Khasib Formation Research Articles

Using the Conventional Method to Estimate Water Saturation of Khasib Formation in East Baghdad Oil Field Central Area

The water saturation level may change due to geological changes or human intervention, like earthquakes, excavation, injection, or extraction of fluids from underground reservoirs. This work helps the reader understand how to use electrical logging to acquire a suitable water saturation value in resistivity and dielectric studies. In the East Baghdad field, two wells that were drilled into the Khasib Formation had their petrophysical parameters assessed using IP software. This allowed for the determination of water saturation using the available well logs, including neutron, density, SP, sonic, gamma ray, and resistivity logs for wells EB-25, and EB-29. The limestone section in the Khasib formation represents calcite, the main mineral found. We counted the amount of shale in each well using gamma-ray logs. The porosity at the reservoir unit was determined using a sonic log. Archie's equation and resistivity data are also used to compute fluid saturation. Taking m=n=2, a=1, x=1.76, and Rw=0.033 for Khasib formation. The link between Archie's and Raiga's coefficients, a, m, n, and x, is primarily the basis for this discussion. There is high agreement when this equation is used. In clean formations (non-shaly). this formula can be regarded as a reliable indicator of water saturation in situations where porosity techniques other than acoustic logs are unavailable. It's important to note that this equation provides accurate and realistic answers for rocks with transit times between 40 and 150 As/ft. Porosity knowledge is not required for such an assessment.

Classification of rock types of porous limestone reservoirs: case study of the A oilfield

Rock types with similar lithological components and pore structures form the basic units of porous limestone reservoirs; this influences the reservoir evaluation efficiency and water injection development. As the main oil and gas pay zone in central Iraq, the Cretaceous Khasib Formation reservoirs are influenced by deposition, dissolution, and cementation. There is strong vertical heterogeneity in the most important zone of the Kh2 layer, with diverse rock types and complex pore structures. Based on core observation and casting thin-section identification, the Kh2 layer in the study area was divided into eight lithofacies types as argillaceous bioclastic wackestone, planktic foraminiferium wackestone, lamellar bioclastic wackestone, intraclastic–bioclastic packstone, patchy green algae packstone, green algae and pelletoid packstone, benthic foraminiferium–bioclastic packstone, and intraclastic grainstone. Along with the reservoir void space types of the lithofacies, capillary pressure curves are used to quantitatively analyze the throat and pore features of the different lithofacies. From the porosity–permeability cross-plot characteristics and distribution of pore types, 14 petrophysical facies are obtained. Finally, based on the differences between the lithofacies and petrophysical facies, the Kh2 member is divided into 13 rock types with different geological origins and petrophysical characteristics. Among these, the rock type RT1-8-14 has the best and rock type RT1-1-1 has the worst physical properties among the reservoir rock types. This study provides an optimization method for carbonate reservoir evaluation and is expected to be beneficial for efficient development of similar carbonate reservoirs.

A Comprehensive Method for Building a Three-Dimensional Geological Model of Khasib Formation, Amara Oil Field

A Comprehensive Method for Building a Three-Dimensional Geological Model of Khasib Formation, Amara Oil Field

Reservoir and Rock Type Characterization: Case Study for Khasib Formation, Southern Iraq

Characterizing the reservoir accurately and understanding its rock’s composition is essential in predicting performance and determining reservoir designs. In this study, the carbonate Khasib formation from the late Cretaceous period for x oil field- southern Iraq has been examined characterizing. To achieve this, different characterization techniques were utilized. Firstly, using the flow zone indicator method revealed five hydraulic flow units (HFUs) of the Khasib formation. Every HFU represents a particular quality of reservoir rock. HFU1 is the one that refers to poor quality, while bad-quality reservoir rock is displayed as HFU2. HFU3 and HFU4 signify the intermediate and good reservoir rock quality respectively. The last hydraulic flow unit was of the highest quality reservoir rock which is denoted as HFU5. Additionally, we utilized cluster analysis to identify five distinct rock types within the Khasib formation. These rock types were labeled as RT-1 (the best reservoir rock type), RT-2 (good reservoir rock type), RT-3 (intermediate reservoir rock type), RT-4 (poor rock type), and RT-5 (very poor rock type). In addition, the recognition of five different HFUs that reflected the physical characteristics unique to each reservoir rock was achieved using Winland’s approach. Rock properties inside the reservoir are classified to HFU1 for best rocks, then HFU2 denotes good rock qualities through a medium one labeled as HFU3 while later HFU4 indicates poor quality, and the poorest quality is marked as HFU5. Finally, Lucia's classification for carbonate rock was employed as another analyzing rock quality method. Utilizing this technique reveals three distinct rock types within the Khasib formation. RC1 is the microfacies of grain stone, RC2 is the representative of pack-stone microfabrics and RC3 denotes muddy materials. The final rock types (facies) for Khasib formation can be identified according to the incorporation of the different characterization methods which can be utilized to create a realistic three-dimensional rock type model and distribute the properties based on the rock type.

Permeability Prediction for Carbonate Rocks using a Modified Flow Zone Indicator Method

Carbonate reservoir rocks are usually heterogeneous, so it is not an easy task to establish a relation between porosity and permeability in these types of reservoir rocks. First, Kozney and Kozney-carmen formulas were used to establish these relations. Later, the flow zone indicator (FZI) method was introduced, which was widely used to find such a relation since it shows better results than the two former methods. In this work, the classical FZI method and a modified form of the FZI method are utilized to identify the hydraulic flow units and rock quality index to predict permeability. In this FZI method, the cementation factor (m) was introduced in calculating the value of FZI. The data collected from core analysis of the cored intervals in the Tanuma and Khasib formations were used as a database for this work. The classical and the modified FZI methods were applied using the database to predict core permeability. The value of the cementation factor was tuned to get a better match between the predicted permeability resulting from applying the modified method and the measured permeability values. Results show that the correlation coefficients resulting from applying the modified FZI method are closer to unity compared with that resulting from the classical FZI method. Cementation factor (m) of m = 3 for Tanuma formation and m = 3 for Khasib formation are the best values used with the modified FZI method. The modified FZI method shows a regression factor of 0.9986 for Tanuma and 0.9942 for Khasib formation.

Reservoir Evaluation Model of the Khasib Formation in Halfaya Oil Field, Mesan Governorate, Southern Iraq.

Evaluating the reservoir characteristics of a formation or geological unit constitutes an essential element and an effective tool in leading the successful exploration project currently prevailing. The Khasib Formation, which belongs to the secondary depositional cycle (Turonian - Lower Campanian) in the study area within Mesan governorate southern Iraq, was chosen as a study site, as the Khasib is one of the main reservoirs within the Mesan oil fields. Seven wells were selected distributed over the field area, which structurally, is represented by two domes oriented from NW to SE, in addition to a thin dome with a length of 38000 m. and a width of 12000 m. The corrected well logs were used as input by creating an Excel sheet and then processing that data through the Petrel Software to prepare maps, sections and Three dimensional diagrams. The Cross-plot diagrams showed that the limestone (calcite) is a main lithology of Khasib with some dolomite. 3-dimensional petrophysical models were prepared, through which identified three reservoir units: (Khasib-A, Khasib-B and Khasib-C). The porosity model shows that there is a good percentage of porosity within the Khasib-A unit, with a low percentage in unit-B. As for unit-C, it was characterized by the best porosity percentages. The water saturation model showed a high percentage at Khasib-A unit, reaching 80%, and it increased at unit-B, reaching 90%, while unit-C was characterized by the lowest percentage of water saturation. The volume of shale model indicates low to moderate rates in the Khasib-A unit, and a slight increase in unit-B, while unit-C showed a low rate of shale volume within the three units with very low values in most of the study wells, which confirms the superior quality of this reservoir unit, which can be considered the main productive reservoir unit of the Khasib Formation in the Halfaya oil field.

Geochemistry and Paleoredox Conditions of the Carbonate Reservoir Khasib Formation in East Baghdad Oilfield-Central Iraq

Geochemistry and Paleoredox Conditions of the Carbonate Reservoir Khasib Formation in East Baghdad Oilfield-Central Iraq

Porosity Evolution and Sequence Stratigraphy of Khasib Formation (Late Turonian-Coniacian) in Selected Oilfields, Central Iraq

The evolution of porosity and sequence stratigraphy study of the Khasib Formation (Late Turonian-Coniacian) in two wells, in central Iraq were conducted. In the first well EB-X, the Khasib Formation sequences are confined to a depth of 2182-2285 m, with a thickness of about 103 meters, and in the second well Hf-Y, the Khasib Formation sequences are confined to a depth of 2941-2860 meters, with a total thickness of 81 meters. The lithology of the formation is predominantly dark chalky limestone rich in planktonic fossils, with a few thin layers of black shale. The formation lithology progressively shifts higher to shaley limestone rich in planktonic fossils and Calcispheres. On the other hand, the depositional environment of the formation was established by diagnosing six mudstone submicrofacies, five wackestone submicrofacies, and a packstone microfacies, which indicate the formation depositional settings in deep marine environments. Furthermore, the formation is split into three zones based on porosity values: A, B, and C, which are characterized by productive reservoir rock, low-yielding reservoir rock, and medium-productive reservoir rock, respectively. The Khasib formation sequences formed during the Late Turonia to Early Coniacian. As a result, the overall sedimentation period reached 3.1 million years, and the stratigraphic sequence is of the third order.

Microfacies Analysis and Diagenesis Processes Development for Khasib Formation of East Baghdad Oil field, Iraq

Microfacies Analysis and Diagenesis Processes Development for Khasib Formation of East Baghdad Oil field, Iraq

2D and 3D Modeling of Rock Mechanical Properties of Khasib Formation in East Baghdad Oil Field

Knowing the distribution of the mechanical rock properties and the far field stresses for the field of interest is an important task for many applications concerning reservoir geomechanics, including wellbore instability analysis, hydraulic fracturing, sand production, reservoir compaction, and subsidence. A major challenge with determining the rock's mechanical properties is that they cannot be directly measured at the borehole. Furthermore, the recovered carbonate core samples for performing measurements are limited and they provide discrete data for specific depths. The purpose of this study is to build 2D and 3D geomechanical models of the Khasib reservoir in the East Baghdad oil field/ Central area. TECHLOG.2015.3 software was used to build the 1D-MEM while Petrel E&P 2018.2 software was used to build the 3D distributions of rock mechanical properties. The Khasib formation has nine units (from K1 to K9). The current results support the evidence that the horizontal stresses are somewhat similar for all layers in the vertical case, but their distribution varies horizontally due to the changes in pore pressures. The pore pressure increases vertically, but its distribution within one layer is different due to the production from different wells. Elastic and strength characteristics of rock, including Young modulus, Poisson ratio, and unconfined compressive strength (UCS), have the same behavior, the highest value of the parameters appeared in the surface layer (K1). This layer is more stiff than other layers that have high porosities and high permeability. The internal friction angle for all formations ranges between 38o-40o, which gives a good harmonization with the limestone friction angle. The 3D distribution of the rock's mechanical properties revealed the carbonate heterogeneity because of its marine depositional environment and complex diagenetic processes. The findings of this study can be used for future geomechanical applications in the East Baghdad oil field including wellbore stability analysis, fault reactivation, and CO2 sequestration.

Reservoir Characteristics for Khasib Formation in selected wells of East Baghdad Oil field, Iraq

Four subsurface sections and electrical, porosity logs, and gamma-ray logs of the Khasib Formation (age Late Turonian-Lower Coniacian) were studied to identify reservoir characteristics and to evaluate the reservoir properties of the Khasib reservoir units in the East Baghdad oilfield. The lithology of the formation is limestone throughout the whole sequence in all studied wells EB-83, EB-87, EB-92, and EB94. It is bounded conformably from the top by Tanuma Formation and has a conformable lower contact with Kifl Formation. The lower and upper boundaries of the formation were determined using well log analysis, and the formation was divided into three main rock units (Kh1, Kh2, and Kh3), depending on the porosity logs. The porosity was calculated using acoustic or sonic, neutron, and density logs. The effective porosity (average 0.0 - 0.32 %) is the predominant porosity in the formation and to less extent; the secondary porosity. The volume of shale is very low (average 0.0 - 0.13 %), indicating limestone is the main rock of the Khasib Formation. The study of the reservoir water (average 0.11- 1.0%) and hydrocarbon saturations (average 0.0 - 0.88 %) showed that the formation contains varying proportions and quantities of water and hydrocarbons suspended in the wall void, and hydrocarbons capable of being produced. The lithological study reflected that the predominant lithic formation is limestone. It was found that Kh 2 unit is the best oil reservoir unit in all selected wells in terms of porosity, water saturation, diagenesis processes, and microfacies analysis.

Determination of Reservoir Hydraulic Flow Units and Permeability Estimation Using Flow Zone Indicator Method

Reservoir characterization plays a crucial role in comprehending the distribution of formation properties and fluids within heterogeneous reservoirs. This knowledge is instrumental in constructing an accurate three-dimensional model of the reservoir, facilitating predictions regarding porosity, permeability, and fluid flow distribution. Among the various methods employed for reservoir characterization, the hydraulic flow unit stands out as a widely adopted approach. By effectively subdividing the reservoir into distinct zones, each characterized by unique petrophysical and geological properties, hydraulic flow units enable comprehensive reservoir analysis. The concept of the flow unit is closely tied to the flow zone indicator, a critical parameter that defines the porosity-permeability relationships of each hydraulic flow unit. Additionally, the flow zone indicator method proves valuable in estimating permeability accurately. In this study, we demonstrate the application of the flow zone indicator method to determine hydraulic flow units within the Khasib formation. By analyzing core data and calculating the Rock Quality Index (RQI) and Flow Zone Indicator (∅Z), we differentiate the formation into four hydraulic flow units based on FZI values. Specifically, HFU 1 represents a rock of poor quality, corresponding to compact and chalky limestone. HFU 2 represents intermediate quality, corresponding to argillaceous limestone, while HFU 3 represents good quality, corresponding to porous limestone. Lastly, HFU 4 signifies an excellent reservoir rock quality characterized by vuggy limestone. By establishing a permeability equation that correlates with effective porosity for each rock type, we successfully estimate permeability. Comparing these estimated permeability values with core permeability reveals a strong agreement with a high correlation coefficient of 0.96%. Consequently, the flow zone indicator method effectively classifies the Khasib formation into four distinct hydraulic flow units and provides an accurate and reliable means of determining permeability in the reservoir. The resulting permeability equations can be applied to wells and depth intervals lacking core measurements, further emphasizing the practical utility of the FZI method.

Sonic Scanner Helps in Identifying Reservoir Potential and Isotropic Characteristics of Khasib Formation

Natural fractures provide an important reservoir space and migration channels for oil and gas reservoirs and control the reservoir potential. Therefore, it is essential to understand the methods for identifying accurate reservoir permeability and characterizing reservoir fractures. In particular, using conventional measurements to identify permeability and characterize fractures is very expensive. While using conventional logging data is very challenging, and an efficient characterization correlation method is urgently needed. In this paper, we have evaluated reservoir potential based on the sensitivity of sonic scanner tools to fluid mobility, maximum stress direction, and fractures presence. This tool provides a continuous estimation of these important parameters along the studied formation using a real field data. Dispersion behavior based on the difference between the maximum and minimum energy of the studied formation is used to detect reservoir heterogeneity and anisotropy. Dispersion analysis shows the presence of inhomogeneous anisotropy in several intervals along the studied formation. The methodology used in this paper provides an accurate estimation of reservoir permeability varies from 1 to 100 md. Also, the application of this technique shows an accepted percent error of reservoir permeability estimation reaches to 7% when compared to laboratory core measurements. The average direction of the maximum horizontal stress in the studied formation is detected to be NW10 to N16E. The study results prove that the proposed technique is effective for the identification of important reservoir properties in the oil industry.

Applying Facies Characterization to Build 3D Rock-Type Model for Khasib Formation, Amara Oil Field

Building a rock-type (facies) model is critical in the process of constructing the geological model.The facies model utilizes the facies obtained from the different characterization methods to represent the structure and the geology of the studied reservoir. Therefore, the importance of building a 3D rock-type model is to distribute the petrophysical properties depending on the rock facies to reflect the actual distribution and achieve a realistic model.Khasib formation in Amara oil field is mainly composed of limestone and exhibits a high degree of heterogeneities in its petrophysical and geological features, showing a complicated porosity-permeability relationship. Hence, the formation should be characterized by facies with specific property relationships and use these facies to build an accurate rock-type model to represent the geological rock modeling for this carbonate formation.The Rock-Type model for Khasib formation has been constructed using the facies obtained from flow zone indicator and cluster analysis characterization methods, these facies were distributed with the PETREL software by applying the sequential indicator simulation (SIS) algorithm.The 3D Rock- type model establishes that a different rock type characterized each unit within Khasib formation; the reservoir units (KH11, KH12, and KH2) were characterized by the presence of RT-1, RT-2,andRT-3, which represent the best, good, and intermediate reservoir quality rocks, respectively. The best rock type RT-1 with the best reservoir petrophysical properties was only noticed in unit KH2. The non-reservoir units (Khasib, Base KH11, Base KH12, and Base KH2) were characterized by RT-4 and RT-5, which reflect the bad rock quality with non-reservoir properties.

A Predictive Model for Estimating Unconfined Compressive Strength from Petrophysical Properties in the Buzurgan Oilfield, Khasib Formation, Using Log Data

Unconfined compressive strength (UCS) of rock is the most critical geomechanical property widely used as input parameters for designing fractures, analyzing wellbore stability, drilling programming and carrying out various petroleum engineering projects. The USC regulates rock deformation by measuring its strength and load-bearing capacity. The determination of UCS in the laboratory is a time-consuming and costly process. The current study aims to develop empirical equations to predict UCS using regression analysis by JMP software for the Khasib Formation in the Buzurgan oil fields, in southeastern Iraq using well-log data. The proposed equation accuracy was tested using the coefficient of determination (R²), the average absolute relative error (AARE%) and the standard deviation error (SD%). It has been found that the developed equation is reliable and capable of predicting the UCS with an acceptable degree of confidence R², AARE% and SD% are 0.8549, 2.619%, and 0.0569%, respectively when compared with field data. Furthermore, when compared to other known correlations, showed better prediction results.

Influence of heterogeneity on fluid property variations in carbonate reservoirs with multistage hydrocarbon accumulation: A case study of the Khasib formation, Cretaceous, AB oilfield, southern Iraq

Abstract The fluid distribution is considerably influenced by the reservoir homogeneity. This study analyzes carbonate reservoir heterogeneity and hydrocarbon accumulation processes in the Khasib reservoirs in AB oilfield in the Middle East to discuss factors controlling the distribution of fluid and the effects of this distribution on the productivity of single wells. The Khasib reservoirs in the AB oilfield show uniform vertical distributions, with a large difference in the longitudinal pore throats, and the upper part of the reservoir is better than the lower one. Because the hydrocarbon accumulation is multiphasic, the heterogeneity of crude oil is based on whether traps are formed in the early or late stage of source rock formation during accumulation. Moreover, the longitudinal physical differences in crude oil properties are mainly attributed to the longitudinal differences in the pore throats. The difference in the pore throat and physical properties of crude oil affords differences in the productivity of horizontal wells in different subzones.

Lithofacies classification and sequence stratigraphic description as a guide for the prediction and distribution of carbonate reservoir quality: A case study of the Upper Cretaceous Khasib Formation (East Baghdad oilfield, central Iraq)

In the East Baghdad oilfield of central Iraq, the Upper Cretaceous Khasib Formation is the largest producing carbonate reservoir. The basic architecture of the “Khasib reservoirs” is heavily impacted by the lithofacies classification and sequence stratigraphic interpretation at East Baghdad field. A description of the Khasib Formation in terms of depositional systems, environments and lithofacies was obtained by studying the vertical distribution of the lithofacies, defined using well-log values and their mutual statistical relationships and constrained by the core data (thin sections). In this paper, a lithofacies classification and sequence stratigraphic interpretation are used to define reservoir geometry, lateral continuity and petrophysical characteristics of the Khasib reservoirs. The “Khasib” carbonate ramp stratigraphy exhibits different lithofacies in different depositional systems at the East Baghdad field. In addition, the log signatures and petrophysical properties of the same lithofacies vary. Multivariate statistical methods (principal component analysis and clustering) have been applied to separate stratigraphic packages and different carbonate lithofacies. Khasib carbonate lithofacies can be better discriminated from cluster analysis based on principal components rather than from arbitrary well log observations alone. The geometry of the strata in the ‘Khasib’ outer ramp is retrogradational, becoming aggradational during the lowstand systems tract (LST) and transgressive systems tract (TST). The highstand systems tract (HST) of the Khasib Formation is typically distinguished by a relatively thick aggradational-to-progradational geometry. This parasequence set is widespread upon the “Khasib” mid- and inner ramp. Petrographic analysis reveals the relative abundance and distribution of characteristic porosity types of the “Khasib” reservoirs. The HST (mid- and inner ramp) of “Khasib” Formation reveals the best reservoir characteristics (thickness, porosity, and hydrocarbon saturation) in the East Baghdad field. This enhancement of the knowledge of the lithofacies within a sequence stratigraphic framework through the application of principal component and cluster analysis is especially important to -optimally delineate and define the potential reservoir intervals of Iraq's Khasib Formation. Such multivariate statistical techniques may have similar beneficial application to carbonate reservoirs elsewhere in the world.

Use of Attributes on 3D Seismic Data for Studying Mishrif Formation in East Abu-Amoud Field, South-Eastern Iraq

The seismic method depends on the nature of the reflected waves from the interfaces between layers, which in turn depends on the density and velocity of the layer, and this is called acoustic impedance. The seismic sections of the East Abu-Amoud field that is located in Missan Province, south-eastern Iraq, were studied and interpreted for updating the structural picture of the major Mishrif Formation for the reservoir in the field. The Mishrif Formation is rich in petroleum in this area, with an area covering about 820 km2. The horizon was calibrated and defined on the seismic section with well logs data (well tops, check shot, sonic logs, and density logs) in the interpretation process to identify the upper and lower boundaries of the Formation. Seismic attributes were used to study the formation, including instantaneous phase attributes and relative acoustic impedance on time slice of 3D seismic data . Also, relative acoustic impedance was utilized to study the top of the Mishrif Formation. Based on these seismic attributes, karst features of the formation were identified. In addition, the nature of the lithology in the study area and the change in porosity were determined through the relative acoustic impedance The overlap of the top of the Mishrif Formation with the bottom of the Khasib Formation was determined because the Mishrif Formation is considered as an unconformity surface.

Reservoir characterization of the upper Turonian – lower Coniacian Khasib formation, South Iraq: Implications from electrofacies analysis and a sequence stratigraphic framework

The Upper Turonian – Lower Coniacian Khasib Formation is a significant hydrocarbon reservoir in southern Iraq. The present study integrates multiple data sets of 33 wireline wells, available core, and thin sections from two important oilfields: Amara and Noor to interpret the lateral and vertical facies changes and petrophysical reservoir variability within a sequence stratigraphic framework. Cluster analysis based on well log data including gamma ray, sonic, neutron, bulk density data were used to classify the Khasib Formation into five carbonate electrofacies and determine the petrophysical properties. These electrofacies consists of compacted marly, argillaceous, chalky, porous, and vuggy limestones which are interpreted to have been deposited in a ramp setting. Sequence stratigraphic analysis shows that the Khasib Formation consists of two third-order sequences with three sequence boundaries refer to global sea-level changes: the Mishrif-Khasib regional unconformity, the intra-Khasib unconformity, and the Khasib-Tanuma formational boundary. Each sequence consists of a transgressive system tract (TST) and a highstand systems tract (HST) which are separated by a maximum flooding surface (MFS). Reservoir correlation and mapping of the Khasib Formation in both the Amara and the Noor oilfields show the best important oil-bearing zones are located dominantly in transgressive system tracts (TSTs).

Importance of Velocity Deviation Technique and Negative Secondary Porosity in Detection of Hydrocarbon Zones in Khasib Formation, East Baghdad Oil Field

The velocity deviation technique is one of the important techniques in hydrocarbon investigations, through which it is possible to identify the types and the content of rock pores. The current study aimed to demonstrate the benefit of this technique in discovering the oil sites of the Khasib formation in the East Baghdad oil field, as well as the possibility of separating the oil and gas zones by combining the velocity deviation technique with the anomalous primary porosity information that leads to negative secondary porosity. In this study, log data of three wells distributed in the study area (EB-04, EB-16, and EB-34) were used. From these data, the velocity was estimated by the sonic log, the porosity was estimated by the neutron and the density log, while the velocity deviation was determined by subtracting the velocity calculated from the density log from the sonic log velocity. The result showed that there is significant agreement between the secondary porosity values that turned positive after the oil effect was removed and the confirmed oil zones derived from the core information. Also, there was a clear correlation between velocity deviation values above -500 m/s and the permeability zone of formation, which may reflect the importance of this technique in the identification of the permeability zone. Both techniques (Velocity Deviation and log porosity analysis) can be correlated to predict the locations of gas, large-scale fractures, and unconsolidated beds in sites of high negative secondary porosity and low-velocity deviation (under -500 m/s).