KR101838249B1 - Method of estimating for size of shale barrier - Google Patents

Abstract

The present invention relates to a method to estimate the size of a shale barrier, comprising: (a) a step of extracting a production inflection point from a daily oil productivity graph in accordance with interposition of a shale layer; and (b) a step of estimating the size of a shale layer from the production inflection point. The step (a) and the step (b) are performed in a processor to monitor the daily oil productivity graph in accordance with the interposition of the shale layer, and the step (a) is performed by extracting four production inflection points of which the shape of a slope is rapidly changed in the daily oil productivity graph in accordance with the interposition of the shale layer. Accordingly, as the size of shale layer reducing productivity of oil produced from oil sand is able to be efficiently understood, production and injection wells are designed to be drilled apart from a position where the shale layer is formed in case new production and injection wells are drilled around previously drilled production and injection wells, thereby increasing oil productivity.

Description

TECHNICAL FIELD The present invention relates to a method for estimating the size of a shale-

The present invention relates to a method for estimating the size of a shale obstacle layer and more particularly to a method for estimating the size of a shale obstacle layer interposed in a reservoir to efficiently produce oil from an oil sand.

Oil sand is a porous sandstone containing crude oil, which has reserves in Alberta, central and western Canada, and is a source of oil sticky to sand.

These oil sands are buried under several tens of meters and are easy to digest. They have an injection well that discharges steam, steam that passes through the oil sludge, The oil is extracted through the production well.

However, as shown in Fig. 1 (a), the thickness B of the reservoir layer is about 20 m, and the sediment layer formed of mud or the like on the oil sand layer 1 has a shale layer 2 having a thickness of 2 m or less 1 (b) and FIG. 2, even if the injection well 100 and the production well 200 are positioned as shown in FIG. 1 (b) The amount of the steam discharged from the oil well 110 is clogged by the shale layer 2 to be passed through the oil sand. As a result, the oil in the liquid state flowing into the oil well 200 is produced when the shale layer 2 is not present. The amount of oil that flows into the combustion chamber is reduced.

Therefore, there is a need for a method of estimating the size of the coalescence of the shale layer 2 in order to increase the oil production amount by drilling the injection well and the production well at a position away from the shale layer 2 interposed in the oil sand.

Korean Patent Publication No. 2011-0096389

SUMMARY OF THE INVENTION The object of the present invention is to efficiently estimate the size of a shale layer that is sandwiched between buried strata and degrades oil production efficiency from an oil sand.

A method for estimating a size of a shale obstacle layer according to an embodiment of the present invention includes the steps of: (a) extracting a production inflection point from a daily oil production graph according to a shale layer association; And (b) estimating a width and a length of the shale layer from the production inflection point.

Wherein the steps (a) and (b) are performed by a processor for monitoring a daily oil production graph according to the shale layer association, wherein the step (a) And is performed by extracting four changing inflection points.

The processor calculates the first production inflection point (FPP), the first production inflation point (FPT), and the second production inflation point (FPT) according to the extracted order of the four production inflection points extracted from the daily oil production graph according to the shale- A third production peak (SPP), and a fourth production inflection point (LIP).

In the step (b), the processor calculates the width of the shale layer as the oil production amount decreases at the second production inflection point and the third production inflection point of the daily oil production graph according to the shale layer association and the RF (recovery factor) Is estimated to be large.

In the step (b), the processor reduces the oil production and RF at the first production inflection point and the second production inflection point of the daily oil production graph according to the shale layer association, and the oil production and RF at the third production inflection point The length of the shale layer is estimated to be longer.

After the size of the shale layer is estimated from the step (b), (c) checking the standard error through a simple linear regression analysis.

Wherein the step (a), the step (b), and the step (b) are performed in a processor for monitoring a daily oil production graph according to the shale layer association, and in the step (c) And the standard error of the estimated value of the size of the shale layer is calculated by considering the correlation coefficient as the coefficient of determination.

According to this characteristic, it is possible to efficiently grasp the size of the shale layer which lowers the oil production of the oil sand layer from the water level (already injected or produced) already drilled in the oil sand layer, When inserting the water level well, it is effective to increase the oil production amount by designing the injection sand and the production well to be drilled in the oil sand layer avoiding the shale layer whose size is grasped.

1 is a view showing an oil sand retention layer to which a shale layer is connected in order to explain a method for estimating the size of a shale obstacle layer according to an embodiment of the present invention.
FIG. 2 is a schematic view illustrating a method of producing oil from an oil sand retention layer using a conventional SAGD method to explain a method for estimating the size of a shale obstacle layer according to an embodiment of the present invention.
3 is a flowchart illustrating a method for estimating the size of a shale obstacle layer according to an embodiment of the present invention.
4 is a graph showing daily oil production according to a shale layer association used in a method for estimating the size of a shale obstacle layer according to an embodiment of the present invention.
FIG. 5 is a view showing a production inflection point extracted from a graph showing oil production amount in a method of estimating the size of a shale obstacle layer according to an embodiment of the present invention.
6 is a view illustrating a method for estimating the width of a shale layer from a graph showing the oil production amount in a method for estimating the size of a shale obstacle layer according to an embodiment of the present invention.
FIG. 7 is a view illustrating a method of estimating the length of a shale layer from a graph showing the oil production amount in a method for estimating the size of a shale obstacle layer according to an embodiment of the present invention.
FIG. 8 is a graph showing points predicted by the width of a shale layer in a method for estimating the size of a shale obstacle layer according to an embodiment of the present invention.
9 is a graph showing a value of a first index according to oil production in a method for estimating the size of a shale obstacle layer according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

A method for estimating the size of a shale obstacle layer according to an embodiment of the present invention will now be described with reference to the accompanying drawings.

As shown in FIG. 3, the method for estimating the size of the shale obstacle layer according to an embodiment of the present invention includes extracting a production inflection point from a daily oil production graph according to a shale layer association (S100) (S200), and checking a standard error through a simple linear regression analysis (S300).

First, referring to FIG. 4, a graph of oil production change according to the shale layer association used in the step S100 of extracting the production inflection point from the daily oil production graph according to the shale layer association will be described. (Y-axis, m3 / d) over time (x-axis, 3 months) as shown in Fig.

Among the graphs, the graph representing the daily oil production has a curve shape that is different from a typical SAGD (steam-assisted gravity drainage) production curve (hereinafter referred to as a 'standard SAGD curve').

In particular, unlike the standard SAGD production curve shown in FIG. 5 (a), the daily oil production amount graph shown in FIG. 5 (b) has a point at which the slopes suddenly change, that is, an inflection point.

Accordingly, when performing the first step S100 of FIG. 3 in the processor with reference to the graph of FIG. 4, a point where the slope suddenly changes in the daily oil production graph is extracted as the production inflection point.

In one example, the processor may be an apparatus for receiving and monitoring information of the graphs of FIG. 4 and for performing subsequent processing operations therefrom, and may preferably be formed in a computer, And output it.

And, in one example, the processor can refer to a standard SAGD graph, where the processor compares the daily oil yield graph to the standard SAGD graph to extract the production inflection point, where the standard SAGD graph is stored in non- It is good to be stored.

The production inflection point extracted from the daily oil production graph in the first step S100 is the first production peak, the first production trough, the second production peak SPP, And last inflection point (LIP).

Then, in order of extraction of each production inflection point, designate the first production inflection point as FPP, the second production inflection point as FPT, the third production inflection point as SPP, and the fourth production inflection point as LIP.

The first production inflection point, FPP, is formed when steam first meets the shale layer (2) and the permeation of the oil sand layer is interrupted. The second production inflection point, FPT, is when the steam bypasses the width of the shale layer .

The third production inflection point SPP is formed when the steam chamber for spraying steam is determined as a point where no image is received on the shale layer 2. The fourth production inflection point LIP is formed by the steam chamber .

Thus, after each production inflection point is designated as a specific point, the processor estimates the size of the shale layer using the production inflection point in the second step (S200).

The second step S200 will be described in more detail. In the case where the impervious layer, that is, the shale layer 2, in which the steam can not pass through the oil sand layer is formed, It is determined that the production inflection point appears, and the size of the shale layer 2 is estimated using the point of production inflection point.

6 (a), in the daily oil production graph, the RF in the FPT and the SPP in the green graph are larger than the recovery factor (RF) in the FPT in the red graph, RF in the FPT and SPP and RF in the SPP have a larger value than the RF in the FPT and the SPP.

That is, in the graph of FIG. 6A, the FPT and SPP in the red graph, the green graph, and the blue graph have increasingly large values. In the second step S200, Is estimated to have a larger size.

At this time, the processor estimates that the width of the shale layer 2 is larger as the oil production is smaller at the point where the FPT and the SPP are formed.

As an example with reference to the graph of FIG. 6 (a), oil production in FPT and SPP of the green graph is smaller than that of oil in FPT and SPP of the red graph, and oil production of FPT and SPP of the blue graph is more It has a small value. Accordingly, the processor estimates that the oil production amount in the FPT and the SPP has a small value, the shale layer 2 is wide.

The graph of FIG. 6 (a), which is referred to in explaining how the processor estimates the width of the shale layer 2 by comparing the RF and oil yields of the graph, assumes that the vertical position and length of the shale layer 2 are the same Lt; RTI ID = 0.0 > 2 < / RTI >

In a more detailed example, if the FPT and SPP are formed in the form of a red graph, a green graph, and a blue graph, respectively, the width of the shale layer 2 may be 30 m, 50 m, and 70 m, respectively.

In this case, the width WD and width of the shale layer 2 estimated by the processor in the second step S200 corresponds to the width of the shade layer 2 inserted into the lower portion of the shale layer 2 as shown in FIG. And is a length perpendicular to the longitudinal direction.

At this time, in the second step S200, the processor can estimate the length of the shale layer 2 from the daily oil production graph, which will be described in more detail with reference to FIG. 7, As oil production and RF in the FPP and FPT are gradually reduced in the red graph, the green graph and the blue graph in the daily oil production graph according to the length of the shale layer (2), and as the oil production and RF in the SPP increase, It is assumed that the length of the shale layer 2 is long.

In a more detailed example, in a red graph when the length of the shale layer 2 is 300 m, a green graph when the length of the shale layer 2 is 500 m, and a blue graph when the length of the shale layer 2 is 700 m, 2), the length of the shale layer 2 can be estimated from the FPP and the FPT because the longer the length of the shale layer 2 is disturbed, and the length of the shake layer 2 can be estimated from the production inflection point SPP The length of the shale layer 2 is estimated.

The graph of FIG. 7 (a), which is referred to by the processor to compare the RF and oil yields of the graph to estimate the length of the shale layer 2, Lt; / RTI > are graphs for different shale layers (2).

The length (LN, length) of the shale layer 2 estimated by the processor in the second step S200 corresponds to the length of the production and injection definition lengths inserted into the lower portion of the shale layer 2 as shown in FIG. Quot; refers to a length formed along a direction.

As described above with reference to FIGS. 6 to 7, in the second step S200, the processor estimates the size of the shale layer from the production inflection point to determine the width and length of the shale layer 2, It can be designed to drill the injection wells and the production wells away from the shale layer where the width and length are grasped when the injection well 100 and the production well 200 are to be newly drilled around the well and the injection well, Can be expected to increase.

Next, referring to FIG. 2, a step S300 of checking a standard error through a simple linear regression analysis, which is a third step performed by the processor, will be described. And performing a simple linear regression analysis on the numerical data of the shale layer 2, which is data, to confirm the standard error.

First, the processor creates a first indicator (LL) by dividing the length of the shale layer 2 into vertical positions, multiplies the width of the shale layer 2 by a vertical position, .

In this step S300, the processor first extracts a correlation coefficient (r) from the indexes included in the daily oil production graph as shown in the following Table 1 and confirms that the correlation coefficient converges to 1.

In one example, the processor can see from Table 1 that the correlation coefficient between the oil production at the second production inflection point (FPT) and the LL index is -9.00, converging to one.

At this time, the LL index is a value obtained by dividing the length of the shale layer by the vertical position.

And, in one example, the processor has a correlation coefficient of 0.916 between the recovery factor (RF) at the second production inflection point (FPT) and the WD (width) index, which is the index representing the width of the shale layer, The coefficient of correlation between the WL index, which is an index indicating the index, is 0.913, respectively.

At this time, the WL index is obtained by multiplying the width of the shale layer by the vertical position.

Thus, the processor considers correlation coefficients converging on Table 1 to 1 as decision coefficients, and calculates SEE (standard error estimate) and WD according to the vertical position (VL) as shown in Table 2 below.

In one example, the standard error of the estimates is calculated for various vertical positions (VL) as shown in Table 2 above, and has a standard error of 5 m on average. Thus, the processor can estimate the width of the shale layer from the linear regression equation that predicts the width of the shale layer to the standard error range of 5m on average.

In a more detailed example, when the vertical length (VL) of the shale layer to be estimated is 10 m, the predicted value of the width of the shale layer according to RF at the second production inflection point (FPT) And is calculated within a linear standard error range.

The relationship between the oil production at the second production inflection point (FPT) and the LL index is as shown in FIG. 9A. When the width (WD) of the shale layer is constant at 50 m, the vertical position (VL) The oil production at the second production inflection point (FPT) increases as the length between the shale layer and the injection well becomes longer, and as the length LN of the shale layer becomes longer, the oil at the second production inflection point (FPT) As the output increases, the LL indicator can be utilized.

Accordingly, as shown in FIG. 9 (b), the value of the LL index linearly decreases as the oil production amount at the second production inflection point (FPT) increases.

Thus, the processor calculates the correlation coefficient between the LL index and the oil production in the FPT using a linear regression equation that predicts the LL index as shown in Table 3 below, by deriving the graph of the linear form shown in FIG. 9 (b) R) is calculated, and the LL index value when the width WD calculated from Table 2 is known is predicted as shown in the following Table 3. < tb > < TABLE >

The processor predicts the LL index according to the width (WD) as shown in Table 3 above. In one example, if the vertical position of the shale layer is 10 m, the length of the shale layer is predicted to be 70 m.

At this time, the average value of the standard error (SEE) of the estimated value is 7.

In addition, the area (WL, wide-length) between the shale layer and the production well is calculated by a linear regression equation as shown in Table 4, and the correlation coefficient has an average value of 0.85.

Thus, in one example with reference to Table 4 above, the processor predicts the WL index, and if the vertical position of the shale layer is 10 m, the width of the shale layer is predicted to be within the error range of 11.3 m.

At this time, the average value of the standard error (SEE) of the estimated value is 113.

As described above, in step S300 of confirming the standard error through the simple linear regression analysis, the processor estimates the length and width of the shale layer by performing linear regression analysis as described with reference to FIG. 9 and Tables 1 to 4 , It is possible to efficiently design the production site and injection site for oil sand development.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It belongs to the scope of right.

1: Oil sand layer 2: Shale layer
100: Injection nozzle 110: Exhaust hole
200: Production

Claims (7)

(a) extracting three production inflection points from the daily oil production graph according to the shale layer association; And
(b) estimating that the width of the shale layer is greater as the oil production at the second production inflection point of the three production inflection points is reduced and the RF (recovery factor) is increased, and the oil at the first production inflection point and the second production inflection point Estimating a size of the shale layer by estimating that the length of the shale layer is long as the amount of production and RF decrease and the oil production amount and RF increase at a third production inflection point;
And estimating the size of the shale obstacle layer.

The method according to claim 1,
Wherein the steps (a) and (b) are performed in a processor for monitoring a daily oil production graph according to the shale layer association,
Wherein the step (a) is performed by extracting four production inflection points whose slope changes rapidly in the daily oil production graph according to the shale layer association.
3. The method of claim 2,
The processor calculates the first production inflection point (FPP), the first production inflation point (FPT), and the second production inflation point (FPT) according to the extracted order of the four production inflection points extracted from the daily oil production graph according to the shale- A third production peak (SPP), and a fourth production inflection point (LIP).
delete delete The method according to claim 1,
After the size of the shale layer is estimated from the step (b)
(c) confirming the standard error through simple linear regression analysis;
And estimating a size of the shale obstacle layer.
The method according to claim 6,
Wherein the steps (a) and (b) are performed in a processor that monitors a daily oil production graph according to the shale layer association, and in the step (c), the processor calculates a width of a shale layer (WL), a first indicator (LL) which is obtained by dividing the length of the shale layer by a vertical length (VL) of the shale layer, a second indicator (WL) which is obtained by multiplying the width of the shale layer and the vertical position of the shale layer -location), the daily oil production at the first production inflection point, the RF at the first production inflection point, the daily oil production at the second production inflection point, and the correlation coefficient between RF at the second production inflection point, And calculating a standard error of the estimated value of the size of the shale layer by considering the coefficient of determination as a coefficient of determination.

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