Configuration-constrained thin reservoir oil-gas-water distribution prediction method

Abstract

The invention relates to a configuration-constrained thin reservoir oil-gas-water distribution prediction method, and belongs to the technical field of oil exploration and development. The invention discloses a configuration-constrained thin reservoir oil-gas-water distribution prediction method, which comprises the following steps of: acquiring previous research data, seismic data, logging data and core data of a target work area, and investigating a sedimentary background and modern sedimentary mode data of the target work area; determining a river type; evaluating and analyzing the connectivity of the narrow strip sand body; evaluating and analyzing the connectivity of the flaky river channel sand body; delineating a sand body range, and determining an oil-gas-containing sand body area in the work area; and finally obtaining the oil-gas-water distribution rule of the thin reservoir under the constraint of the configuration level. According to the method, configuration level division and configuration unit and configuration interface recognition are carried out, forward modeling is combined, the sand body superposition relation of an actual seismic section is verified, and under the constraints of various conditions, the thin reservoir oil-gas-water distribution rule under the configuration constraints is finally obtained.

Description

Technical Field

[0001] This invention relates to a configuration-constrained method for predicting the distribution of oil, gas and water in thin reservoirs, belonging to the field of petroleum exploration and development technology. Background Technology

[0002] As oilfield exploration and development deepen, the water cut within thin reservoirs continues to rise, reservoir heterogeneity intensifies, and the structural relationships within and between sand bodies become complex, making it difficult to clearly define the distribution patterns of oil, gas, and water. The oil, gas, and water relationship analysis results obtained using conventional geological methods are no longer sufficient to meet the needs of current exploration and development. Therefore, accurately identifying the distribution patterns of oil, gas, and water in thin reservoirs is of great significance for the later stages of oilfield exploration and development.

[0003] Currently, the research on the distribution patterns of oil, gas and water in high water-cut areas of old oilfields is mainly conducted through the following methods: (1) Multi-parameter hierarchical superposition of single-well facies, logging facies, water cut and physical properties of wells in the work area to determine the distribution patterns of oil, gas and water; (2) Establishing a sample library for simulation training, studying the dynamic data of the work area since its history, dividing the well teams, and simultaneously calibrating the effective thickness of the formation and the prediction and superposition of the zoning boundaries; (3) Using multi-source heterogeneous data acquisition, multi-modal fusion machine learning models and multi-dimensional impact assessment of topography and geomorphology to predict the distribution area of ​​oil, gas and water; (4) Upgrading the frequency of the original seismic data, and combining the seismic data information after frequency upgrading, and combining the velocity field, to predict the distribution of oil, gas and water in the well network based on the structural interpretation results; (5) Using oilfield drilling data to perform four-dimensional geological structure dynamic monitoring of standard seismic wave reflection signals, thereby generating dynamic monitoring data of underground strata structure in the oilfield, and using the dynamic monitoring data to predict the distribution patterns of oil, gas and water.

[0004] The above methods are applicable to large-scale exploration and development, or to densely networked well areas and thick sand bodies with abundant logging and seismic data, and have advantages in predicting the distribution of oil, gas and water. However, they are less effective for the exploration and development of shallow and medium-depth thin reservoir sand bodies, and it is difficult to accurately predict the distribution patterns of oil, gas and water. Summary of the Invention

[0005] To address the aforementioned problems, this invention aims to overcome the shortcomings of existing technologies by proposing a configuration-constrained method for predicting the distribution of oil, gas, and water in thin reservoirs.

[0006] The technical solution provided by this invention to solve the above-mentioned technical problems is: a configuration-constrained method for predicting the distribution of oil, gas and water in thin reservoirs, comprising the following steps: Step S10: Obtain previous research data, seismic data, well logging data, and core data for the target work area, and investigate the sedimentary background and modern sedimentary model data of the target work area; Step S20: Determine the river type; Step S30: Perform modern sedimentary model, well-seismic combined analysis and narrow channel intersection relationship analysis on the narrow strip channel sand body, and use forward modeling to verify the channel intersection relationship to complete the connectivity evaluation and analysis of the narrow strip sand body. Step S40: Based on the modern sedimentary model and well-seismic combined analysis of the sheet channel, perform the division of structural elements, the division of structural interfaces, and the characterization of structural units. Analyze the abandoned channel and the shading conditions of the flood mudstone. Use forward modeling to verify the shading conditions and complete the evaluation and analysis of the connectivity of the sheet channel sand bodies. Step S50: Delineate the sand body range, analyze the oil-gas-water relationship, sand fault matching relationship, calculate the oil column height, analyze the top surface structure, delineate the oil-gas-water range, and determine the area of ​​oil-gas-bearing sand bodies within the work area; Step S60: Under the constraints of configuration hierarchy, the distribution law of oil, gas and water in thin reservoirs is finally obtained.

[0007] A further technical solution is that the specific process of step S20 is as follows: Step S21: Based on the relevant knowledge of sequence stratigraphy, and according to the logging curve characteristics and lithological sedimentary cycle characteristics of the wells in the work area, floodplains and sequence interfaces of different sedimentary cycle levels are selected, and finally a high-precision sequence stratigraphic framework is established for single wells and interconnected wells in the work area. Step S22: Based on the well sequence stratigraphic results, conduct seismic stratigraphic tracking and interpretation, and finally establish a high-precision sequence stratigraphic framework for the entire area; Step S23: Establish the sequence boundaries based on the sequence stratigraphic framework, determine the system tract where the target layer is located, and further determine the river type based on the characteristics of the upper and lower system tracts. Step S24: Calculate the vertical resolution that can be identified based on the dominant frequency and propagation velocity of the seismic data volume, and compare the calculated vertical resolution with the thickness of the sand body in the work area. If the vertical resolution is found to be greater than the thickness of the sand body, convert the seismic data volume from 0° phase to -90° phase. Step S25: Based on the high-frequency sequence stratigraphic framework, perform conventional seismic attribute slicing and RGB frequency sub-attribute analysis on the target layer in the work area, and determine the river type based on the results.

[0008] A further technical solution is that the specific process of step S30 is as follows: Step S31: Based on modern geological sedimentary models, and combined with well-ground lithological interpretation and sedimentary microfacies interpretation, determine the evolution of the channel, as well as the lithological assemblage and morphology formed by the internal units of the channel during deposition. Step S32: Based on the responses of single wells, interconnected wells, and seismic profiles, determine the lithology and continuity within the river channel, and analyze the intersection and connectivity between river channels. Step S33: Perform forward modeling on the overlapping narrow river channels on the seismic profile. Based on the results of the forward modeling, verify the accuracy of the river channel intersection relationship and finally obtain the connectivity between the narrow river channels in the target layer.

[0009] A further technical solution is that the specific process of step S40 is as follows: Step S41: Based on the responses from single wells, interconnected wells, and seismic profiles, classify the structural elements, define the structural interfaces, characterize the structural units of the platy sand bodies, and conduct a preliminary analysis of their connectivity. Step S42: Based on the identified configuration interfaces, analyze the configuration units that have the function of shielding and dividing the platy sand body, and perform forward modeling to verify the accuracy of their ability to divide the sand body, and finally obtain the connectivity of the platy sand body inside the target layer.

[0010] A further technical solution is that the specific process of characterizing the configuration unit is as follows: based on the original well information and seismic information, composite meandering is characterized according to the actual situation of the work area and the composite meandering pattern. Then, under the constraints of the single meandering pattern and the composite meandering characterization, single meandering is characterized. Under the guidance of the single point dam pattern and the constraints of the single meandering characterization, single point dam is characterized. Finally, under the guidance of the internal pattern of the point dam and the constraints of the single point dam characterization, lateral accumulation layer characterization is performed.

[0011] A further technical solution is that the specific process of step S50 is as follows: Step S51: Delineate the area of ​​favorable sand bodies in the target layer; Step S52: Based on the results of the drilled wells, determine the relationship between oil, gas and water within the work area; Step S53: Determine the sand breaking matching relationship; Step S54: Based on the results of oil and water interpretation of single well and well-connected profiles, calculate the oil and gas column height of all single wells; Step S55: Based on the top surface structure diagram of the target layer in the work area, and combining the height of the oil and gas column with the top surface structure, reasonably extrapolate the oil and gas-bearing area in the plane, and then delineate the oil and gas distribution range in the target layer sand body to finally obtain the area of ​​the oil and gas-bearing sand body.

[0012] A further technical solution is that step S51 specifically involves: delineating favorable sand body locations based on conventional seismic attributes, RGB frequency division attributes, and interpretation results of single and continuous wells within the work area.

[0013] A further technical solution is that step S53 specifically involves: analyzing the distribution of dominant migration channels based on single and continuous well profiles and seismic profiles, as well as the relationship between the location of the target layer sand body and the fault location, and making a preliminary judgment on the distribution pattern of oil, gas and water in conjunction with the oil, gas and water relationship.

[0014] A further technical solution is that step S55 specifically involves: creating a top surface structural map of the target layer in the work area; simultaneously, based on the sand body range delineated in step S51, overlaying contour maps onto the sand map; and analyzing the single-well oil and gas column height obtained in step S54, as well as the range of contour lines on the top surface structural map; matching the contour line values ​​with the single-well oil and gas column height values ​​at the well point; reasonably extending the oil and gas-bearing area outwards; and further predicting the oil and gas-bearing sand body area in the uncontrolled area based on finding the dominant migration channels and the overlap relationship of the sand bodies.

[0015] The beneficial effects of this invention are as follows: This invention has carried out configuration hierarchy division, configuration unit and configuration interface identification, and combined with forward modeling, it has verified the sand body stacking relationship of actual seismic profiles. By comprehensively analyzing the oil-gas-water relationship, fault-sand matching relationship, oil and gas column height measurement and top surface structural diagram, under the constraints of various conditions, the oil, gas and water distribution law of thin reservoir under configuration constraints was finally obtained. Attached Figure Description

[0016] Figure 1 Divide the high-frequency system domain into diagrams; Figure 2 Diagram of a modern geological sedimentary model; Figure 3 This is a flowchart of the present invention. Detailed Implementation

[0017] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] like Figure 3 As shown, the present invention provides a configuration-constrained method for predicting the distribution of oil, gas and water in thin reservoirs, comprising the following steps: Step S10: Obtain previous research data, seismic data, well logging data, and core data for the target work area, and investigate the sedimentary background and modern sedimentary model data of the target work area; Step S20: Determine the river type; Step S21: Based on the relevant knowledge of sequence stratigraphy, and according to the logging curve characteristics and lithological sedimentary cycle characteristics of the wells in the work area, select floodplains and sequence interfaces of different sedimentary cycle levels to establish the sequence stratigraphic framework for single wells and interconnected wells in the work area. In this embodiment, a multi-level floodplain was selected to establish the sequence stratigraphic framework.

[0019] Floodplain interfaces are relatively easy to identify and interpret in drilling and seismic data. In drilling, they typically appear as a thick layer of mudstone, with GR curves showing high values ​​greater than 90 API, and opposite depositional cycles above and below the interface. In seismic data, they appear as strong, continuous peaks with high reflection. In this embodiment, based on the high GR values ​​corresponding to the interface and the principles of layer-by-layer correlation, the following methods are used: 1. Well-seismic integration (good matching between well-logging stratigraphic framework and seismic stratigraphic framework); 2. Isochronous correlation (finding floodplain mudstone); 3. Grading control (grading based on the relationship between sequence stratigraphic correlation and depositional cycles); 4. Full-area closure (achieving three-dimensional closure when constructing a continuous well framework profile); 5. Model guidance (generally using the "equielevation correlation method" in fluvial sediments, and dividing single layers corresponding to single-stage channel sand bodies under the control of floodplain mudstone).

[0020] Multiple sixth-order floodplains were identified within a quasi-sequence, and a single-well integrated columnar section was completed. A well-connected framework profile was constructed in the work area in a grid pattern. High-frequency sequence stratigraphy was divided and compared on the connected wells, and a high-frequency sequence stratigraphic framework was established. Step S22: Based on the well sequence stratigraphic results, conduct seismic horizon tracking and interpretation, and establish a sequence stratigraphic framework for the entire region; Specifically, based on the well-ground division results, a synthetic seismic record is produced, and well-seismic calibration is performed on the seismic horizons. At the same time, the seismic facies changes and typical termination relationships at the interfaces can also be used as identification markers for sequence boundaries and floodplain boundaries.

[0021] Sequence boundaries often exhibit seismic response characteristics of medium amplitude and poor continuity. Sandstone is developed above and below the boundary, with the lithology mainly being medium to fine sandstone. The sandstone content is higher below the boundary and lower above it. In contrast, flood boundaries often correspond to a stable set of mudstone with varying thickness. The seismic phase axes at the boundary generally show medium to strong amplitude and good continuity.

[0022] Seismic horizons are interpreted on the seismic skeleton profile, and then horizons are interpreted and tracked throughout the region, ultimately establishing a high-frequency sequence stratigraphic framework for the entire region.

[0023] Step S23: Establish the sequence boundaries based on the sequence stratigraphic framework, determine the system tract where the target layer is located, and further determine the river type based on the characteristics of the upper and lower system tracts. like Figure 1 As shown, the study area has 6 systems tracts developed from bottom to top (3 low-accommodation systems tracts - LAST and 3 high-accommodation systems tracts - HAST), and 3 sedimentary cycles of "interbedded sand and mud - mud-rich sediments" can be identified as a whole.

[0024] The SQ1 sequence is the first third-order sequence of the Mingxia section. The bottom interface of the SQ1 sequence can clearly distinguish the thick sandstone and conglomerate body of the Guantao Formation and the lithological assemblage of thick mudstone interbedded with thin sandstone in the Mingxia section. The top interface of the SQ1 sequence is a lithological abrupt change surface, where the large mudstone in the SQ1 sequence is transformed into the sand-mud interbedded layer in the SQ2 sequence. The SQ2 sequence is the second third-order sequence in the lower section of the Ming Dynasty. Overall, it is dominated by a lithological assemblage of interbedded sand and mudstone. Its top interface is also a lithological abrupt change surface, from thick mudstone to thick sandstone. The SQ3 sequence is the third-order sequence with the thickest lower section, consisting of thick mudstone in the upper half and thick sandstone in the lower half. The target layers studied were SQ2-HAST2 and SQ3-LAST3.

[0025] HAST2 is a highstand systems tract, belonging to the period from sea level rise to stability, with accommodation space and sedimentation rate in balance. It has extensive development of floodplain mudstone and sand-mudstone interbedded structures. Sediments alternate between channel sand bodies (point bars, breach fans, natural dikes, channel sand and overflow sand) and floodplain mudstone, forming narrow strip channel sand bodies. LAST3 is a lowstand systems tract, which is part of the period of sea-level decline. The sea-level decline led to the exposure of more terrigenous areas, forming a sedimentary environment with abundant sediment supply and strong river transport capacity. As a result, the accommodation space was less than the sediment supply rate, and the sediments were mainly channel sand bodies and retained gravel. Vertical accretion and lateral migration occurred simultaneously, forming continuous sand bodies. In summary, based on the establishment of a high-frequency sequence stratigraphic framework, the study area can be preliminarily identified as having two river types: "meandering river-narrow strip type" and "meandering river-platy sand type". Step S24: Calculate the vertical resolution that can be identified based on the dominant frequency and propagation velocity of the seismic data volume, and compare the calculated vertical resolution with the thickness of the sand body in the work area. If the vertical resolution is found to be greater than the thickness of the sand body, convert the seismic data volume from 0° phase to -90° phase. In this embodiment, the dominant frequency of the original seismic data in the work area is about 60 Hz, and the average velocity of the target layer is about 2400 m / s; The minimum vertical resolution is approximately 10 meters. Based on the thickness of the target sand body in the wellbore, the thickness of a single sand body is approximately 5 meters, which is less than the vertical resolution of the seismic data. Therefore, the original seismic data volume is converted from 0° phase to -90° phase to ensure a better correspondence between the single sand body in the work area and the seismic phase axis. Comparing the seismic profiles with the 0° phase and the -90° phase, the relationship between the sand body and the negative amplitude is significantly improved on the seismic profile converted to the -90° phase. Step S25: Based on the high-frequency sequence stratigraphic framework, perform conventional seismic attribute slicing and RGB frequency sub-attribute attribute analysis on the target layer in the work area, and determine the river type based on the results; Based on the high-frequency sequence stratigraphic framework, conventional attributes are extracted from the target layer. Since the seismic bodies in the work area are phase-shifted by -90°, the minimum amplitude attribute of the target layer is extracted and the color scale is reversed. The location of strong amplitude can roughly show the trend of river flow and the distribution range of sand bodies.

[0026] Analysis of the original seismic data revealed that the original seismic body bandwidth was 30Hz-90Hz, with a dominant frequency of 60Hz. Therefore, 30Hz, 60Hz, and 90Hz were selected as a group for RGB wideband attribute fusion, while 60Hz, 75Hz, and 90Hz were selected as a group for RGB narrowband attribute fusion. This clearly showed the river flow path and the distribution range of the sand bodies.

[0027] Combining all the above steps, the river type was finally determined to be: "meandering river - narrow strip type" and "meandering river - platy sand type".

[0028] Step S30: Perform modern sedimentary model, well-seismic combined analysis and narrow channel intersection relationship analysis on the narrow strip channel sand body, and use forward modeling to verify the channel intersection relationship to complete the connectivity evaluation and analysis of the narrow strip sand body. Step S31: Based on modern geological sedimentary models, determine the river channel evolution and the connectivity between internal river units; like Figure 2 As shown, based on the modern sedimentary model of the narrow strip in the figure, and combined with well-ground lithological interpretation and sedimentary microfacies interpretation, the evolution of the narrow strip and the lithological assemblage and morphology (natural dikes, breach fans, channel sands, point bars, overflow sands) formed during sedimentation of the internal units of the channel were determined. It was found that breach fans are prone to form where the channel curvature increases, developing on the concave bank of the channel, and their lithology is fine sandstone. As shown in step S23, the narrow strip channel sand bodies in the study area existed during the period of sea-level rise, belonging to a highly accommodative space, and the sedimentary environment was prone to flooding. Fine-grained natural embankment deposits formed along both sides of the channel. It was found that the natural embankments and crevasse fan deposits within the work area had good vertical connectivity, while the channel sands had good lateral connectivity with the natural embankments and crevasse fans. Point bars were prone to form where the channel curvature increased, developing on the convex bank of the channel. Their lithology was predominantly medium sandstone. The connectivity between the point bars and the channel sands was lateral and vertical, with generally limited connectivity (due to the presence of lateral deposits within the narrow channel point bars, the resulting obstruction led to generally limited connectivity between the point bars and the channel sands). In summary, the "meandering river-narrow strip type" has relatively good overall connectivity among its internal units; Step S32: Based on the responses of single wells, interconnected wells, and seismic profiles, determine the lithology and continuity within the river channel, and analyze the intersection and connectivity between river channels. The lithology of the narrow strip sand bodies in the work area was found to be generally medium sandstone with good continuity. At the same time, based on the observation of conventional attributes and RGB attribute maps, it was found that the narrow strips exhibited vertical superposition and that river channels in different directions intersected. Through seismic profiles, it was found that there was a lateral overlapping relationship between the river channels. The places in the work area where river channels superimposed and intersected were identified and recorded, and the types of river channel superposition and intersection were statistically analyzed.

[0029] Step S33: Perform forward modeling on the narrow strip channels superimposed on the seismic profile, and determine the connectivity between the narrow strip channels in the target layer based on the results of the forward modeling. The overlapping relationships between narrow strip river sands in the work area were classified into: ① lateral overlapping, ② lateral isolation, ③ lateral splicing and vertical stacking, and ④ lateral and vertical overlapping. Based on the original well data of the work area, the parameters of the sand body model were set, and finally, forward modeling of the narrow strip river sand bodies was carried out. The simulation results showed that the connectivity between lateral overlapping and lateral and vertical overlapping narrow strip river sands was the best, the connectivity between lateral splicing and vertical stacking narrow strip river sands was poor, and the lateral isolation narrow strip river sands were not connected. Step S40: Based on the modern sedimentary model and well-seismic combined analysis of the sheet channel, perform the division of structural elements, the division of structural interfaces, and the characterization of structural units. Analyze the abandoned channel and the shading conditions of the flood mudstone. Use forward modeling to verify the shading conditions and complete the evaluation and analysis of the connectivity of the sheet channel sand bodies. Step S41: Based on the responses from single wells, interconnected wells, and seismic profiles, classify the structural elements, define the structural interfaces, characterize the structural units of the platy sand bodies, and conduct a preliminary analysis of their connectivity. The classification scheme of the internal structure interface system of the work area is as follows: Level 8 - Unconformity surface (lower section of Minghuazhen Formation), Level 7 - Maximum floodplain (MFS1, MFS2, MFS3), Level 6 - Composite meandering zone (a complete set of lithological combinations within the oil formation), Level 5 - Single channel sand body (a set of lithological combinations), Level 4 - Single point dam / abandoned channel (single sedimentary facies), Level 3 - Lateral accretion layer inside the point dam (internal structure of a single sedimentary facies).

[0030] The process of characterizing the internal configuration units of the work area is as follows: Based on the original well information and seismic information, composite meandering is characterized according to the actual situation of the work area and the composite meandering model. Then, under the constraints of the single meandering model and the composite meandering characterization, single meandering is characterized. Under the guidance of the single point dam model and the constraints of the single meandering characterization, single point dam is characterized. Finally, under the guidance of the internal model of the point dam and the constraints of the single point dam characterization, lateral accretion layer characterization is performed.

[0031] The work area was divided into two categories based on its configuration elements: (1) floodplains; (2) abandoned river channels. (1) Floodplain: Floodplains with stable mudstone deposits are formed at the edge of the channel zone, which can form good lithological lateral shielding. The seismic phase is characterized by weak amplitude and good continuity. RGB attribute graph: represented by dark areas; Minimum amplitude attribute map: weak amplitude is visible, color and shape are clear and easy to identify.

[0032] Connectivity: The connectivity between sand bodies is poor under the conditions of floodplain obstruction.

[0033] (2) Abandoned river channels: isolated from the main river channels, they only receive suspended mud and silty mud deposits carried by floodwaters, forming a ring-shaped lithological non-permeable shielding strip on the plane.

[0034] ① Straighten the bend: The seismic phase is characterized by: a significant decrease in the amplitude of the same phase axis, continuous changes, and a clear V-shaped downcutting pattern; RGB attribute graph: It is represented by a black, highly curved river channel in the shape of "O / Ω", which is easy to identify; Minimum amplitude attribute map: The "O / Ω" type weak amplitude high curvature river channel is faintly visible and easy to identify.

[0035] ② Drainage and Abandonment - Gradual Abandonment Type: The seismic phases are characterized by good continuity of the same phase axis, no obvious discontinuity, and weak overall changes in the seismic phases. RGB attribute graph: It is represented by a dark river channel with low curvature and long extension; Minimum amplitude attribute map: It can be seen that the river branch is obvious. The branch river is characterized by low curvature, long extension, and strong amplitude beading inside the branch river.

[0036] ③ The interior of the late-stage channel—the strip-shaped channel sand body: The seismic phase is characterized by strong amplitude patterns and good internal continuity. RGB attribute image: The dark river channel with moderate curvature is visible, but its shape is blurry and difficult to identify; Minimum amplitude attribute map: The general shape of the river channel can be seen. Within its strip, it shows a strong amplitude beaded pattern, which is relatively clear and easy to identify.

[0037] Based on the above summary of the characteristics of abandoned river channels, it is found that different abandoned river channels have varying abilities to cut sand bodies. Therefore, the abandoned river channels in the study area are divided into two types: Class I abandoned river channels and Class II abandoned river channels. Class I abandoned waterways: Characteristics: The seismic phase axis is significantly discontinuous, and there is a significant elevation difference between the phase axis and the adjacent point dam at the abandoned river channel. This type of abandoned river channel has a strong ability to cut sand bodies and can form a good lateral shield.

[0038] Seismic profile characteristics: There is a significant elevation difference between the phase axis of the abandoned river channel and the adjacent point dam; RGB planar map features: Abandoned river channels show C-shaped or Ω-shaped black bands on the RGB attribute fusion map; Minimum amplitude planar property characteristics: The minimum amplitude property value is approximately -360.76 to 90.31; Connectivity: Not connected.

[0039] Class II abandoned river channels: Characteristics: There is an elevation difference between the development of abandoned river channels and the phase axis of adjacent point dams, but the phase axis is not obviously discontinuous, only the amplitude changes. Abandoned river channels can cut sand bodies, but there is a risk of insufficient cutting. There is a risk of bottom connectivity between sand bodies.

[0040] Seismic profile characteristics: The elevation difference between the development of abandoned river channels and the adjacent point dam is small, the dislocation of the same phase axis is not obvious, and the amplitude intensity varies. RGB planar map features: Abandoned river channels stand out as black or dark continuous stripes on the RGB attribute fusion map; Minimum amplitude planar property characteristics: The minimum amplitude is approximately -165.15 to -270.17; Connectivity: Risk of bottom connectivity; Step S42: Based on the identified configuration interfaces, analyze the configuration units that have the function of shielding and dividing the platy sand body, and perform forward modeling to finally obtain the connectivity inside the platy sand body of the target layer. Based on the identified configuration interfaces, forward modeling was performed on different types of shading conditions to verify the ability of shading conditions to segment sand bodies. According to the responses of single wells, interconnected wells, and seismic profiles, it was found that the lithology of the platy sand bodies in the work area is generally medium sandstone with good continuity. Lateral and vertical overlapping relationships were found in the platy sand on the seismic profile. Places with similar situations in the work area were identified and recorded, and the superposition and intersection types of abandoned river channels and sand bodies were statistically analyzed.

[0041] As shown in the figure, the types of sand bodies segmented by abandoned river channels in the work area are divided into: ① abandoned river channel with elevation difference between concave and convex banks, ② floodplain blocking, ③ abandoned river channel between concave and concave banks, ④ abandoned river channel blocking, and ⑤ abandoned river channel between concave and convex banks. Based on the original well data of the work area, the parameters of the sand body model are set, and finally, a forward modeling simulation of sheet-like sand bodies is performed. The simulation results show that: abandoned river channel with elevation difference between concave and convex banks, abandoned river channel between concave and concave banks, and abandoned river channel blocking have a strong ability to segment sand bodies, resulting in low connectivity of sand bodies on both sides of the abandoned river channel. Oil and gas are generally distributed on both sides of the abandoned river channel, and the abandoned river channel plays a blocking role in it. Floodplain shielding: Floodplains are generally composed of stable mudstone, which can block sand bodies, reducing the connectivity between sand bodies and thus blocking the migration of oil and gas. As shown in the diagram, the abandoned river channel on the concave bank and convex bank provides shelter: the obstruction of the abandoned river channel allows oil and gas to be distributed in different locations, accumulating on both sides or in the middle of the abandoned river channel. Step S50: Delineate the sand body range, analyze the oil-gas-water relationship, sand fault matching relationship, calculate the oil column height, analyze the top surface structure, delineate the oil-gas-water range, and determine the area of ​​oil-gas-bearing sand bodies within the work area; Step S51: Based on conventional seismic attributes, RGB frequency division attributes, and interpretation results of single and connected wells within the work area, delineate the favorable sand body locations; Based on the extracted minimum amplitude attribute and the lithology of the target layer in the well, a sand map is created. After the minimum amplitude attribute map is inverted by color scale, the strong amplitude and weak-strong amplitude regions on the map can represent the distribution of sand bodies and delineate them (lithological traps).

[0042] Step S52: Based on the results of the drilled wells, determine the relationship between oil, gas and water within the work area; Step S53: Based on single and continuous well profiles and seismic profiles, as well as the relationship between the location of the target layer sand body and the fault location, analyze the distribution of dominant migration channels, and combine with the oil, gas and water relationship to make a preliminary judgment on the distribution pattern of oil, gas and water. Extract seismic profiles from the wells and analyze the relationship between faults and the target layer. Identify faults that have good overlap with the sand bodies in the target layer (the greater the degree to which a fault penetrates the interior of the sand body, the better its connectivity with the sand body). Analyze the profile combination relationship between the sand body and the fault.

[0043] Given limited oil and gas injection capacity, when the dip angle of the fault on the profile is acute (angle < 90°) or obtuse (angle > 90°), oil and gas will fill a large area of ​​the sand body on the right side of the fault if the angle between the sand body and the horizontal plane is greater than 0° and less than the dip angle of the fault; while oil and gas will fill a large area of ​​the sand body on the left side of the fault if the angle between the sand body and the horizontal plane is greater than the dip angle of the fault and less than 180°. Step S54: Based on the results of oil and water interpretation of single well and well-connected profiles, calculate the oil and gas column height (vertical depth) of all single wells. Step S55: Create a structural diagram of the top surface of the target layer in the work area and analyze the distribution of oil, gas and water. Step S56: Based on the top surface structure diagram of the target layer in the work area, and combining the height of the oil and gas column with the top surface structure, reasonably extrapolate the oil and gas-bearing area in the plane, and then delineate the oil and gas distribution range in the sand body of the target layer to finally obtain the area of ​​the oil and gas-bearing sand body. Create a top surface structural map of the target layer in the work area. At the same time, based on the sand body range (lithological trap) delineated in step S51, overlay the contour map onto the scanning map and analyze the single-well oil and gas column height obtained in step S54, as well as the range of contour lines on the top surface structural map. At the well point, match the contour line values ​​with the single-well oil and gas column height values, and reasonably extend the oil and gas area outward. At the same time, based on step S53, find the overlap relationship between the dominant migration channel and the sand body, which can further predict the area of ​​oil and gas sand bodies in areas without well control. Step S60: Under the constraints of configuration hierarchy, the distribution law of oil, gas and water in thin reservoirs is finally obtained.

[0044] The above description is not intended to limit the present invention in any way. Although the present invention has been disclosed through the above embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall fall within the scope of the present invention.

Claims

1. A configuration-constrained method for predicting oil, gas, and water distribution in thin reservoirs, characterized in that, Includes the following steps: Step S10: Obtain previous research data, seismic data, well logging data, and core data for the target work area, and investigate the sedimentary background and modern sedimentary model data of the target work area; Step S20: Determine the river type; Step S30: Perform modern sedimentary model, well-seismic combined analysis and narrow channel intersection relationship analysis on the narrow strip channel sand body, and use forward modeling to verify the channel intersection relationship to complete the connectivity evaluation and analysis of the narrow strip sand body. Step S40: Based on the modern sedimentary model and well-seismic combined analysis of the sheet channel, perform the division of structural elements, the division of structural interfaces, and the characterization of structural units. Analyze the abandoned channel and the shading conditions of the flood mudstone. Use forward modeling to verify the shading conditions and complete the evaluation and analysis of the connectivity of the sheet channel sand bodies. Step S50: Delineate the sand body range, analyze the oil-gas-water relationship, sand fault matching relationship, calculate the oil column height, analyze the top surface structure, delineate the oil-gas-water range, and determine the area of ​​oil-gas-bearing sand bodies within the work area; Step S60: Under the constraints of configuration hierarchy, the distribution law of oil, gas and water in thin reservoirs is finally obtained.

2. The method for predicting oil, gas and water distribution in configuration-constrained thin reservoirs according to claim 1, characterized in that, The specific process of step S20 is as follows: Step S21: Based on the relevant knowledge of sequence stratigraphy, and according to the logging curve characteristics and lithological sedimentary cycle characteristics of the wells in the work area, floodplains and sequence interfaces of different sedimentary cycle levels are selected, and finally a high-precision sequence stratigraphic framework is established for single wells and interconnected wells in the work area. Step S22: Based on the well sequence stratigraphic results, conduct seismic stratigraphic tracking and interpretation, and finally establish a high-precision sequence stratigraphic framework for the entire area; Step S23: Establish the sequence boundaries based on the sequence stratigraphic framework, determine the system tract where the target layer is located, and further determine the river type based on the characteristics of the upper and lower system tracts. Step S24: Calculate the vertical resolution that can be identified based on the dominant frequency and propagation velocity of the seismic data volume, and compare the calculated vertical resolution with the thickness of the sand body in the work area. If the vertical resolution is found to be greater than the thickness of the sand body, convert the seismic data volume from 0° phase to -90° phase. Step S25: Based on the high-frequency sequence stratigraphic framework, perform conventional seismic attribute slicing and RGB frequency sub-attribute analysis on the target layer in the work area, and determine the river type based on the results.

3. The method for predicting oil, gas and water distribution in configuration-constrained thin reservoirs according to claim 1, characterized in that, The specific process of step S30 is as follows: Step S31: Based on modern geological sedimentary models, and combined with well-ground lithological interpretation and sedimentary microfacies interpretation, determine the evolution of the channel, as well as the lithological assemblage and morphology formed by the internal units of the channel during deposition. Step S32: Based on the responses of single wells, interconnected wells, and seismic profiles, determine the lithology and continuity within the river channel, and analyze the intersection and connectivity between river channels. Step S33: Perform forward modeling on the overlapping narrow river channels on the seismic profile. Based on the results of the forward modeling, verify the accuracy of the river channel intersection relationship and finally obtain the connectivity between the narrow river channels in the target layer.

4. The method for predicting oil, gas and water distribution in configuration-constrained thin reservoirs according to claim 3, characterized in that, The specific process of step S40 is as follows: Step S41: Based on the responses from single wells, interconnected wells, and seismic profiles, classify the structural elements, define the structural interfaces, characterize the structural units of the platy sand bodies, and conduct a preliminary analysis of their connectivity. Step S42: Based on the identified configuration interfaces, analyze the configuration units that have the function of shielding and dividing the platy sand body, and perform forward modeling to verify the accuracy of their ability to divide the sand body, and finally obtain the connectivity of the platy sand body inside the target layer.

5. The method for predicting oil, gas and water distribution in configuration-constrained thin reservoirs according to claim 4, characterized in that, The specific process for characterizing the configuration unit is as follows: Based on the original well information and seismic information, composite meandering is characterized according to the actual situation of the work area and the composite meandering pattern. Then, under the constraints of the single meandering pattern and the composite meandering characterization, single meandering is characterized. Under the guidance of the single point dam pattern and the constraints of the single meandering characterization, single point dam is characterized. Finally, under the guidance of the internal pattern of the point dam and the constraints of the single point dam characterization, lateral accumulation layer characterization is performed.

6. The method for predicting oil, gas and water distribution in configuration-constrained thin reservoirs according to claim 1, characterized in that, The specific process of step S50 is as follows: Step S51: Delineate the area of ​​favorable sand bodies in the target layer; Step S52: Based on the results of the drilled wells, determine the relationship between oil, gas and water within the work area; Step S53: Determine the sand breaking matching relationship; Step S54: Based on the results of oil and water interpretation of single well and well-connected profiles, calculate the oil and gas column height of all single wells; Step S55: Based on the top surface structure diagram of the target layer in the work area, and combining the height of the oil and gas column with the top surface structure, reasonably extrapolate the oil and gas-bearing area in the plane, and then delineate the oil and gas distribution range in the target layer sand body to finally obtain the area of ​​the oil and gas-bearing sand body.

7. The method for predicting oil, gas and water distribution in configuration-constrained thin reservoirs according to claim 6, characterized in that, Specifically, step S51 involves delineating favorable sand body locations based on conventional seismic attributes, RGB frequency division attributes, and interpretation results of single and connected wells within the work area.

8. The method for predicting oil, gas and water distribution in configuration-constrained thin reservoirs according to claim 6, characterized in that, Specifically, step S53 involves analyzing the distribution of dominant migration channels based on single and continuous well profiles and seismic profiles, as well as the relationship between the location of the target layer sand body and the fault location, and making a preliminary judgment on the distribution pattern of oil, gas and water in conjunction with the oil, gas and water relationship.

9. The method for predicting oil, gas and water distribution in configuration-constrained thin reservoirs according to claim 6, characterized in that, Step S55 specifically involves: creating a top surface structural map of the target layer in the work area; simultaneously, based on the sand body range delineated in step S51, overlaying contour maps onto the sand map; and analyzing the single-well oil and gas column height obtained in step S54, as well as the range of contour lines on the top surface structural map. At the well point, the contour line values ​​are matched with the single-well oil and gas column height values, and the oil and gas-bearing area is reasonably extended outward. At the same time, based on finding the dominant migration channels and the overlap relationship of the sand bodies, the area of ​​oil and gas-bearing sand bodies in the uncontrolled area is further predicted.

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