Method for obtaining prospective area exploration success rate

Abstract

The invention belongs to the technical field of geological research, and particularly relates to a method for obtaining the prospecting success rate of a prospecting area. The exploration success rate S is determined through the oil source coefficient O, the reservoir coefficient R, the cover layer coefficient C and the trap coefficient T. The prospective area exploration success rate determined by the method truly reflects the actual exploration potential and the drilling risk of the prospective area, and the error between the pre-drilling prediction result and the post-drilling actual result is reduced, so that an effective and accurate prospective area exploration potential evaluation and exploration deployment scheme is obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of geological research, and in particular relates to a method for obtaining the success rate of exploration of a prospecting zone. Background Art

[0002] A prospective zone is an exploration zone in a basin where drilling operations have not yet been carried out to verify its oil and gas content. The exploration success rate of a prospective zone is a direct parameter for predicting the exploration risk of a prospective zone and determining whether it is worth investing in drilling work. The exploration success rate of a prospective zone refers to the probability of oil and gas discovery in a prospective zone predicted by comprehensive evaluation methods or expert scoring methods before the actual drilling work is invested. How to obtain the exploration success rate of a prospective zone has become the biggest bottleneck restricting the exploration potential analysis, exploration risk assessment, and exploration deployment decision-making of a prospective zone.

[0003] At present, most researchers usually directly assign exploration success rates to prospective zones based on personal experience or expert scoring methods when queuing prospective zones and predicting exploration risks. The exploration success rates of prospective zones obtained in this way cannot truly reflect the actual exploration potential and drilling risks of the prospective zones. There is an obvious error between the pre-drilling prediction results and the actual post-drilling results, which directly affects the exploration potential evaluation and exploration deployment plan of the prospective zones.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] In order to make the exploration success rate of a prospective zone truly reflect the actual exploration potential and drilling risk of the prospective zone, reduce the error between the pre-drilling prediction result and the actual result after drilling, and obtain an effective and accurate exploration potential evaluation and exploration deployment plan for the prospective zone; the present invention provides a method for obtaining the exploration success rate of a prospective zone.

[0006] The present invention includes the following technical solutions:

[0007] The present invention provides a method for obtaining the exploration success rate of a prospecting zone, and the exploration success rate S is determined by an oil source coefficient O, a reservoir coefficient R, a cap rock coefficient C and a trap coefficient T.

[0008] Furthermore, the exploration success rate S is determined by the following formula:

[0009] S=25*(O+R+C+T).

[0010] Further, the following steps are included:

[0011] Determine the oil source coefficient O;

[0012] Determine the reservoir coefficient R;

[0013] Determine the capping coefficient C;

[0014] Determine the trap coefficient T;

[0015] The exploration success rate S is determined by the oil source coefficient O, reservoir coefficient R, cap rock coefficient C and trap coefficient T.

[0016] Furthermore, the oil source coefficient O is determined by the following formula:

[0017] O=O ex *O ef ;

[0018] Among them: ex Indicates the existence of oil source, O ef Indicates the effectiveness of the oil source.

[0019] Furthermore, the existence of the oil source is determined by the following formula: ex =min{H o / H omax ,A o / A omax};

[0020] Where: H o is the mudstone thickness of the potential source rock layer in the sag where the prospective zone is located, H omax is the stratigraphic thickness of the potential source rock layer in the depression where the prospecting zone is located, A o is the mudstone distribution area of ​​the depression where the prospecting zone is located, A omax is the maximum area of ​​the depression where the prospect zone is located;

[0021] And / or the oil source effectiveness is determined by:

[0022] If the prospecting zone is completely within the hydrocarbon supply range of known source rocks, then O ef =1;

[0023] If part of the prospecting zone is located within the hydrocarbon supply range of known source rocks, then O ef =A ot / A c ;

[0024] Among them: A ot A is the intersection area between the hydrocarbon supply range of known source rocks and the prospecting zone, c is the area of ​​the prospect zone;

[0025] If the prospecting zone is located outside the hydrocarbon supply range of known source rocks, then O ef =1-L ot L oc ;

[0026] Where: L oc is the maximum distance between the hydrocarbon supply center and the edge of the prospecting zone, Lot It is the minimum distance between the edge of the prospecting zone and the hydrocarbon supply edge.

[0027] Furthermore, the reservoir coefficient R is determined by the following formula:

[0028] R=R ex *R ef ;

[0029] Where: R ex Represents the existence of reservoir, R ef Indicates reservoir effectiveness.

[0030] Further, the existence of the reservoir is determined by:

[0031] If the prospecting zone is completely within the known reservoir facies, then R ex =1;

[0032] If the prospecting zone is partially located within the known reservoir facies zone, then R ex =A rt / A c ;

[0033] Among them: A rt A is the intersection area between the known reservoir facies belt and the prospective facies belt. c is the area of ​​the prospect zone;

[0034] If the prospective zone is outside the known reservoir facies zone:

[0035] When L rt <L r , then R ex =1-L rt / L r , when L rt ≥L r When R ex =0.

[0036] Where: L r is the maximum length of the reservoir facies belt within the known reservoir facies belt range, L rt is the minimum distance between the edge of the prospective belt and the edge of the known reservoir facies belt;

[0037] And / or the reservoir effectiveness is determined by the following formula:

[0038] R ef =min{H ri / H rmax ,P ri / P rmax ,K ri / K rmax};

[0039] Where: H ri H is the mid-range number of reservoir thickness in the prospecting zone, rmax is the maximum reservoir thickness within the known reservoir facies range, P ri is the mid-range number of reservoir porosity in the prospecting zone, P rmax is the maximum reservoir porosity within the known reservoir facies range, K ri is the mid-range number of reservoir permeability in the prospecting zone, K rmax is the maximum reservoir permeability within the known reservoir facies range.

[0040] Furthermore, the mid-range number of reservoir thickness in the prospect zone is determined by the following formula:

[0041] H ri =(H rimin +H rimax ) / 2;

[0042] Where: H rimin is the minimum reservoir thickness in the prospecting zone, H rimax is the maximum reservoir thickness within the prospective zone;

[0043] And / or the mid-range number of reservoir porosity in the prospect zone is determined by the following formula:

[0044] P ri =(P rimin +P rimax ) / 2;

[0045] Where: P rimin is the minimum reservoir porosity in the prospecting zone, P rimax is the maximum reservoir porosity within the prospective zone;

[0046] And / or the mid-range number of reservoir permeability in the prospect zone is determined by the following formula:

[0047] K ri =(K rimin +K rimax ) / 2;

[0048] Where: K rimin is the minimum reservoir permeability in the prospecting zone, K rimax is the maximum reservoir permeability in the prospecting zone.

[0049] Furthermore, the capping coefficient C is determined by the following formula:

[0050] C=C ex *C ef ;

[0051] Where: C exIt indicates the probability of the existence of a caprock phase belt at the location of the prospective zone, C ef It indicates the probability that the caprock at the location of the prospect zone has effective sealing capacity;

[0052] Preferably, the probability of the presence of a caprock phase belt at the location of the prospective zone is determined by:

[0053] If the prospecting zone is completely within the known caprock facies zone, then C ex =1;

[0054] If the prospecting zone is partially located within the known caprock facies zone, then C ex =A ct / A c ;

[0055] If the prospective zone is outside the known caprock facies zone:

[0056] When L cc <L c , then C ex =1-L cc / L c ;

[0057] When L cc ≥L c When C ex =0.

[0058] Among them: A ct A is the intersection area between the known caprock facies belt and the prospective facies belt. c is the area of ​​the prospect zone; L c is the maximum length of the cap layer phase belt within the known cap layer phase belt range, L cc is the minimum distance between the edge of the prospecting zone and the edge of the caprock facies zone;

[0059] And / or the probability that the cap layer at the location of the prospect zone has effective capping ability is determined by the following formula:

[0060] C ef =min{H ci / H cmax ,P cmin / P ci ,K cmin / K ci};

[0061] Where: H ci H is the mid-range value of the caprock thickness in the prospecting zone, ci =(H cimin +H cimax ) / 2,H cimin is the minimum thickness of the caprock in the prospecting zone, Hcimax is the maximum thickness of the caprock in the prospecting zone, H cmax is the maximum thickness of the cap rock in the known cap rock phase belt range, P cmin is the minimum porosity of the cap rock in the known cap rock phase belt range, P ci is the mid-range porosity of the cap rock in the prospecting zone, P ci =(P cimin +P cimax ) / 2,P cimax is the maximum porosity of the cap rock in the prospecting zone, P cimin is the minimum porosity of the cap rock in the known cap rock phase belt range, K ci is the mid-range permeability of the cap rock in the prospecting zone, K ci =(K cimin +K cimax ) / 2,K cimin is the minimum reservoir permeability within the known caprock facies range, K cimax is the maximum permeability of the caprock in the prospecting zone, K cmin is the minimum reservoir permeability within the known cap rock facies range.

[0062] Furthermore, the closure coefficient T is determined by the following formula:

[0063] T=T ex *T ef ;

[0064] Where: T ex is the existence of the trap; T ef For the effectiveness of the trap;

[0065] Preferably, the existence of the trap is determined by:

[0066] If the prospecting zone is within the coverage of 3D seismic, then T ex =1;

[0067] If the prospecting zone is within the coverage of 2D seismic, then T ex =min{1 / X1,1 / X2};

[0068] Among them: X1 is the minimum spacing of 2D seismic lines in the direction of the main survey line, and X2 is the minimum spacing of 2D seismic lines in the direction of the connecting survey line.

[0069] And / or the trap effectiveness is determined by the following formula:

[0070] T ef =min{H ti / H t ,1 / (N t +1)};

[0071] Where: Hti H is the mid-range thickness of the lateral butt plugging layer of all traps in the prospecting zone, ti =(H timin +H timax ) / 2,H timin is the minimum thickness of the lateral butt sealing layer of all traps in the prospecting zone, H timax is the maximum thickness of the lateral butt sealing layer of all traps in the prospecting zone, H t H is the mid-range number of closure heights of all traps in the prospecting zone, t =(H tmin +H tmax ) / 2,H tmin is the minimum closure height of all traps in the prospecting zone, H tmax is the maximum closure height of all traps in the prospect zone, N t is the average number of faults controlling all traps in the prospective zone, Where: n is the number of closures within the prospective area, N ti is the number of faults controlling the ith trap in the prospect zone.

[0072] By adopting the above technical solution, the present invention has the following advantages:

[0073] 1. Based on hydrocarbon source rocks, reservoirs, cap rocks, traps and other reservoir-forming elements, the present invention comprehensively evaluates and quickly obtains the exploration success rate of prospective zones that is close to the actual underground situation, improves the accuracy of risk assessment of prospective zones, and enhances the effectiveness of exploration deployment plans.

[0074] 2. The exploration success rate of the prospect area determined by the present invention truly reflects the actual exploration potential and drilling risk of the prospect area, reduces the error between the pre-drilling prediction result and the post-drilling actual result, and thus obtains an effective and accurate exploration potential evaluation and exploration deployment plan for the prospect area. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be determined based on these drawings without paying creative work.

[0076] Figure 1 is an implementation flow chart of a method for obtaining the exploration success rate of a prospecting zone in an embodiment of the present invention;

[0077] Figure 2 Schematic diagram of a method for determining an oil source coefficient in an embodiment of the present invention;

[0078] Figure 3 Schematic diagram of a reservoir coefficient determination method in an embodiment of the present invention;

[0079] Figure 4 Schematic diagram of a method for determining a cap layer coefficient in an embodiment of the present invention

[0080] Figure 5 Schematic diagram of the method for determining the trap coefficient in an embodiment of the present invention

[0081] Figure 6 It is a schematic diagram of a prospecting zone exploration success rate quantification chart (ORCT chart) in an embodiment of the present invention. DETAILED DESCRIPTION

[0082] The following description provides many different embodiments or examples for implementing different features of the present invention. The components and arrangements described in the following specific examples are only used to simplify the present invention and are only used as examples, not to limit the present invention.

[0083] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments determined by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0084] The present invention provides a method for obtaining the exploration success rate of a prospecting zone, such as Figure 1 As shown, the following steps are included:

[0085] Determine the oil source coefficient O. The oil source coefficient indicates the probability that the prospecting area has favorable oil source conditions. The size of the oil source coefficient depends on the existence of the oil source O ex and oil source availability ef Two parameters, namely O=O ex *O ef The existence of oil source O ex It indicates the probability that source rocks exist in the sag where the prospective zone is located, expressed as O ex =min{H o / H omax ,A o / A omax}, H o is the mudstone thickness of the potential source rock layer in the sag where the prospective zone is located, H omax is the stratigraphic thickness of the potential source rock layer in the depression where the prospecting zone is located, A o is the mudstone distribution area of ​​the depression where the prospecting zone is located, A omax It is the maximum area of ​​the depression where the prospecting zone is located.ef It indicates the probability that the prospective zone has the ability to effectively supply hydrocarbons. If the prospective zone is completely located within the hydrocarbon supply range of known source rocks, then O ef = 1; if the prospective zone is partially located within the hydrocarbon supply range of the known source rock (i.e. the prospective zone partially intersects with the hydrocarbon supply range of the known source rock), then O ef =A ot / A c , where A ot A is the intersection area between the hydrocarbon supply range of known source rocks and the prospecting zone, c is the area of ​​the prospective zone; if the prospective zone is located outside the hydrocarbon supply range of the known source rock (i.e., the prospective zone does not intersect with the hydrocarbon supply range of the known source rock), it is expressed as O ef =(L oc -L ot ) / L oc =1-L ot / L oc , where L oc is the maximum distance between the hydrocarbon supply center and the edge of the prospecting zone, L ot is the minimum distance between the edge of the prospecting zone and the hydrocarbon supply edge. Figure 2 As shown, the thickness of the mudstone H in the potential hydrocarbon source layer of the prospect zone A in an African basin is o The thickness of the potential source rock layer in the depression where the prospective zone is located is H omax is 85m, then H o / H omax =65 / 85=0.765, the mudstone distribution area A in the depression where the A prospective zone is located o 3000km 2 , the maximum area of ​​the depression where the A prospect zone is located is A omax 5000km 2 , then A o / A omax =3000 / 5000=0.600, so in this example, the oil source existence probability of prospect zone A is O ex =min{H o / H omax ,A o / A omax In this embodiment, the prospect zone A is partially located within the hydrocarbon supply range of the known source rock (that is, the prospect zone intersects with the hydrocarbon supply range of the known source rock), then the oil source effectiveness O ef =A ot / A c , where the intersection area A between the known source rock supply range and the A prospect zone is ot 500km2 , the area of ​​prospect zone A c 1200km 2 , then in this embodiment, the oil source effectiveness of prospect area A is ef =A ot / A c =500 / 1200=0.417.

[0086] Determine the reservoir coefficient R. The reservoir coefficient indicates the probability that the prospective zone has favorable reservoir conditions. The size of the reservoir coefficient depends on the existence of the reservoir R. ex and reservoir effectiveness R ef Two parameters, namely R = R ex *R ef , where the reservoir existence R ex It indicates the probability that there is a reservoir facies belt at the location of the prospective zone. If the prospective zone is completely within the range of the known reservoir facies belt, then R ex = 1; if the prospective zone is partially located within the known reservoir facies range (i.e. the prospective zone partially intersects with the known reservoir facies range), then R ex =A rt / A c , where A rt A is the intersection area between the known reservoir facies belt and the prospective facies belt. c is the area of ​​the prospective zone; if the prospective zone is outside the known reservoir facies zone (i.e., the prospective zone does not intersect with the known reservoir facies zone) and L rt <L r , then it is represented by R ex =(L r -L rt ) / L r =1-L rt / L r , where L r is the maximum length of the reservoir facies belt within the known reservoir facies belt range, L rt is the minimum distance between the edge of the prospective zone and the edge of the known reservoir facies zone; when L rt ≥L r When R ex = 0. Reservoir effectiveness R ef It indicates the probability that the reservoir in the prospective zone has effective storage capacity, R ef =min{H ri / H rmax ,P ri / P rmax ,K ri / K rmax}, where H ri is the mid-range number of reservoir thickness in the prospecting zone, expressed as H ri =(Hrimin +H rimax ) / 2,H rimin is the minimum reservoir thickness in the prospecting zone, H rimax is the maximum reservoir thickness in the prospecting zone, H rmax is the maximum reservoir thickness within the known reservoir facies range, P ri is the mid-range number of reservoir porosity in the prospect zone, expressed as P ri =(P rimin +P rimax ) / 2,P rimin is the minimum reservoir porosity in the prospecting zone,

[0087] P rimax is the maximum reservoir porosity in the prospecting zone, P rmax is the maximum reservoir porosity within the known reservoir facies range, K ri is the mid-range number of reservoir permeability in the prospecting zone, expressed as K ri =(K rimin +K rimax ) / 2,K rimin is the minimum reservoir permeability in the prospecting zone,

[0088] K rimax is the maximum reservoir permeability in the prospecting zone, K rmax is the maximum reservoir permeability within the known reservoir phase range.

[0089] R ef =min{(H rimin +H rimax ) / 2H rmax ,(P rimin +P rimax ) / 2P rmax ,(K rimin +K rimax ) / 2K rmax}.like Figure 3 As shown in the example of a basin in Africa, the prospective zone A is partially located within the range of the known reservoir facies belt (that is, the prospective zone partially intersects with the known reservoir facies belt range), so the reservoir existence R ex =A rt / A c , where the intersection area A between the known reservoir facies belt range and the A prospective belt is rt 450km 2 , the area of ​​prospect zone A c 1200km 2 , then the reservoir existence R ex =A rt / A c=450 / 1200=0.375. In this embodiment, the reservoir effectiveness R ef =min{H ri / H rmax ,P ri / P rmax ,K ri / K rmax}, where the minimum reservoir thickness H in the A prospect zone rimin The maximum reservoir thickness H in the A prospect zone is 18m. rimax is 40 m, then the reservoir thickness in the A prospect zone is ri =(H rimin +H rimax ) / 2 = (18 + 40) / 2 = 29 m, the maximum reservoir thickness H in the known reservoir facies belt range rmax is 45m, then H ri / H rmax

[0090] =29 / 45=0.644; Minimum reservoir porosity P in prospect zone A rimin is 0.32, and the maximum reservoir porosity P in prospect zone A rimax is 0.13, then the mid-range number of reservoir porosity P in prospect zone A is ri =(P rimin +P rimax ) / 2=(0.32+0.13) / 2=0.225, the maximum reservoir porosity P in the known reservoir phase belt range rmax is 0.44, then P ri / P rmax =0.225 / 0.44=0.511; Minimum reservoir permeability K in prospect zone A rimin is 0.19 md, and the maximum permeability of the reservoir in the A prospect zone is K rimax is 0.33md, then A is far

[0091] The mid-range number K of reservoir permeability in the scenic area ri =(K rimin +K rimax ) / 2

[0092] =(0.19+0.33) / 2=0.26, the maximum reservoir permeability K of the known reservoir phase belt range rmax is 0.41, then K ri / K rmax =0.634. Therefore, in this example, the reservoir effectiveness R ef =min{H ri / H rmax ,P ri / P rmax ,Kri / K rmax}=min{0.644,0.511,0.634}=0.511.

[0093] Determine the cap layer coefficient C. The cap layer coefficient indicates the probability that the prospecting area has favorable cap layer conditions. The size of the cap layer coefficient depends on the existence of the cap layer C. ex and cover effectiveness C ef Two parameters, namely C = C ex *C ef , where the cap layer existence C ex It indicates the probability that there is a cap layer facies belt at the location of the prospective zone. If the prospective zone is completely within the range of the known cap layer facies belt, then C ex = 1; if the prospective zone is partially located within the known caprock facies range (i.e. the prospective zone partially intersects with the known caprock facies range), then C ex =A ct / A c , where A ct A is the intersection area between the known caprock facies belt and the prospective facies belt. c is the area of ​​the prospective zone; if the prospective zone is outside the known caprock facies range (i.e., the prospective zone does not intersect with the known caprock facies range) and L cc <L c , then C ex =(L c -L cc ) / L c =1-L cc / L c , where L c is the maximum length of the cap layer phase belt within the known cap layer phase belt range, L cc is the minimum distance between the edge of the prospecting zone and the edge of the caprock facies zone; when L cc ≥L c When C ex = 0. Cover layer effectiveness C ef It indicates the probability that the caprock at the prospect zone has effective sealing ability, C ef =min{H ci / H cmax ,P cmin / P ci ,K cmin / K ci}, where H ci is the mid-range number of caprock thickness in the prospecting zone, expressed as H ci =(H cimin +H cimax ) / 2,H cimin is the minimum thickness of the caprock in the prospecting zone, H cimaxis the maximum thickness of the caprock in the prospecting zone, H cmax is the maximum thickness of the cap rock in the known cap rock phase belt range, P ci is the mid-range porosity of the cap rock in the prospecting zone, expressed as P ci =(P cimin +P cimax ) / 2,P cimin is the minimum porosity of the cap rock in the prospecting zone, P cimax is the maximum porosity of the cap rock in the prospecting zone, P cmin is the minimum porosity of the cap rock in the known cap rock phase belt range, K ci is the mid-range permeability of the cap rock in the prospecting zone, expressed as K ci =(K cimin +K cimax ) / 2,K cimin is the minimum permeability of the caprock in the prospecting zone, K cimax is the maximum permeability of the cap rock in the prospecting zone, K cmin is the minimum reservoir permeability within the known caprock phase range.

[0094] C ef =min{(H cimin +H cimax ) / 2H cmax ,2P cmin / (P cimin +P cimax ),2K cmin / (K cimin +K cimax )}.like Figure 4 As shown, in the embodiment of a basin in Africa, the prospective zone A is partially located within the range of the known caprock facies zone (i.e., the prospective zone partially intersects with the known caprock facies zone range), wherein the intersection area A between the known caprock facies zone range and the prospective zone is ct 600km 2 , the area of ​​the prospect zone is A c 1200km 2 , then in this embodiment, the caprock existence C of the A prospect zone ex =A ct / A c =600 / 1200=0.500. In this embodiment, the cover layer effectiveness C ef =min{H ci / H cmax ,P cmin / P ci ,K cmin / K ci}, the minimum thickness of the caprock in the A prospect zone H cimin The maximum thickness of the caprock in the A prospect zone is Hcimax is 45 m, then the mid-range thickness of the caprock in the A prospect zone is H ci =(H cimin +H cimax ) / 2 = (20 + 45) / 2 = 32.5 m. The maximum thickness of the cap layer in the known cap layer phase belt is H cmax is 45m, then H ci / H cmax =32.5 / 45=0.722; Minimum porosity of caprock in prospect zone A P cimin is 0.1, and the maximum porosity of the caprock in the A prospect zone is P cimax is 0.2, and the mid-range porosity of the cap rock in the A prospect zone is P ci =(P cimin +P cimax ) / 2=(0.2+0.1) / 2=0.15, the minimum porosity P of the cap rock in the known cap rock phase belt range cmin is 0.09, then P cmin / P ci =0.09 / 0.15=0.600; Minimum permeability of caprock in prospect zone A K cimin is 0.1md, and the maximum permeability of the caprock in the A prospect zone is K cimax is 0.19 md, then the mid-range permeability of the cap rock in the A prospect zone is K ci =(K cimin +K cimax ) / 2=(0.1+0.19) / 2=0.145, the minimum reservoir permeability K in the known caprock phase range cmin is 0.1md, then K cmin / K ci =0.1 / 0.145=0.690. Therefore, in this example, the effectiveness of the caprock in the A prospect zone is

[0095] C ef =min{H ci / H cmax ,P cmin / P ci ,K cmin / K ci}=min{0.722,0.600,0.690}=0.600.

[0096] Determine the closure coefficient T. The closure coefficient indicates the probability that the prospecting area has favorable closure conditions. The size of the closure coefficient depends on the existence of the closure T. ex and the trap effectiveness T ef Two parameters, namely T = T ex *T ef , where the trap existence T exIt indicates the probability of a trap existing in the prospective zone. If the prospective zone is located within the coverage of 3D seismic data, then T ex =1, if the prospect zone is within the coverage of 2D seismic, then T ex =min{1 / X1,1 / X2}, where X1 is the minimum spacing of 2D seismic lines in the direction of the main survey line, and X2 is the minimum spacing of 2D seismic lines in the direction of the tie survey line. Trap effectiveness T ef It indicates the probability that the traps in the prospect zone have effective trapping capacity, T ef =min{H ti / H t ,1 / (N t +1)}, where H ti The mid-range thickness of the lateral butt plugging layer of all traps in the prospecting zone is expressed as H ti =(H timin +H timax ) / 2,H timin is the minimum thickness of the lateral butt sealing layer of all traps in the prospecting zone, H timax is the maximum thickness of the lateral butt sealing layer of all traps in the prospecting zone, H t is the mid-range number of closure heights of all traps in the prospect zone, expressed as H t =(H tmin +H tmax ) / 2,H tmin is the minimum closure height of all traps in the prospecting zone, H tmax It is the maximum closure height of all the traps in the prospecting zone. t is the average number of faults controlling all traps in the prospective zone, Where: n is the number of closures within the prospective area, N ti is the number of faults controlling the ith trap in the prospect zone. ti ≥0, N of anticline trap ti =0, n>0. Therefore, like Figure 5 As shown in the example of a basin in Africa, the prospect zone A is located within the coverage of 2D seismic data, so the trap existence probability T ex =min{1 / X1,1 / X2}, where the minimum spacing X1 of the two-dimensional seismic survey lines in the main survey line direction is 1 km, and the minimum spacing X2 of the two-dimensional seismic survey lines in the connecting survey line direction is 1.2 km. In this embodiment, the trap existence probability T of the A prospect zone is ex =min{1 / X1,1 / X2}=min{1 / 1,1 / 1.2}=min{1,0.833}=0.833. A. Trap effectiveness of prospective zone

[0097] T ef=min{H ti / H t ,1 / (N t +1)}, where the minimum thickness of the lateral butt plugging layer of all traps in the A prospect zone is H timin The maximum thickness of the lateral butt plugging layer of all the traps in the A prospect zone is H timax The mid-range thickness of the lateral butt plugging layer of all traps in the A prospect zone is H. ti =(H timin +H timax ) / 2 = (17 + 28) / 2 = 22.5; The minimum closure height H of all traps in the prospect zone A tmin The maximum closure height H of all traps in the A prospect zone is 22m. tmax The mid-range number H of the closing height of all the traps in the A prospect zone is 49m. t =(H tmin +H tmax ) / 2=(22+49) / 2=35.5, then H ti / H t =22.5 / 35.5=0.634; the average number of faults controlling all traps in prospect zone A

[0098] =(1+2+1+3+1+0+1+1+0+2+3+4+1+0) / 14=20 / 14=1.429, then 1 / (N t

[0099] +1)=1 / (1+1.429)=0.412. Therefore, in this example, the trap effectiveness T of the A prospect zone is ef =min{H ti / H t ,1 / (N t +1)}=min{0.634,0.412}=0.412.

[0100] Determine the exploration success rate S of the prospective zone. Establish a quantitative chart of exploration success rate of the prospective zone (abbreviated as ORCT chart). The X-axis of the quantitative chart is the existence axis, the Y-axis is the effectiveness axis, the X-axis and the Y-axis are divided into 10 equal parts, and the 5-point intersection of the X-axis and the Y-axis is 0. The values ​​of the left and right of the X-axis are 0-5, and the values ​​of the upward and downward Y-axis are 0-5, which is equivalent to dividing the quantitative chart of exploration success rate of the prospective zone into 4 areas, each with an area of ​​25 and a total area of ​​100. The upper right corner area is the oil source coefficient O area, where the X-axis value is O ex *5, Y-axis value is 0 ef *5, then the area of ​​zone O is O ex *O ef*25. The upper left corner area is the reservoir coefficient R area, where the X-axis value is R ex *5, Y-axis value is R ef *5, then the area of ​​R zone is R ex *R ef *25. The lower left corner area is the cap coefficient C area, where the X-axis value is C ex *5, Y-axis value is C ef *5, then the area of ​​zone C is C ex *C ef *25. The lower right corner is the T area, where the X-axis value is T ex *5, Y-axis value is T ef *5, then the area of ​​the T zone is T ex *T ef *25. The exploration success rate S of the prospecting zone is expressed as the sum of the areas of the oil source coefficient area, the reservoir coefficient area, the cap rock coefficient area, and the trap coefficient area, that is, S = (O ex *O ef *25+R ex *R ef *25+C ex *C ef *25+T ex *T ef *25)=25*(O ex *O ef +R ex *R ef +C ex *C ef +T ex *T ef )=25*(O+R+C+T). Figure 6 As shown, in the embodiment of a basin in Africa, the oil source coefficient (O) of the prospect zone A has an X-axis value of 0. ex *5=0.600*5=3.000, the Y-axis value is 0 ef *5=0.417*5=2.085; the X-axis value of the reservoir coefficient R area is R ex *5=0.375*5=1.875, the Y-axis value is R ef *5=0.511*5=2.555; the X-axis value of the cap coefficient (C) area is C ex *5=0.500*5=2.500, the Y-axis value is C ef *5=0.600*5=3.000; the X-axis value of the closure coefficient (T) area is T ex *5=0.833*5=4.165, the Y-axis value is T ef*5=0.412*5=2.060. The exploration success rate S of prospective area A is expressed as the sum of the areas of the oil source coefficient area, the reservoir coefficient area, the cap rock coefficient area, and the trap coefficient area. In this embodiment, the exploration success rate S of prospective area A=(0 ex *O ef *25+R ex *R ef *25+C ex *C ef *25+T ex *T ef *25)=25*(0.600*0.417+0.375*0.511+0.500*0.600+0.833*0.412)=25*(0.2502+0.1916+0.3000+0.3432)=27.125, that is, the exploration success rate S of prospective area zone A is 27.125%.

[0101] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for obtaining the success rate of exploration of a prospecting zone, characterized by: The exploration success rate S is determined by the oil source coefficient O, reservoir coefficient R, cap rock coefficient C and trap coefficient T.

2. A method for determining the success rate of prospecting zone exploration according to claim 1, characterized in that: The exploration success rate S is determined by the following formula: S=25*(O+R+C+T).

3. A method for obtaining the exploration success rate of a prospecting zone as claimed in claim 2, characterized in that: The steps include: Determine the oil source coefficient O; Determine the reservoir coefficient R; Determine the capping coefficient C; Determine the trap coefficient T; The exploration success is determined by the oil source coefficient O, reservoir coefficient R, cap rock coefficient C and trap coefficient T. Power S.

4. A method for obtaining the exploration success rate of a prospecting zone according to any one of claims 1 to 3, characterized in that: The oil source coefficient O is determined by the following formula: O=O ex *O ef ; Among them: ex Indicates the existence of oil source, O ef Indicates the effectiveness of the oil source.

5. A method for obtaining the exploration success rate of a prospecting zone as claimed in claim 4, characterized in that: The existence of the oil source is determined by the following formula: O ex =min{H o / H omax ,A o / A omax }; Where: Ho is the mudstone thickness of the potential source rock layer in the sag where the prospective area is located, H omax is the stratigraphic thickness of the potential source rock layer in the depression where the prospecting zone is located, A o is the mudstone distribution area of ​​the depression where the prospecting zone is located, A omax is the maximum area of ​​the depression where the prospect zone is located; And / or the oil source effectiveness is determined by: If the prospecting zone is completely within the hydrocarbon supply range of known source rocks, then O ef =1; If part of the prospecting zone is located within the hydrocarbon supply range of known source rocks, then O ef =A ot / A c ; Among them: A ot A is the intersection area between the hydrocarbon supply range of known source rocks and the prospecting zone, c is the area of ​​the prospect zone; If the prospecting zone is located outside the hydrocarbon supply range of known source rocks, then O ef =1-L ot L oc ; Where: L oc is the maximum distance between the hydrocarbon supply center and the edge of the prospecting zone, L ot It is the minimum distance between the edge of the prospecting zone and the hydrocarbon supply edge.

6. A method for obtaining the success rate of exploration of a prospecting zone according to any one of claims 1 to 3, characterized in that: The reservoir coefficient R is determined by the following formula: R=R ex *R ef ; Where: R ex Represents the existence of reservoir, R ef Indicates reservoir effectiveness.

7. A method for obtaining the success rate of prospecting zone exploration according to claim 6, characterized in that: The existence of the reservoir is determined by: If the prospecting zone is completely within the known reservoir facies, then R ex =1; If the prospecting zone is partially located within the known reservoir facies zone, then R ex =A rt / A c ; Among them: A rt A is the intersection area between the known reservoir facies belt and the prospective facies belt. c is the area of ​​the prospect zone; If the prospective zone is outside the known reservoir facies zone: When L rt <L r , then R ex =1-L rt / L r , when L rt ≥L r When R ex =0. Where: L r is the maximum length of the reservoir facies belt within the known reservoir facies belt range, L rt is the minimum distance between the edge of the prospective belt and the edge of the known reservoir facies belt; And / or the reservoir effectiveness is determined by the following formula: R ef =min{H ri / H rmax ,P ri / P rmax ,K ri / K rmax }; Where: H ri H is the mid-range number of reservoir thickness in the prospecting zone, rmax is the maximum reservoir thickness within the known reservoir facies range, P ri is the mid-range number of reservoir porosity in the prospecting zone, P rmax is the maximum reservoir porosity within the known reservoir facies range, K ri is the mid-range number of reservoir permeability in the prospecting zone, K rmax is the maximum reservoir permeability within the known reservoir facies range.

8. A method for obtaining the success rate of prospecting zone exploration according to claim 7, characterized in that: The mid-range number of reservoir thickness in the prospect zone is determined by the following formula: H ri =(H rimin +H rimax ) / 2; Where: H rimin is the minimum reservoir thickness in the prospecting zone, H rimax is the maximum reservoir thickness within the prospective zone; And / or the mid-range number of reservoir porosity in the prospect zone is determined by the following formula: P ri =(P rimin +P rimax ) / 2; Where: P rimin is the minimum reservoir porosity in the prospecting zone, P rimax is the maximum reservoir porosity within the prospective zone; And / or the mid-range number of reservoir permeability in the prospect zone is determined by the following formula: K ri =(K rimin +K rimax ) / 2; Where: K rimin is the minimum reservoir permeability in the prospecting zone, K rimax is the maximum reservoir permeability in the prospecting zone.

9. A method for obtaining the success rate of exploration of a prospecting zone according to any one of claims 1 to 3, characterized in that: The capping coefficient C is determined by the following formula: C=C ex *C ef ; Where: C ex Indicates the probability that there is a caprock facies belt at the location of the prospective zone, C ef It indicates the probability that the caprock at the location of the prospect zone has effective sealing capacity; Preferably, the probability of the presence of a caprock phase belt at the location of the prospective zone is determined by: If the prospecting zone is completely within the known caprock facies zone, then C ex =1; If the prospecting zone is partially located within the known caprock facies zone, then C ex =A ct / A c ; If the prospective zone is outside the known caprock facies zone: When L cc <L c , then C ex =1-L cc / L c ; When L cc ≥L c When C ex =0. Among them: A ct A is the intersection area between the known caprock facies belt and the prospective facies belt. c is the area of ​​the prospect zone; L c is the maximum length of the cap layer phase belt within the known cap layer phase belt range, L cc is the minimum distance between the edge of the prospecting zone and the edge of the caprock facies zone; And / or the probability that the cap layer at the location of the prospect zone has effective capping ability is determined by the following formula: C ef =min{H ci / H cmax ,P cmin / P ci ,K cmin / K ci }; Where: H ci H is the mid-range value of the caprock thickness in the prospecting zone, ci =(H cimin +H cimax ) / 2,H cimin is the minimum thickness of the caprock in the prospecting zone, H cimax is the maximum thickness of the caprock in the prospecting zone, H cmax is the maximum thickness of the cap rock in the known cap rock phase belt range, P cmin is the minimum porosity of the cap rock in the known cap rock phase belt range, P ci is the mid-range porosity of the cap rock in the prospecting zone, P ci =(P cimin +P cimax ) / 2,P cimax is the maximum porosity of the cap rock in the prospecting zone, P cimin is the minimum porosity of the cap rock in the known cap rock phase belt range, K ci is the mid-range permeability of the cap rock in the prospecting zone, K ci =(K cimin +K cimax ) / 2,K cimin is the minimum reservoir permeability within the known caprock facies range, K cimax is the maximum permeability of the caprock in the prospecting zone, K cmin is the minimum reservoir permeability within the known cap rock facies range.

10. A method for obtaining the exploration success rate of a prospecting zone according to any one of claims 1 to 3, characterized in that: The trap coefficient T is determined by the following formula: T=T ex *T ef ; Where: T ex is the existence of the trap; T ef For the effectiveness of the trap; Preferably, the existence of the trap is determined by: If the prospecting zone is within the coverage of 3D seismic, then T ex =1; If the prospecting zone is within the coverage of 2D seismic, then T ex =min{1 / X1,1 / X2}; Among them: X1 is the minimum spacing of 2D seismic lines in the direction of the main survey line, and X2 is the minimum spacing of 2D seismic lines in the direction of the connecting survey line. And / or the trap effectiveness is determined by the following formula: T ef =min{H ti / H t ,1 / (N t +1)}; Where: H ti H is the mid-range thickness of the lateral butt plugging layer of all traps in the prospecting zone, ti =(H timin +H timax ) / 2,H timin is the minimum thickness of the lateral butt sealing layer of all traps in the prospecting zone, H timax is the maximum thickness of the lateral butt sealing layer of all traps in the prospecting zone, H t H is the mid-range number of closure heights of all traps in the prospecting zone, t =(H tmin +H tmax ) / 2,H tmin is the minimum closure height of all traps in the prospecting zone, H tmax is the maximum closure height of all traps in the prospect zone, N t is the average number of faults controlling all traps in the prospective zone, Where: n is the number of closures within the prospective area, N ti is the number of faults controlling the ith trap in the prospect zone.

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