Reservoir Modelling L4 PDF

Reservoir Modelling 4 th Year Seismic data: Seismic data is one of the most important sources of data used in reservoir modeling. It provides information about the subsurface structure, including the depth, thickness, and location of rese...

Reservoir Modelling 4 th Year Seismic data: Seismic data is one of the most important sources of data used in reservoir modeling. It provides information about the subsurface structure, including the depth, thickness, and location of reservoirs. Seismic data is obtained by sending sound waves into the ground and measuring the time it takes for the waves to bounce back. Seismic exploration can be divided into three main stages: data acquisition, processing and interpretation. The seismic sweep is the set of sound frequencies directed into the subsurface (Fig. 11). Seismic reflections indicate potential rock transitions, and these properties of the reflections provide information on the relative nature of the transition. Fig. 11: Seismic Reflection Method 18 Dr. Maha M. Al-Dabagh Petroleum and Mining Engineering  Reservoir Modelling 4 th Year Seismic data represents the primary source for horizon and fault input to the reservoir model (Fig.12). Seismic data provide information on fault locations, large- scale reservoir geometry, and large-scale variations in facies proportions. Fig. 12: Seismic Section A- Horizon: Interpreted seismic horizon time data are imported from the database to the project data store. Depth-converted versions of the horizons should also be stored. A Seismic Horizon is defined as a set of free points/lines in time that are effectively continuous over large parts of the area of interest. (The contact between two bodies of rock having different seismic velocity, density, porosity, fluid content or all of those). B- Faults Polygons and Sticks: Fault Polygons are line data representing the hanging wall and footwall for each horizon (Fig-13 and 14). 19 Dr. Maha M. Al-Dabagh Petroleum and Mining Engineering  Reservoir Modelling 4 th Year Fault Sticks: set of data that represent the fault plane (fault surface) (Fig-13 and 14). Input Fault Plain #2 Horizon Input Input #4 #1 Horizon Input #3 Fig-13: Fault input data Fig-14: Fault walls and plane 20 Dr. Maha M. Al-Dabagh Petroleum and Mining Engineering  Reservoir Modelling 4 th Year C- Velocity Model: The velocity model is generally stored in the project data store either as a function, a grid or as a cube. The data can be loaded into the project if depth conversion is to be carried out as part of the modelling exercise. Alternatively, depth-converted surfaces and fault information are provided. Fig-15 D- Seismic Data Volume: A number of different seismic volumes may be loaded depending on the different processing results; different products may aid structural interpretation or enhance attribute analysis. Capture the structural and stratigraphic framework of a field in 3D dimensions. 21 Dr. Maha M. Al-Dabagh Petroleum and Mining Engineering  Reservoir Modelling 4 th Year Fig-16 3D seismic Data 8.2.3 Dynamic Data: A dynamic reservoir model is a representation of the changes in fluid flow in the reservoir model that need to be validated with reservoir performance data-pressure changes, production and injection rates. A- Fluid Data Oil and gas fluid data are required to evaluate the properties of produced fluids at reservoir conditions, in production tubing, in process facilities and in pipeline transportation. The key PVT (pressure–volume–temperature) properties to be determined for a reservoir fluid include the following: Original reservoir fluid composition Saturation pressure at reservoir temperature Oil and gas densities and viscosities. 22 Dr. Maha M. Al-Dabagh Petroleum and Mining Engineering  Reservoir Modelling 4 th Year Gas solubility in reservoir oil Liquid content of a reservoir gas Shrinkage (volume) factors (Bo, Bg, Bw) of oil, gas and water from reservoir to surface conditions. Compositional variation with depth B- Well Test Data Well test data can be used to determine effective permeability. It is divided into the following types: Transient well test (DST) raw data: rates and pressures. Well tests: perforation intervals and main interpretation data, Permeability thickness, boundaries. Production log interpretations: oil, gas and water rates in the well, plus pressure distribution. 8.2.4 Important Specialist Data Special Core Analysis: Special core analysis data should be collected for defining petrophysical interpretation parameters and for dynamic measurements. Routinely collected data include the Archie parameters a, m and n, capillary pressure, wettability and relative permeability. These values are collected and used in the petrophysical assessment for the reservoir and later in dynamic modelling. 23 Dr. Maha M. Al-Dabagh Petroleum and Mining Engineering