CN113919140A - Method for evaluating static connectivity of offshore large-well-spacing fan delta thin interbed reservoir - Google Patents
Method for evaluating static connectivity of offshore large-well-spacing fan delta thin interbed reservoir Download PDFInfo
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Abstract
The invention discloses a method for evaluating static connectivity of an offshore large-well-spacing fan delta thin interbed reservoir, which comprises the following steps: acquiring sub-layer pressure measurement data of a produced well, and determining a lower limit of communication thickness according to the sub-layer pressure measurement data; respectively counting the thickness of each single sand body in different wells in a target time unit, and taking the accumulated thickness of each well which is greater than the lower limit of the communication thickness as the effective communication thickness; taking the effective communication thickness as an indication parameter of the communication, and counting the proportion of the accumulated effective sandstone thickness in each well to the total sandstone thickness; determining a plane distribution diagram of effective sandstone thickness ratio by combining the trend of a sedimentary phase diagram; according to historical information of the associated oil fields, the thickness ratios of the main riverway development zone and the communicating sandstone of the riverway edge and the matting sand development zone are counted, the target threshold values of the communicating thickness ratios of different development zones are determined, and the historical information comprises information of deposition microphase plane distribution; and finally, extracting the contour line at the target threshold value. The invention improves the precision and the data utilization rate, and can be widely applied to the technical field of oil and gas field development geological research.
Description
Technical Field
The invention relates to the technical field of oil and gas field development geological research, in particular to a method for evaluating the static connectivity of an offshore large-well-spacing fan delta thin interbed reservoir.
Background
The evaluation of the connectivity of the delta thin interbed is always the key point of development attention of oil and gas fields. Due to the limitations of large well spacing, low recognition degree, frequent reservoir migration and superposition, fast reservoir transverse change, low seismic reservoir description precision, high dynamic data acquisition cost and the like, how to effectively perform static evaluation on reservoir connectivity has important significance on deployment of an oil field injection-production well pattern and improvement of recovery ratio. The current common method for statically evaluating reservoir connectivity is as follows:
(1) sandstone thickness method
And accumulating the sandstone thicknesses of all wells in the divided stratum or time units to obtain a sandstone thickness plane distribution diagram, wherein the area with large sandstone thickness has better connectivity.
(2) Sand-to-ground ratio method
The sand-to-ground ratio represents the sand-rich degree in a time unit, the method measures the enrichment degree of sand bodies by adopting the ratio of the thickness of the sandstone to the thickness of a stratum, reflects the distance of the delta sand bodies from a source to a certain extent, and generally, a region with the high sand-to-ground ratio is near-source deposition and has better connectivity. The method is a common method for judging the connectivity strength in reservoir connectivity research.
(3) Fine deposition microphase description method
The fine sedimentary microfacies description method is to obtain the plane distribution of sedimentary microfacies by counting sedimentary parameters such as the thickness of sandstone at a well point, sand-ground ratio and the like or combining with the prediction result of a seismic reservoir. From the view of the sedimentary microphotograph, the development position of the main river channel has better connectivity, and the positions of the side edge of the river channel, the estuary dam, the mat sand and the like are always poor in connectivity.
Because the thin interbed sediment hydrodynamic condition of the delta-shaped is intermittent and unstable, the sediments in each period are mixed, and the connectivity reflected by the similar sandstone thickness or sand-to-ground ratio is often different greatly; years of oil field production practice shows that in the same development layer system, the injection-production connectivity and the development effect are usually determined by the sandstone thickness and the spread of the prime layer, and the injection-production connectivity and the development effect are not directly related to the accumulated sandstone thickness and sand-ground ratio. And in the offshore large-well-spacing fan delta thin interbed reservoir, the reservoir recognition uncertainty is large, the reservoir description accuracy is low and fine depositional microfacies description is difficult to form due to the fact that well data are few and sand-shale interaction and overlapping are frequent. Therefore, aiming at how to fully excavate parameter information of well points of the reservoirs, developing effective evaluation of connectivity and connectivity range is always a difficult problem which needs to be solved urgently.
Disclosure of Invention
In view of this, the embodiment of the invention provides a method for evaluating the static connectivity of an offshore large-well-spacing fan delta thin interbed reservoir, which can fully excavate the parameter information of a well point, and further provide a reliable basis for efficient development of an offshore oilfield and reasonable utilization of reserves.
One aspect of the invention provides a method for evaluating static connectivity of an offshore large-well-spacing fan delta thin interbed reservoir, which comprises the following steps:
acquiring sub-layer pressure measurement data of a produced well, and determining a lower limit of communication thickness according to the sub-layer pressure measurement data;
respectively counting the thickness of each single sand body in different wells in a target time unit, judging the accumulated thickness greater than the lower limit of the communication thickness, and taking the accumulated thickness of each well greater than the lower limit of the communication thickness as the effective communication thickness;
taking the effective communication thickness as an indication parameter of the communication, and counting the proportion of the accumulated effective sandstone thickness in each well to the total sandstone thickness;
determining a plane distribution diagram of the effective sandstone thickness ratio by combining the sedimentary phase diagram trend;
according to historical information of the associated oil fields, the thickness ratios of the main riverway development zone and the communicating sandstone of the riverway edge and the matting sand development zone are counted, the target threshold values of the communicating thickness ratios of different development zones are determined, and the historical information comprises information of deposition microphase plane distribution;
combining the target threshold and the plane distribution map, and extracting a contour line at the target threshold;
wherein, the contour line is used for determining a preferred area with good connectivity;
the preferred area is used for guiding the classified utilization of reserves, the establishment of an injection-production well pattern, the difference analysis of injection-production well distances and the recovery ratio of different areas.
Optionally, the method further comprises:
and dividing single sand bodies of different periods for each well in the target time unit, and counting the number of the single sand bodies in the target time unit and the net thickness of the sandstone of the single sand body in each period.
Optionally, the method further comprises:
combining rich pressure measurement data of produced blocks of the oil field or the oil field in the similar deposition environment, and making a junction diagram of the thickness of the single sand body and the pressure measurement coefficient in each period aiming at the production well;
determining the thickness threshold of the sandstone used and not used in the single sand body by combining the intersection map;
using the single sand body with strong connectivity higher than the sandstone thickness threshold value and using the single sand body with non-connectivity or poor connectivity lower than the sandstone thickness threshold value;
taking the sandstone thickness threshold value as a calculation value of the sandstone communication thickness;
wherein the calculation value is used for characterizing the strength of the connectivity.
Optionally, the method further comprises:
and compiling a connected sandstone thickness ratio plane distribution diagram by combining the sedimentary facies trend and the connected sandstone thickness ratio numerical value of each well point, and performing smooth interpolation processing and gridding processing on the plane distribution diagram.
Optionally, the historical information of the associated oil field is combined, statistics is performed on the thickness ratios of the main channel development zone and the connected sandstone of the channel edge and the matting sand development zone, and a target threshold of the connected thickness ratios of different development zones is determined, where the historical information includes information of deposition microphase plane distribution, and the historical information includes:
acquiring a similar oilfield sedimentary microfacies plan with similar area positions, similar sedimentary environments and detailed sedimentary microfacies understanding;
according to a main riverway development zone, a riverway edge development zone, mat-shaped sand and a estuary dam development zone, the thickness ratio of communicated single sand layers of wells of the three zones in the same time unit is counted;
and determining the difference of the main riverway development zone and the riverway edge development zone in the communicated single sand layer thickness ratio according to the statistical result, and defining the threshold of the communicated single sand layer thickness ratio of the main riverway development zone as the target threshold.
Optionally, the extracting the contour line at the target threshold in combination with the target threshold and the histogram includes:
on a gridded plane distribution diagram of the thickness proportion of the communicated single sand layer, extracting a thickness proportion isoline of the communicated single sand layer near the target threshold as an outer boundary line with good connectivity according to the target threshold; the area above the contour line is confirmed to be a main riverway development area with good connectivity;
and extracting the contour line of the domain values between the mat-shaped sand and the side edge of the river channel, and determining the outer edge of the contour line as a mat-shaped sand development area with poor connectivity.
An aspect of the present invention further provides an apparatus, including:
the first module is used for acquiring the sub-layer pressure measurement data of the produced well and determining the lower limit of the communication thickness according to the sub-layer pressure measurement data;
the second module is used for respectively counting the thickness of each single sand body in different wells in a target time unit, judging the accumulated thickness greater than the lower limit of the communication thickness and taking the accumulated thickness of each well greater than the lower limit of the communication thickness as the effective communication thickness;
the third module is used for taking the effective communication thickness as an indication parameter of connectivity and counting the proportion of the accumulated effective sandstone thickness in each well to the total sandstone thickness;
the fourth module is used for determining a plane distribution diagram of the effective sandstone thickness ratio by combining the sedimentary phase diagram trend;
the fifth module is used for counting the thickness ratio of the main riverway development zone to the communicated sandstone of the riverway edge and the matting sand development zone by combining historical information of the associated oil field, and determining a target threshold value of the communicated thickness ratio of different development zones, wherein the historical information comprises information of deposition microphase plane distribution;
a sixth module for extracting a contour at the target threshold in combination with the target threshold and the histogram;
wherein, the contour line is used for determining a preferred area with good connectivity;
the preferred area is used for guiding the classified utilization of reserves, the establishment of an injection-production well pattern, the difference analysis of injection-production well distances and the recovery ratio of different areas.
The method comprises the steps of obtaining sub-layer pressure measurement data of a produced well, and determining a lower limit of communication thickness according to the sub-layer pressure measurement data; respectively counting the thickness of each single sand body in different wells in a target time unit, judging the accumulated thickness greater than the lower limit of the communication thickness, and taking the accumulated thickness of each well greater than the lower limit of the communication thickness as the effective communication thickness; taking the effective communication thickness as an indication parameter of the communication, and counting the proportion of the accumulated effective sandstone thickness in each well to the total sandstone thickness; determining a plane distribution diagram of the effective sandstone thickness ratio by combining the sedimentary phase diagram trend; according to historical information of the associated oil fields, the thickness ratios of the main riverway development zone and the communicating sandstone of the riverway edge and the matting sand development zone are counted, the target threshold values of the communicating thickness ratios of different development zones are determined, and the historical information comprises information of deposition microphase plane distribution; combining the target threshold and the plane distribution map, and extracting a contour line at the target threshold; wherein, the contour line is used for determining a preferred area with good connectivity; the preferred area is used for guiding the classified utilization of reserves, the establishment of an injection-production well pattern, the difference analysis of injection-production well distances and the recovery ratio of different areas. The method realizes the quantitative delineation and analysis of different reservoir types and connectivity distribution zones under the conditions of complex reservoir and insufficient seismic description precision in the early development stage of the offshore oil and gas field, and can provide important support for reserve utilization and efficient development of the offshore large-well-spacing fan delta thin interbed oil and gas reservoir.
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In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
FIG. 1 is a flowchart illustrating the overall steps provided by an embodiment of the present invention;
FIG. 2 is a schematic diagram of the longitudinal division of a single sand layer according to an embodiment of the present invention;
FIG. 3 is a cross-section of the sand pressure coefficient and single sand thickness of an oilfield provided by an embodiment of the present invention;
FIG. 4 is a graph illustrating the ratio of the thickness of the connected sand bodies according to an embodiment of the present invention;
FIG. 5 is a cross-sectional view of a B-field connected sand thickness ratio plot and a sedimentary microfacies type provided by an embodiment of the present invention;
FIG. 6 is a reflection of different thresholds on a contour plot;
FIG. 7 is a planar distribution of deposited microphases combined with a connected thickness ratio refinement.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.
Aiming at the problems in the prior art, the invention provides a method for evaluating the static connectivity of an offshore large-well-spacing fan delta thin interbed reservoir, which comprises the following steps of:
acquiring sub-layer pressure measurement data of a produced well, and determining a lower limit of communication thickness according to the sub-layer pressure measurement data;
respectively counting the thickness of each single sand body in different wells in a target time unit, judging the accumulated thickness greater than the lower limit of the communication thickness, and taking the accumulated thickness of each well greater than the lower limit of the communication thickness as the effective communication thickness;
taking the effective communication thickness as an indication parameter of the communication, and counting the proportion of the accumulated effective sandstone thickness in each well to the total sandstone thickness;
determining a plane distribution diagram of the effective sandstone thickness ratio by combining the sedimentary phase diagram trend;
according to historical information of the associated oil fields, the thickness ratios of the main riverway development zone and the communicating sandstone of the riverway edge and the matting sand development zone are counted, the target threshold values of the communicating thickness ratios of different development zones are determined, and the historical information comprises information of deposition microphase plane distribution;
combining the target threshold and the plane distribution map, and extracting a contour line at the target threshold;
wherein, the contour line is used for determining a preferred area with good connectivity;
the preferred area is used for guiding the classified utilization of reserves, the establishment of an injection-production well pattern, the difference analysis of injection-production well distances and the recovery ratio of different areas.
Optionally, the method further comprises:
and dividing single sand bodies of different periods for each well in the target time unit, and counting the number of the single sand bodies in the target time unit and the net thickness of the sandstone of the single sand body in each period.
Optionally, the method further comprises:
combining rich pressure measurement data of produced blocks of the oil field or the oil field in the similar deposition environment, and making a junction diagram of the thickness of the single sand body and the pressure measurement coefficient in each period aiming at the production well;
determining the thickness threshold of the sandstone used and not used in the single sand body by combining the intersection map;
using the single sand body with strong connectivity higher than the sandstone thickness threshold value and using the single sand body with non-connectivity or poor connectivity lower than the sandstone thickness threshold value;
taking the sandstone thickness threshold value as a calculation value of the sandstone communication thickness;
wherein the calculation value is used for characterizing the strength of the connectivity.
Optionally, the method further comprises:
and compiling a connected sandstone thickness ratio plane distribution diagram by combining the sedimentary facies trend and the connected sandstone thickness ratio numerical value of each well point, and performing smooth interpolation processing and gridding processing on the plane distribution diagram.
Optionally, the historical information of the associated oil field is combined, statistics is performed on the thickness ratios of the main channel development zone and the connected sandstone of the channel edge and the matting sand development zone, and a target threshold of the connected thickness ratios of different development zones is determined, where the historical information includes information of deposition microphase plane distribution, and the historical information includes:
acquiring a similar oilfield sedimentary microfacies plan with similar area positions, similar sedimentary environments and detailed sedimentary microfacies understanding;
according to a main riverway development zone, a riverway edge development zone, mat-shaped sand and a estuary dam development zone, the thickness ratio of communicated single sand layers of wells of the three zones in the same time unit is counted;
and determining the difference of the main riverway development zone and the riverway edge development zone in the communicated single sand layer thickness ratio according to the statistical result, and defining the threshold of the communicated single sand layer thickness ratio of the main riverway development zone as the target threshold.
Optionally, the extracting the contour line at the target threshold in combination with the target threshold and the histogram includes:
on a gridded plane distribution diagram of the thickness proportion of the communicated single sand layer, extracting a thickness proportion isoline of the communicated single sand layer near the target threshold as an outer boundary line with good connectivity according to the target threshold; the area above the contour line is confirmed to be a main riverway development area with good connectivity;
and extracting the contour line of the domain values between the mat-shaped sand and the side edge of the river channel, and determining the outer edge of the contour line as a mat-shaped sand development area with poor connectivity.
An aspect of the present invention further provides an apparatus, including:
the first module is used for acquiring the sub-layer pressure measurement data of the produced well and determining the lower limit of the communication thickness according to the sub-layer pressure measurement data;
the second module is used for respectively counting the thickness of each single sand body in different wells in a target time unit, judging the accumulated thickness greater than the lower limit of the communication thickness and taking the accumulated thickness of each well greater than the lower limit of the communication thickness as the effective communication thickness;
the third module is used for taking the effective communication thickness as an indication parameter of connectivity and counting the proportion of the accumulated effective sandstone thickness in each well to the total sandstone thickness;
the fourth module is used for determining a plane distribution diagram of the effective sandstone thickness ratio by combining the sedimentary phase diagram trend;
the fifth module is used for counting the thickness ratio of the main riverway development zone to the communicated sandstone of the riverway edge and the matting sand development zone by combining historical information of the associated oil field, and determining a target threshold value of the communicated thickness ratio of different development zones, wherein the historical information comprises information of deposition microphase plane distribution;
a sixth module for extracting a contour at the target threshold in combination with the target threshold and the histogram;
wherein, the contour line is used for determining a preferred area with good connectivity;
the preferred area is used for guiding the classified utilization of reserves, the establishment of an injection-production well pattern, the difference analysis of injection-production well distances and the recovery ratio of different areas.
The following detailed description of the implementation principle of the present invention is made with reference to the accompanying drawings:
as shown in fig. 1, an example of the present invention includes the steps of:
step 1: in a time unit needing to be researched, each well is divided into single sand bodies of different periods, and the number of the single sand bodies in the time unit and the net thickness of the sandstone of the single sand body in each period are counted.
Step 2: and combining rich pressure measurement data of produced blocks of the oil field or the oil field in the similar deposition environment, and making a junction diagram of the thickness of the single sand body and the pressure measurement coefficient in each period aiming at the production well. The unused single sand body is the original pressure coefficient, and the used single sand body shows the pressure coefficient reduction and good connectivity. And determining the thickness threshold of the sandstone which is used and not used in the single sand body by combining the intersection map, wherein the single sand body which is higher than the threshold is regarded as the single sand body with strong connectivity, and the single sand body which is lower than the threshold is regarded as the single sand body without connectivity or with poor connectivity. And the threshold value is used as a calculation value of the sandstone communication thickness to measure the connectivity strength.
And step 3: and compiling a connected sandstone thickness ratio plane distribution diagram by combining the sedimentary facies diagram trend and the connected sandstone thickness ratio numerical value of each well point, and performing smooth interpolation and gridding on the plane distribution diagram.
And 4, step 4: according to the similar oil field deposition microfacies plan with similar area positions, similar deposition environments and detailed deposition microfacies understanding, the method carries out statistics on the communicated single sand layer thickness ratio of the three zones in the same time unit of the well according to a main river channel development zone, a river channel edge development zone, mat-shaped sand and a estuary dam development zone, determines the difference of the main river channel development zone and the river channel edge development zone on the communicated single sand layer thickness ratio through statistical analysis, and defines the threshold value of the communicated single sand layer thickness ratio of the main river channel development zone.
And 5: on the gridded communicated single sand layer thickness ratio plane graph, combining the threshold determined in the above steps, extracting a communicated single sand layer thickness ratio contour line near the threshold as an outer boundary line with good connectivity, wherein the area above the contour line is a main river channel development area with good connectivity; and (4) extracting the contour line of the domain values between the mat-shaped sand and the side edge of the river channel, wherein the outer edge of the contour line is the mat-shaped sand development area with poor connectivity.
The embodiment of the invention provides a quantitative depiction method for the development zone of the oil and gas reservoir advantage communication area under the conditions of large offshore well spacing, insufficient well control degree, multi-phase superposition of fan delta thin interbed and unclear description of an earthquake reservoir, and the quantitative depiction method has important guiding significance for the deployment of an injection-production well pattern.
The process of the invention is illustrated in the following by way of a more detailed example.
The method is characterized in that an oil field A is assumed to be a delta block oil reservoir and is in the early stage of development, basically only 1-2 exploratory wells are arranged in one block, the buried depth is deep, an effective reservoir prediction means is not provided for earthquake, the characteristics of each well are represented as thin interbed development, and a subphase level sedimentary facies plane distribution diagram is sketched by combining well points. The large sedimentary tendency and phase zone distribution of the sedimentary facies diagram are clear, but no clear method is available for evaluating connectivity, particularly determining how to determine a good-connectivity region and a poor-connectivity region boundary under the condition of no effective reservoir prediction means, and the method is not strong in guiding the injection and production well pattern and the reserve exploitation. In combination with the method of the present invention, the following studies were carried out:
for the target layer L to be studied3Oil group, a division of individual sand periods was developed for a total of 16 wells in the field in conjunction with well log interpretation. As shown in FIG. 2, taking A-3 well as an example, 12 periods of single sand bodies are divided on the well, the statistical thickness of the sandstone of the 12 periods of single sand bodies is shown in Table 1, and L is shown in Table 13I oil group each single sand body thickness distribution table.
TABLE 1
| Single sand body numbering | Thickness (m) |
| 1 | 5.7 |
| 2 | 4.7 |
| 3 | 1.7 |
| 4 | 1.1 |
| 5 | 1.6 |
| 6 | 1.2 |
| 7 | 0.8 |
| 8 | 1.3 |
| 9 | 1.7 |
| 10 | 1 |
| 11 | 2.2 |
| 12 | 1.7 |
As shown in table 1 and fig. 2, a total of 16 wells were each subjected to single sand compartmentalization and single sand thickness parameter statistics by example.
However, the researched oil field A is in the early development stage, dynamic and pressure measurement data are insufficient, the adjacent oil field B has similar deposition environment and is also a reservoir stratum deposited by a sector delta thin interbed layer, the well pattern is relatively complete, the dynamic data of pressure measurement and production are relatively rich, the connectivity is relatively clear, and the research on the connectivity of the reservoir stratum in the oil field A has relatively strong guiding significance. The analysis of the relation between the thickness of the single sand layer and the pressure measurement is carried out for the oil field B and is shown in figure 3, and the original pressure coefficient of the oil reservoir is 1.2. From the intersection graph of the thickness of each single sand layer and the pressure coefficient, the single sand layers with the thickness more than 3m basically show the conditions that the pressure coefficient is reduced and the reserve of the sand layers is used; only 1 single sand layer with the thickness less than 3m is used, and the rest are original pressure coefficients. Therefore, from regional experience, the thickness of a single sand layer of 3m can be used as a thickness threshold value for determining the connectivity strength, and the thickness of the single sand layer of more than 3m is defined as the thickness of the interconnected sandstone.
Combining the above experience, 16 wells L for the A field3The I oil group carries out statistics on the thickness of a single sand layer (the thickness of the connected sandstone) with the thickness of more than 3m and the proportion of the thickness of the connected sandstone in the accumulated sandstone thickness, and the Table 2 is a statistical table of the thickness of the connected sandstone in the A oil field.
TABLE 2
As can be seen from Table 2, the thickness ratio of the single sand layer of more than 3m determines the connectivity of the reservoir in the well region. And a connected sandstone thickness ratio plane distribution diagram is compiled by combining the sedimentary facies diagram trend, as shown in figure 4.
Similarly, analysis of the proportion relationship between the planar facies zone type and the thickness of the connected sand body of the well is carried out by combining the thin interbed oil field B of the sector delta in the same area with more sufficient well data, higher sedimentary facies research precision and similar sedimentary facies type (as shown in fig. 5, fig. 5 is a junction diagram of the thickness proportion diagram of the connected sand body of the oil field B and the sedimentary microfacies type). And determining a threshold value of the ratio of the communicated sand bodies in the main river channel area with good connectivity as a basis for defining a communication dominant area on the plane. The intersection graph shows that the thickness ratio of the communicated sand bodies in the main riverway development area on the oilfield deposition microphase plan B is basically over 40 percent, so that the dominant connecting band is determined when the thickness ratio index of the main force layer of the oilfield is over 40 percent; the thickness of the main force layer between the side edge of the river channel and the mat-shaped sand development zone is basically below 25%, so that the area less than 25% is a reservoir development zone with extremely poor connectivity.
By combining the threshold values, 40% and 25% of contour lines are extracted from the communicated sand body thickness ratio plane distribution diagram and are used as boundary lines of good and bad connectivity areas, a communication dominant area is defined, and meanwhile quantification bases of a main river channel development area, a river channel side edge development area and a mat-shaped sand development area of the deposition microphase plane distribution diagram are obtained, as shown in fig. 6 and 7.
The flow realizes the basis of further refining the connected advantageous area and the sedimentary microphase map through quantized threshold values under the conditions of complicated reservoir and insufficient seismic description precision. Therefore, in the earlier development scheme research of the offshore oil and gas field, the reserve utilization and the recovery ratio of difference are considered for areas with different connectivity, and a foundation is laid for the efficient development of the thin interbed of the offshore large-well-spacing fan delta.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
While embodiments of the invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.
While the preferred embodiments of the present invention have been illustrated and described, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (7)
1. The method for evaluating the static connectivity of the offshore great-well-spacing fan delta thin interbed reservoir is characterized by comprising the following steps of:
acquiring sub-layer pressure measurement data of a produced well, and determining a lower limit of communication thickness according to the sub-layer pressure measurement data;
respectively counting the thickness of each single sand body in different wells in a target time unit, judging the accumulated thickness greater than the lower limit of the communication thickness, and taking the accumulated thickness of each well greater than the lower limit of the communication thickness as the effective communication thickness;
taking the effective communication thickness as an indication parameter of the communication, and counting the proportion of the accumulated effective sandstone thickness in each well to the total sandstone thickness;
determining a plane distribution diagram of the effective sandstone thickness ratio by combining the sedimentary phase diagram trend;
according to historical information of the associated oil fields, the thickness ratios of the main riverway development zone and the communicating sandstone of the riverway edge and the matting sand development zone are counted, the target threshold values of the communicating thickness ratios of different development zones are determined, and the historical information comprises information of deposition microphase plane distribution;
combining the target threshold and the plane distribution map, and extracting a contour line at the target threshold;
wherein, the contour line is used for determining a preferred area with good connectivity;
the preferred area is used for guiding the classified utilization of reserves, the establishment of an injection-production well pattern, the difference analysis of injection-production well distances and the recovery ratio of different areas.
2. The method of evaluating the static connectivity of an offshore great-hole-spacing fan delta thin interbed reservoir of claim 1, further comprising:
and dividing single sand bodies of different periods for each well in the target time unit, and counting the number of the single sand bodies in the target time unit and the net thickness of the sandstone of the single sand body in each period.
3. The method of evaluating the static connectivity of an offshore great-hole-spacing fan delta thin interbed reservoir of claim 1, further comprising:
combining rich pressure measurement data of produced blocks of the oil field or the oil field in the similar deposition environment, and making a junction diagram of the thickness of the single sand body and the pressure measurement coefficient in each period aiming at the production well;
determining the thickness threshold of the sandstone used and not used in the single sand body by combining the intersection map;
using the single sand body with strong connectivity higher than the sandstone thickness threshold value and using the single sand body with non-connectivity or poor connectivity lower than the sandstone thickness threshold value;
taking the sandstone thickness threshold value as a calculation value of the sandstone communication thickness;
wherein the calculation value is used for characterizing the strength of the connectivity.
4. The method of evaluating the static connectivity of an offshore great-hole-spacing fan delta thin interbed reservoir of claim 1, further comprising:
and compiling a connected sandstone thickness ratio plane distribution diagram by combining the sedimentary facies trend and the connected sandstone thickness ratio numerical value of each well point, and performing smooth interpolation processing and gridding processing on the plane distribution diagram.
5. The method for evaluating the static connectivity of the offshore large-well-spacing fan delta thin interbed reservoir according to claim 1, wherein the method is characterized in that historical information of the associated oil fields is combined, the thickness ratios of the connected sandstones of a main channel development zone, the channel edge and a mat sand development zone are counted, the target threshold values of the connected thickness ratios of different development zones are determined, and the historical information comprises information of deposition microphase plane distribution, and comprises the following steps:
acquiring a similar oilfield sedimentary microfacies plan with similar area positions, similar sedimentary environments and detailed sedimentary microfacies understanding;
according to a main riverway development zone, a riverway edge development zone, mat-shaped sand and a estuary dam development zone, the thickness ratio of communicated single sand layers of wells of the three zones in the same time unit is counted;
and determining the difference of the main riverway development zone and the riverway edge development zone in the communicated single sand layer thickness ratio according to the statistical result, and defining the threshold of the communicated single sand layer thickness ratio of the main riverway development zone as the target threshold.
6. The method for evaluating the static connectivity of an offshore great well spacing fan delta thin interbed reservoir according to claim 1, wherein the extracting the contour line at the target threshold in combination with the target threshold and the floorplan comprises:
on a gridded plane distribution diagram of the thickness proportion of the communicated single sand layer, extracting a thickness proportion isoline of the communicated single sand layer near the target threshold as an outer boundary line with good connectivity according to the target threshold; the area above the contour line is confirmed to be a main riverway development area with good connectivity;
and extracting the contour line of the domain values between the mat-shaped sand and the side edge of the river channel, and determining the outer edge of the contour line as a mat-shaped sand development area with poor connectivity.
7. An apparatus, comprising:
the first module is used for acquiring the sub-layer pressure measurement data of the produced well and determining the lower limit of the communication thickness according to the sub-layer pressure measurement data;
the second module is used for respectively counting the thickness of each single sand body in different wells in a target time unit, judging the accumulated thickness greater than the lower limit of the communication thickness and taking the accumulated thickness of each well greater than the lower limit of the communication thickness as the effective communication thickness;
the third module is used for taking the effective communication thickness as an indication parameter of connectivity and counting the proportion of the accumulated effective sandstone thickness in each well to the total sandstone thickness;
the fourth module is used for determining a plane distribution diagram of the effective sandstone thickness ratio by combining the sedimentary phase diagram trend;
the fifth module is used for counting the thickness ratio of the main riverway development zone to the communicated sandstone of the riverway edge and the matting sand development zone by combining historical information of the associated oil field, and determining a target threshold value of the communicated thickness ratio of different development zones, wherein the historical information comprises information of deposition microphase plane distribution;
a sixth module for extracting a contour at the target threshold in combination with the target threshold and the histogram;
wherein, the contour line is used for determining a preferred area with good connectivity;
the preferred area is used for guiding the classified utilization of reserves, the establishment of an injection-production well pattern, the difference analysis of injection-production well distances and the recovery ratio of different areas.
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