3D Geological Modeling with Petrel Software: Estimating Original Oil in Place of Lower Cretaceous Y- Formation: A Case Study in a Selected Oilfield

Three-dimensional (3D) geological modeling for predicting reservoir performance and acquisition a better understanding of the unique characteristics of the Y- Formation (an important oil reservoir). The study uses geostatistics and computer visualization technology to quantitatively characterize various geological attributes in 3D space, storing the results as grid data. It focuses on building a 3D reservoir geological model of the X oilfield by using Petrel software. The model integrates data from 14 wells, including geology, geophysics, and petrophysics, to accurately depict the subsurface internal structure and reservoir heterogeneity. The data of the Y- Formation (Lower Cretaceous Carbonates) were taken from 14 wells of X Oilfield, Selected oilfield (Well-1, Well-2, Well-3, Well-5, Well-6, Well-9, Well-10, Well-11, Well-12, Well-13, Well-14, Well-15, Well-25, Well-34 and Well-35). The input data is used to build the structural model, Facies model, and Petrophysical properties (porosity, permeability, saturation, and N/G model), ultimately determining the reservoir volume. The 3D model visualizes the distribution of Petrophysical properties and classifies the formation into distinct layers or reservoir units (MA, MB, and MC). Petrophysical modeling for Y- Formation was set-up from values of CPI using Sequential Gaussian Simulation algorithm. This research has indicated the reliability of the three-dimensional model technique as a suitable tool to provide a sufficient understanding of Petrophysical distribution. Original oil in place (OOIP) refer to the volume of hydrocarbons initially stored in a reservoir prior to production. Volumetric approaches of estimating HIIP can be employed immediately after first discovery, before production initiates. The aim of the study is to estimate the oil in place from the available data in Y- Formation. After finalizing the Petrophysical distribution and applying the volumetric calculation, oil in place estimated by the geological model equal to (658 *106 SM3 or 4132.24 million barrels).