Reserve estimation method and system for oil and gas reservoir with developed reservoir performance fault

Abstract

The invention provides a method and a system for estimating reserves of oil and gas reservoirs with developed reservoir performance faults. The estimation method comprises the following steps: determining three-dimensional spatial distribution of the faults; determining a fault fracture structure, a fault fracture range and reservoir performance by utilizing the geological data; determining the stratum oil gas saturation of the fault fracture structural zone by using the rock core and / or logging information; and estimating the oil-gas geological reserves by adopting a volumetric method according to the stratum oil-gas saturation. The geological reserves can be estimated more accurately, and more accurate numerical support is provided for reserves estimation and development scheme formulation.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas exploration and development, and in particular to a method and system for estimating the reserves of an oil and gas reservoir with a reservoir performance fault. Background Art

[0002] A lot of research has been carried out on faults at home and abroad, especially in recent years, a large number of fault structure studies have been carried out, which have confirmed that a fault is not a surface but a body. A closed fault can serve as a barrier to oil reservoirs, and an open or unconsolidated fault can serve as an oil and gas migration channel and reservoir.

[0003] Faults play an important role in the formation and preservation of oil and gas reservoirs. Unconsolidated faults connect oil sources and can serve as channels for oil and gas migration. Faults can also serve as channels for oil and gas adjustment, migrating from one stratum to another. At the same time, faults that are not completely cemented and closed can also store oil and gas and become effective reservoir spaces. This type of situation is more common in brittle volcanic rocks, metamorphic rocks, carbonate rocks, and tight sandstone and conglomerate formations. They can become important oil and gas reservoirs with huge reserves. Faults have their own particularity as oil and gas reservoirs. Their reservoir space type is different from that of the original rock formation. Fault reservoirs have more cracks than original rocks, and the cracks have greater permeability. Some fault dissolution pores are more developed. The oil and gas saturation in the fault structure zone is higher, reaching more than 90%, which is much higher than the oil and gas saturation of the original rock formation.

[0004] The current reserve calculation regards the fault zone with reservoir properties as the same reservoir as the original rock formation, and uses the same average value for its oil and gas saturation. Its volume calculation is also parallel to the original rock formation. However, most faults have a certain angle with the original rock formation, and most faults do not extend to another wellbore. When the fault is particularly developed, it will not be encountered by drilling, and it will be missed in the reserve calculation, resulting in undercalculation of oil and gas reserves. When calculating the reserves of carbonate reservoirs dominated by fracture dissolution, the main focus is on the seismic phase identification of fractures and dissolution bodies, and faults and fault structural zones are not taken as the main research objects to calculate reserves. Due to the complexity and variability of fractures and dissolution zones and the resolution of earthquakes, their seismic characteristics vary greatly and have great uncertainty. It is still difficult to accurately determine the volume of the reservoir using only seismic data, resulting in large errors in reserve calculations. Summary of the invention

[0005] In view of the above problems, the present invention is proposed to provide a method and system for estimating reserves of an oil and gas reservoir with reservoir performance faults that overcome the above problems or at least partially solve the above problems.

[0006] According to one aspect of the present invention, a method for estimating reserves of an oil and gas reservoir with reservoir performance faults is provided, the method comprising:

[0007] Determine the three-dimensional spatial distribution of faults;

[0008] Use geological data to determine fault fracture structure, extent, and reservoir properties;

[0009] Determine the oil and gas saturation of the formation in the fault fracture structure zone using core and / or logging data;

[0010] The volumetric method is used to estimate the geological reserves of oil and gas based on the oil and gas saturation of the formation.

[0011] Optionally, the determining the three-dimensional spatial distribution of the fault specifically includes: using geophysical data and drilling data to determine the three-dimensional spatial distribution of the fault.

[0012] Optionally, the geophysical data and drilling data specifically include: seismic, gravity, magnetic, logging, coring, logging, and gas logging data.

[0013] Optionally, the three-dimensional spatial distribution of the fault includes the inclination angle, strike direction, fault distance, strike-slip amount on the plane, fault trajectory and fault plane distribution in the fault space.

[0014] Optionally, the geological data specifically includes: well logging, coring, field profiles and / or seismic.

[0015] Optionally, the method of using geological data to determine the fault structure, range and reservoir performance specifically includes:

[0016] Determine the fault throw and strike-slip amount using seismic event displacement and / or seismic attributes;

[0017] Use drilling coring, logging and mud logging data to determine the extent of the fault zone, fault fracture structure, fault filling and dissolution conditions, fault porosity and permeability values, and differences from the original formation;

[0018] The mathematical fitting method is used to obtain the quantitative calculation model of fault scale, fault zone and fault structure. The fault scale is characterized by fault distance and / or fault slip parameters.

[0019] Geophysical data are used to establish the relationship between fault throw and / or fault slip and fault zones, fault structures, and formation physical properties, and mathematical methods are used to fit quantitative calculation models.

[0020] Optionally, the geophysical data specifically include: seismic, well logging, coring, and field profile data.

[0021] Optionally, the method of determining the oil and gas saturation of the fault fracture structure zone formation by using core and / or logging data specifically includes:

[0022] The oil and gas saturation of the formation is obtained by core experiment measurement;

[0023] The formation oil and gas saturation is obtained by using nuclear magnetic resonance logging calculations;

[0024] Conventional logging uses Archie's formula to obtain formation oil and gas saturation:

[0025]

[0026] In the formula: So is the original formation oil and gas saturation, %; Swi is the original formation bound water saturation, %; φ is the effective porosity of the oil layer, f; Rw is the formation water resistivity, Ω·m; Rt is the oil layer resistivity, Ω·m; m is the pore structure index; n is the saturation index; a and b are coefficients related to lithology.

[0027] Optionally, estimating the oil and gas geological reserves by using a volumetric method according to the oil and gas saturation of the formation specifically includes:

[0028] Using formula (2):

[0029] N=100A o h o / B oi (2)

[0030] Where: N is the volume of crude oil geological reserves, 10 4 m 3 ; A o is the oil-bearing area, km 2 ; h is the effective thickness, m; Φ is the effective porosity, f; S o is the original oil saturation, f; B oi is the crude oil volume coefficient;

[0031] When expressing crude oil geological reserves in mass units, the formula is:

[0032] N z =Nρ o (3)

[0033] Where: N z is the geological reserves of crude oil, 10 4 t;ρ o is the density of crude oil on the ground, t / m 3 .

[0034] The present invention also provides a system for estimating reserves of oil and gas reservoirs with reservoir performance faults, which uses the above-mentioned method for estimating reserves of oil and gas reservoirs with reservoir performance faults, and is characterized in that the estimation method comprises:

[0035] A three-dimensional spatial distribution module is used to determine the three-dimensional spatial distribution of faults;

[0036] Fault structure determination module, used to determine fault fracture structure, extent and reservoir performance using geological data;

[0037] The oil and gas saturation determination module is used to determine the oil and gas saturation of the formation in the fault fracture structure zone using core and / or logging data;

[0038] The geological reserve estimation module is used to estimate the geological reserves of oil and gas by using the volume method according to the oil and gas saturation of the formation.

[0039] The present invention provides a method and system for estimating the reserves of oil and gas reservoirs with reservoir performance faults. The estimation method includes: determining the three-dimensional spatial distribution of faults; determining the fault fracture structure, range and reservoir performance using geological data; determining the oil and gas saturation of the fault fracture structure zone strata using core and / or logging data; and estimating the oil and gas geological reserves using the volumetric method based on the oil and gas saturation of the strata. The method can estimate the geological reserves more accurately and provide more accurate numerical support for reserve estimation and development plan formulation.

[0040] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0042] Figure 1 A flow chart of a method for estimating reserves of an oil and gas reservoir with reservoir performance faults provided by an embodiment of the present invention;

[0043] Figure 2 A fault plane distribution diagram provided by an embodiment of the present invention;

[0044] Figure 3 A schematic diagram of a fault trajectory on a cross-sectional view provided by an embodiment of the present invention;

[0045] Figure 4 A sketch of a fault coring section of a well drilling provided by an embodiment of the present invention;

[0046] Figure 5 A schematic diagram of calculating the size of a fault zone structure provided by an embodiment of the present invention;

[0047] Figure 6A schematic diagram of formation physical properties provided by an embodiment of the present invention;

[0048] Figure 7 A schematic diagram of oil saturation calculated using Archie's formula parameters provided in an embodiment of the present invention;

[0049] Figure 8 A schematic diagram of seismic data provided by an embodiment of the present invention;

[0050] Fig. 9 A fault track on a cross-sectional view provided by an embodiment of the present invention;

[0051] Fig.10 A fault plane distribution map of the top surface of the target layer is drawn according to the three-dimensional spatial distribution of the fault provided in the embodiment of the present invention;

[0052] Fig.11 This is a stratigraphic cross-section diagram provided for Example 3 of the present invention. DETAILED DESCRIPTION

[0053] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0054] The terms "comprises" and "having" and any variations thereof in the description embodiments, claims and drawings of the present invention are intended to cover non-exclusive inclusions, for example, including a series of steps or units.

[0055] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0056] In a specific embodiment 1 of the present invention, Figure 1 As shown, Figure 1 The flowchart of the method for estimating the reserves of fault oil and gas reservoirs with reservoir performance of the present invention. The method for estimating the reserves of fault oil and gas reservoirs with reservoir performance of the present invention comprises the following steps:

[0057] Collect geophysical data and drilling data from the study area of ​​the embodiment, including seismic, well logging, gravity, magnetic, coring, well logging, gas logging and other data.

[0058] The location and spatial distribution of faults are determined using seismic, gravity, magnetic and logging data.

[0059] The fault plane distribution is determined by using the earthquake phase axis displacement and / or earthquake coherence attributes, and the fault plane distribution map is drawn. Figure 2; According to the seismic phase axis displacement or seismic attribute characteristics, the distribution of each fault in the depth profile is implemented, including the dip angle, strike, fault distance, slip amount on the plane, fault continuous trajectory, etc. in the fault space, and the three-dimensional spatial distribution of the fault is clarified, see Figure 3 Fault trajectory on the cross-section.

[0060] According to logging, coring and experimental data, it is determined that the lithology of the target oil-bearing strata is mainly andesite and basalt.

[0061] By coring the fault section, we can determine the fault structure, range and reservoir performance by observing whether the fault has associated small faults, the filling and dissolution of the fault rupture zone, the fault fracture structure, the range of the fault zone and the difference in physical properties and oil and gas content with the original formation. Figure 4 This is a sketch of the fault coring in the drilling coring section. The lithology is volcanic rock. The fault is filled with carbonate rock with a filling degree of about 65%. Some dissolution occurs. The rock cracks or broken rocks are completely filled with crude oil. The fault can be divided into the fault core, the broken zone, and the fracture zone. The entire width is 1.9m. The core is the most severely broken with scratches. The broken zone is mainly broken rock. The layered rock in the fault broken zone is layered with a dip of 45°, which basically coincides with the dip of the fault. The rock in the fracture zone is relatively complete and has a large number of fractures.

[0062] By comparing the fault segment core sampling with the imaging logging data, the fault logging characteristics of the imaging logging were determined, and the fault identification and fault structure pattern diagrams were established. Figure 5 The fault appears dark in the electrical imaging map, that is, it has low resistivity characteristics. The fault dip angle calculated by imaging is 47°, which is basically consistent with the actual measurement of the core. The imaging logging changes from dark to brighter from the core to the fracture zone, and its brightness is second only to the original formation.

[0063] By comparing conventional logging with coring and imaging logging through faults, conventional logging is established to identify faults and fault structures, physical property change patterns, or to establish logging data to identify faults, fault structures, physical property characteristic parameters and identification standards.

[0064] Example 1 The western and northern parts of the study area are high areas, with a large number of field profile outcrops developed. The lithology is volcanic rock, which is the same as the lithology of the oil and gas bearing layers in the example. By observing the faults associated with the faults, the filling and dissolution of the faults, the range of the fault zone, the fault fracture structure, the fault porosity and permeability values ​​and the difference with the original formation, the size, fault fracture structure, range and reservoir performance of fault fracture zones of different levels were determined, providing data for quantifying the influence range of fault physical properties of different sizes, fracture density and fault zones.

[0065] The established models and standards are used to identify faults and divide fault structures in the wells in the study area, and to calculate the physical parameters of the fault zone.

[0066] A large number of cross-fault coring, imaging logging, logging analysis and field profiles are used to establish quantitative models of the scale of faults and fracture structures of different sizes, and the magnitude and range of the impact of faults on formation physical properties; Figure 5 This is a graph showing the relationship between the fault throw of different faults and the density of cracks at a distance from the fault core. Figure 6 This is a chart showing the relationship between the porosity of different fault throws and the distance from the fault core relative to the porosity of the original formation.

[0067] Under the condition of no fault coring and imaging logging, conventional logging, mud logging and gas logging data are used to identify and calculate faults, fault structures and fault reservoir properties. Figure 4 The first column is the fault identification parameter, and the shaded part is the fault zone range and has reservoir properties.

[0068] The seismic characteristics of the fault section of the cross-fault well are used to calibrate the seismic, and the seismic characteristics of the faults with effective reservoir performance and the seismic characteristics of the faults without effective reservoir performance are established.

[0069] When no well is drilled through the fault, the fault distance, strike slip and other data reflecting the size of the fault are determined by earthquakes. Figure 5 , Figure 6 The plate calculates the structural size of the fault zone and the physical properties of the strata.

[0070] The established chart was used to calculate the drilling faults, fault structure range, and fault zone physical properties in the example area. Figure 3 Schematic representation of the fault fracture zone.

[0071] The oil and gas saturation of the fault fracture zone formation is determined using core and / or logging data, using one or more of the following methods:

[0072] (1) When drilling and coring through faults, cores at different locations in the fault zone are selected for experiments to measure the oil and gas saturation. Cores from the original formation are selected for experiments to measure the oil and gas saturation. The oil and gas saturation differences are compared between the original formation and different locations in the fault zone.

[0073] (2) Nuclear magnetic resonance logging can obtain relatively accurate porosity and permeability parameters. Combining nuclear magnetic resonance with conventional logging, using conventional logging resistivity and nuclear magnetic resonance to calculate porosity and using Archie's formula can obtain relatively accurate formation oil and gas saturation;

[0074] (3) Using conventional logging resistivity, AC and / or DEN, CNL, GR, SP curves, and Archie's formula to obtain oil saturation:

[0075]

[0076] Wherein: So is the original formation oil and gas saturation, %; Swi is the original formation bound water saturation, %; φ is the effective porosity of the oil layer, f; Rw is the formation water resistivity, Ω·m, obtained by experimental measurement or by logging calculation, and is 0.43-0.51 in the embodiment area; Rt is the oil layer resistivity, Ω·m; m is the pore structure index; n is the saturation index; a and b are coefficients related to lithology; m, n, a, and b are obtained by core experiments.

[0077] The core test method is used as the standard for obtaining oil and gas saturation using the above three methods. The other two methods are then used to perform large-scale calculations to obtain more accurate oil and gas saturation.

[0078] Figure 7 The oil saturation is calculated using the parameters of the Archie formula. It can be seen that the oil saturation in the fault zone is significantly higher than that in the non-fault formation. This is consistent with the observations under the core microscope. Under the microscope, almost all cracks and large pores contain oil, while small pores have a lower oil saturation and higher bound water. The fault zone is dominated by cracks and large pores.

[0079] The oil saturation of the target layer after well drilling was calculated using Archie's formula parameters.

[0080] Based on the core analysis of the fracture zones and original faults in the oil-bearing sections of multiple wells, the porosity and oil saturation relationship diagram was established, and a quantitative relationship model was fitted:

[0081] S o =32.02*lnΦ-40.771 (5)

[0082] In the formula: So is the original formation oil and gas saturation, %, Φ is the porosity, %.

[0083] For faults in undrilled areas, the porosity of the fault zone is obtained according to the size of the fault, and then the oil saturation is obtained using the relationship model between porosity and oil saturation.

[0084] The volumetric method is used to calculate the geological reserves of oil and gas using Formula 6:

[0085] N=100A o h o / B oi (6)

[0086] Where: N is the volume of crude oil geological reserves, 10 4 m 3 ; A o is the oil-bearing area, km 2 ; h is the effective thickness, m; Φ is the effective porosity, f; S o is the original oil saturation, f; Boi is the volume coefficient of crude oil.

[0087] The parameter oil-bearing area A in formula 6 o , the oil-bearing area is determined according to the delineated oil-bearing range, see Figure 2 The oil-bearing area, minus the area affected by the fault, the effective thickness h is determined based on the interpretation of the single well and the lower limit of the effective reservoir, excluding the fault part, the effective porosity Φ is determined based on the oil test or core experiment, and the original oil saturation S o According to one or more of the above three methods, the crude oil volume coefficient B oi Determined by crude oil experiment; the oil-bearing area A of the fault part o Determined according to the fault fracture structure range, the effective thickness h is the thickness of the fracture structure range, the effective porosity Φ is obtained by logging calculation, and the original oil saturation S o Determined by one or more of the above three methods, other parameters are the same as above.

[0088] The oil-bearing volume of the fault determines the porosity and range according to the scale of the fault, and the oil saturation is determined by the porosity-oil saturation relationship. The effective oil-bearing volume of the fault is calculated using mathematical methods based on the three-dimensional distribution of the fault and the oil-bearing height, and the geological reserves of oil and gas are calculated using the volumetric method.

[0089] Specifically, the oil-bearing area A of the fault section o Determined according to the fault fracture structure range, the effective thickness h is the thickness of the fracture structure range, the effective porosity Φ is obtained by logging calculation, and the original oil saturation S o The oil saturation is determined using the porosity-oil saturation relationship, and the other parameters are the same as above.

[0090] When expressing crude oil geological reserves in mass units, the formula is:

[0091] N z =Nρ o (7)

[0092] Where: N z is the geological reserves of crude oil, 10 4 t;ρ o is the density of crude oil on the ground, t / m 3 , determined using crude oil experiments.

[0093] The oil and gas geological reserves calculated by the present invention are 1.6 times the oil and gas geological reserves calculated by the original volume method, which makes up for the reserves of the fault rupture zone that were not originally calculated. The result is more credible and provides a basis for reserve declaration and development plan formulation.

[0094] Example 2

[0095] In a specific embodiment 2 of the present invention, the method for estimating the reserves of a fault oil and gas reservoir with reservoir performance of the present invention comprises the following steps:

[0096] The geophysical data and drilling data of the study area of ​​the embodiment are collected, and the collected data include seismic, well logging, coring, well logging, and gas logging data.

[0097] Use well logging, coring, mud logging, and gas logging data to identify faults, and combine them with seismic data to clarify the seismic characteristics of the faults. Figure 8 To illustrate the seismic data in the example area, the faults were determined by combining well-seismic data.

[0098] The faults in the study area were identified using 3D seismic data, and the 3D spatial distribution of the faults was determined, including the dip angle, strike, fault distance, slip amount on the plane, and continuous trajectory of the faults. Figure 8 Faults and Fig. 9 Fault trajectory on the cross-section.

[0099] According to the three-dimensional spatial distribution of faults, the plane distribution map of the faults on the top surface of the target layer was drawn. Fig.10 .

[0100] According to the logging, coring and experimental data, the lithology of the oil-bearing target layer is determined to be mainly limestone, dolomite and argillaceous dolomite.

[0101] The imaging logging, conventional logging and coring data were used to determine the fault structure, range and reservoir performance of different fault throws or strike-slip faults. Fig. 9 .

[0102] The fault throw is determined by using the seismic event displacement and seismic attributes. The seismic event displacement in this area is 8 to 30 ms, the formation velocity is about 6400 m / s, and the fault throw is 51 to 192 m. Figure 8 .

[0103] Well 1 and Well 2 have both been drilled through faults. The fault zone range, fault fracture structure, fault filling and dissolution, fault porosity and permeability values, and differences from the original strata were analyzed using core drilling, imaging logging, conventional logging, and logging data. It was found that fault-associated dissolution is particularly developed, with dissolution holes and wells. The wellbore fault affects an area of ​​180 m. Comparison with seismic data shows that earthquakes have obvious reflections. The dissolution range, fault zone range, and physical properties can be identified using the morphology and attributes of seismic waves.

[0104] Using the established seismic identification model or algorithm for dissolution range and fault zone, the dissolution range, fault zone and physical properties of the undrilled section were predicted.

[0105] The relationship between fault throw and fault zone range, physical property changes and oil saturation in the example area was statistically analyzed, and a quantitative relationship model was established.

[0106] Based on the data of fault throw and slip determined by earthquakes, the fault structure size of the undrilled fault is calculated using the fault size and fault structure quantitative model. Thus, the effective reservoir area and the distribution area of ​​physical properties in the example area are obtained, see Fig.10 The oil-bearing range was determined in combination with the oil-bearing properties. The target layers in the fault and dissolution zones are all oil-bearing areas, with an oil-bearing height of 230m.

[0107] The oil and gas saturation of the fault fracture structure zone formation is determined by using core and / or logging data. Based on the data of the study area in Example 2, the oil and gas saturation of the formation is calculated by using nuclear magnetic resonance logging. First, the porosity calculated by nuclear magnetic resonance is combined with conventional logging resistivity to obtain the oil saturation using Archie's formula:

[0108]

[0109] Where: So is the original formation oil and gas saturation, %; Swi is the original formation bound water saturation, %; φ is the effective porosity of the oil layer, f; Rw is the formation water resistivity, Ω·m, and the value of the oil layer section is 0.3Ω·m; Rt is the oil layer resistivity, Ω·m; m is the pore structure index, and the experimental value is 1.63; n is the saturation index, and the experimental value is 1.86; a and b are coefficients related to lithology, which are 1.4 and 1 respectively.

[0110] The oil saturation of the target layer after well drilling was calculated using Archie's formula parameters.

[0111] The volume method is used to calculate the geological reserves of oil and gas using Formula 9:

[0112] N=100A o h o / B oi (9)

[0113] Where: N is the volume of crude oil geological reserves, 10 4 m 3 ; A o is the oil-bearing area, km 2 ; h is the effective thickness, m; Φ is the effective porosity, f; S o is the original oil saturation, f; B oi is the volume coefficient of crude oil.

[0114] When expressing crude oil geological reserves in mass units, the formula is:

[0115] N z =Nρ o (10)

[0116] Where: N z is the geological reserves of crude oil, 10 4 t;ρ o is the density of crude oil on the ground, t / m 3 , in this embodiment, the value is 0.857.

[0117] The parameter oil-bearing area A in formula 10 o , the oil-bearing area is determined according to the delineated oil-bearing range, see Fig. 9 The effective thickness h is determined based on the single well interpretation and the lower limit of the effective reservoir, excluding the fault part. The effective porosity Φ is determined based on oil testing or core experiments. The original oil saturation S o According to the above NMR calculation, the crude oil volume coefficient B oi Using crude oil experiments to determine the density of ground crude oil ρ o Determined using crude oil experiments, minus the area affected by faults.

[0118] The oil-bearing volume of the fault is based on the range of the fault structure zone and dissolution zone determined jointly by seismic and well logging. The porosity is calculated using nuclear magnetic resonance and conventional logging data. The oil saturation is determined using the porosity-oil saturation relationship. The effective oil-bearing volume of the fault is calculated using mathematical methods based on the three-dimensional distribution of the fault and its fracture zones, dissolution zones and oil-bearing height. The geological reserves of oil and gas are calculated using the volumetric method.

[0119] Embodiment 3:

[0120] In a specific embodiment 3 of the present invention, the Figure 1 The flow chart of the method for estimating the reserves of a fault oil and gas reservoir with reservoir performance of the present invention. The method for estimating the reserves of a fault oil and gas reservoir with reservoir performance comprises the following steps:

[0121] Collect geophysical data and drilling data, including seismic, well logging, coring, mud logging, and gas logging data.

[0122] The fault is identified by using logging, coring, mud logging and gas logging data, and combined with the seismic data, the seismic characteristics of the fault are clarified. In this embodiment, the fault is a strong axial reflection.

[0123] Based on the geological characteristics of the region in Example 3, the nappe at the basin margin of the study area is used to identify faults based on fault characteristics using three-dimensional seismic data, determine the three-dimensional spatial distribution of faults, including the inclination angle, strike direction, slip amount on the plane, fault trajectory and fault plane distribution in the fault space, draw fault plane distribution maps and fault profiles, Fig.11 This is the stratigraphic profile of Example 3, where five strike-slip faults are developed. The strata above the F1 fault are nappes, and the strata below the F1 fault are undisturbed strata.

[0124] Based on logging, coring and experimental data, it is determined that the lithology of the oil-bearing target layer is mainly volcanic rock, which is very brittle.

[0125] The drilling coring, logging and mud recording data were used to determine the small faults associated with the fault, the filling and dissolution of the fault, the range of the fault zone, the fault fracture structure, the porosity and permeability values ​​of the fault and the difference with the original formation, which clarified that the fault and its fault structure zone have reservoir properties.

[0126] Since the strike-slip amount of the strike-slip fault is very large, it is difficult to determine the strike-slip amount with existing data. Imaging logging, conventional logging and coring data are mainly used to determine the thickness and size of the impact of the faults F1, F2, F3, F2-1 and F2-2 encountered on the formation physical properties, and the porosity and permeability are calculated using logging data.

[0127] According to the coring, logging oil and gas display and gas logging, well logging data analysis, the oil and gas layers in the Example 3 formation are all broken zones formed by strike-slip faults, the geological morphology is anticline, and a single oil reservoir has a unified oil-water interface and bottom water. Fig.11 Oil and gas layer.

[0128] Core and conventional logging data were used to determine the oil and gas saturation of the fault fracture structure zone. The core of the fault section was distinguished by different fault structures and porosity, and the oil saturation was measured in the laboratory and marked on the comprehensive logging map according to depth.

[0129] Conventional logging uses Archie's formula to obtain oil saturation:

[0130]

[0131] Where: So is the original formation oil and gas saturation, %; Swi is the original formation bound water saturation, %; φ is the effective porosity of the oil layer, f; Rw is the formation water resistivity, Ω·m, and the value of the oil layer section is 0.3Ω·m; Rt is the oil layer resistivity, Ω·m; m is the pore structure index, and the experimental value is 1.46; n is the saturation index, and the experimental value is 1.75; a and b are coefficients related to lithology, which are 1.6 and 1 respectively.

[0132] The oil and gas saturation calculated by logging was compared with the oil saturation of core analysis, and the parameters were appropriately adjusted to calculate the oil and gas saturation of the target layer.

[0133] The volume method is used to calculate the geological reserves of oil and gas using Formula 12:

[0134] N=100A o h o / B oi (12)

[0135] Where: N is the volume of crude oil geological reserves, 104 m 3 ; A o is the oil-bearing area, km 2 ; h is the effective thickness, m; Φ is the effective porosity, f; S o is the original oil saturation, f; B oi is the volume coefficient of crude oil.

[0136] The parameter oil-bearing area A in formula (12) o The oil-bearing area is determined by the oil-bearing range delineated by the anticline trap formed by the fault. The effective thickness h is the fault fracture structure zone. The effective porosity Φ is the fault fracture structure zone. The original oil saturation S is obtained by using conventional logging data. o According to the relationship between porosity and oil saturation, the crude oil volume coefficient B oi The area affected by the fault was deducted based on the crude oil experimental measurement.

[0137] The oil-bearing volume of the fault determines the porosity and range according to the scale of the fault, and the oil saturation is determined by the porosity-oil saturation relationship. The effective oil-bearing volume of the fault is calculated using mathematical methods based on the three-dimensional distribution of the fault and the oil-bearing height, and the geological reserves of oil and gas are calculated using the volumetric method.

[0138] When expressing crude oil geological reserves in mass units, the formula is:

[0139] N z =Nρ o (13)

[0140] Where: N z is the geological reserves of crude oil, 10 4 t;ρ o is the density of crude oil on the ground, t / m 3 , determined using crude oil experiments.

[0141] Beneficial effects: The relative original reserves estimation method of the present invention fully considers the three-dimensional spatial distribution of faults, the number of faults, the fracture structure, and its reservoir performance, oil and gas saturation, etc., clarifies the parameters and factors affecting the reserves such as the three-dimensional spatial distribution of faults, fault reservoir space, and oil and gas saturation, and can more accurately estimate the geological reserves, providing more accurate numerical support for reserve estimation and development plan formulation.

[0142] The above specific implementation methods further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific implementation methods of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for estimating reserves of an oil and gas reservoir with reservoir performance faults, characterized in that: The estimation method includes: Determine the three-dimensional spatial distribution of faults; Use geological data to determine fault fracture structure, extent, and reservoir properties; Determine the oil and gas saturation of the formation in the fault fracture structure zone using core and / or logging data; The volumetric method is used to estimate the geological reserves of oil and gas based on the oil and gas saturation of the formation.

2. The method for estimating reserves of an oil and gas reservoir with reservoir performance faults according to claim 1, characterized in that: The determining of the three-dimensional spatial distribution of faults specifically includes: using geophysical data and drilling data to determine the three-dimensional spatial distribution of faults.

3. The method for estimating reserves of an oil and gas reservoir with reservoir performance faults according to claim 2, characterized in that: The geophysical data and drilling data specifically include: seismic, gravity, magnetic, logging, coring, well logging, and gas logging data.

4. The method for estimating reserves of an oil and gas reservoir with reservoir performance faults according to claim 1, characterized in that: The three-dimensional spatial distribution of the fault includes the inclination angle, strike direction, fault distance, slip amount on the plane, fault trajectory and fault plane distribution in the fault space.

5. The method for estimating reserves of an oil and gas reservoir with reservoir performance faults according to claim 1, characterized in that: The geological data specifically include: well logging, coring, field profiles and / or seismic data.

6. The method for estimating reserves of an oil and gas reservoir with reservoir performance faults according to claim 1, characterized in that: The method of using geological data to determine the fault structure, scope and reservoir performance specifically includes: Determine the fault throw and strike-slip amount using seismic event displacement and / or seismic attributes; Use drilling coring, logging and mud logging data to determine the extent of the fault zone, fault fracture structure, fault filling and dissolution conditions, fault porosity and permeability values, and differences from the original formation; The mathematical fitting method is used to obtain the quantitative calculation model of fault scale, fault zone and fault structure. The fault scale is characterized by fault distance and / or fault slip parameters. Geophysical data are used to establish the relationship between fault throw and / or fault slip and fault zones, fault structures, and formation physical properties, and mathematical methods are used to fit quantitative calculation models.

7. A method for estimating reserves of an oil and gas reservoir with reservoir performance faults according to claim 6, characterized in that: The geophysical data specifically include: seismic, well logging, coring, and field profile data.

8. The method for estimating reserves of an oil and gas reservoir with reservoir performance faults according to claim 1, characterized in that: Determining the oil and gas saturation of the fault fracture zone formation by using core and / or logging data specifically includes: The oil and gas saturation of the formation is obtained by core experiment measurement; The formation oil and gas saturation is obtained by using nuclear magnetic resonance logging calculations; Conventional logging uses Archie's formula to obtain formation oil and gas saturation: In the formula: So is the original formation oil and gas saturation, %; Swi is the original formation bound water saturation, %; φ is the effective porosity of the oil layer, f; Rw is the formation water resistivity, Ω·m; Rt is the oil layer resistivity, Ω·m; m is the pore structure index; n is the saturation index; a and b are coefficients related to lithology.

9. The method for estimating reserves of an oil and gas reservoir with reservoir performance faults according to claim 1, characterized in that: The method of estimating the oil and gas geological reserves by the volume method according to the oil and gas saturation of the formation specifically includes: Using formula (2): N=100A o hΦS o / B oi (2) Where: N is the volume of crude oil geological reserves, 10 4 m 3 ; A o is the oil-bearing area, km 2 ; h is the effective thickness, m; Φ is the effective porosity, f; S o is the original oil saturation, f; B oi is the crude oil volume coefficient; When expressing crude oil geological reserves in mass units, the formula is: N z =Nρ o (3) Where: N z is the geological reserves of crude oil, 10 4 t;ρ o is the density of crude oil on the ground, t / m 3 .

10. A system for estimating the reserves of an oil and gas reservoir with a reservoir performance fault, using the method for estimating the reserves of an oil and gas reservoir with a reservoir performance fault as described in any one of claims 1 to 9, characterized in that: The estimation method includes: A three-dimensional spatial distribution module is used to determine the three-dimensional spatial distribution of faults; Fault structure determination module, used to determine fault fracture structure, range and reservoir performance using well logging data; The oil and gas saturation determination module is used to determine the oil and gas saturation of the formation in the fault fracture structure zone using core and / or logging data; The geological reserve estimation module is used to estimate the geological reserves of oil and gas by using the volume method according to the oil and gas saturation of the formation.

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