and petroleum system analyses to improve reservoir characterization and hydrocarbon productivity evaluation (Adegoke et al., 2020; Ojo et al., 2018; Osterloff et al., 2020). This method has proven effective in revealing the depositional and diagenetic processes influencing reservoir quality and hydrocarbon accumulation (Ojo et al., 2018; Osterloff et al., 2020).
This study integrates core and well data to investigate the sedimentology and petroleum system of the Agbada paralic sequence in the Niger Delta Basin. By providing detailed sedimentological core analysis and evaluating the hydrocarbon productivity potential of the X-021 Well, this research offers valuable insights into the characteristics of the Agbada Formation, guiding future exploration activities.
Location
The X-21 Well is located in the Niger Delta Basin, a well-known hydrocarbon-producing region in West Africa. The onshore part of the Niger Delta Province, covering an area of 300,000 km², encompasses the Tertiary Niger Delta (Akata-Agbada) Petroleum System (Fig. 1B). Numerous studies have explored the geology and petroleum potential of this region. This study investigated core samples from the X-21 Well to determine the sedimentology and hydrocarbon productivity of the Agbada Formation.