Methods and systems for determining the location of oil and gas reservoirs

Abstract

This invention relates to a method and system for determining the location of oil and gas reservoirs using a mechanical property model of a subsurface geological region. The method (10, 20) includes the steps of: creating multiple hypothetical seismic profiles at the time of deposition based on seismic interpretation of the subsurface geological region and the influence of tectonic time data and tectonic pressure data (11, 21); and creating a mechanical property model of the subsurface geological region based on the multiple hypothetical seismic profiles at the time of deposition and the influence of tectonic time data and tectonic pressure data (12, 22).

Description

Technical Field

[0001] This invention relates to geological modeling, and more specifically, to methods and systems for creating mechanical property models of subsurface geological regions and for determining the location of oil and gas reservoirs. Background Technology

[0002] Geological modeling is used to create a computer-based representation of a subsurface area, known as a geological model. This model can then be used to simulate oil and gas reservoirs or sedimentary basins. Geological models can be used for a variety of purposes. For example, they can be used as input to computer programs to simulate the movement of fluids within the modeled subsurface area. These computer programs can then be used to predict oil and gas productivity, the volume of an oil and gas reservoir as a function of time, or to predict the existence of oil and gas reservoirs.

[0003] Geological modeling of subsurface areas can be based on various geological features, such as clinoforms or plummets. Clinnoforms are sloping subsurface sedimentary structures and are well-known in structural geology. These sedimentary structures are formed by the retreat of the continental shelf as sea level falls. Clinnoforms thus describe a two-dimensional surface that can be defined as extending downwards from the basement (below sea level) to the bottom of a generally flat basin. Due to this erosion-based formation process, clinnoforms typically form in areas with fine-grained rocks (such as those found in silt or clay), thin and homogeneous bedding, and exhibit linear flow marks resulting from seawater retreat. Many subsurface structures discovered in Abu Dhabi, UAE, have historically been associated with sea-level retreat and are therefore described as clinnoforms.

[0004] However, certain structures and tectonic impacts observed in the subsurface areas of Abu Dhabi exhibit characteristics or properties that cannot be explained using the aforementioned continental slope topography formation models. Therefore, the sedimentary surfaces discovered in Abu Dhabi require characterization using different standards and methods. The sedimentary surfaces in Abu Dhabi typically exhibit complex sedimentary accumulations that can be termed “vertical slopes.” These vertical slopes are difficult to map, and a new method is needed to reliably simulate the formation of these sedimentary surfaces.

[0005] Vertical slopes have been thoroughly studied from structural, stratigraphic, and sedimentological perspectives. Unlike continental slope topography, vertical slopes describe assessments of tectonic impacts leading to complex layered layouts of sediments. Vertical slopes are observed in many reservoirs in the Abu Dhabi oilfield, and are particularly found in Aptian, Turonian / Coniacian, Berriasian-Valangnian, and Tithonian strata. A common feature of all these strata is that they are carbonate formations. In Abu Dhabi, these carbonate formations typically contain significant amounts of hydrocarbons.

[0006] Understanding the formation of vertical slopes can improve the reliability of identifying and developing hydrocarbon accumulations or oil fields in the subsurface areas of Abu Dhabi. Unlike continental slope topography, vertical slopes are not sedimentological features. Vertical slopes also originate from the impact of tectonic activity acting simultaneously with sediment supply, resulting in the formation of vertical slope zones parallel to the controlling or major fault lines. Typically, vertical slopes are found only parallel to the major fault lines prevalent in Abu Dhabi. Furthermore, the combination of sea-level oscillations over time and tectonic activity in the subsurface areas supports the fact that vertical slope growth is usually characterized by tectonic events.

[0007] Vertical slopes are a characteristic feature of basin margin strata and can be defined as two-dimensional surfaces with an S-shaped (inclined) geometry. Evidence for the presence of vertical slopes can be identified from seismic, well logging, and outcrop data and is used to define basin margins, accumulation patterns, and shelf trajectories. Paleobasin depth and relative sea-level fluctuations are also inferred from the height and geometry of the vertical slope. Therefore, a deeper understanding of vertical slope formation contributes to sequence geology and basin analysis, and this understanding enables more accurate predictions of the location and size of subsurface hydrocarbon accumulations.

[0008] However, it is necessary to update the model for the Abu Dhabi oilfield to improve oil and gas recovery, as heterogeneous reservoirs throughout the field are not depleted in equal quantities. Therefore, a deeper understanding of the establishment of specific target zones within the reservoir is useful for assessing factors that have the greatest impact on oil and gas production and recovery, such as compartmentalization, flow paths, and fault patterns. The term "compartmentalization," in this context, is used to define the geological division of a once continuous reservoir into isolated compartments. A fault is a planar fracture or discontinuity in a rock volume caused by significant displacement due to rock block movement.

[0009] Existing technology

[0010] Numerous patent documents are known concerning the creation of models of the mechanical properties of subsurface geological regions. For example, granted U.S. Patent US 9,733,391 B2 (Dimitrov et al.; assigned to ExxonMobil Upstream Research Company) relates to methods and systems for modeling one or more geophysical properties of a subsurface volume. The method includes: obtaining a subsurface volume; obtaining an interpretation of the subsurface volume; defining flexible geological concepts; and applying one or more geological concepts to the interpretation of the subsurface volume by a computer system. The method further includes flexible geological concepts to obtain a modified interpretation of the subsurface volume based on the applied geological concepts. Specifically, the methods and systems of this application relate to using computers to interpret and analyze geophysical and geological data. The patent describes methods and systems for repeatedly calculating subsurface structures using geological input data and computer systems. The described methods include calculating the stacking patterns of different subsurface structural layers and causing these stacking patterns to interact. However, the method disclosed in this U.S. patent does not explicitly detail the influence of progradation surfaces on the predicted presence of hydrocarbon reservoirs.

[0011] Granted U.S. Patent US 8,903,659 B2 (Gesbert et al.; assigned to Shell Oil Company) describes a method for stratigraphic analysis of seismic data. The method includes: selecting a seismic data volume; selecting several horizons or layers within the geological data volume; and selecting a scale of interest within the seismic data volume. A property function is then applied to at least one of the selected horizons at the selected scale of interest. This patent describes a method for calculating large-scale geological features of subsurface structures using geological input data and a computer system. The method uses different geological resources to calculate basin development over time. However, no model specifically designed to incorporate the mechanical properties of subsurface geological regions is described.

[0012] International patent application WO2019 / 231681 A1 (Mezghani et al.; assigned to Aramco Services Co. and Saudi Arabian Oil Co.) discloses a method for formation modeling using linear and nonlinear algorithms. In a first step, a defined range value is selected for each of a plurality of hydrodynamic input parameters. Simulated topographic results are generated using the selected range values ​​and a forward model. A detailed seismic interpretation is generated to represent specific seismic features or observed topography. A calculated deviation value representing the distance between the simulated topographic results and the detailed seismic interpretation is provided. The deviation value is then calculated based on thickness and porosity data extracted from well data, and simulation results are generated. This patent application describes a method for predicting subsurface oil reservoirs. The focus is on using forward formation modeling to predict oil and gas reservoirs. However, this patent application does not disclose a method for predicting subsurface reservoirs using the mechanical properties of subsurface geological regions and the formation processes involved in oil and gas reservoir traps.

[0013] International patent application WO2010 / 110824 A1 (Benson et al.; assigned to ExxonMobil Upstream Research Company) discloses a method for selecting an expression to approximate measurement-based values ​​of geological properties along a certain dimension of a subsurface stratum. The values ​​of each term of the expression are determined such that the expression satisfies an objective function within a predetermined range. This objective function indicates the difference between the output of the expression and the measurement-based values ​​at similar points along that dimension. The expression and the values ​​of its terms are output, which includes mapping the terms of the expression to represent geological properties in the subsurface stratum, such that the expression and the values ​​of its terms describe the geological properties at all locations within the subsurface stratum. This patent application describes a theoretical method for computation to determine the presence of subsurface oil and gas reservoirs. However, the focus of this patent application is on theoretically modeling subsurface patterns without further exploring the mechanical aspects that dominate the formation of subsurface structures.

[0014] US Patent 8,494,827 B2 (Dasari et al.; assigned to ExxonMobil Upstream Research Company) describes a method for predicting localized failure and naturally occurring fractures in subsurface areas. This invention uses a hybrid FEM-DEM (i.e., finite discrete element method) framework combined with fracture risk analysis and fracture initiation and propagation criteria to model the transition of rock from a continuum to a discontinuous state. Risk analysis incorporates results from other natural fracture prediction tools to enhance the FEM-DEM solution, such as by providing remote and local boundary conditions and identifying potential areas of anticipated failure and fracturing. Natural fracture and failure information is extracted from the modeling results and can be used directly for prediction or as input to other fracture analysis tools or techniques. FEM-DEM and risk analysis techniques can be incorporated into various numerical simulation software packages using finite discrete method solvers. This patent focuses on using the FEM-DEM method to predict localized failure modeling. Various mechanical properties of predicted natural fractures and the resulting effects are analyzed and described. This application focuses on using complex simulation models to predict fractional patterns in subsurface structures. However, the disclosed method does not specifically investigate the presence of hydrocarbon accumulation. Summary of the Invention

[0015] A method is provided for predicting the presence of hydrocarbon accumulation using a mechanical property model of a created subsurface geological region. The method includes creating multiple hypothetical seismic profiles at the time of deposition based on seismic interpretation of the subsurface geological region and the influence of tectonic time and pressure data. A mechanical property model of the subsurface geological region is created based on these hypothetical seismic profiles at the time of deposition and the influence of such tectonic time and pressure data. The mechanical property model is further analyzed for the presence of progradation surfaces. Using the analyzed progradation surface locations, the mechanical property model is used to indicate the presence of hydrocarbon accumulation within the subsurface geological region.

[0016] This subsurface geological region is a subsurface area defined by its common geological characteristics. The seismic interpretation of this subsurface geological region involves subsurface geological information, specifically information about sedimentary structures or layers within this region. This seismic interpretation can be derived based on well logging measurements and well logging correlations between polygon well models and outcrop models. An outcrop is a visible exposure of bedrock. A seismic profile or seismic line is seismic data displayed along a line. A hypothetical seismic profile at deposition time is hypothetical seismic data displayed along a line at the time of deposition. This hypothetical seismic profile is a display of a seismic profile with hypothetical characteristics of a seismic profile at deposition time. These hypothetical characteristics define the properties of the seismic profile because the properties of the seismic profile are estimated to have existed at the time of deposition.

[0017] Tectonic impacts are the mechanical processes that control the structure and properties of the Earth's crust and its evolution over time. Tectonic temporal data refers to time-related data describing these tectonic processes. Tectonic pressure data refers to pressure data describing the mechanical processes of tectonic geology.

[0018] The mechanical property model described in this document is a computer-implemented model of the mechanical properties of a subsurface geological region, and more specifically, a model of a subsurface geological region whose profiles are classified based on its mechanical properties. This mechanical property model can be created using a geomechanical modeling simulator, and more specifically a 3D simulator, which includes a simulation engine that uses geomechanics to generate the mechanical property model and assumes seismic profiles. The 3D simulator has the ability to recover and back-extract data stored in the mechanical property model.

[0019] Data recovery involves gradually restoring rock masses or strata to their original shape to validate the interpretations used to construct models of their mechanical properties. Restoration to the original shape describes the process of reverse calculation of a present-day subsurface geological region. This restoration is accomplished by calculating the initial shape of the layers in the subsurface geological region before they were subjected to the forces generated by the mechanical processes of tectonic processes. Such calculations for restoration to the original shape include calculating the thickness of pre-deformed layers of rock strata or rock masses in the subsurface geological region, and this calculation further includes using seismic profiles to estimate the present-day morphology of the subsurface geological region. This back-stripping involves quantitatively estimating the thickness of the rock mass or strata characterized at initial formation or deposition. Quantitatively estimating the thickness of the rock mass or strata includes calculating sediment deposition over time and sediment erosion over time. The estimation of back-stripping allows determination of the initial thickness and mechanical properties of the facies in the subsurface geological region. Using the calculated properties of the rock mass or strata present at deposition, the resulting mechanical stresses and strains can be calculated.

[0020] The method used to predict the presence of hydrocarbon accumulation in subsurface geological regions is based on the concept that the most readily correlated sedimentary bodies are undeformed cake strata. Therefore, the subsurface geological region is first regressed to the past by generating multiple seismic profiles. These profiles are generated based on the seismic interpretation of the subsurface geological region and the influence of tectonic time and pressure data, removing all faults and folds, thus forming the assumed geometry of the quasi-sequence at the time of deposition. Folds are stacks of originally flat surfaces that have bent or curved during permanent deformation, such as sedimentary strata. For example, such cake strata enable seismic correlations between well data of the well of interest. Forward geomechanical modeling then models the sediments as they have progressed forward in time to the present, where all the complexities of deformation reappear, but high sedimentary characteristics remain visible.

[0021] The method outlined in this document is not based on the concept of continental slope topography in the prior art, but rather on the so-called vertical slope, as described above. As described in the introduction, the vertical slope is characterized by tectonic processes and is a feature of basin margin strata, defined as a two-dimensional surface with an S-shaped geometry. It has been shown that the vertical slope is not a sedimentological feature, but its formation is caused by the impact of tectonic processes occurring simultaneously with sediment supply.

[0022] Methods for predicting the existence of hydrocarbon reservoirs also consider structural and tectonic impacts. An improved geological modeling method is presented compared to existing techniques.

[0023] Subsurface geological regions may contain one or more oil and gas reservoirs. This method enables the improvement of oilfield modeling details by introducing high-resolution reservoir characterization into the region of interest. High-resolution reservoir characterization takes into account structural and tectonic impacts. In this case, the method may further include the following steps: for oil and gas reservoirs, determining the location of the corresponding reservoirs based on a mechanical property model; and transmitting information about the location of the oil and gas reservoirs to enable the extraction of oil and gas from one or more reservoirs based on the determined location.

[0024] In one aspect, the step of creating multiple hypothetical seismic profiles at the time of deposition further includes deriving tectonic time data from geometric features within the seismic interpretation. Since sedimentary systems are controlled by tectonic processes, the unique geometric configurations of bedding surfaces can be used to identify sediment deposits leading to the formation of vertical slopes. This allows for the derivation and identification of the internal characteristics of subsurface geological regions from well logging measurements. Specifically, stratigraphic growth patterns reflect the dynamics and geometry of continuously growing folds and slips on thrust faults and allow for temporal constraints on how the geometry evolves over time. Therefore, based on knowledge of tectonic processes, the corresponding tectonic time data can then be derived in a simple manner.

[0025] The steps of creating multiple hypothetical seismic profiles during deposition further include deriving tectonic pressure data from geometric features within the seismic interpretation. Specifically, mechanical models of the faults and characteristic signatures of thrust faults that emerge during deposition can be used to characterize the corresponding sediments. Stratigraphic growth patterns reflect the dynamics and geometry of folds and slips that continuously develop on thrust faults and allow for temporal constraints on how the geometry evolves over time. Based on the mechanical models of the faults, tectonic pressure data can then be derived in a simple manner.

[0026] The method may further include the steps of: detecting the boundaries in the plurality of assumed seismic profiles at the time of deposition; developing a model including optimal well logging correlations based on the boundaries; and adjusting the model including optimal well logging correlations based on the influence of tectonic time data and tectonic pressure data. In this context, the term boundary refers to the upper and lower boundaries of different quasi-sequences, which then define the boundaries of the vertical slope. Using these boundary definitions and applying them to well logging, the seismic profiles and the well logging distribution of the vertical slope are superimposed on each other. The term "superimposition" describes the correlation between the well logging and the seismic profile stored in the model. Using knowledge of the changes in major depositional and erosion events over time, a thrust fault is created at the contact between the two vertical slopes. The created superimposed well logging distribution then shows reservoir characteristics at very high resolution. For example, reservoir characteristics are gamma-ray values ​​indicating sediment type and density values ​​in meters. Then, a geomechanical modeling simulator is used and the vertical slope is advanced to its present state over time by incorporating a series of deformation events. This forward calculation reintroduces faults and folds into the region of interest stored in the mechanical property model. The step of detecting boundaries in multiple seismic profiles may include using data related to gamma rays in the so-called gamma-ray spectrum. In other non-limiting instances, acoustic data and measured density data can be used to detect boundaries. Gamma-ray spectroscopy is a fast and non-destructive analytical technique. Using gamma-ray spectroscopy, various data items about the subsurface region can be obtained. This data is then input for further processing and to estimate the location of oil and gas reservoirs, as will be explained later.

[0027] The steps for creating a mechanical property model of a subsurface geological region further include assessing the mechanical response of one or more hydrocarbon reservoirs to tectonic time and pressure data. This mechanical property model is then created based on the mechanical response of one or more hydrocarbon reservoirs to the tectonic time and pressure data. The presence of mechanical stress (especially in the presence of faults) in hydrocarbon accumulation zones can lead to complex hydrodynamic effects within the hydrocarbon accumulation area.

[0028] Changes in reservoir pressure lead to changes in in-situ stress in subsurface geological regions. These stress changes are related to the distribution of hydrocarbons within the areas where they accumulate. Therefore, assessing the mechanical response of hydrocarbon reservoirs to structural time and pressure data, and considering this mechanical response when creating mechanical property models, will further ensure the correct placement of wells in low-strain zones within the reservoir. Similarly, rock mechanical properties can be calibrated with any rock physical properties, which may include density, porosity, permeability, etc., for geomechanical modeling.

[0029] According to another aspect of the invention, a method is provided for determining the location of one or more oil and gas reservoirs in a subsurface geological region. The method includes the steps of: creating a mechanical property model of the subsurface geological region including one or more oil and gas reservoirs using a method for creating a mechanical property model as described above; and determining the location of the oil and gas reservoirs based on the mechanical property model.

[0030] Therefore, an improved method is provided for determining the location of oil and gas reservoirs in subsurface geological regions, taking into account structural and tectonic impacts, and wherein a quick and simple routine is used to improve the modeling details of the oilfield by introducing high-resolution reservoir characterization in problem areas with structural and tectonic impacts.

[0031] According to another aspect of the invention, an apparatus is provided for creating a mechanical property model of an underground geological region, wherein the apparatus comprises: one or more processors, including a seismic profile module processor configured to determine a plurality of hypothetical seismic profiles at the time of deposition based on the seismic interpretation of the underground geological region and the influence of tectonic time data and tectonic pressure data; and a mechanical property model configured to create the mechanical property model of the underground geological region based on the plurality of hypothetical seismic profiles at the time of deposition and the influence of tectonic time data and tectonic pressure data.

[0032] This apparatus considers the concept that the most readily correlated sedimentary bodies are undeformed cake strata. Therefore, the subsurface geological region is first modeled to reflect its ancient structure by generating multiple seismic profiles based on the seismic interpretation of the subsurface geological region and the influence of tectonic time and pressure data, removing all faults and folds, thus forming an assumed geometry of the quasi-sequence at the time of deposition. For example, such cake strata can then enable seismic correlations between wells of interest. The next step involves forward geomechanical modeling, which models the sediments as they have progressed over time to the present. These forward-calculated sediments include complexities resulting from deformation. In these forward-calculated sediments of the mechanical property model, sediment characteristics are visible at high resolution.

[0033] The device is configured to operate the method, as described above, which is based not on continental slope topography but on the concept of vertical slope. The device also considers structural and tectonic impacts. Therefore, this document describes an improved apparatus for creating a model of the mechanical properties of subsurface geological regions.

[0034] The underground geological area may include one or more oil and gas reservoirs, and the device may further include a reservoir module configured to determine the location of such oil and gas reservoirs based on the mechanical property model.

[0035] The processor may include a tectonic time derivation module configured to derive tectonic time data from geometric features within seismic interpretation. Since sedimentary systems are controlled by tectonic activity, the unique geometry of bedding surfaces can be used to identify sediments. Internal characteristics of subsurface geological regions can be derived and identified from well logging measurements. Specifically, stratigraphic growth patterns reflect the dynamics and geometry of continuously growing folds and slips on thrust faults and allow for temporal constraints on how the geometry evolves over time. Therefore, based on knowledge of tectonic processes, the corresponding tectonic time data can then be derived in a simple manner.

[0036] The processor may also include a tectonic pressure data module configured to derive tectonic pressure data from geometric features within seismic interpretation. Since sedimentary systems are controlled by tectonic activity, the unique geometry of bedding surfaces can be used to identify sediments. Internal characteristics of subsurface geological regions can be derived and identified from well logging measurements. Specifically, stratigraphic growth patterns reflect the dynamics and geometry of continuously growing folds and slips on thrust faults and allow for time constraints on how the geometry evolves over time. Based on fracture mechanics models, tectonic pressure data can then be derived in a simple manner.

[0037] In one aspect, the apparatus further includes: a detector configured to detect boundaries in the plurality of hypothetical seismic profiles at the time of deposition; a model development module configured to develop a model including optimal well logging correlations based on these boundaries; and a model adjustment module configured to adjust the model including optimal well logging correlations based on the influence of the tectonic time data and tectonic pressure data. The boundaries describe the upper and lower boundaries of different quasi-sequences, specifically, the boundaries of the vertical slope. Using the definition of these boundaries in the well logging, the seismic profiles can then be overlaid on top of each other with the well logging distribution of the vertical slope having quasi-sequences. By applying knowledge of major depositional and erosion events, a thrust fault can be selected to appear at the contact between the two vertical slopes. This distribution then reveals the characteristics of the reservoir at very high resolution. The model then allows for modeling the vertical slope as it has progressed over time to the present using a geomechanical modeling simulator by incorporating a series of deformations.

[0038] Information about underground areas can be obtained using gamma-ray spectroscopy. In this aspect of the invention, a gamma-ray source is used to detect boundaries. This is accomplished by emitting and receiving gamma rays emitted from the gamma-ray source. Gamma-ray spectroscopy is a rapid and non-destructive analytical technique that can be used to detect boundaries.

[0039] In other aspects, the apparatus further includes: an evaluation device configured to evaluate the mechanical response of one or more oil and gas reservoirs to the influence of structural time data and structural pressure data, wherein a second creation device is configured to create a mechanical property model also based on the mechanical response of one or more oil and gas reservoirs to the influence of structural time data and structural pressure data. The presence of mechanical stress (especially faults) within an oil and gas accumulation zone leads to complex hydrodynamic effects within the accumulation. Changes in reservoir pressure can cause changes in in-situ stress in subsurface geological areas that can be calculated by the apparatus. These stress changes in subsurface geological areas are related to the distribution of oil and gas within the accumulation zone. Therefore, evaluating the mechanical response of oil and gas reservoirs to the influence of structural time data and structural pressure data, and considering the mechanical response when creating the mechanical property model, will further lead to the correct placement of wells in low-strain zones within the oil and gas reservoir. Similarly, rock mechanical properties can be calibrated with any rock physical properties and then used for geomechanical modeling, wherein such rock physical properties can be density, porosity, permeability, etc.

[0040] According to another aspect of the invention, a system for determining the location of one or more oil and gas reservoirs in an underground geological region is disclosed. The method includes: means for creating a mechanical property model of the underground geological region as described above; and a determining device configured to determine the location of the oil and gas reservoir based on the mechanical property model.

[0041] Therefore, a system for determining the location of oil and gas reservoirs in subsurface geological regions is provided. The system includes apparatus for creating a mechanical property model of the subsurface geological region, which also takes into account structural and tectonic impacts. Specifically, a system is provided comprising an apparatus configured to run routines that improve the modeling detail of the oilfield by introducing high-resolution reservoir characterization in problem areas with structural and tectonic impacts.

[0042] In this paper, since the determination of oil and gas reservoir locations is based on an improved geological modeling apparatus, the determination of oil and gas reservoir locations can also be improved. Therefore, a system is provided that includes equipment for predicting the existence of one or more oil and gas reservoirs in a subsurface geological region. This system takes into account structural and tectonic impacts, and thus provides an improved apparatus for predicting the existence of one or more oil and gas reservoirs in a subsurface geological region. Specifically, a system is provided that includes equipment configured to run routines that improve the modeling detail of an oilfield by introducing high-resolution reservoir characterization in problem areas with structural and tectonic impacts.

[0043] Oil and gas extraction is based on an improved apparatus used to create a mechanical property model of the underground geological area, and thus, using this mechanical property model, improvements in gasoline extraction can be achieved. It will be understood that, for example, the extraction equipment could be oil drilling equipment.

[0044] Also disclosed is a computer program product including a computer-readable storage medium storing instructions that, when executed by a processor, perform a method for creating a model of the mechanical properties of an underground geological region as described above.

[0045] The computer program product includes a computer-readable storage medium storing instructions that, when executed by the processor, perform a method for creating a mechanical property model of a subsurface geological region, taking into account structural and tectonic impacts. Specifically, a routine is disclosed to improve the modeling detail of an oil and gas reservoir by introducing high-resolution reservoir characterization into a problem area with structural and tectonic impacts. This routine uses, for example, available well logging data (e.g., using sonic and density data) to calculate the mechanical properties, and the instructions executing the computer program product further include the use of well-known equations, such as the Terzaghi principle. The Terzaghi principle states that when stress is applied to a porous material, the stress is counteracted by the fluid pressure in the pores filling the material. Attached Figure Description

[0046] Figure 1 The illustration shows the terrain of the land slope.

[0047] Figure 2 The illustration shows a flowchart of a method for creating a mechanical property model of an underground geological region according to a first aspect of the present invention.

[0048] Figure 3 The illustration shows a flowchart of a method for creating a mechanical property model of an underground geological region according to a second aspect of the present invention.

[0049] Figure 4 The diagram illustrates what is known as a vertical slope.

[0050] Figure 5 The illustrations depict apparatus for creating mechanical property models according to different aspects of the present invention. Detailed Implementation

[0051] Geological modeling is typically used to create computer-based representations of subsurface areas, known as geological models. These models can then be used to simulate oil and gas reservoirs or sedimentary basins. Furthermore, after their formation, these geological models can be used for a variety of purposes. For instance, the geological model can be used as input to computer programs to simulate the movement of fluids within the modeled subsurface area. These programs can then be used again to predict oil and gas productivity, the volume of oil and gas reservoirs as a function of time, and so on.

[0052] As outlined in the introduction, geological modeling of underground areas can be based on different geological features, such as continental slope topography or vertical slope. Figure 1 The illustration shows a slope terrain 1, such as a slope terrain known in the Abu Babi oil field.

[0053] Slope topography is defined as a sloping sedimentary surface deposited without wave disturbance, where the continental shelf has retreated with the drop in sea level. Slope topography is predominantly muddy and lacks abundant fossils. Rock properties used to identify slope topography are defined as having fine grains carried by suspended, thin, and homogeneous bedding, and the presence of flow marks and grooves / stripes as evidence of gravity flow.

[0054] However, this description is not applicable to areas showing tectonic breaks and must conform to, for example, regional tectonic geology in Abu Dhabi. Specifically, as in Figure 1 As can be seen, the slope topography in such a region no longer shows a consistent slope and shelf correlation, but rather different dip directions, which is assumed to be illogical in relation to actual geological features. There is also no phase change, and the main orientation is parallel to the strike of the main fault.

[0055] Therefore, it is necessary to update the static models of these Abu Dhabi oilfields to a certain level to improve recovery, as heterogeneous reservoirs are not depleted equally throughout the field. Thus, a deeper understanding of the accumulation in specific target areas within the reservoir is useful for identifying factors with the greatest impact on production, such as compartmentalization, flow paths, and fault patterns.

[0056] Figure 2 The illustration shows a flowchart of a method 10 for creating a mechanical property model of a subsurface geological region according to a first aspect of the present invention. Method 10 includes the following steps: in step 11, multiple hypothetical seismic profiles at the time of deposition are created based on seismic interpretation of the subsurface geological region and the influence of tectonic time data and tectonic pressure data. In step 12, a mechanical property model of the subsurface geological region is created based on these multiple hypothetical seismic profiles at the time of deposition and the influence of such tectonic time data and tectonic pressure data.

[0057] Method 10 is based on the concept that the most readily correlated sedimentary bodies are undeformed cake strata. Therefore, Method 10 first models the past subsurface geological region by generating multiple seismic profiles based on the seismic interpretation of the subsurface geological region and the influence of tectonic time and pressure data, removing all faults and folds, thereby forming an assumed geometry of the quasi-sequence at the time of deposition. For example, such “cake strata” enable seismic correlation between well data of interest. Forward geomechanical modeling simulates the sediments advancing forward in time to the present, where all the complex deformations reappear, but high sedimentary characteristics remain visible. As previously mentioned, Method 10 is not based on continental slope topography, but rather on so-called vertical slopes. Vertical slopes are characterized by growth from tectonic events. Vertical slopes are characteristics of basin margin strata and are defined as two-dimensional surfaces with S-shaped geometry. Specifically, vertical slopes are not sedimentological features, but rather originate from tectonic geological impacts that act simultaneously with sediment supply.

[0058] Therefore, Method 10 also considers structural and tectonic impacts to create a model of the mechanical properties of subsurface geological regions. These subsurface geological regions include one or more oil and gas reservoirs, and thus Method 10 enables routines to improve the modeling detail of oilfields by introducing high-resolution reservoir characterization into problem areas with structural and tectonic impacts.

[0059] Step 11, which involves creating multiple hypothetical seismic profiles at the time of deposition, further includes deriving tectonic time data and tectonic pressure data from geometric features within the seismic interpretation.

[0060] According to the mechanical model of fracture, a strike-slip fault evolves when σ2 is a vertical stress and σ1 and σ3 are the maximum and minimum horizontal stresses, respectively. When the maximum compressive stress σ1 forms an acute angle with the cracks between the main fault segments, these cracks cause stress rotation, and σ3 will be nearly vertical, resulting in a vertical slope thrust fault. When σ1 replaces σ3, a vertical slope normal evolves.

[0061] Furthermore, the upward movement of material from the hanging wall over the footwall forms the typical stratigraphic signature of a thrust fault: older rock is placed on top of younger rock, with strata repeating. This characteristic signature of thrust faults can be used to identify them, even if such thrust faults subsequently fold or are reactivated as normal faults. A shovel-shaped geometry resulting from gravity sliding of the fault is common, as is a horizontal sub-segment connected by short dip segments. These short dip segments are often referred to as the plane and the slope. The movement of material on the slope and plane requires deformation of the material in the hanging wall of the thrust fault; specifically, the slope-plane geometry is associated with characteristic folds (called fault bending folds) in the hanging wall of the thrust fault. These folds are often associated with blind faults. Since blind faults terminate in the middle of a rock block, the displacement along the fault must cross the buried fault tip and transfer to a more widely distributed strain. These folds form at the tip of the blind fault. More generally, when the slip rate along a fault exceeds the propagation rate of the fault tip itself, the fault remains invisible for most of its history and forms fault propagation folds. Thrust faults and their folds occur during sedimentary processes characterizing vertical slopes.

[0062] Stratigraphic growth patterns reflect the dynamics and geometry of continuously growing folds and slips on thrust faults, and allow for strict temporal constraints on how the geometry evolves over time. This is analogous to growth strata in extensional environments. Folds and thrust fault zones are typically associated with the deformation of layered sediments. Sedimentary stratification provides a pre-existing mechanical anisotropy along which faults propagate. In other words, sedimentary stratification provides ideal initial conditions for slope-plane geometry. It should be noted that although thrust faults typically do not move simultaneously, this effect plays only a secondary role in the formation of sedimentary stratification.

[0063] The method further includes the following step 13: determining the location of one or more oil and gas reservoirs based on a mechanical property model.

[0064] Figure 3 The diagram illustrates a flowchart of a method 20 for predicting the presence of one or more oil and gas reservoirs in an underground geological region.

[0065] As in Figure 3 As shown, method 20 includes the following step 21: creating multiple hypothetical seismic profiles at the time of deposition based on the seismic interpretation of the subsurface geological region and the influence of tectonic time data and tectonic pressure data. Furthermore, in step 22, a mechanical property model of the subsurface geological region is created based on these multiple hypothetical seismic profiles at the time of deposition and the influence of such tectonic time data and tectonic pressure data.

[0066] In this article, according to Figure 3The method shown in the figure further includes step 22 of creating a mechanical property model, which further includes: step 23, detecting the boundaries in the plurality of assumed seismic profiles at the time of deposition; step 24, developing a model including optimal well logging correlation based on the boundaries; and step 25, adjusting the model including optimal well logging correlation based on the influence of the tectonic time data and tectonic pressure data.

[0067] The most readily correlated sedimentary bodies are undeformed cake strata. Therefore, the corresponding 3D geomechanical modeling simulator can attempt to push the sediments back in time, removing all faults and folds to form the assumed geometry of the quasi-sequence at the time of deposition. Once the correlation is established, the lower and upper boundaries of different quasi-sequences can be defined in the seismic profile. Using the definitions of these boundaries in well logging, the seismic profile can then be overlaid with the well logging distribution of the vertical slope with the quasi-sequence. By applying knowledge of major depositional and erosion events, a thrust fault can be selectively introduced at the contact between the two vertical slopes. The created distribution shows reservoir characteristics such as gamma rays and density at very high resolution. However, the created image still represents the state of the sediments at deposition, providing a very simplistic view of the present situation. Thus, the model is capable of advancing the vertical slope forward in time to its present state by incorporating a series of deformation events that reintroduce faults and folds in the region. The resulting models of gamma ray, neutron, density, and sound velocity distributions are used to create a synthetic seismic profile, which can then be evaluated and compared with the original seismic data. Virtual wells can be drilled to compare the modeled well logging distribution with the original well logging signals and to predict well logging signals in areas where no wells have been previously drilled. Step 23, detecting boundaries in multiple seismic profiles, includes using data collected using gamma rays to detect the boundaries.

[0068] Furthermore, in method 20, step 22, which involves creating a mechanical property model of the subsurface geological region, further includes the following step: In step 26, evaluating the mechanical response of one or more oil and gas reservoirs to the influence of tectonic time data and tectonic pressure data. Also in step 26, a mechanical property model is created based on the mechanical response of one or more oil and gas reservoirs to the influence of tectonic time data and tectonic pressure data.

[0069] Figure 4 The diagram illustrates a vertical slope of 30°, and specifically... Figure 4 The diagram illustrates the vertical slope 30 thrust fault formed in response to a strike-slip fault. (As shown in...) Figure 4 As can be seen, the surface of vertical slope 30 is a low-angle thrust fault with a slope-plane geometry, indicating that the thrust fault moved horizontally and thus stepped upward through the strata. Specifically, vertical slope 30 is a characteristic of the basin margin strata and is defined as a two-dimensional surface with an S-shaped geometry.

[0070] Vertical slope 30 is not a sedimentological feature, but it originates from the impact of tectonic processes that occur simultaneously with sediment supply. Specifically, vertical slope 30 acts as a component of a thrust fault, where it is deposited synchronously in response to compressive forces, resulting in a closure at its top.

[0071] Figure 5 The illustration shows an apparatus 40 for creating a mechanical property model. Apparatus 40 includes a first creation device 41 configured to create multiple hypothetical seismic profiles at the time of deposition based on seismic interpretation of the subsurface geological region and the influence of tectonic time data and tectonic pressure data. Apparatus 40 further includes a second creation device 42 configured to create a mechanical property model of the subsurface geological region based on the multiple hypothetical seismic profiles at the time of deposition and the influence of tectonic time data and tectonic pressure data.

[0072] For example, the first creation device 41 and the second creation device 42 can be simulation engines or computing devices configured to run a geomechanical modeling simulator. The computing device includes at least one processor and at least one memory. The processor is used for calculations and operation of the geomechanical modeling simulator. The memory is used to store the calculated geomechanical modeling simulator data.

[0073] In addition, such as in Figure 5 As shown, the first creation device 41 further includes a first export device 43 configured to export tectonic time data from geometric features within seismic interpretation. The first creation device 41 also includes a second export device 44 configured to export tectonic pressure data from geometric features within seismic interpretation. The first export device 43 and the second export device 44 are computational devices configured to analyze data derived from seismic interpretation and well logging measurements.

[0074] according to Figure 5 In terms of the second creation device 42, it includes a detection device 45 configured to detect boundaries in multiple hypothetical seismic profiles at the time of deposition. The second creation device 42 also includes a development device 46 configured to develop a model incorporating optimal well logging correlations based on the boundaries. The second creation device 42 further includes an adjustment device 47 configured to adjust the model incorporating optimal well logging correlations based on the influence of tectonic time data and tectonic pressure data.

[0075] The first detection device 45 can be a computing device configured to analyze seismic interpretation and data derived from well logging measurements (as described above). The development device 46 can also be a simulation engine configured to simulate well logging correlations, serving as a computing device. The adjustment device 47 can be a simulation engine or computing device configured to run a geomechanical modeling simulator.

[0076] The apparatus 40 further includes an evaluation device 48 configured to evaluate the mechanical response of one or more oil and gas reservoirs to the influence of structural time data and structural pressure data, wherein a second creation device 42 is also configured to create a mechanical property model. The creation of the mechanical property model is accomplished based on the mechanical response of one or more oil and gas reservoirs to the influence of structural time data and structural pressure data.

[0077] Also shown is a determining device 49, which is configured to determine the location of one or more oil and gas reservoirs, and together with the device 40 forms a system for determining the location of one or more oil and gas reservoirs.

Claims

1. A method for determining the location of oil and gas reservoirs using a mechanical property model of an created subsurface geological region, the method comprising the following steps performed by a computer: Receive gamma-ray data, acoustic data, or density data measured in wells in the underground geological area; Using seismic interpretation of the aforementioned underground geological region and data from well logging measurements, tectonic timing and tectonic pressure data are derived. Based on the seismic interpretation of the subsurface geological region and the derived tectonic time data and tectonic pressure data, multiple hypothetical seismic profiles at the time of deposition are generated; Using the received gamma-ray data, the acoustic data, or the measured density data, boundaries in multiple hypothetical seismic profiles are detected during deposition; A mechanical property model of the subsurface geological region is created based on the multiple hypothetical seismic profiles at the time of deposition, the derived tectonic time data and tectonic pressure data, and the boundaries detected at the time of deposition in the multiple hypothetical seismic profiles. The mechanical property model of the underground geological region is analyzed to determine the existence and location of the progradation surface in the underground geological region; as well as The location of the oil and gas reservoir in the underground geological region is determined by the determining device (49) using the location of the protrusion surface.

2. The method according to claim 1, wherein, The underground geological region includes multiple oil and gas reservoirs.

3. The method according to claim 1 or 2, wherein, The steps for creating a mechanical property model further include the following: A model incorporating optimal well logging correlation is developed based on the aforementioned boundary; and The model, which includes optimal logging correlation, is adjusted based on the derived tectonic time and tectonic pressure data.

4. The method according to claim 1 or 2, wherein, The step of creating a mechanical property model of the subsurface geological region further includes evaluating the mechanical response of one or more oil and gas reservoirs to the derived tectonic time data and tectonic pressure data, wherein the mechanical property model is also created based on the mechanical response of the one or more oil and gas reservoirs to the influence of the tectonic time data and tectonic pressure data.

5. A system configured to determine the location of one or more oil and gas reservoirs in a subsurface geological region, wherein the system comprises: An apparatus (40) configured to create a model of the mechanical properties of an underground geological region, the apparatus (40) comprising: A device configured to receive gamma-ray data, acoustic data, or density data measured in a well log in the underground geological region. The first export device (43) is configured to export tectonic time data from geometric features within seismic interpretation and data from well logging measurements; The second export device (44) is configured to export tectonic pressure data from the geometric features within the seismic interpretation and data from well logging measurements; The first creation device (41) is configured to create multiple hypothetical seismic profiles at the time of deposition based on the seismic interpretation of the subsurface geological region and the derived tectonic time data and tectonic pressure data; The detection device (45) is configured to detect boundaries in multiple hypothetical seismic profiles during deposition using the received gamma-ray data, the acoustic data, or the measured density data; and The second creation device (42) is configured to create a mechanical property model of the subsurface geological region based on the plurality of assumed seismic profiles at the time of deposition, the derived tectonic time data and tectonic pressure data, and the boundaries detected at the time of deposition in the plurality of assumed seismic profiles. The system further includes: The device (49) is configured to analyze the mechanical property model of the underground geological region to determine the presence and location of the progradation surface in the underground geological region, and to use the location of the progradation surface to determine the location of one or more oil and gas reservoirs in the underground geological region.

6. The system according to claim 5, wherein, The second creation device (42) further includes: a development device (46) configured to develop a model including optimal logging correlation based on the boundary; and an adjustment device (47) configured to adjust the model including optimal logging correlation based on the derived construction time data and construction pressure data.

7. The system according to claim 5 or 6, wherein, The apparatus (40) further includes: an evaluation device (48) configured to evaluate the mechanical response of one or more oil and gas reservoirs to the derived structural time data and structural pressure data, wherein the second creation device (42) is configured to also create the mechanical property model based on the mechanical response of the one or more oil and gas reservoirs to the derived structural time data and structural pressure data.

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