Reservoir Evaluation and Volumetric Analysis of Rancho Field, Niger Delta, Using Well Log and 3D Seismic Data

Abstract

Exploration and exploitation for hydrocarbon are associated with a lot of complexities, it is therefore necessary to integrate available geologic models for accurate hydrocarbon prospecting and risk analysis. This study is aimed at determining the structural, petrophysical and volumetric parameters for reservoir evaluation within the Rancho field. 3D seismic data was used for evaluating the hydrocarbon potential of the field. A suite of well logs but not limited to gamma ray logs (GR), deep resistivity log (DRES), neutron log (NPHI) and density log (RHOB) from four (4) wells were employed in characterising dynamic properties of the reservoirs. The GR log was used in lithology identification while the resistivity log was used in identifying probable hydrocarbon bearing sands. A correlation exercise was carried out to identify lateral continuity and discontinuity of facies across the wells. Thereafter petrophysical parameters were analysed from the suite of wire line logs. Major faults were mapped on the 3D seismic data and identified hydrocarbon bearing sand tops from the well logs were mapped as horizons on the seismic section, maps were generated and volumetric analysis was done. Nine (9) hydrocarbon sands (Sands A -I) were identified within the study area. The well log revealed an alternation of sand and shale layers as well as shale layers increased in thickness with depth, while the sand bodies reduced in thickness with depth which characterized the Abgada Formation of the Niger Delta. The effective porosities of the sands range from 21% -31%, the permeability ranges from 28% -44%, 70% -80% for the net to gross, volume of shale range from 14% -40% and hydrocarbon saturation ranges from 63% -82%. Twelve (12) faults were mapped within the study area and the structural styles revealed a fault assisted closures. The volumetric analysis showed that Sand F had Stock Tank Oil Initially In Place

Reservoir Characterization and Volumetric Analysis of “Lee” Field, Onshore Niger Delta, Using 3D Seismic and Well Log Data

“…After the time slice being created, a velocity model ( Figure 9) was created which was used in the conversion of time to depth surface map ( Figure 10). The depth structure map was then used to quantify the oil in place and also provided the basis for modelling of the petrophysical parameters (Obiora et al, 2016;Okwoli et al, 2015). The integrated time-depth structure map is displayed in Figure 11.…”

“…Methodology: Following the approaches adopted by Inichinbia et al (2014 a,b,c); Ulasi et al, (2013); Stacy et al, (2010); Okwoli et al, (2015); Obiora et al (2016), suites of four geophysical well logs and 3D seismic data recorded at various locations within the Lee field were used for the study. The seismic data set comprises of both inline and crossline sections.…”

“…This involves the use of empirical formula to estimate the reservoir parameters such as volume of shale, Formation factor, porosity, water saturation, permeability, hydrocarbon saturation etc. Calculations of such reservoir parameters will help to determine if a reservoir is exploitable (Obiora et al, 2016;Stacy et al, 2010;Okwoli et al, 2015;Obiora et al, 2016;Shepherd, 2009). The objective of this study was to characterize the reservoirs and determine the hydrocarbon in place through detail volumetric analysis.…”

3D structural and stratigraphic characterization of X field Niger Delta: implications for CO2 sequestration

“…The uppermost Benin Formation is Oligocene to Recent in age and composed of continental fluvial sands (Avbovbo 1978;Doust and Omatsola 1990;Owolabi et al 2019). The 2 km thick unit is generally friable and consists of white, fine to coarse and pebbly, poorly sorted sands (Avbovbo 1978;Adegoke et al 2017).…”

Reservoir characterization and identification of new prospect in Srikail gas field using wireline and seismic data

“…To minimize drilling risk and maximize well and reservoir productivity, adequate analyses of seismic and petrophysical data are very important (Ameloko et al 2019). Many researchers conclude that integration of seismic and well log data plays an important role in determining the structural framework and reserves of a field (Fajana et al 2019;Owolabi et al 2019;Oyeyemi et al 2018Oyeyemi et al , 2019Sanuade et al 2018). In fact, the combination of structural interpretation, seismic stratigraphy, core data and logging, geological knowledge of depositional facies and modeling are crucial elements in building reservoir geological model and characterization (Norden and Frykman 2013;Edigbue et al 2015;Jegede et al 2015;Akm et al 2016;Al-Fatlawi 2018;Eahsanul Haque et al 2018;Kalu et al 2019).…”