Occurrence and distribution of dibenzofurans and benzo[b]naphthofurans in the crude oils from the Northern and offshore Niger Delta basin, Nigeria

Occurrence and geochemical significance of fluorene and alkylfluorenes in crude oils and source rock extracts from Niger Delta basin, Nigeria

“…In the present study, the values of TPP's/(TPP's + C 27 Dia), C 29 H/(C 29 H + C 30 H), C 35 H/(C 35 H + C 34 H), Hopane/sterane and oleanane index in the crude oils are the ranges of 0.18–0.98, 0.04 to 0.57, 0.26 to 0.54, 5.23 to 29.70 and 0.23 to 0.75, respectively ( Table 5 ), indicating crude oils derived from source rocks of mixed origin of terrestrial and marine organic matter [ 13 , 33 ]. This interpretation is consistent with the recent studies on Niger Delta crude oils [ 16 , 17 , 64 , 79 ]. The cross plots of hopane/sterane versus Pr/Ph ( Figure 7 a), TPP's/(TPP's + C 27 Dia) versus hopane/sterane ( Figure 7 b) and C 29 H/(C 29 H + C 30 H) versus C 35 H/(C 35 H + C 34 H) ( Figure 8 c) further support terrestrial-marine organic matter for the oil samples.…”

“…The methyl phenanthrene index (MPI-1; Radke et al., 1982) appears to be useful to estimate vitrinite reflectance (VRc) [ 60 , 63 ]. The MPI-1, MPI-2 and calculated vitrinite reflectance (VRc) calculated for the rock samples are in the range of 0.12–0.62 [ 16 , 17 , 45 , 64 ] 0.13 to 0.68 [ 16 ] and 0.47 %–0.77 %, respectively ( Table 4 ), indicating immature to early oil generation window [ 65 ]. The trimethylnaphthalene ratio 1 (TMNr-1, Table 4 ) was compared with the sterane isomerization ratio (20S/20R), showing that the sterane isomerization ratio of the oils reaches equilibrium when the TNR-1 ratio is >1 [ 66 ], while the trimethylnaphthalene ratio 2 (TMNr-2) was used to estimate the vitrinite reflectance (Rcb) and shows good agreement with the increase in thermal maturity [ 67 ].…”

“…The source facies, depositional environments and thermal maturity parameters based on saturated and aromatic biomarkers are used to assess the origin, environments of deposition and thermal maturity of the crude oils (Tables 5 , 6 , and 7 ). The Pr/Ph ratio shows a range of values from 1.48 to 4.71 [ 41 , 64 ] ( Table 5 ), suggesting crude oils derived from terrestrial-marine organic matter and deposited in a lacustrine-fluvial/deltaic environment under oxic to suboxic conditions [ 42 , 43 , 44 ]. For some of the samples, the Pr/Ph values >3 indicate crude oils derived from predominant terrestrial organic matter [ 33 , 42 , 43 , 44 ].…”

Paleoenvironmental and Maturity Indicator of Cepu Block Oil, Wonocolo Formation, East Java-Indonesia

“…MDBF biomarkers are found as 4-MDBF; (3 + 2) -MDBF and 1-MDBF, while the presence of nine DMDBF isomers has not been identified in Cepu oil samples [18]. The high amount of 4-MDBF and (3 +2)-MDBF compared to other isomers, show an indicator of organic input from terrestrial environment [61]. In addition, DBF, MDBF and DMDBF also indicate mosses organic input [18,61].…”

“…The high amount of 4-MDBF and (3 +2)-MDBF compared to other isomers, show an indicator of organic input from terrestrial environment [61]. In addition, DBF, MDBF and DMDBF also indicate mosses organic input [18,61].…”