Drilling shut-in boundary chart and method for predicting drilling shut-in boundaries

Abstract

The present application relates to the field of petrochemical engineering, and particularly to a chart for predicting the shut-in limits in well shut-in during drilling and a method for predicting the shut-in limits in well shut-in during drilling. The chart for predicting the shut-in limits is generally circular in shape and includes a shut-in distance limit zone, a shut-in pressure limit zone, and a shut-in time limit zone that are concentrically arranged. The shut-in pressure limit zone is disposed between the shut-in distance limit zone and the shut-in time limit zone. The shut-in distance limit zone includes a plurality of distance regions divided by a first parameter; the shut-in pressure limit zone includes a plurality of pressure regions divided by a second parameter; the shut-in time limit zone includes a plurality of time regions divided by a third parameter; each of the plurality of distance regions corresponds to a first predetermined number of pressure regions, and each of the plurality of pressure regions corresponds to a second predetermined number of time regions. Through the chart for predicting the shut-in limits and the method of the present application, the shut-in distance limit, the shut-in pressure limit, and the shut-in time limit can be directly and conveniently read.

Description

Technical Field

[0001] The present application relates to the field of petrochemical engineering, and particularly to a drill - shut - in boundary chart for predicting drill - shut - in boundaries and a method for using the same. Background Art

[0002] Currently, the drill - shut - in boundary standard in use in oilfields stipulates that injection wells within 300 meters of the adjustment well to be drilled must release overflow to reduce the wellhead pressure to 0 MPa, and the shut - in recovery pressure cannot exceed 2 MPa; injection wells within 300 - 600 meters of the adjustment well to be drilled must stop injection, and the shut - in wellhead pressure after stopping injection cannot exceed 3 MPa. Otherwise, overflow must also be released until after the acoustic amplitude of the relevant adjustment well is measured before resuming injection.

[0003] When this drill - shut - in boundary standard was formulated, it mainly targeted medium - high permeability reservoirs (such as medium - high permeability reservoirs in the Daqing Placanticline). Currently, when drilling in low - permeability reservoirs (such as drilling in low - permeability reservoirs in the outer area of the Daqing Oilfield), this drill - shut - in boundary standard is still used, and there are mainly the following problems, which affect the oilfield development effect and the drilling and construction speed:

[0004] First, the drill - shut - in pressure reduction time is long. Due to the poor physical properties of the reservoir, the process of pressure reduction during drill - shut - in of injection wells lasts for a long time, generally lasting for several months or even several years.

[0005] Second, the pressure recovery speed after drill - shut - in is slow. Due to the poor physical properties of the reservoir and slow energy transfer, after a long - time drill - shut - in, the energy loss of the reservoir is large, seriously affecting the oilfield development effect.

[0006] Third, the difficulty of liquid handling is large. In order to shorten the drill - shut - in time, overflow is released from injection wells, resulting in great pressure on environmental protection and sewage treatment, and an increased risk of casing damage.

[0007] Fourth, the pressure on safety and environmental protection is large. The pressure - relief methods mainly include methods such as water hauling by tanker trucks, on - site tanks, and connecting return oil pipelines. With a large number of wells and a large amount of water, the bearing capacity of the station system increases, bringing potential safety and environmental protection hazards. Summary of the Invention

[0008] In view of the problems such as single reference factors for existing drill - shut - in boundaries and poor adaptability to low - permeability reservoirs, the inventors of the present application comprehensively considered geological and development factors such as different types of well patterns and well spacings, different reservoir permeabilities, and different pre - shut - in pressures, studied new drill - shut - in boundaries, and formed a drill - shut - in boundary chart.

[0009] According to a first aspect of the present application, there is provided a drilling shut-in limit chart for predicting the drilling shut-in limit. The drilling shut-in limit chart is integrally circular and includes: a drilling shut-in distance limit area, a drilling shut-in pressure limit area, and a drilling shut-in time limit area that are concentrically arranged. The drilling shut-in pressure limit area is arranged between the drilling shut-in distance limit area and the drilling shut-in time limit area, wherein: the drilling shut-in distance limit area includes a plurality of distance areas divided by a first parameter; the drilling shut-in pressure limit area includes a plurality of pressure areas divided by a second parameter; the drilling shut-in time limit area includes a plurality of time areas divided by a third parameter; each of the plurality of distance areas corresponds to a first predetermined number of the pressure areas, and each of the plurality of pressure areas corresponds to a second predetermined number of the time areas.

[0010] In an embodiment of the present application, the first parameter is the injection-production well spacing, the second parameter is the reservoir permeability, and the third parameter is the time based on the pressure before shut-in.

[0011] In an embodiment of the present application, each of the distance areas includes a distance limit determined at least based on its respective injection-production well spacing, each of the pressure areas includes a pressure limit determined at least based on its respective reservoir permeability, and each of the time areas includes a time limit determined based on the pressure limit and the pressure before shut-in.

[0012] In an embodiment of the present application, the distance limit is determined at least based on the formation pressure coefficient prediction chart at different injection-production well spacings generated by the following plane radial flow formula and the pressure coefficient distribution chart under stable seepage at different injection-production well spacings:

[0013]

[0014] where P 1 is the pressure at any point in the formation, P e is the pressure at the supply boundary, P w is the bottom-hole flowing pressure of the production well, R e is the supply radius, R w is the wellbore radius, R 1 is the distance between the well to be drilled and the oil well in the basic well pattern.

[0015] In an embodiment of the present application, the drilling shut-in distance limit area includes a first distance area, a second distance area, a third distance area, a fourth distance area, a fifth distance area, and a sixth distance area divided by the injection-production well spacing, and the injection-production well spacing of each of the distance areas corresponds to its respective distance limit.

[0016] In the embodiments of the present application, the drilling shut-in pressure boundary zone includes a first pressure zone, a second pressure zone, …, and an eighteenth pressure zone divided by the reservoir permeability, and the reservoir permeability of each of the pressure zones corresponds to its respective pressure boundary.

[0017] In the embodiments of the present application, the drilling shut-in time boundary zone includes a first time zone, a second time zone, …, and a fifty-fourth time zone divided by the time based on the pre-shut-in pressure.

[0018] In the embodiments of the present application, the injection-production well distances of the first distance zone, the second distance zone, the third distance zone, the fourth distance zone, the fifth distance zone, and the sixth distance zone are respectively: 0 - 200 m, 200 - 250 m, 250 - 300 m, 300 - 350 m, 350 - 400 m, 400 - 450 m, and the distance boundaries corresponding to the injection-production well distances of the first distance zone, the second distance zone, the third distance zone, the fourth distance zone, the fifth distance zone, and the sixth distance zone are respectively: 300 m, 350 m, 420 m, 500 m, 550 m, 630 m.

[0019] In the embodiments of the present application, the first predetermined quantity is three. The first distance zone corresponds to the first pressure zone, the second pressure zone, and the third pressure zone. The second distance zone corresponds to the fourth pressure zone, the fifth pressure zone, and the sixth pressure zone. The third distance zone corresponds to the seventh pressure zone, the eighth pressure zone, and the ninth pressure zone. The fourth distance zone corresponds to the tenth pressure zone, the eleventh pressure zone, and the twelfth pressure zone. The fifth distance zone corresponds to the thirteenth pressure zone, the fourteenth pressure zone, and the fifteenth pressure zone. And the sixth distance zone corresponds to the sixteenth pressure zone, the seventeenth pressure zone, and the eighteenth pressure zone.

[0020] In the embodiments of the present application, the reservoir permeabilities of the three pressure zones corresponding to the same distance zone are respectively: 0 - 30 mD, 30 - 60 mD, 60 - 90 mD.

[0021] In the embodiments of the present application, the pressure limits corresponding to the reservoir permeabilities of the first pressure region, the second pressure region, and the third pressure region are 7 MPa, 5 MPa, and 3 MPa respectively; the pressure limits corresponding to the reservoir permeabilities of the fourth pressure region, the fifth pressure region, and the sixth pressure region are 8 MPa, 6 MPa, and 4 MPa respectively; the pressure limits corresponding to the reservoir permeabilities of the seventh pressure region, the eighth pressure region, and the ninth pressure region are 9 MPa, 7 MPa, and 5 MPa respectively; the pressure limits corresponding to the reservoir permeabilities of the tenth pressure region, the eleventh pressure region, and the twelfth pressure region are 10 MPa, 8 MPa, and 6 MPa respectively; the pressure limits corresponding to the reservoir permeabilities of the thirteenth pressure region, the fourteenth pressure region, and the fifteenth pressure region are 11 MPa, 9 MPa, and 7 MPa respectively; and the pressure limits corresponding to the reservoir permeabilities of the sixteenth pressure region, the seventeenth pressure region, and the eighteenth pressure region are 12 MPa, 10 MPa, and 8 MPa respectively.

[0022] In the embodiments of the present application, the second predetermined quantity is three. The first pressure region corresponds to the first time region, the second time region, and the third time region; the second pressure region corresponds to the fourth time region, the fifth time region, and the sixth time region; the third pressure region corresponds to the seventh time region, the eighth time region, and the ninth time region; the fourth pressure region corresponds to the tenth time region, the eleventh time region, and the twelfth time region; the fifth pressure region corresponds to the thirteenth time region, the fourteenth time region, and the fifteenth time region; the sixth pressure region corresponds to the sixteenth time region, the seventeenth time region, and the eighteenth time region;... and the eighteenth pressure region corresponds to the fifty-second time region, the fifty-third time region, and the fifty-fourth time region.

[0023] In the embodiments of the present application, the time boundaries of the first time region, the second time region, and the third time region are 6 months, 7 months, and 8 months respectively; the fourth time region, the fifth time region, and the sixth time region are 4 months, 5 months, and 6 months respectively; the seventh time region, the eighth time region, and the ninth time region are 2 months, 3 months, and 4 months respectively; the tenth time region, the eleventh time region, and the twelfth time region are 7 months, 8 months, and 9 months respectively; the thirteenth time region, the fourteenth time region, and the fifteenth time region are 5 months, 6 months, and 7 months respectively; the sixteenth time region, the seventeenth time region, and the eighteenth time region are 3 months, 4 months, and 5 months respectively; the nineteenth time region, the twentieth time region, and the twenty-first time region are 8 months, 9 months, and 10 months respectively; the twenty-second time region, the twenty-third time region, and the twenty-fourth time region are 6 months, 7 months, and 8 months respectively; the twenty-fifth time region, the twenty-sixth time region, and the twenty-seventh time region are 4 months, 5 months, and 6 months respectively; the twenty-eighth time region, the twenty-ninth time region, and the thirtieth time region are 9 months, 10 months, and 11 months respectively; the thirty-first time region, the thirty-second time region, and the thirty-third time region are 7 months, 8 months, and 9 months respectively; the thirty-fourth time region, the thirty-fifth time region, and the thirty-sixth time region are 5 months, 6 months, and 7 months respectively; the thirty-seventh time region, the thirty-eighth time region, and the thirty-ninth time region are 10 months, 11 months, and 12 months respectively; the fortieth time region, the forty-first time region, and the forty-second time region are 8 months, 9 months, and 10 months respectively; the forty-third time region, the forty-fourth time region, and the forty-fifth time region are 6 months, 7 months, and 8 months respectively; the forty-sixth time region, the forty-seventh time region, and the forty-eighth time region are 11 months, 12 months, and 13 months respectively; the forty-ninth time region, the fiftieth time region, and the fifty-first time region are 9 months, 10 months, and 11 months respectively; and the fifty-second time region, the fifty-third time region, and the fifty-fourth time region are 7 months, 8 months, and 9 months respectively.

[0024] According to a second aspect of the present application, a method for predicting the drilling and shut-in well drilling and shut-in limit is provided. This method is based on the drilling and shut-in limit chart described in the present application, and the method includes: obtaining the injection-production well spacing, reservoir permeability, and average pressure before shut-in of the block to be drilled and shut-in; selecting the corresponding distance area in the drilling and shut-in distance limit area of the drilling and shut-in limit chart according to the obtained injection-production well spacing, and obtaining the distance limit in the corresponding distance area; in the corresponding pressure area corresponding to the corresponding distance area, selecting the corresponding pressure area according to the obtained reservoir permeability, and obtaining the pressure limit in the corresponding pressure area; in the corresponding time area corresponding to the corresponding pressure area, selecting the corresponding time area according to the obtained average pressure before shut-in to obtain the time limit.

[0025] Using the drilling and shut-in limit chart and method described in the present application, the drilling and shut-in distance limit, drilling and shut-in pressure limit, and drilling and shut-in time limit under conditions such as different well pattern well spacings, reservoir permeabilities, and pressures before shut-in can be directly read, which is convenient, intuitive, and greatly saves time.

[0026] In an embodiment of the present application, the drilling and shut-in limit chart described in the present application is applied to the drilling and shut-in adjustment work of 21 blocks, and 65 well-times of drilling and shut-in adjustment work are carried out. After applying this chart, compared with the previous drilling and shut-in blocks, 90 wells are drilled and shut-in less, the average shut-in time is reduced by 2 months, the annual water injection impact is reduced by 228,000 cubic meters, and the annual oil production impact is reduced by 2,300 tons, achieving good drilling and shut-in effects and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] To more fully understand the embodiments of the present application, reference should be made to the more detailed description in the drawings and the embodiments described by way of example below, where:

[0028] Figure 1 A schematic diagram of a drilling and shut-in limit chart for predicting the drilling and shut-in limit of a drilling and shut-in well according to an embodiment of the present application is shown;

[0029] Figure 2 A pressure coefficient prediction chart at an injection-production well spacing of 200 m is shown;

[0030] Figure 3 A pressure coefficient distribution chart under steady-state seepage at an injection-production well spacing of 200 m is shown;

[0031] Figure 4 A schematic diagram of a drilling and shut-in limit chart for predicting the drilling and shut-in limit of a drilling and shut-in well according to another embodiment of the present application is shown; and

[0032] Figure 5 A flowchart of a method for predicting the drilling and shut-in limit of a drilling and shut-in well according to an embodiment of the present application is shown. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] Embodiments of the present disclosure are described below. However, it should be understood that the disclosed embodiments are merely examples, and other embodiments may take various alternative forms. The accompanying drawings are not necessarily drawn to scale; certain features may be exaggerated or minimized to show details of particular components. Thus, the specific structural and functional details disclosed herein should not be construed as limiting, but merely as a representative basis for teaching one skilled in the art to use the present application in various ways. As will be understood by one skilled in the art, the various features shown and described with reference to any one of the accompanying drawings may be combined with features shown in one or more other drawings to produce embodiments that are not explicitly shown or described. Combinations of the shown features provide representative embodiments for typical applications. However, various combinations and modifications of the features consistent with the teachings of the present disclosure may be desirable for certain particular applications or implementations.

[0034] Furthermore, in this document, relational terms such as first and second are used solely to distinguish one entity or action from another entity or action, and do not necessarily require or imply any actual such relationship or order between those entities or actions. The terms "comprises," "comprising," or any other variation thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0035] One or more embodiments of the present application will be described below in conjunction with the accompanying drawings. The flowchart illustrates the process executed by the system according to the present application. It can be understood that the execution of the flowchart does not need to be in sequence, one or more steps may be omitted, one or more execution steps may be added, and the steps may be in sequence or reverse order, and even in some embodiments, one or more steps may be executed simultaneously.

[0036] According to the present invention, there is provided a drilling shut-in limit chart 100 for predicting the drilling shut-in limit, as Figure 1 shown, the drilling shut-in limit chart 100 is integrally circular and includes: a drilling shut-in distance limit area 110, a drilling shut-in pressure limit area 120, and a drilling shut-in time limit area 130 that are concentrically arranged. The drilling shut-in pressure limit area 120 is arranged between the drilling shut-in distance limit area 110 and the drilling shut-in time limit area 130, wherein: the drilling shut-in distance limit area 110 includes a plurality of distance areas divided by a first parameter; the drilling shut-in pressure limit area 120 includes a plurality of pressure areas divided by a second parameter; the drilling shut-in time limit area 130 includes a plurality of time areas divided by a third parameter; each of the plurality of distance areas corresponds to a first predetermined number of pressure areas, and each of the plurality of pressure areas corresponds to a second predetermined number of time areas.

[0037] In Figure 1In the illustrated embodiment, the shut-in boundary chart 100 may include three parameter variable adjustment regions, namely, the shut-in distance boundary region 110, the shut-in pressure boundary region 120, and the shut-in time boundary region 130, which are concentrically arranged from the inside to the outside in sequence. The first parameter is the injection-production well spacing R, the second parameter is the reservoir permeability k, and the third parameter is the time based on the pre-shut-in pressure. For example, the time when the cumulative pre-shut-in pressure increases from low to high.

[0038] The injection-production well spacings R of different injection wells and production wells are different. Generally, the injection-production well spacing R can be divided into the following six cases: 0 - 200m, 200 - 250m, 250 - 300m, 300 - 350m, 350 - 400m, 400 - 450m. The shut-in distance boundary region 110 can be divided into six distance regions based on these six injection-production well spacings R, that is, the first distance region 111 1 to the sixth distance region 111 6 , which are arranged in a clockwise direction. If it is bounded between the first distance region 111 1 and the sixth distance region 111 6 , then the injection-production well spacings R corresponding to these six distance regions increase in a clockwise direction from the first distance region 111 1 to the sixth distance region 111 6 . The injection-production well spacing R of each distance region can correspond to its respective distance boundary L. As Figure 1 shown, the injection-production well spacing R of 0 - 200m (R < 200) corresponds to a distance boundary L of 300m, the injection-production well spacing R of 200 - 250m (R < 250) corresponds to a distance boundary L of 350m, the injection-production well spacing R of 250 - 300m (R < 300) corresponds to a distance boundary of 420m, the injection-production well spacing R of 300 - 350m (R < 350) corresponds to a distance boundary L of 500m, the injection-production well spacing R of 350 - 400m (R < 400) corresponds to a distance boundary L of 550m, and the injection-production well spacing R of 400 - 450m (R < 450) corresponds to a distance boundary L of 630m. Correspondingly, the distance boundaries L corresponding to the six distance regions can also increase in a clockwise direction.

[0039] In the embodiments of the present application, each distance region includes at least a distance boundary determined based on its respective injection-production well spacing. The corresponding shut-in distance L can be obtained from the injection-production well spacing R, that is, the range of the shut-in distance boundary is judged by the well spacing.

[0040] The formation pressure coefficient prediction chart under different injection-production well spacings is generated through the following plane radial flow formula. Considering the drilling shut-in pressure of 10 MPa (the current limit of drilling shut-in tests) and the pressure coefficient should be lower than 1.6 (the controllable range of drilling mud density), the drilling shut-in distance at this time is the drilling shut-in safety distance. The safety drilling shut-in distance limit for the corresponding injection-production well spacing can be obtained from the chart of different injection-production well spacings. Refer to Figure 2 , Figure 2 shows the pressure coefficient prediction chart for an injection-production well spacing of 200 m. As Figure 2 shown, the minimum drilling shut-in safety distance for a 200 m well spacing is 100 m. Refer to Figure 3 , from Figure 3 the pressure coefficient distribution diagram under steady-state seepage for an injection-production well spacing of 200 m shown (this diagram is obtained based on the numerical simulation theoretical model of the plane radial flow formula), it can be obtained that in the well pattern with a 200 m well spacing, the maximum area where the pressure coefficient around the injection well is greater than 1.6 is approximately 300 m. Therefore, the maximum drilling shut-in distance for the 200 m well pattern is 300 m. Similarly, the drilling shut-in limit ranges for other distances can be obtained.

[0041]

[0042] Among them, P 1 is the pressure at any point in the formation, with the unit of MPa / m; P e is the pressure at the supply boundary, with the unit of MPa; P w is the bottom-hole flowing pressure of the production well, with the unit of MPa; R e is the supply radius, with the unit of m; R w is the wellbore radius, with the unit of m; R 1 is the distance between the well to be drilled and the oil well in the basic well pattern, with the unit of m.

[0043] According to different reservoir permeabilities k, the permeability k can be divided into three cases: 0 - 30 mD, 30 - 60 mD, 60 - 90 mD. The drilling shut-in pressure limit area 120 can be divided into eighteen pressure regions based on these three reservoir permeabilities k, that is, the first pressure region 121 1 to the eighteenth pressure region 121 18 , the first pressure region 121 1 to the eighteenth pressure region 121 18 can be arranged clockwise, and the reservoir permeabilities k of the three pressure regions corresponding to the same distance region correspond to their respective pressure limits P. The reservoir permeabilities k of the three pressure regions corresponding to the same distance region can be 0 - 30 mD, 30 - 60 mD, and 60 - 90 mD respectively.

[0044] Each distance region can correspond to a predetermined number of pressure regions. In the Figure 1 embodiment shown, the first distance region 1111 corresponding to the first pressure region 121 1 and the second pressure region 121 2 and the third pressure region 121 3 and the second distance region 111 2 corresponds to the fourth, fifth, and sixth pressure regions (reference numerals not shown in the figure for simplicity), and so on, and the sixth distance region 111 6 corresponds to the sixteenth, seventeenth, and eighteenth pressure regions (reference numerals not shown in the figure for simplicity).

[0045] Each pressure region may include a pressure limit P determined at least based on the respective reservoir permeability. For example, the corresponding shut-in pressure limit P is obtained from different reservoir permeabilities k, that is, the shut-in pressure limit range is determined by permeability.

[0046] Based on the actual geology and development parameters of the oilfield in question and considering the starting pressure, a numerical simulation theoretical model is established to calculate the wellhead pressure changes under different shut-in pressures. The pressure relief amplitude is obvious at the initial stage of shut-in, and the greater the permeability, the faster the initial decline rate. Since the pressure drop is not obvious in the later stage, the stage with a monthly shut-in pressure decline of less than 0.5 MPa is taken as the effective shut-in stage. Further, the shut-in pressure limits under different injection-production well distances and different permeabilities are obtained.

[0047] In Figure 1 the illustrated embodiment, the reservoir permeability k of the first pressure region 121 1 is 0 - 30 mD (k < 30), and the corresponding shut-in pressure limit P for this pressure region is 7 Mpa; the reservoir permeability k of the second pressure region 121 2 is 30 - 60 mD (k < 60), and the corresponding shut-in pressure limit P for this pressure region is 5 Mpa; the reservoir permeability k of the third pressure region 121 3The reservoir permeability k of [the relevant part] is 60 - 90 mD (k < 90), and the corresponding well shut-in pressure limit P for this pressure region is 3 Mpa; the reservoir permeability k of the fourth pressure region is 0 - 30 mD, and the corresponding well shut-in pressure limit P for this pressure region is 8 Mpa; the reservoir permeability k of the fifth pressure region is 30 - 60 mD, and the corresponding well shut-in pressure limit P for this pressure region is 6 Mpa; the reservoir permeability k of the sixth pressure region is 60 - 90 mD, and the corresponding well shut-in pressure limit P for this pressure region is 4 Mpa; the reservoir permeability k of the seventh pressure region is 0 - 30 mD, and the corresponding well shut-in pressure limit P for this pressure region is 9 Mpa; the reservoir permeability k of the eighth pressure region is 30 - 60 mD, and the corresponding well shut-in pressure limit P for this pressure region is 7 Mpa; the reservoir permeability k of the ninth pressure region is 60 - 90 mD, and the corresponding well shut-in pressure limit P for this pressure region is 5 Mpa; the reservoir permeability k of the tenth pressure region is 0 - 30 mD, and the corresponding well shut-in pressure limit P for this pressure region is 10 Mpa; the reservoir permeability k of the eleventh pressure region is 30 - 60 mD, and the corresponding well shut-in pressure limit P for this pressure region is 8 Mpa; the reservoir permeability k of the twelfth pressure region is 60 - 90 mD, and the corresponding well shut-in pressure limit P for this pressure region is 6 Mpa; the reservoir permeability k of the thirteenth pressure region is 0 - 30 mD, and the corresponding well shut-in pressure limit P for this pressure region is 11 Mpa; the reservoir permeability k of the fourteenth pressure region is 30 - 60 mD, and the corresponding well shut-in pressure limit P for this pressure region is 9 Mpa; the reservoir permeability k of the fifteenth pressure region is 60 - 90 mD, and the corresponding well shut-in pressure limit P for this pressure region is 7 Mpa; the reservoir permeability k of the sixteenth pressure region is 0 - 30 mD, and the corresponding well shut-in pressure limit P for this pressure region is 12 Mpa; the reservoir permeability k of the seventeenth pressure region is 30 - 60 mD, and the corresponding well shut-in pressure limit P for this pressure region is 10 Mpa; the reservoir permeability k of the eighteenth pressure region is 60 - 90 mD, and the corresponding well shut-in pressure limit P for this pressure region is 8 Mpa.

[0048] The first time region 131 can be divided based on the time of the pressure before well shut-in 1 and the second time region 131 2 and... and the fifty-fourth time region 131 54 , and each pressure region can correspond to a predetermined number of time regions. In Figure 1 the illustrated embodiment, the first pressure region 121 1 corresponds to the first time region 131 1 and the second time region 131 2 and the third time region 131 3 , the second pressure region 121 2Corresponding to the fourth time region, the fifth time region, and the sixth time region (reference numerals are not shown in the figure for the sake of simplicity), and so on, and the eighteenth pressure region corresponds to the fifty-second time region, the fifty-third time region, and the fifty-fourth time region 131 54 (For the sake of simplicity, reference numerals of some time regions are not shown in the figure).

[0049] Each time region includes a time limit determined based on the pressure limit and the pre-shut-in pressure. On the one hand, there is a corresponding relationship between the drill shut-in pressure limit P and time, that is, the drill shut-in time limit is judged by the wellhead pressure value of the injection well. Under the same injection-production well spacing and permeability, the wellhead pressure drop rate after the injection well is shut in is related to the pressure before drill shut-in. The drill shut-in time of the well with a lower pressure before drill shut-in is shorter. Therefore, the drill shut-in time limits of different pressures before drill shut-in are corrected according to the empirical values of the work area where they are located. On the other hand, after the drill shut-in pressure limit P is determined, according to the empirical values of the pressure before shut-in in the oilfield where the block is located, it is divided into three levels: low pressure, medium pressure, and high pressure. The higher the pressure before shut-in, the higher the shut-in cycle value. According to the magnitude of the pressure before drill shut-in of the drill shut-in wells in the block, the corresponding pressure level before shut-in is determined, the outermost Arabic numerals of the corresponding arc are selected, and the drill shut-in time limit is determined to be how many months.

[0050] In Figure 1 the illustrated embodiment, the first time region 131 1 , the second time region 131 2 and the third time region 131 3The time limits are respectively: 6 months, 7 months, 8 months. The fourth time region, the fifth time region and the sixth time region are respectively: 4 months, 5 months, 6 months. The seventh time region, the eighth time region and the ninth time region are respectively: 2 months, 3 months, 4 months. The tenth time region, the eleventh time region and the twelfth time region are respectively: 7 months, 8 months, 9 months. The thirteenth time region, the fourteenth time region and the fifteenth time region are respectively: 5 months, 6 months, 7 months. The sixteenth time region, the seventeenth time region and the eighteenth time region are respectively: 3 months, 4 months, 5 months. The nineteenth time region, the twentieth time region and the twenty-first time region are respectively: 8 months, 9 months, 10 months. The twenty-second time region, the twenty-third time region and the twenty-fourth time region are respectively: 6 months, 7 months, 8 months. The twenty-fifth time region, the twenty-sixth time region and the twenty-seventh time region are respectively: 4 months, 5 months, 6 months. The twenty-eighth time region, the twenty-ninth time region and the thirtieth time region are respectively: 9 months, 10 months, 11 months. The thirty-first time region, the thirty-second time region and the thirty-third time region are respectively: 7 months, 8 months, 9 months. The thirty-fourth time region, the thirty-fifth time region and the thirty-sixth time region are respectively: 5 months, 6 months, 7 months. The thirty-seventh time region, the thirty-eighth time region and the thirty-ninth time region are respectively: 10 months, 11 months, 12 months. The fortieth time region, the forty-first time region and the forty-second time region are respectively: 8 months, 9 months, 10 months. The forty-third time region, the forty-fourth time region and the forty-fifth time region are respectively: 6 months, 7 months, 8 months. The forty-sixth time region, the forty-seventh time region and the forty-eighth time region are respectively: 11 months, 12 months, 13 months. The forty-ninth time region, the fiftieth time region and the fifty-first time region are respectively: 9 months, 10 months, 11 months. And the fifty-second time region, the fifty-third time region and the fifty-fourth time region are respectively: 7 months, 8 months, 9 months.

[0051] It should be understood that although in this application, R less than 200 is taken as the first distance region and R greater than 450 is taken as the sixth distance region, however, this division method is only for illustration. In other embodiments, the first distance region can also be divided according to the region where other R value ranges are located, and the first pressure region and the first time region are divided accordingly. Such different embodiments are also included within the scope of this application. In addition, this application is equally applicable to other parameters, or other parameter values.

[0052] According to the second aspect of this application, a method for predicting the drilling shut-in limits is provided. This method is based on the drilling shut-in limit chart described in this application, as Figure 5As shown in the figure, the method includes the following steps:

[0053] S501. Obtain the injection-production well spacing, reservoir permeability, and average pressure before shut-in of the block where the well shut-in during drilling is to be implemented;

[0054] S503. Select the corresponding distance area within the shut-in distance limit area of the shut-in limit chart according to the obtained injection-production well spacing, and obtain the distance limit within the corresponding distance area;

[0055] S505. Within the pressure area corresponding to the corresponding distance area, select the corresponding pressure area according to the obtained reservoir permeability, and obtain the pressure limit within the corresponding pressure area; and

[0056] S507. Within the time area corresponding to the corresponding pressure area, select the corresponding time area according to the obtained average pressure before shut-in to obtain the time limit.

[0057] Through the above method, the shut-in distance limit, shut-in pressure limit, and shut-in time limit under conditions such as different well pattern well spacings, reservoir permeabilities, and pressures before shut-in can be directly and conveniently obtained, which is convenient, intuitive, and greatly saves time.

[0058] The following uses a specific embodiment to illustrate the present application:

[0059] In 2020, it is planned to implement well shut-in during drilling in Block S.

[0060] Basic situation of Block S: The injection-production well spacing in Block S is 300 - 350 m, the reservoir permeability in Block S is 30 - 60 md, and the average pressure before shut-in in Block S is 10.1 MPa.

[0061] As Figure 4 shown, using the shut-in limit chart 100 for predicting the shut-in limits of wells during drilling, first, according to the injection-production well spacing of 300 - 350 m in Block S, read the shut-in distance limit as 500 m in the shut-in distance limit area 110 (the yellow area indicated by the reference numeral 111 in Figure 4 ); next, according to the reservoir permeability of 30 - 60 mD in Block S, read the shut-in pressure limit as 8 Mpa in the shut-in pressure limit area 120 (the yellow area indicated by the reference numeral 121 in Figure 4 ); finally, based on the empirical values of the pressure before shut-in in the block, it is divided into three levels: low, medium, and high. The higher the pressure before shut-in, the higher the well shut-in cycle value. The pressure in the oilfield where Block S is located is less than 13 MPa for the low-pressure area, 13 MPa - 16 MPa for the medium-pressure area, and greater than 16 MPa for the high-pressure area. The average pressure before shut-in in Block S is 10.1 MPa, which is in the low-pressure area. Read the time limit as 7 months in the shut-in time limit area 130 (the yellow area indicated by the reference numeral 131 in Figure 4 ).

[0062] Thus, it is possible to quickly and conveniently know the shut-in distance limit, shut-in pressure limit, and shut-in time limit under conditions such as different well patterns and well spacings, reservoir permeability, and pressure before closure, which is convenient, intuitive, and greatly saves time.

[0063] This application document is intended to illustrate how to use the disclosed technology and various embodiments, rather than to limit the scope and spirit of what it actually refers to and what is equivalent. Moreover, the above description does not exhaust all possibilities or limit the scope of protection to the exact forms disclosed. According to the above teachings, changes and variations are possible. The selected and described embodiments provide the best illustration of the principles of the technology and its practical applications, and enable those skilled in the art to use the disclosed technology for various changes in various conceivable specific applications. Therefore, all changes and modifications made to the above embodiments are intended to be included within the scope of this disclosure without materially departing from the spirit and principles of the technology described herein.

Claims

1. A method for drawing a drilling shut-in boundary chart for predicting the drilling shut-in boundary, characterized in that, the drilling shut-in boundary chart as a whole is circular and includes a drilling shut-in distance boundary area, a drilling shut-in pressure boundary area, and a drilling shut-in time boundary area that are concentrically arranged. The drilling shut-in pressure boundary area is arranged between the drilling shut-in distance boundary area and the drilling shut-in time boundary area, where: the drilling shut-in distance boundary area includes a plurality of distance areas divided by a first parameter, and the first parameter is the injection-production well spacing; the drilling shut-in pressure boundary area includes a plurality of pressure areas divided by a second parameter, and the second parameter is the reservoir permeability; the drilling shut-in time boundary area includes a plurality of time areas divided by a third parameter, and the third parameter is the time based on the pressure before shut-in; each of the plurality of distance areas corresponds to a first predetermined number of the pressure areas, and each of the plurality of pressure areas corresponds to a second predetermined number of the time areas, wherein each distance area includes a distance boundary determined at least based on its respective injection-production well spacing, each pressure area includes a pressure boundary determined at least based on its respective reservoir permeability, and each time area includes a time boundary determined based on the pressure boundary and the pressure before shut-in, the drilling shut-in distance boundary area includes a first distance area to a sixth distance area divided by the injection-production well spacing, and the injection-production well spacing of each distance area corresponds to its respective distance boundary; the drilling shut-in pressure boundary area includes a first pressure area to an eighteenth pressure area divided by the reservoir permeability, and the reservoir permeability of each pressure area corresponds to its respective pressure boundary; the drilling shut-in time boundary area includes a first time area to a fifty-fourth time area divided by the time based on the pressure before shut-in, wherein the distance boundary is determined at least based on the formation pressure coefficient prediction chart under different injection-production well spacings generated by the following plane radial flow formula and the pressure coefficient distribution map under stable seepage of different injection-production well spacings: Among them, P 1 is the pressure at any point in the formation, P e is the supply boundary pressure, P w is the flowing bottom-hole pressure of the oil production well, R e is the supply radius, R w is the wellbore radius, R 1 is the distance between the well to be drilled and the oil wells in the basic well pattern.

2. The method for drawing a drilling shut-in boundary chart according to claim 1, characterized in that, the injection-production well spacings of the first distance area, the second distance area, the third distance area, the fourth distance area, the fifth distance area, and the sixth distance area are respectively: injection-production well spacing < 200m, 200m ≤ injection-production well spacing < 250m, 250m ≤ injection-production well spacing < 300m, 300m ≤ injection-production well spacing < 350m, 350m ≤ injection-production well spacing < 400m, 400m ≤ injection-production well spacing < 450m, and the distance boundaries corresponding to the injection-production well spacings of the first distance area, the second distance area, the third distance area, the fourth distance area, the fifth distance area, and the sixth distance area are respectively: 300m, 350m, 420m, 500m, 550m, 630m.

3. The method for drawing a drilling shut-in boundary chart according to claim 2, characterized in that, The first predetermined quantity is three. The first distance region corresponds to a first pressure region, a second pressure region, and a third pressure region. The second distance region corresponds to a fourth pressure region, a fifth pressure region, and a sixth pressure region. The third distance region corresponds to a seventh pressure region, an eighth pressure region, and a ninth pressure region. The fourth distance region corresponds to a tenth pressure region, an eleventh pressure region, and a twelfth pressure region. The fifth distance region corresponds to a thirteenth pressure region, a fourteenth pressure region, and a fifteenth pressure region. And the sixth distance region corresponds to a sixteenth pressure region, a seventeenth pressure region, and an eighteenth pressure region.

4. The method for drawing a drilling shut-in boundary chart according to claim 3, wherein, The reservoir permeabilities of the three pressure regions corresponding to the same distance region are respectively: reservoir permeability < 30 mD, 30 mD ≤ reservoir permeability < 60 mD, 60 mD ≤ reservoir permeability < 90 mD.

5. The method for drawing a drilling shut-in boundary chart according to claim 4, wherein, The pressure boundaries corresponding to the reservoir permeabilities of the first pressure region, the second pressure region, and the third pressure region are respectively: 7 MPa, 5 MPa, 3 MPa. The pressure boundaries corresponding to the reservoir permeabilities of the fourth pressure region, the fifth pressure region, and the sixth pressure region are respectively: 8 MPa, 6 MPa, 4 MPa. The pressure boundaries corresponding to the reservoir permeabilities of the seventh pressure region, the eighth pressure region, and the ninth pressure region are respectively: 9 MPa, 7 MPa, 5 MPa. The pressure boundaries corresponding to the reservoir permeabilities of the tenth pressure region, the eleventh pressure region, and the twelfth pressure region are respectively: 10 MPa, 8 MPa, 6 MPa. The pressure boundaries corresponding to the reservoir permeabilities of the thirteenth pressure region, the fourteenth pressure region, and the fifteenth pressure region are respectively: 11 MPa, 9 MPa, 7 MPa. And the pressure boundaries corresponding to the reservoir permeabilities of the sixteenth pressure region, the seventeenth pressure region, and the eighteenth pressure region are respectively: 12 MPa, 10 MPa, 8 MPa.

6. The method for drawing a drilling shut-in boundary chart according to claim 5, wherein, The second predetermined quantity is three. The first pressure region corresponds to a first time region, a second time region, and a third time region. The second pressure region corresponds to a fourth time region, a fifth time region, and a sixth time region. The third pressure region corresponds to a seventh time region, an eighth time region, and a ninth time region. The fourth pressure region corresponds to a tenth time region, an eleventh time region, and a twelfth time region. The fifth pressure region corresponds to a thirteenth time region, a fourteenth time region, and a fifteenth time region. The sixth pressure region corresponds to a sixteenth time region, a seventeenth time region, and an eighteenth time region. The seventh pressure region corresponds to a nineteenth time region, a twentieth time region, and a twenty-first time region. The eighth pressure region corresponds to a twenty-second time region, a twenty-third time region, and a twenty-fourth time region. The ninth pressure region corresponds to a twenty-fifth time region, a twenty-sixth time region, and a twenty-seventh time region. The tenth pressure region corresponds to a twenty-eighth time region, a twenty-ninth time region, and a thirtieth time region. The eleventh pressure region corresponds to a thirty-first time region, a thirty-second time region, and a thirty-third time region. The twelfth pressure region corresponds to a thirty-fourth time region, a thirty-fifth time region, and a thirty-sixth time region. The thirteenth pressure region corresponds to a thirty-seventh time region, a thirty-eighth time region, and a thirty-ninth time region. The fourteenth pressure region corresponds to a fortieth time region, a forty-first time region, and a forty-second time region. The fifteenth pressure region corresponds to a forty-third time region, a forty-fourth time region, and a forty-fifth time region. The sixteenth pressure region corresponds to a forty-sixth time region, a forty-seventh time region, and a forty-eighth time region. The seventeenth pressure region corresponds to a forty-ninth time region, a fiftieth time region, and a fifty-first time region, and the eighteenth pressure region corresponds to a fifty-second time region, a fifty-third time region, and a fifty-fourth time region.

7. The method for drawing a drilling shut-in boundary chart according to claim 6, wherein, The time boundaries of the first time zone, the second time zone, and the third time zone are 6 months, 7 months, and 8 months respectively. The fourth time zone, the fifth time zone, and the sixth time zone are 4 months, 5 months, and 6 months respectively. The seventh time zone, the eighth time zone, and the ninth time zone are 2 months, 3 months, and 4 months respectively. The tenth time zone, the eleventh time zone, and the twelfth time zone are 7 months, 8 months, and 9 months respectively. The thirteenth time zone, the fourteenth time zone, and the fifteenth time zone are 5 months, 6 months, and 7 months respectively. The sixteenth time zone, the seventeenth time zone, and the eighteenth time zone are 3 months, 4 months, and 5 months respectively. The nineteenth time zone, the twentieth time zone, and the twenty-first time zone are 8 months, 9 months, and 10 months respectively. The twenty-second time zone, the twenty-third time zone, and the twenty-fourth time zone are 6 months, 7 months, and 8 months respectively. The twenty-fifth time zone, the twenty-sixth time zone, and the twenty-seventh time zone are 4 months, 5 months, and 6 months respectively. The twenty-eighth time zone, the twenty-ninth time zone, and the thirtieth time zone are 9 months, 10 months, and 11 months respectively. The thirty-first time zone, the thirty-second time zone, and the thirty-third time zone are 7 months, 8 months, and 9 months respectively. The thirty-fourth time zone, the thirty-fifth time zone, and the thirty-sixth time zone are 5 months, 6 months, and 7 months respectively. The thirty-seventh time zone, the thirty-eighth time zone, and the thirty-ninth time zone are 10 months, 11 months, and 12 months respectively. The fortieth time zone, the forty-first time zone, and the forty-second time zone are 8 months, 9 months, and 10 months respectively. The forty-third time zone, the forty-fourth time zone, and the forty-fifth time zone are 6 months, 7 months, and 8 months respectively. The forty-sixth time zone, the forty-seventh time zone, and the forty-eighth time zone are 11 months, 12 months, and 13 months respectively. The forty-ninth time zone, the fiftieth time zone, and the fifty-first time zone are 9 months, 10 months, and 11 months respectively. And the fifty-second time zone, the fifty-third time zone, and the fifty-fourth time zone are 7 months, 8 months, and 9 months respectively.

8. A method for predicting the drilling and shut-in boundary of a drilling and shut-in operation, the method being based on the drilling and shut-in boundary charting method described in any one of claims 1-7. Characterized in that The method for predicting the drilling and shut-in boundary of a drilling and shut-in operation includes: Obtaining the injection-production well spacing, reservoir permeability, and average pressure before shut-in of the block where the drilling and shut-in operation is to be carried out; Selecting the corresponding distance area in the drilling distance boundary area of the drilling and shut-in boundary chart according to the obtained injection-production well spacing, and obtaining the distance boundary in the corresponding distance area; In the pressure area corresponding to the corresponding distance area, selecting the corresponding pressure area according to the obtained reservoir permeability, and obtaining the pressure boundary in the corresponding pressure area. Within the time region corresponding to the corresponding pressure region, select the corresponding time region according to the obtained average pressure before closing to obtain the time limit.

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