Well log rock physics and seismic facies analysis was carried out with a view to enhancing reservoir sand characterization of Mafe Field of Niger Delta. Lithofacies were identified using suites of well logs and correlated across the block. Rock properties were estimated from wireline logs using empirical methods. Vp-porosity crossplot was used to characterize the delineated sandstone reservoirs by comparing observed clusters and trends with various rock physics models. Seismic attribute analysis was employed to detect lateral changes in lithology across the field. Reservoir A is a relatively clean sand, with low average volume of shale of 0.4, average thickness of 55m, good average porosity of 0.26 and average water saturation of 0.45. Reservoir B is also a relatively clean sand with low average volume of shale of 0.35, average thickness of 85m, high average porosity of 0.27 and average water saturation of 0.54. Reservoir C has an estimated volume of shale of 0.21 average total porosity of 0.23, and an average thickness of 70m with average water saturation of 0.65. Reservoir A conforms to the friable sand model while Vp-porosity crossplot cluster trend for both reservoir B and C show trend and properties imitating the contact cement model. The time slices extracted at different time intervals from the envelope and instantaneous frequency cubes show lateral variation in lithofacies across the delineated sandstones. Instantaneous frequency decreases from southwest to northeast which corresponds to decrease in shalines. Reservoir quality information can be predicted or even derived from the estimated petrophysical properties since these parameters such as porosity and volume of shale are sometimes closely associated with rock properties such as sorting, lithofacies and grain maturity.
Seismic facies analysis constrained with well log information have been used to predict lithofacies distribution across the Okam Field of Niger Delta. Density and gamma ray logs were cross-plotted and the seismic section was subdivided vertically into different seismic facies. The delineated lithologies, from well logs were correlated with seismic facies signatures using lines of intersection across the wells. Gamma ray and resistivity logs were used to identify the interfaces between the lithofacies and correlated across the field. Structural interpretation was carried out. Time slices were generated and examined at different intervals within the identified reservoirs. Stratigraphic related attribute and envelope were extracted on these
... Show MoreAn integrated seismic sequence stratigraphy and facies analysis has been carried out with a view to understanding the depositional environment and stratal stacking pattern of Nandy Field of Niger Delta. Well logs and biostratigraphic information were used to identify the lithologies, stratal stacking patterns, stratigraphic surfaces, system tracts and reservoir potentials of the field. Seismic sequence stratigraphy and seismic reflection patterns were used to identify the seismic facies. Facies-related attributes were employed to identify the continuity and amplitude of seismic events. Three seismic facies packages and three reservoir sands were identified. The environments of deposition of the area consist of marginal marine to continen
... Show MoreThe Yamama Formation includes important carbonates reservoir that belongs to the Lower Cretaceous sequence in Southern Iraq. This study covers two oil fields (Sindbad and Siba) that are distributed Southeastern Basrah Governorate, South of Iraq. Yamama reservoir units were determined based on the study of cores, well logs, and petrographic examination of thin sections that required a detailed integration of geological data and petrophysical properties. These parameters were integrated in order to divide the Yamama Formation into six reservoir units (YA0, YA1, YA2, YB1, YB2 and YC), located between five cap rock units. The best facies association and petrophysical properties were found in the shoal environment, wh
... Show MoreDisequilibrium compaction, sometimes referred to as under compaction, has been identified as a major mechanism of abnormal pore pressure buildup in sedimentary basins. This is attributed to the interplay between the rate at which sediments are deposited and the rate at which fluids associated with the sediments are expelled with respect to burial depth. The purpose of this research is to analyze the mechanisms associated with abnormal pore pressure regime in the sedimentary formation. The study area “Jay field†is an offshore Niger Delta susceptible to abnormal pore pressure regime in the Agbada –Akata formations of the basin. Well log analysis and cross plots were applied to determine the unde
... Show MoreSeismic inversion technique is applied to 3D seismic data to predict porosity property for carbonate Yamama Formation (Early Cretaceous) in an area located in southern Iraq. A workflow is designed to guide the manual procedure of inversion process. The inversion use a Model Based Inversion technique to convert 3D seismic data into 3D acoustic impedance depending on low frequency model and well data is the first step in the inversion with statistical control for each inversion stage. Then, training the 3D acoustic impedance volume, seismic data and porosity wells data with multi attribute transforms to find the best statistical attribute that is suitable to invert the point direct measurement of porosity from well to 3D porosity distribut
... Show MoreIn this research, a qualitative seismic processing and interpretation is made up
through using 3D-seismic reflection data of East-Baghdad oil field in the central part
of Iraq. We used the new technique, this technique is used for the direct hydrocarbons
indicators (DHI) called Amplitude Versus Offset or Angle (AVO or AVA) technique.
For this purposes a cube of 3D seismic data (Pre-stack) was chosen in addition to the
available data of wells Z-2 and Z-24. These data were processed and interpreted by
utilizing the programs of the HRS-9* software where we have studied and analyzed
the AVO within Zubair Formation. Many AVO processing operations were carried
out which include AVO processing (Pre-conditioning for gathe
This study was carried out to estimate the effect of shaliness on water saturation from TN field of Niger Delta. The conventional Archie and the Shaly-sand water saturation models was used in the evaluation of wells. Two sand bodies (Sand 01 and 02) were mapped with thicknesses range from 76.8ft to 119.3ft across the three wells for Sand 01 and 187.5 to 339.9ft across wells TN_1 and TN_4 for Sand 02. The cross plot of the effective porosity (φe) versus volume of shale (Vsh) show a decrease in the effective porosity with an increase in shale volume. This reveals a laminated shale pattern across the reservoir sands. The estimations from the conventional method and the Shaly-sand models of Simandoux and Indonesia show a clear disparity due
... Show MoreThis study aims to determine the petrophysical characteristics of the three wells in the Kifl Oilfield, central Iraq. The well logs were used to characterize hydrocarbon reservoirs to assess the hydrocarbon prospectivity, designate hydrocarbon and water-bearing zones, and determine the Nahr Umr Formation's petrophysical parameters. The Nahr Umr reservoir mainly consists of sandstone at the bottom and has an upper shale zone containing a small proportion of oil. The geophysical logs data from three oil wells include gamma-ray, resistivity, neutron, density, acoustic, and spontaneous potential logs. A gamma-ray log was employed for lithology differentiation, and a resistivity log was used to determine the response of distinct zones
... Show MorePetrophysical properties including volume of shale, porosity and water saturation are significance parameters for petroleum companies in evaluating the reservoirs and determining the hydrocarbon zones. These can be achieved through conventional petrophysical calculations from the well logs data such as gamma ray, sonic, neutron, density and deep resistivity. The well logging operations of the targeted limestone Mishrif reservoirs in Ns-X Well, Nasiriya Oilfield, south of Iraq could not be done due to some problems related to the well condition. The gamma ray log was the only recorded log through the cased borehole. Therefore, evaluating the reservoirs and estimating the perforation zones has not performed and the drilled well was
... Show MoreThis study deals with the interpretation of structural 3D seismic reflection of the Kumait oil field in southern Iraq within the administrative boundaries of the Maysan Governorate. Synthetic seismograms are prepared by using available data of the Kt-1 oil field by using Petrel software to define and pick the reflector on the seismic section of the Zubair Formation, Which represents the Cretaceous Age. The study shows that the Kumait structure is an anticline fold. It is thought to be a structure trap caused by the collision of the Arabian and Iranian plates and trending in the same direction as driving factors in the area, which are from the northwest to the southeast, and the overall trend of strata is north and northeast. Sei
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