CN110644978A - Quantitative evaluation method for filling strength and dissipation degree of dense gas reservoir - Google Patents
Quantitative evaluation method for filling strength and dissipation degree of dense gas reservoir Download PDFInfo
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Abstract
The invention provides a quantitative evaluation method for filling strength and dissipation degree of a dense gas reservoir, which comprises the following specific steps: 1) establishing a relation curve of reservoir permeability and irreducible water saturation, and selecting a core sample in a permeability range according to a permeability distribution range of a tight gas reservoir; 2) collecting an electrical logging curve and an explanation result of the gas well in the research range, extracting the physical property of the target gas reservoir and the corresponding water saturation, and fitting a relation curve; 3) performing qualitative and quantitative analysis on filling degree; 4) analyzing the loss degree qualitatively and quantitatively; 5) and (4) overall evaluation of filling strength and dissipation degree of the gas reservoir formation. The invention does not need to collect a large amount of rock samples and perform experimental analysis, and only needs to analyze the well logging explanation of the existing well. The method has universality for the dense gas reservoir, can give quantitative evaluation results, and is beneficial to the comparative analysis among the gas reservoirs of the same type.
Description
Technical Field
The invention relates to the field of natural gas development, in particular to a method for simply and quickly realizing quantitative evaluation of filling degree and dissipation degree of a compact gas reservoir through logging parameters, which is suitable for compact gas reservoir formation condition evaluation and formation water cause analysis, and particularly relates to a quantitative evaluation method for filling strength and dissipation degree of the compact gas reservoir.
Background
The compact gas reservoir has poor physical properties, complex reservoir formation control factors and more water produced by a gas well in the gas reservoir development process. The method is one of important contents of gas reservoir evaluation for improving development effect and accurately evaluating filling strength and dissipation degree of the compact gas reservoir so as to provide basis for judging formation water cause. At present, evaluation on the filling strength and the dissipation degree of the reservoir depends on a large number of experiments and researches such as hydrocarbon source rock analysis, cover layer sealing evaluation, basin simulation and the like, and the method has the advantages of large workload, long period and high cost. In addition, a large amount of hydrocarbon source rock and reservoir samples need to be collected, and the samples which can be provided in most regions are limited and difficult to accurately evaluate. At present, no effective method capable of rapidly and quantitatively evaluating filling strength and dissipation degree of gas reservoir formation exists at home and abroad.
Disclosure of Invention
The invention provides a quantitative evaluation method for filling strength and dissipation degree of a compact gas reservoir, aiming at solving the problems of large workload, long period and high cost of a large number of experiments and mathematical calculations such as a large number of hydrocarbon source rock analyses, reservoir storage condition evaluation, basin simulation and the like in the original gas reservoir evaluation process. Based on the rule, the filling intensity and the storage condition of the compact gas reservoir can be judged through analyzing the relation between the existing physical property and the gas content of the gas reservoir. The invention does not need to collect a large amount of rock samples and perform experimental analysis, and only needs to analyze the well logging explanation of the existing well. The method has universality for the dense gas reservoir, can give quantitative evaluation results, and is beneficial to the comparative analysis among the gas reservoirs of the same type.
The technical scheme adopted by the invention is as follows:
a quantitative evaluation method for filling strength and dissipation degree of a dense gas reservoir comprises the following specific steps:
1) establishing a relation curve of reservoir permeability and irreducible water saturation, and selecting a core sample in a permeability range according to a permeability distribution range of a tight gas reservoir;
2) collecting an electrical logging curve and an explanation result of the gas well in the research range, extracting the physical property of the target gas reservoir and the corresponding water saturation, and fitting a relation curve;
3) performing qualitative and quantitative analysis on filling degree;
4) analyzing the loss degree qualitatively and quantitatively;
5) and (4) overall evaluation of filling strength and dissipation degree of the gas reservoir formation.
In the step 1), the sample is selected to meet the following conditions:
(1) sample penetrationThe ratio must cover 0.01 × 10-3μm2～1.0×10-3μm2；
(2) Permeability of 0.01X 10-3μm2～0.1×10-3μm2Samples of (4) with a permeability interval of less than 0.03X 10-3μm2Permeability of 0.1X 10-3μm2～1.0×10-3μm2Samples of (4) with a permeability interval of less than 0.2X 10-3μm2。
In the step 1), a natural gas filling method is adopted to establish a relation curve of permeability and irreducible water saturation, a relation formula of permeability and irreducible water saturation, and Swi (k) = ai*ln(K)+bi(ii) a Wherein k is permeability, aiAnd biIs a constant.
In the step 2), collecting an electrical logging curve and an interpretation result of the gas well in the research range, extracting the physical property of the target gas reservoir and the corresponding water saturation, and fitting a relation curve, wherein the concrete steps are as follows:
(1) and on the basis of the existing logging interpretation data, selecting and recording the water saturation corresponding to the sandstone section by combining the logging physical property interpretation result.
(2) The requirement must include a non-reservoir section sandstone interpretation permeability and water saturation less than or below the permeability lower limit; i.e. permeability of 0.01X 10-3μm2～0.1×10-3μm2The water saturation corresponding to the sandstone;
(3) establishing a relation curve of the well permeability and the water saturation; the relationship between the well permeability and the water saturation, Swo(k)=ao*ln(k)+bo(ii) a Wherein k is permeability, aoAnd boIs a constant;
(4) and (4) repeating the steps (1) to (3) to establish the relation curves and the relation formulas of the permeability and the water saturation of all the drilled wells.
The filling degree qualitative and quantitative analysis in the step 3) comprises the following specific steps:
(1) well completion permeability-water saturation scatter point is placed in compact gas reservoir formation filling strengthIn the qualitative judgment plate of the loss degree, if the permeability is 0.01 multiplied by 10-3μm2～0.1×10-3μm2In the interval range, if the dispersion point is positioned below the saturation curve of the bound water, the filling strength of the well is high, and if the dispersion point is positioned above the saturation curve of the bound water, the filling strength is insufficient;
(2) filling intensity index k =0.01 × 10-3μm2Time Swi(k)-Swo(k) Is greater than 0, indicating a high degree of filling, and is less than 0, indicating a low degree of filling. The larger the filling intensity index is, the higher the stocking filling degree is;
(3) and calculating the filling intensity index from well to well, completing the drawing of a filling intensity index plane equivalent graph, wherein the filling degree of the high-value area is high, and the high-value area is a favorable accumulation area.
In the step 4), the loss degree is qualitatively and quantitatively analyzed, and the method specifically comprises the following steps:
(1) if the well permeability-water saturation relation curve is nearly parallel or the slope is smaller than the permeability-irreducible water saturation curve, the gas reservoir or the area where the well is located can be judged to be not lost; if the slope of the relation curve of permeability-water saturation is larger than the permeability-irreducible water saturation curve, the loss of the gas reservoir or the area where the well is located can be judged;
(2) defining a difference a between the slope of a permeability-water saturation relationship curve and the slope of a permeability-irreducible water saturation relationship curvei-aoIs a loss index; if the scattering index is negative, scattering does not occur, if the scattering index is normal, scattering exists, and the scattering is more serious if the scattering index value is larger;
(3) and calculating the loss index well by well, completing the drawing of a loss index plane equivalent diagram, wherein the negative value area has good storage condition, the positive value area has loss of natural gas, and the negative value area is a favorable accumulation area.
And 5) integrally evaluating filling strength and dissipation degree of the gas reservoir formation, which comprises the following specific steps:
(1) putting the quantitative evaluation result data of the gas reservoir filling strength and the scattering index into an integral evaluation chart of the gas reservoir filling strength and the scattering degree, and then carrying out integral evaluation on the gas reservoir filling strength and the scattering degree; the area A shows that the gas reservoir filling intensity is high, and the storage condition is good; the area B shows that the gas reservoir filling intensity is high, and the storage condition is poor; the area C shows that the gas reservoir filling intensity is insufficient, and the storage condition is poor; the area D shows that the gas reservoir filling intensity is insufficient, and the storage condition is met;
(2) and overlapping the region with positive filling intensity index plane equivalence map and the region with negative dissipation index plane equivalence map curve, wherein the overlapping region of the two regions is a favorable natural gas accumulation region.
The invention has the beneficial effects that:
the invention provides an economic, effective, simple and quick evaluation method aiming at the analysis of the compact gas reservoir formation condition. The defects of large workload, long period, high cost and the like of a large amount of experiments and mathematical calculations such as analysis of a large amount of hydrocarbon source rocks, evaluation of reservoir storage conditions, basin simulation and the like in the original gas reservoir evaluation process are overcome. The method is applied to the evaluation project of the gas reservoir of the Surieger tight sandstone in the Ordos basin, so that the analysis and test costs are saved by 551.3 ten thousand yuan, the project research period is shortened by 150 days, and the gas reservoir research efficiency and reliability are improved.
The following will be further described with reference to the accompanying drawings.
Drawings
FIG. 1 is a diagram of qualitative judgment of filling strength and dissipation degree of dense gas reservoir.
FIG. 2 is a chart of the overall evaluation of occlusion filling strength and extent of effusivity.
Detailed Description
Example 1:
the invention provides a quantitative evaluation method for filling strength and dissipation degree of a compact gas reservoir, aiming at solving the problems of large workload, long period and high cost of a large number of experiments and mathematical calculations such as a large number of hydrocarbon source rock analyses, reservoir storage condition evaluation, basin simulation and the like in the original gas reservoir evaluation process. Based on the rule, the filling intensity and the storage condition of the compact gas reservoir can be judged through analyzing the relation between the existing physical property and the gas content of the gas reservoir. The invention does not need to collect a large amount of rock samples and perform experimental analysis, and only needs to analyze the well logging explanation of the existing well. The method has universality for the dense gas reservoir, can give quantitative evaluation results, and is beneficial to the comparative analysis among the gas reservoirs of the same type. A quantitative evaluation method for filling strength and dissipation degree of a dense gas reservoir comprises the following specific steps:
1) establishing a relation curve of reservoir permeability and irreducible water saturation, and selecting a core sample in a permeability range according to a permeability distribution range of a tight gas reservoir;
2) collecting an electrical logging curve and an explanation result of the gas well in the research range, extracting the physical property of the target gas reservoir and the corresponding water saturation, and fitting a relation curve;
3) performing qualitative and quantitative analysis on filling degree;
4) analyzing the loss degree qualitatively and quantitatively;
5) and (4) overall evaluation of filling strength and dissipation degree of the gas reservoir formation.
The process shows that the method mainly comprises three steps of firstly establishing a permeability-irreducible water saturation chart, mainly selecting different reservoir characteristic rock cores to perform physical property analysis, preferably selecting different permeability rock cores, establishing irreducible water saturation in a gas water driving mode, and establishing the permeability-irreducible water saturation chart according to an experimental result. And secondly, collecting a logging data band and explaining, extracting data according to the change characteristics of the permeability of the reservoir, and establishing a relation curve between the permeability and the water saturation. On the basis of the two steps, the filling degree and the dissipation degree are qualitatively evaluated through a permeability and water saturation chart, and can also be quantitatively evaluated through a related mathematical formula. And finally, according to the quantitative evaluation result, the overall evaluation of the gas reservoir filling degree and the dissipation degree can be completed through an overall evaluation chart of the filling strength and the dissipation degree.
Example 2:
based on the example 1, in this example, preferably, in the step 1), the sample is selected to satisfy the following condition:
(1) the sample permeability must cover 0.01X 10-3μm2～1.0×10-3μm2；
(2) Permeability of 0.01X 10-3μm2～0.1×10-3μm2Samples of (4) with a permeability interval of less than 0.03X 10-3μm2Permeability of 0.1X 10-3μm2～1.0×10-3μm2Samples of (4) with a permeability interval of less than 0.2X 10-3μm2。
Preferably, the natural gas filling method is adopted in the step 1), a relation curve of permeability and irreducible water saturation is established, and a relation formula of permeability and irreducible water saturation is established, wherein Swi (k) = ai*ln(K)+bi(ii) a Wherein k is permeability, aiAnd biIs a constant. In a certain area, ao、boIs a constant, which is different for each field during the application process, aiAnd biThe value of (c) depends on the different gas fields.
Preferably, in the step 2), an electrical logging curve and an interpretation result of the gas well in the research range are collected, the physical property of the target gas reservoir and the corresponding water saturation are extracted, and a relation curve is fitted, wherein the specific steps are as follows:
(1) and on the basis of the existing logging interpretation data, selecting and recording the water saturation corresponding to the sandstone section by combining the logging physical property interpretation result.
(2) The requirement must include a non-reservoir section sandstone interpretation permeability and water saturation less than or below the permeability lower limit; i.e. permeability of 0.01X 10-3μm2～0.1×10-3μm2The water saturation corresponding to the sandstone;
(3) establishing a relation curve of the well permeability and the water saturation; the relationship between the well permeability and the water saturation, Swo(k)=ao*ln(k)+bo(ii) a Wherein k is permeability, aoAnd boIs a constant; in the application process, each gas field is tested, the constants are different, aoAnd boThe value of (c) depends on the different gas fields.
(4) And (4) repeating the steps (1) to (3) to establish the relation curves and the relation formulas of the permeability and the water saturation of all the drilled wells.
Preferably, the filling degree qualitative and quantitative analysis in the step 3) comprises the following specific steps:
(1) placing the well completion permeability-water saturation scattering point in a qualitative judgment plate of the filling strength and scattering degree of the compact gas reservoir, if the permeability is 0.01 multiplied by 10-3μm2～0.1×10-3μm2In the interval range, if the dispersion point is positioned below the saturation curve of the bound water, the filling strength of the well is high, and if the dispersion point is positioned above the saturation curve of the bound water, the filling strength is insufficient;
(2) filling intensity index k =0.01 × 10-3μm2Time Swi(k)-Swo(k) Is greater than 0, indicating a high degree of filling, and is less than 0, indicating a low degree of filling. The larger the filling intensity index is, the higher the stocking filling degree is;
(3) and calculating the filling intensity index from well to well, completing the drawing of a filling intensity index plane equivalent graph, wherein the filling degree of the high-value area is high, and the high-value area is a favorable accumulation area.
Preferably, in the step 4), the loss degree is qualitatively and quantitatively analyzed, and the method specifically comprises the following steps:
(1) if the well permeability-water saturation relation curve is nearly parallel or the slope is smaller than the permeability-irreducible water saturation curve, the gas reservoir or the area where the well is located can be judged to be not lost; if the slope of the relation curve of permeability-water saturation is larger than the permeability-irreducible water saturation curve, the loss of the gas reservoir or the area where the well is located can be judged;
(2) defining a difference a between the slope of a permeability-water saturation relationship curve and the slope of a permeability-irreducible water saturation relationship curvei-aoIs a loss index; if the loss index is negative, the loss index is not lostThe scattering is normal, and the scattering is more serious when the scattering index value is larger;
(3) and calculating the loss index well by well, completing the drawing of a loss index plane equivalent diagram, wherein the negative value area has good storage condition, the positive value area has loss of natural gas, and the negative value area is a favorable accumulation area.
Preferably, in the step 5), the overall evaluation of the filling strength and the dissipation degree of the gas reservoir formation is carried out by the following specific steps:
(1) putting the quantitative evaluation result data of the gas reservoir filling strength and the scattering index into an integral evaluation chart of the gas reservoir filling strength and the scattering degree, and then carrying out integral evaluation on the gas reservoir filling strength and the scattering degree; the area A shows that the gas reservoir filling intensity is high, and the storage condition is good; the area B shows that the gas reservoir filling intensity is high, and the storage condition is poor; the area C shows that the gas reservoir filling intensity is insufficient, and the storage condition is poor; the area D shows that the gas reservoir filling intensity is insufficient, and the storage condition is met;
(2) and overlapping the region with positive filling intensity index plane equivalence map and the region with negative dissipation index plane equivalence map curve, wherein the overlapping region of the two regions is a favorable natural gas accumulation region.
As shown in FIG. 1, FIG. 1 is a qualitative identification chart of filling intensity and dissipation degree of dense gas reservoir, which is 0.01 × 10-3μm2～0.1×10-3μm2And the permeability interval is a filling strength rapid identification area, if the water saturation of the storage layer in the permeability section is below the irreducible water gas saturation line, the filling degree is high, and if the water saturation is above the irreducible water saturation line, the gas reservoir filling strength is insufficient. If the fitted permeability saturation curve is substantially parallel to the irreducible water saturation curve, it is indicated that the storage condition is good, and if the slope of the fitted permeability saturation curve is greater than the irreducible water saturation curve, it is indicated that scattering exists, and the scattering is more serious if the slope is greater.
As shown in fig. 2, fig. 2 is an overall evaluation chart of the reservoir filling strength and the depletion degree, which is an overall evaluation chart of the dense gas reservoir filling strength and the depletion degree, and if the calculated gas reservoir filling index and the depletion index are located in the region a, the gas reservoir filling strength is high, and the storage condition is good; if the gas reservoir data point falls in the B area, the gas reservoir filling strength is high, and the storage condition is poor; if the gas reservoir data point falls in the C area, the gas reservoir filling strength is insufficient, and the storage condition is poor; if the gas reservoir data point falls in the D area, the gas reservoir filling strength is insufficient, and the storage condition is good.
The invention provides an economic, effective, simple and quick evaluation method aiming at the analysis of the compact gas reservoir formation condition. The defects of large workload, long period, high cost and the like of a large amount of experiments and mathematical calculations such as analysis of a large amount of hydrocarbon source rocks, evaluation of reservoir storage conditions, basin simulation and the like in the original gas reservoir evaluation process are overcome. The method is applied to the evaluation project of the gas reservoir of the Surieger tight sandstone in the Ordos basin, so that the analysis and test costs are saved by 551.3 ten thousand yuan, the project research period is shortened by 150 days, and the gas reservoir research efficiency and reliability are improved.
Example 3:
based on embodiments 1 and 2, the present embodiment provides a method for quantitatively evaluating filling strength and dissipation degree of a dense gas reservoir, which includes the following specific steps:
1) and establishing a relation curve of the reservoir permeability and the irreducible water saturation.
Selecting a core sample within the permeability range according to the permeability distribution range of the compact gas reservoir, wherein the sample selection meets the following conditions:
(1) the sample permeability must cover 0.01X 10-3μm2～1.0×10-3μm2。
(2) Permeability of 0.01X 10-3μm2～0.1×10-3μm2Samples of (4) with a permeability interval of less than 0.03X 10-3μm2Permeability of 0.1X 10-3μm2～1.0×10-3μm2Samples of (4) with a permeability interval of less than 0.2X 10-3μm2。
(3) And establishing a relation curve of permeability and irreducible water saturation by adopting a natural gas filling method. The natural gas filling method is prior art, and will not be further described in the present invention.
(4) Establishing a relation between permeability and irreducible water saturation, Swi (k) = ai*ln(K)+bi。
2) Collecting an electrical logging curve and an explanation result of a gas well in a research range, extracting physical properties of a target gas reservoir and corresponding water saturation, and fitting a relation curve, wherein the concrete steps are as follows:
(1) and on the basis of the existing logging interpretation data, selecting and recording the water saturation corresponding to the sandstone section by combining the logging physical property interpretation result.
(2) The requirement must include a non-reservoir segment sandstone interpretation permeability and water saturation less than or below the lower permeability limit. I.e. permeability of 0.01X 10-3μm2～0.1×10-3μm2The sandstone rock of (a).
(3) And establishing a relation curve of the well permeability and the water saturation.
(4) Establishing a relationship, Sw, between the well permeability and the water saturationo(k)=ao*ln(k)+bo。
(5) And (4) repeating the steps (1) to (4) to establish the relation curves and the relation formulas of the permeability and the water saturation of all the drilled wells.
3) Qualitative and quantitative analysis of filling level
(1) The permeability-water saturation scatter of the well completion is placed in the plate shown in figure 1 if the permeability is 0.01 x 10-3μm2～0.1×10-3μm2In the interval range, if the dispersion point is positioned below the saturation curve of the bound water, the filling strength of the well is high, and if the dispersion point is positioned above the saturation curve of the bound water, the filling strength is insufficient.
(2) Filling intensity index k =0.01 × 10-3μm2Time Swi(k)-Swo(k) Is greater than 0, indicating a high degree of filling, and is less than 0, indicating a low degree of filling. The greater the filling strength index, the greater the degree of occlusal filling.
(3) And calculating the filling intensity index from well to well, completing the drawing of a filling intensity index plane equivalent graph, wherein the filling degree of the high-value area is high, and the high-value area is a favorable accumulation area.
4) Qualitative and quantitative analysis of loss degree
(1) If the well permeability-water saturation relation curve is nearly parallel or the slope is smaller than the permeability-irreducible water saturation curve, the gas reservoir or the area where the well is located can be judged to be not lost; if the slope of the well permeability-water saturation relationship curve is greater than the permeability-irreducible water saturation curve, then it can be determined that there is loss in the gas reservoir or the area where the well is located.
(2) Defining a difference a between the slope of a permeability-water saturation relationship curve and the slope of a permeability-irreducible water saturation relationship curvei-aoIs an index of loss. If the scattering index is negative, scattering does not occur, if the scattering index is normal, scattering exists, and the scattering is more serious if the scattering index value is larger.
(3) And calculating the loss index well by well, completing the drawing of a loss index plane equivalent diagram, wherein the negative value area has good storage condition, the positive value area has loss of natural gas, and the negative value area is a favorable accumulation area.
5) Overall evaluation of filling strength and dissipation degree of gas reservoir formation
(1) And putting the quantitative evaluation result data of the gas reservoir filling strength and the gas reservoir loss index into a chart as shown in the attached figure 2, so that the gas reservoir filling strength and the gas reservoir loss degree can be integrally evaluated. The area A shows that the gas reservoir filling intensity is high, and the storage condition is good; the area B shows that the gas reservoir filling intensity is high, and the storage condition is poor; the area C shows that the gas reservoir filling intensity is insufficient, and the storage condition is poor; and the area D shows that the gas reservoir filling strength is insufficient and the storage condition is good.
(2) And overlapping the region with positive filling intensity index plane equivalence map and the region with negative dissipation index plane equivalence map curve, wherein the overlapping region of the two regions is a favorable natural gas accumulation region.
For example, the sux block box 8 tight sandstone reservoir:
firstly, selecting a typical rock sample to complete physical property analysis.
Secondly, selecting the materials of.01 multiplied by 10 according to the physical property test results-3μm2-0.1×10-3μm2Sample 5, 0.1X 10-3μm2-1.0×10-3μm2Sample 5, 1.0X 10-3μm2-10.0×10-3μm2And 2 samples are subjected to a gas drive water bound water saturation experiment, and a relation curve of permeability and bound water saturation is established.
Collecting 25 well logging interpretation data uniformly distributed in the research area, and extracting the permeability of 0.01 multiplied by 10 from the well logging interpretation data-3μm2-0.1×10-3μm2And 0.1X 10-3μm2-1.0×10-3μm2And (4) the water saturation corresponding to the data points and a fitting formula.
Fourthly, the extracted data is arranged in the plate shown in the attached figure 1, and the well permeability is 0.01 multiplied by 10-3μm2-0.1×10-3μm2The data points within the range are all below the irreducible water saturation line, indicating that the area is highly filled.
And fifthly, the slope of the curve fitted according to the data points is greater than the slope of the saturation line of the irreducible water, and therefore loss of the area is indicated.
Sixthly, calculating the filling intensity index and the loss index of the selected 25 wells one by one, placing the calculated filling intensity index and loss index into the chart shown in the attached figure 2, and locating the calculated filling intensity index and loss index in the area B to show that the gas reservoir forming and filling intensity of the block box 8 is high, but the storage condition is poor, and obvious natural gas leakage exists.
The above examples are merely illustrative of the present invention and should not be construed as limiting the scope of the invention, which is intended to be covered by the claims and any design similar or equivalent to the scope of the invention. The process steps described in detail in the present invention are prior art and will not be further described in the present invention.
Claims (7)
1. A quantitative evaluation method for filling strength and loss degree of a dense gas reservoir is characterized by comprising the following steps: the method comprises the following specific steps:
1) establishing a relation curve of reservoir permeability and irreducible water saturation, and selecting a core sample in a permeability range according to a permeability distribution range of a tight gas reservoir;
2) collecting an electrical logging curve and an explanation result of the gas well in the research range, extracting the physical property of the target gas reservoir and the corresponding water saturation, and fitting a relation curve;
3) performing qualitative and quantitative analysis on filling degree;
4) analyzing the loss degree qualitatively and quantitatively;
5) and (4) overall evaluation of filling strength and dissipation degree of the gas reservoir formation.
2. The method for quantitatively evaluating the filling strength and the dissipation degree of the dense gas reservoir as claimed in claim 1, wherein: in the step 1), the sample is selected to meet the following conditions:
(1) the sample permeability must cover 0.01X 10-3μm2～1.0×10-3μm2；
(2) Permeability of 0.01X 10-3μm2～0.1×10-3μm2Samples of (4) with a permeability interval of less than 0.03X 10-3μm2Permeability of 0.1X 10-3μm2～1.0×10-3μm2Samples of (4) with a permeability interval of less than 0.2X 10-3μm2。
3. The method for quantitatively evaluating the filling strength and the dissipation degree of the dense gas reservoir as claimed in claim 1, wherein: in the step 1), a natural gas filling method is adopted to establish a relation curve of permeability and irreducible water saturation, a relation formula of permeability and irreducible water saturation, and Swi (k) = ai*ln(K)+bi(ii) a Wherein k is permeability, aiAnd biIs a constant.
4. The method for quantitatively evaluating the filling strength and the dissipation degree of the dense gas reservoir as claimed in claim 1, wherein: in the step 2), collecting an electrical logging curve and an interpretation result of the gas well in the research range, extracting the physical property of the target gas reservoir and the corresponding water saturation, and fitting a relation curve, wherein the concrete steps are as follows:
(1) on the basis of the existing logging interpretation data, the logging physical property interpretation result is combined, and the water saturation corresponding to the sandstone section is selected and recorded;
(2) the requirement must include a non-reservoir section sandstone interpretation permeability and water saturation less than or below the permeability lower limit; i.e. permeability of 0.01X 10-3μm2～0.1×10-3μm2The water saturation corresponding to the sandstone;
(3) establishing a relation curve of the well permeability and the water saturation; the relationship between the well permeability and the water saturation, Swo(k)=ao*ln(k)+bo(ii) a Wherein k is permeability, aoAnd boIs a constant;
(4) and (4) repeating the steps (1) to (3) to establish the relation curves and the relation formulas of the permeability and the water saturation of all the drilled wells.
5. The method for quantitatively evaluating the filling strength and the dissipation degree of the dense gas reservoir as claimed in claim 1, wherein: the filling degree qualitative and quantitative analysis in the step 3) comprises the following specific steps:
(1) placing the well completion permeability-water saturation scattering point in a qualitative judgment plate of the filling strength and scattering degree of the compact gas reservoir, if the permeability is 0.01 multiplied by 10-3μm2～0.1×10-3μm2In the interval range, if the dispersion point is positioned below the saturation curve of the bound water, the filling strength of the well is high, and if the dispersion point is positioned above the saturation curve of the bound water, the filling strength is insufficient;
(2) filling intensity index k =0.01 × 10-3μm2Time Swi(k)-Swo(k) The filling strength index is larger than 0 in unit percent, which indicates that the filling degree is high, and the filling strength index is smaller than 0, which indicates that the filling degree is low; the larger the filling intensity index is, the higher the stocking filling degree is;
(3) and calculating the filling intensity index from well to well, completing the drawing of a filling intensity index plane equivalent graph, wherein the filling degree of the high-value area is high, and the high-value area is a favorable accumulation area.
6. The method for quantitatively evaluating the filling strength and the dissipation degree of the dense gas reservoir as claimed in claim 1, wherein: in the step 4), the loss degree is qualitatively and quantitatively analyzed, and the method specifically comprises the following steps:
(1) if the well permeability-water saturation relation curve is nearly parallel or the slope is smaller than the permeability-irreducible water saturation curve, the gas reservoir or the area where the well is located can be judged to be not lost; if the slope of the relation curve of permeability-water saturation is larger than the permeability-irreducible water saturation curve, the loss of the gas reservoir or the area where the well is located can be judged;
(2) defining a difference a between the slope of a permeability-water saturation relationship curve and the slope of a permeability-irreducible water saturation relationship curvei-aoIs a loss index; if the scattering index is negative, scattering does not occur, if the scattering index is normal, scattering exists, and the scattering is more serious if the scattering index value is larger;
(3) and calculating the loss index well by well, completing the drawing of a loss index plane equivalent diagram, wherein the negative value area has good storage condition, the positive value area has loss of natural gas, and the negative value area is a favorable accumulation area.
7. The method for quantitatively evaluating the filling strength and the dissipation degree of the dense gas reservoir as claimed in claim 1, wherein: and 5) integrally evaluating filling strength and dissipation degree of the gas reservoir formation, which comprises the following specific steps:
(1) putting the quantitative evaluation result data of the gas reservoir filling strength and the scattering index into an integral evaluation chart of the gas reservoir filling strength and the scattering degree, and then carrying out integral evaluation on the gas reservoir filling strength and the scattering degree; the area A shows that the gas reservoir filling intensity is high, and the storage condition is good; the area B shows that the gas reservoir filling intensity is high, and the storage condition is poor; the area C shows that the gas reservoir filling intensity is insufficient, and the storage condition is poor; the area D shows that the gas reservoir filling intensity is insufficient, and the storage condition is met;
(2) and overlapping the region with positive filling intensity index plane equivalence map and the region with negative dissipation index plane equivalence map curve, wherein the overlapping region of the two regions is a favorable natural gas accumulation region.
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