A method for adjusting the well deviation before landing in horizontal wells based on dual constraints of marker layer and angle

Abstract

The present invention relates to the technical field of shale gas exploration and development, and specifically to a method for adjusting the well inclination before landing of a horizontal well based on dual constraints of a marker layer and an angle. The method comprises obtaining data on a standard well, a drilled horizontal well, and a horizontal well to be drilled; establishing a corresponding relationship between the standard well and the drilled horizontal well; obtaining a model empirical coefficient by marking the thickness h and the angle γ of the corresponding standard well spacing A target; establishing a marker layer and angle chart for the standard well using a regression equation; calculating the well inclination that should be adjusted to the corresponding marker layer for the horizontal well to be drilled; controlling the trajectory of the horizontal well to be drilled before landing according to the calculated result; and controlling the attitude of the horizontal well to be drilled when landing at the A target. The method is highly operational and easy to promote and apply on-site, achieving the purpose of controlling a smooth trajectory before landing and precise landing, and meeting the needs of fast, safe, and efficient drilling for multi-layer three-dimensional development of gas fields.

Description

Technical Field

[0001] The present invention relates to the technical field of shale gas exploration and development, and in particular to a method for adjusting the well inclination before landing of a horizontal well based on dual constraints of a marker layer and an angle. Background Art

[0002] Accurate landing is a key technology for horizontal well geosteering. Traditionally, pre-landing trajectory adjustment for horizontal wells relies on the constant-thickness method, dynamically predicting the vertical depth of target A and adjusting it in real time. This dynamic adjustment method requires dynamic tracking while drilling and relies on the judgment and understanding of the well steering operator. It requires numerous parameters and a complex calculation process. In particular, when the trajectory orientation changes before landing, large errors in the calculated apparent dip angle of the formation are very likely to occur. This can affect pre-landing trajectory control, landing attitude, and trajectory smoothness, further impacting the construction of subsequent horizontal sections.

[0003] CN108316859A discloses a method for controlling the trajectory of a shale gas horizontal well while drilling and guiding the formation before landing. The core of the method is to provide empirical parameters for matching the vertical depth, vertical thickness, displacement, and inclination rate of the marker layer, but it does not mention a fast calculation method for adjusting the angle between the trajectory and the formation.

[0004] Therefore, for strata with comparable spacing before landing and relatively stable formation occurrence before landing, there is an urgent need to establish a simple calculation method for segmented adjustment of horizontal well inclination before landing based on marker layers and angle constraints that is highly operational and easy to widely apply on site, so as to achieve the purpose of controlling the trajectory smoothness and precise landing before landing, and meet the needs of fast, safe and efficient drilling for multi-layer three-dimensional development of gas fields. Summary of the Invention

[0005] The purpose of the present invention is to address the shortcomings of the existing technology and provide a method for adjusting the well inclination before landing of a horizontal well based on the dual constraints of the marker layer and the angle. The method has strong operability and is easy to be widely promoted and applied on site, so as to achieve the purpose of controlling the trajectory smoothness and precise landing before landing, and meet the needs of fast, safe and efficient drilling for the three-dimensional development of multi-layer gas fields.

[0006] The present invention provides a method for adjusting the well inclination before landing of a horizontal well based on dual constraints of a marker layer and an angle, which is characterized by comprising:

[0007] Obtain data on standard wells, drilled horizontal wells, and horizontal wells to be drilled;

[0008] Establish the corresponding relationship between standard wells and drilled horizontal wells;

[0009] The model empirical coefficients are obtained by marking the corresponding standard well spacing A, target thickness h, and angle γ;

[0010] Use regression equation to establish the marker layer and angle chart of standard well;

[0011] Calculate the well inclination that should be adjusted to the corresponding marker layer of the horizontal well to be drilled;

[0012] Control the trajectory of the horizontal well to be drilled before landing according to the calculation results;

[0013] Enter target A attitude control when landing in the horizontal well to be drilled.

[0014] Preferably, the data of the standard well, the drilled horizontal well, and the horizontal well to be drilled are obtained by:

[0015] Obtain geological stratification, lithology, natural gamma, gas logging, geochemistry, and element data of standard wells;

[0016] Obtain geological stratification, lithology, natural gamma, gas logging, and well deviation data for drilled horizontal wells;

[0017] Obtain lithology, natural gamma, gas logging, while-drilling depth, well inclination, and azimuth data for the horizontal well to be drilled.

[0018] Preferably, the method for selecting the drilled horizontal wells includes:

[0019] Representative drilled horizontal wells with relatively stable formation occurrence, thickness, displacement of 250-350 m before landing, average full-angle change rate of landing trajectory less than 15° / 100 m, and precise landing were selected as modeling wells.

[0020] Preferably, establishing the corresponding relationship between the standard well and the drilled horizontal well includes:

[0021] By comparing the formations of the standard well with those of the drilled horizontal well, all marker layers up to S1 meter from target point A are identified and numbered from top to bottom;

[0022] Read the well depth, well inclination and azimuth data from the first marker layer to target point A in the drilled horizontal well;

[0023] By comparing the lithology, natural gamma, and gas logging characteristics of the marker layers of the standard well and the drilled horizontal well, the depth values ​​and well deviation data on the well deviation data table of the drilled horizontal well are marked to the corresponding standard well;

[0024] The standard well depth value corresponding to the mark is converted into the thickness h from the target point A, and the well inclination data is converted into the angle γ, which refers to the angle between the trajectory line and the formation.

[0025] Preferably, the model empirical coefficients are obtained by marking the corresponding standard well spacing target thickness h and angle γ, including:

[0026] By marking the corresponding standard well distance A target point thickness h and angle γ data samples, a cross-plot of angle γ and distance A target point thickness h is drawn;

[0027] A polynomial regression equation is established with the target thickness h from A as the independent variable and the angle γ as the dependent variable;

[0028] Obtain model γ=Ah 3 +Bh 2 +Ch+2.00 model empirical coefficients A, B, C.

[0029] Preferably, the method of establishing the marker layer and angle chart of the standard well by using the regression equation includes:

[0030] Draw a chart of standard wells from top to bottom, including well depth, natural gamma, marker layers, lithology, and angle items.

[0031] Preferably, the calculation of the well deviation that should be adjusted from the horizontal well to be drilled to the corresponding marker layer includes:

[0032] According to the formula γ = 90-α-β, the angle γ between the trajectory line and the formation is converted into the well inclination that should be adjusted from the horizontal well to the corresponding marker layer;

[0033] Among them, β is the apparent dip of the formation, and α is the well inclination angle.

[0034] Preferably, controlling the trajectory of the horizontal well to be drilled before landing according to the calculation results includes:

[0035] Adopting the principle of adjacent similarity, the apparent dip angle of the current layer is obtained according to the result of the apparent dip angle calculation of the previous marker layer.

[0036] Determine the well inclination based on the angle, including

[0037] During actual drilling, if the apparent dip angles of adjacent strata change, for example, if the marker layer is pushed back, that is, if the drilling is not carried out to the next marker layer at the corresponding angle and well inclination, the exploration layer can be continued according to the angle γ calculated on the plate; if the marker layer is advanced, the well inclination can be rapidly increased to the required well inclination at the specified inclination rate according to the angle γ calculated on the plate.

[0038] Preferably, the attitude control of landing on target A when the horizontal well to be drilled includes:

[0039] When landing, the angle is determined according to the thickness of the target frame;

[0040] Among them, when the target frame thickness is K meters, control the angle K degrees to enter the A target frame.

[0041] The beneficial effects of the present invention are:

[0042] 1) The present invention selects a drilled horizontal well with precise landing and smooth trajectory as a modeling well, providing a reference for the pre-landing trajectory well deviation control method for horizontal wells to be drilled with similar conditions.

[0043] 2) The present invention provides a method for quickly calculating the angle corresponding to any marker layer within S1 meters of target point A by establishing a marker layer and angle map, thereby solving the problem of using the equal thickness method to dynamically predict the vertical depth of target point A and adjust the required drilling parameters in real time, resulting in a complex calculation process.

[0044] 3) The included angle is converted into the well inclination that should be adjusted from the horizontal well to the corresponding marker layer to avoid the influence of the occurrence changes of different formations on the trajectory before landing.

[0045] 4) The present invention controls the trajectory of the horizontal well to be drilled according to the calculated well inclination, eliminating the frequent trajectory adjustments caused by large errors in the calculation of the formation apparent dip angle under the condition of changing azimuth before landing. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a schematic diagram of the process of the present invention;

[0047] Figure 2 is the relationship diagram of well deviation α, formation dip β, and angle γ between trajectory and formation;

[0048] Figure 3 is the intersection diagram of the thickness h from the target point A and the angle γ between the trajectory and the formation;

[0049] Figure 4 This is the small layer (marker layer) and angle chart of Well A in the standard well of J work area. DETAILED DESCRIPTION

[0050] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, this application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0051] In the following description, specific details such as specific system structures and techniques are provided for purposes of illustration rather than limitation to facilitate a thorough understanding of the embodiments of the present application. However, it will be apparent to those skilled in the art that the present application may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid obscuring the description of the present application with unnecessary detail.

[0052] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, integers, steps, operations, elements and / or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or collections thereof.

[0053] It will also be understood that the term "and / or" used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0054] As used in this specification and the appended claims, the term "if" can be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" can be interpreted as meaning "upon determination" or "in response to determining" or "upon detection of [described condition or event]" or "in response to detecting [described condition or event]," depending on the context.

[0055] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0056] References to "one embodiment" or "some embodiments" in the present specification mean that one or more embodiments of the present application include a particular feature, structure or characteristic described in conjunction with the embodiment. Thus, phrases such as "in one embodiment," "in some embodiments," "in other embodiments," and "in other embodiments" appearing in different places in the present specification do not necessarily refer to the same embodiment, but rather mean "one or more but not all embodiments," unless otherwise specifically emphasized. The terms "include," "comprising," "having," and variations thereof all mean "including but not limited to," unless otherwise specifically emphasized. "Multiple" means "two or more"

[0057] Example 1

[0058] Figure 1 Shows the preferred embodiment of this application ( Figure 1 A flow chart of a method for adjusting the well inclination before landing a horizontal well based on dual constraints of a marker layer and an angle, provided in the first embodiment of the present application, is shown. For ease of explanation, only the portion relevant to this embodiment is shown, and the method is described in conjunction with Block J of the Fuling shale gas exploration area. The details are as follows:

[0059] Step 1: Obtain data on standard wells, drilled horizontal wells, and horizontal wells to be drilled;

[0060] Step 2: Establishing the corresponding relationship between the standard well and the drilled horizontal well;

[0061] Step 3, obtain the model empirical coefficient by marking the corresponding standard well spacing target thickness h and angle γ;

[0062] Step 4, using the regression equation to establish the marker layer and angle chart of the standard well;

[0063] Step 5: Calculate the well inclination that should be adjusted from the horizontal well to the corresponding marker layer;

[0064] Step 6: Control the trajectory of the horizontal well to be drilled before landing according to the calculation results;

[0065] Step 7: Enter target A attitude control when the horizontal well to be drilled lands.

[0066] In one embodiment, in step 1, obtaining data on the standard well, the drilled horizontal well, and the horizontal well to be drilled includes:

[0067] Obtain geological stratification, lithology, natural gamma, gas logging, geochemistry, elements and other data of standard wells. Standard wells refer to vertical wells and pilot wells drilled in different parts of the structure.

[0068] Obtain data such as geological stratification, lithology, natural gamma, gas logging, and well deviation data tables for drilled horizontal wells; the specific methods are as follows:

[0069] Select existing horizontal wells within the region with formation dip variation less than 5°, thickness within 120 m above target point A with a relative error of less than 10% compared to standard wells, pre-landing displacement of 250-350 m, and an average full-angle change rate of landing trajectory less than 15° / 100 m, as representative wells for precise landing as modeling wells. If pre-landing displacement variation is significant, select another existing horizontal well and follow the same process to create the chart.

[0070] Pre-landing displacement refers to the difference in coordinate displacement. The azimuth should be adjusted as far as possible before landing. If not, the azimuth change should be controlled within 10°-20°. Azimuth exceeding the range will affect the calculation results of the apparent dip angle of the formation.

[0071] The well deviation data table includes data such as well depth, well deviation, azimuth, and coordinate displacement difference.

[0072] Obtain data such as lithology, natural gamma, gas logging, well depth while drilling, well inclination, and azimuth of the horizontal well to be drilled.

[0073] In one embodiment, in step 2, establishing a correspondence between the standard well and the drilled horizontal well includes:

[0074] By comparing the formations of the standard well with those of the drilled horizontal well, all marker layers S1 meters above target point A are identified and numbered from top to bottom. The optimal S1 meter is 120 meters.

[0075] Read the well depth, well deviation, and azimuth data from the first marker layer of the drilled horizontal well to target point A. The reading interval shall be based on the interval in the well deviation data table and shall be controlled within 10m.

[0076] By comparing the lithology, natural gamma, and gas logging characteristics of the marker layers of the standard well and the drilled horizontal well, the depth values ​​and well deviation data on the well deviation data table of the drilled horizontal well are marked to the corresponding standard well;

[0077] The standard well depth value corresponding to the mark is converted into the thickness h from the target point A, and the well inclination data is converted into the angle γ, which refers to the angle between the trajectory line and the formation.

[0078] Convert the standard well depth value corresponding to the mark into the thickness h from target point A:

[0079] The conversion is performed according to the following formula:

[0080] Thickness from target point A h = depth of target point A in standard well - depth corresponding to the marker layer in standard well

[0081] In one embodiment, in step 3, obtaining the model empirical coefficient by marking the corresponding standard well spacing A target point thickness h and angle γ includes:

[0082] By marking the corresponding standard well distance target thickness h and angle γ data samples, draw the angle γ-distance target thickness h intersection diagram, as shown in Figure 3 As shown;

[0083] A polynomial regression equation is established with the target thickness h from A as the independent variable and the angle γ as the dependent variable;

[0084] Set the Y-intercept to 2.00, the polynomial order to 3, and find the model γ = Ah 3 +Bh 2 The empirical coefficients A, B, and C for the model with +Ch+2.00 are: When the Y-intercept is 2.00, the optimal fit is achieved at a 2.00-degree angle into target A. A polynomial order of 3 provides the best fit.

[0085] The model coefficient A has the dimension of ° / m 3 , B is ° / m 2 , the dimension of C is ° / m.

[0086] Taking the standard well A in Block J of the Fuling shale gas field as an example, the corresponding relationship between the standard well A and the drilled horizontal well B is established, and the model coefficients A=0.000028, B=-0.008321, C=0.971720, R 2 =0.984765.

[0087] In one embodiment, in step 4, establishing a marker layer and angle map of a standard well using a regression equation includes:

[0088] Draw a standard well from top to bottom, including the well depth, natural gamma, marker layer, lithology, and angle items.

[0089] Taking the standard well A in Block J of the Fuling shale gas field as an example, ResForm, Kaben, DGR3000 and other software were used to draw a chart from top to bottom including well depth, natural gamma, marker layer, lithology, angle and other items, such as Figure 4 shown.

[0090] In one embodiment, in step 5, the calculation of the well deviation that should be adjusted to the corresponding marker layer of the horizontal well to be drilled includes:

[0091] like Figure 2 As shown, according to the formula γ=90-α-β, the angle γ between the trajectory line and the formation is converted into the well inclination that should be adjusted to the corresponding marker layer of the horizontal well to be drilled;

[0092] Wherein, β is the apparent dip angle of the formation, where downdip is + and updip is -, unit is °; α is the well inclination angle, unit is °.

[0093] In one embodiment, in step 6, controlling the trajectory of the horizontal well to be drilled before landing according to the calculation results includes:

[0094] Adopting the principle of adjacent similarity, the apparent dip angle of the current layer is obtained according to the result of the apparent dip angle calculation of the previous marker layer.

[0095] Determine the well inclination based on the angle, including

[0096] During actual drilling, if the apparent dip angles of adjacent strata change, for example, if the marker layer is pushed back, that is, if the drilling is not carried out to the next marker layer at the corresponding angle and well inclination, the exploration layer can be continued according to the angle γ calculated on the plate; if the marker layer is advanced, the well inclination can be rapidly increased to the required well inclination at the specified inclination rate according to the angle γ calculated on the plate.

[0097] In one embodiment, in step 7, the posture control of landing on target A in the horizontal well to be drilled includes:

[0098] When landing, the angle is determined according to the thickness of the target frame;

[0099] Among them, when the target frame thickness is K meters, control the angle of K degrees to enter the target frame A. For example, when the target frame thickness is 10m, control the angle of 10° to enter the target frame A, and when the target frame thickness is 2m, control the angle of 2° to enter the target frame A.

[0100] Under the premise of equivalent pre-landing displacement, the model system data of this invention can be directly applied to other work areas. It should be noted that the present invention does not specifically describe technical methods such as stratigraphic correlation and marker layer identification, which are common knowledge in the field. Furthermore, those skilled in the art will be able to make various improvements without departing from the main implementation steps of the present invention, and these improvements should also be considered within the scope of protection of this invention.

[0101] This method has been applied in more than 70 wells in oil and gas fields such as FL, FX, and HX, achieving 100% geological landing accuracy. The calculated angle between the formation and the trajectory is close to the actual landing control angle, meeting the needs of rapid on-site guidance. The method effectively solves the problem of rapidly calculating well inclination adjustment during the on-site landing phase. The method is simple and easy to implement, with a wide range of applications, providing an innovative technology for geological guidance.

[0102] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0103] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present application, and should all be included in the scope of protection of the present application.

Claims

1. A method for adjusting the well inclination before landing in a horizontal well based on dual constraints of marker layer and angle, characterized in that: include: Obtain data on standard wells, drilled horizontal wells, and horizontal wells to be drilled; Establish the corresponding relationship between standard wells and drilled horizontal wells; The model empirical coefficient is obtained by marking the corresponding standard well spacing A, target point thickness h, and angle γ; Use regression equation to establish the marker layer and angle chart of standard well; Calculate the well inclination that should be adjusted to the corresponding marker layer of the horizontal well to be drilled; Control the trajectory of the horizontal well to be drilled before landing according to the calculation results; Attitude control of entering target A when landing in the horizontal well to be drilled; The angle γ refers to the angle between the trajectory line and the formation, and the regression equation is a polynomial regression equation with the thickness h from the target A as the independent variable and the angle γ as the dependent variable.

2. The method for adjusting the horizontal well inclination before landing based on the dual constraints of the marker layer and the angle according to claim 1 is characterized in that: The data obtained for the standard well, the drilled horizontal well, and the horizontal well to be drilled include: Obtain geological stratification, lithology, natural gamma, gas logging, geochemistry, and element data of standard wells; Obtain geological stratification, lithology, natural gamma, gas logging, and well deviation data for drilled horizontal wells; Obtain lithology, natural gamma, gas logging, well depth while drilling, well inclination, and azimuth data for the steerable horizontal well to be drilled.

3. The method for adjusting the horizontal well inclination before landing based on the dual constraints of the marker layer and the angle according to claim 1 is characterized in that: The method for selecting the drilled horizontal wells includes: Representative drilled horizontal wells with relatively stable formation occurrence, thickness, displacement of 250-350 m before landing, average full-angle change rate of landing trajectory less than 15° / 100 m, and precise landing were selected as modeling wells.

4. The method for adjusting the horizontal well inclination before landing based on the dual constraints of the marker layer and the angle according to claim 1 is characterized in that: Establishing the corresponding relationship between the standard well and the drilled horizontal well includes: By comparing the formations of the standard well with those of the drilled horizontal well, all marker layers up to S1 meter from target point A are identified and numbered from top to bottom; Read the well depth, well inclination and azimuth data from the first marker layer to target point A in the drilled horizontal well; By comparing the lithology, natural gamma, and gas logging characteristics of the marker layers of the standard well and the drilled horizontal well, the depth values ​​and well deviation data on the well deviation data table of the drilled horizontal well are marked to the corresponding standard well; The standard well depth value corresponding to the mark is converted into the thickness h from the target point A, and the well inclination data is converted into the angle γ, which refers to the angle between the trajectory line and the formation.

5. The method for adjusting the horizontal well inclination before landing based on the dual constraints of marker layer and angle according to claim 1 is characterized in that: The model empirical coefficients obtained by marking the corresponding standard well spacing target thickness h and angle γ include: By marking the corresponding standard well distance target thickness h and angle γ data samples, draw the angle γ-distance target thickness h intersection diagram; A polynomial regression equation is established with the target thickness h from A as the independent variable and the angle γ as the dependent variable; Obtain the model γ=Ah 3 +Bh 2 +Ch+2.00 model empirical coefficients A, B, C.

6. The method for adjusting the horizontal well inclination before landing based on the dual constraints of the marker layer and the angle according to claim 1 is characterized in that: The method of establishing the marker layer and angle chart of the standard well by using the regression equation includes: Draw a standard well from top to bottom, including the well depth, natural gamma, marker layer, lithology, and angle items.

7. The method for adjusting the well inclination before landing of a horizontal well based on dual constraints of marker layer and angle according to claim 1, characterized in that: The calculation of the well deviation that should be adjusted from the horizontal well to the corresponding marker layer includes: According to the formula γ=90-α-β, the angle γ between the trajectory line and the formation is converted into the well inclination that should be adjusted from the horizontal well to the corresponding marker layer; Among them, β is the apparent dip of the formation, and α is the well inclination angle.

8. The method for adjusting the horizontal well inclination before landing based on the dual constraints of marker layer and angle according to claim 1 is characterized in that: The controlling of the trajectory of the horizontal well to be drilled before landing according to the calculation results includes: Adopting the principle of adjacent similarity, the apparent dip angle of the current layer is obtained according to the result of the apparent dip angle calculation of the previous marker layer. Determine the well inclination based on the angle, including During actual drilling, if the apparent dip angles of adjacent strata change, for example, if the marker layer is pushed back, that is, if the next marker layer is not drilled at the corresponding angle and well inclination, the exploration layer can be continued according to the angle γ calculated on the plate; if the marker layer is advanced, the well inclination can be quickly increased to the required well inclination according to the specified inclination rate according to the angle γ calculated on the plate.

9. The method for adjusting the horizontal well inclination before landing based on the dual constraints of the marker layer and the angle according to claim 1, characterized in that: The attitude control of landing on target A during the horizontal well to be drilled includes: When landing, the angle is determined according to the thickness of the target frame; Among them, when the target frame thickness is K meters, control the angle K degrees to enter the A target frame.

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