In practical terms, petrophysics is used for two types of calculations: determination of original hydrocarbons in place [original oil in place (OOIP) or original gas in place (OGIP or GIP)] and their distribution, and reservoir-engineering dynamic flow calculations. For the development geoscientists (geologists, geophysicists, and geostatisticians), petrophysics means developing the detailed reservoir characteristics in terme of Porosity, Permeability, Water saturation, net pay, cut-offs etc. as well as reservoir lithology determination, diagenetic descriptions both vertically and lareally, etc . To make accurate calculations of OOIP or OGIP and the various flow calculations, accurate foot-by-foot calculations reservoir parameters are necessary. These calculations need to be made not only as overall calculations, but also so that the variation and distribution of these parameters are determined appropriately.
Some of the petrophysical calculations can be made in several ways. One key to arriving at an accurate petrophysical calculation is to obtain the same quantitative result with a variety of techniques. An important consideration is the acquisition and handling of the various types of petrophysical data and, for each reservoir, the preparation of its unique petrophysical database. Petrophysical data take many forms and, for many reservoirs, may not be as comprehensive as desired. The technical personnel working with these data have to review what data are available, their quality, and what additional data might be acquired from the existing wellbores and from preserved and unpreserved cores. Finally, if there are sufficient financial stakes, new wells might be drilled, cores cut, various additional sample measurements made, and both conventional and special logs run to obtain other desired petrophysical information.
Our Geoscientist team perform the following processing and interpretation:
OPEN HOLE FORMATION EVALUATION
Interactive Petrophysics– A weighted-least-squares error minimization technique to evaluate formation lithology, porosity, and fluid saturations. The IP program will use its error minimization methods to ensure results are in agreement with core and petrophysical data.Complex lithology analysis. Provides an accurate, detailed description of complex lithology reservoirs Primary use is evaluating formations that contain shale, sand, limestone, dolomite, and anhydrite, Uses density/neutron crossplot and can also incorporate acoustic, spectral gamma ray, and Pe logs for volumetric lithologies evaluation and also effective porosity, water oil & gas saturations.Evaluation of feldspathicshaley sands when the presence of radioactive potassium feldspars and non-radioactive kaolinitic clays make the GR a poor shale indicator.Laminated Reservoir Analysis — An evaluation program that determines lithology volumes, fluid saturations, effective porosity, and many other results by using high resolution shale indicators.Clay Mineralogy Analysis – An analysis of the amount and types of clays present in the formation, using neutron, density, Pe and spectral gamma ray data. Pressure Transient Analysis — Evaluation of raw pressure-versus-time data recorded by the formation testing tool. Either radial or spherical flow models can be used. Output includes Horner plot analysis, permeability, and pressure build up. Improves evaluation of porosity and lithology in thin beds or rapidly changing environments. Preferred input for laminated reservoir analysis, complex lithology, and coal seam evaluation. High resolution logging is recommended. Uses wireline or LWD log data from NMR Tool to determine hydrocarbon saturation, free fluid volumes, and formation permeability using pore size and saturation.
ACOUSTIC & WAVEFORM PROCESSING
TechLog Anisotropy Analysis – Analyze Dipole Sonic tool waveform data to identify fast and slow shear wave travel times and their orientation in the formation. Sonic anisotropy and the orientation of the anisotropy can be used to determine the orientation of natural fractures. Sonic attributes such as P-wave slowness, fast and slow shear wave travel time, can be used for identification of compressive fluids in the pore space. This allows planning of the best completion method and builds reservoir understanding to be applied to the next well.
Rock Mechanics Formation Strength/Sanding Potential Log – Using density, acoustic, and lithology data, and calculates standard mechanical rock properties such as Young’s Modulus, Poisson’s Ratio, Bulk Modulus and Compressibility. The analysis accounts for vertical and deviated wells.
Unconsolidated formations: Sanding potential prediction from rock mechanical properties, bottomhole pressure, and borehole stress Analysis.
Consolidated formations: This analysis determines formation mechanical properties and formation fracture closure pressures.
Fracturing Parameter Log– Combines into one log presentation all of the wireline logging data required as input into 3-D hydraulic fracturing simulators. The data is zoned by stress relationships aid in fracture design and creates tabular and ASCII listings for direct input into fracture design models.FRAC PRESSURE This analysis determines formation mechanical properties, formation fracture closure pressures and describes vertical hydraulic fracture growth.
Instantaneous Waveform Characteristics K-Sonic Plots instantaneous waveform characteristics (IWC) of sonic waveforms, where transmissivity, frequency, and phase are shown. Useful for lithology and fracture detection.
Analyzes Stoneley delta-T, amplitude, and attenuation, and other waveform permeability indicators to determine a permeability index. This method is useful in detecting fractures.
IMAGE PROCESSING AND DIPMETER PRODUCTS
ImagePro Image data processing from electrical & Acoustic imaging tool . Includes histogram equalization and horizontal/vertical enhancements, if required.supports also AFR, ALD, AGR and ADR and includes image display, image rotation, bedding/fractures dip analysis, dip statistics, structural dip removal, histogram analysis, sedimentary facies analysis, fracture aperture, dip uncertainty and 3D visualization is identified and presented on a photo-quality color printDipmeter Analysis Program. A global mapping, dip computation method to determine most likely planar formation dip at each depth in a well.Estimate the sand and pay counts within the subsurface sedimentary sequence logged by Electrical imager tool.