Hydrocarbon Reservoirs Management
TEMPLE N CHIKWE; Remy Ukachukwu Duru
Abstract
The Asphaltene and metal naphthenate components of crude oil samples from ten different wells within an oil reservoir were determined using different analytical techniques. The asphaltene content was determined by gravimetric analyses while the metal naphthenate components were determined by obtaining ...
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The Asphaltene and metal naphthenate components of crude oil samples from ten different wells within an oil reservoir were determined using different analytical techniques. The asphaltene content was determined by gravimetric analyses while the metal naphthenate components were determined by obtaining the metal ion concentration of the produced water and the naphthenic acid concentration of the crude using Atomic absorption spectrometer (AAS) and potentiometric titration respectively. Results obtained showed that the asphaltene content of the crude samples ranges from 2.0000 – 8.000 %w while the naphthenic acid concentration indicated by the total acid number (TAN) ranges from 0.3000 – 1.4600 mg/KOH/g. All the crude samples possess asphaltene components as well as the propensity to form calcium and sodium naphthenate scale deposits having a Ca2+ concentration between 32.5000 – 94.5000 mg/L and a Na+ concentration between 27.7 – 105.1 mg/L respectively, however the formation of naphthenate scale deposits is highly dependent on the pH of the produced water of the crude which makes well FT01 less likely to form naphthenate scales since it has a pH < 6. Both asphaltene and naphthenate deposits are directly proportional to the specific gravity of the crude and inversely proportional to the API gravity implying that both components reduce the quality of the crude. Asphaltene and metal naphthenate solid deposits in the crude can cause a lot of flow assurance difficulties such as, blocking of expedition lines, pore plugging, wettability, crude oil parameter alteration, as well as reduction in oil recovery.
Petroleum Engineering – Reservoir
Temple N Chikwe; Mudiaga Onojake
Abstract
The geochemical investigation of trace metals in crude oils from some producing oil fields in the Niger Delta, Nigeria, was carried out to ascertain the petroleum source rocks and organic matter deposits. The concentrations of trace metals in crude oil samples obtained from eight producing fields from ...
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The geochemical investigation of trace metals in crude oils from some producing oil fields in the Niger Delta, Nigeria, was carried out to ascertain the petroleum source rocks and organic matter deposits. The concentrations of trace metals in crude oil samples obtained from eight producing fields from Niger Delta, Nigeria, were analyzed using a 700 model Perkin Elmer atomic absorption spectrophotometer. The results showed the following ranges for the trace metals: Cu (0.01–0.04 mg/kg), Fe (0.05–5.90 mg/kg), Ni (0.09–0.72 mg/kg); and V (0.008–1.05 mg/kg). Pb and Zn were lower than 0.01 mg/kg. Trace metal ratios such as V/Ni, V/Fe, and (V/V + Ni) were used to unravel the genetic correlation among the oils. All the crude samples except the sample from Nembe South-2 have a V/N ratio lower than 1.0, indicating that the organic materials produced the petroleum source rock. A cross plot of V/Ni revealed two genetic families for the crude oils, derived from a terrestrial and marine origin, which was confirmed by the ternary plot of V, Ni, and Fe, discriminating the crude oils from the producing fields into two distinct groups. The V/(Ni + V) of smaller than 0.5 showed that most crude oils were deposited in an oxic environment. A cross-plot of V/(Ni + V) and V/Fe showed a weak correlation, suggesting that it could not substitute for the V/Ni ratio in determining the origin and depositional environment of crude oil samples. Therefore, an in-depth knowledge of the concentration of trace metals, especially vanadium and nickel, within an environment during oil exploration is essential in developing new oil locations.
