A horizontal well landing analysis chart method

Abstract

The present invention discloses an analysis chart method for horizontal well landing. The present invention realizes automatic analysis and prediction of horizontal well landing operations through a series of algorithms, thereby reducing calculation errors caused by differences in personnel experience. The present invention adopts multi-neighboring well marker layer comparison to predict the position of the target layer being drilled, thereby improving the prediction accuracy of the target layer position. The present invention proposes a landing window calculation method, which quantitatively calculates the drilling trajectory control by calculating the upper and lower boundary vertical depths. The present invention proposes an analysis chart method for horizontal well landing operations, which organically combines geological prediction analysis with engineering operation implementation, facilitates operators with different professional backgrounds to quickly obtain key information on landing operations, realizes process control of landing operations, and improves decision-making analysis efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of upstream exploration and development drilling of oil, natural gas, etc., and in particular to an analysis chart method for horizontal well landing. Background Art

[0002] The horizontal wellbore trajectory control includes two key well sections: the landing section and the horizontal section. The landing section is the basis of the horizontal section operation. Good landing operation can reduce drilling risks such as filling the well and side drilling due to drilling through the reservoir, and large adjustments to the wellbore trajectory at the beginning of the horizontal section. Block operators usually use geosteering drilling technology to support landing operations to improve their success rate.

[0003] The landing operation of a horizontal well essentially means placing the drilling trajectory into the target layer at the correct depth, inclination and azimuth. To this end, the landing operation requires a close combination of formation position prediction and drilling trajectory control. Due to the limitations of the prediction method, the vertical depth error of the formation position prediction ranges from a few meters to more than ten meters, and the corresponding trajectory adjustment needs to be dynamically synchronized with the prediction results. Usually, a multi-professional downhole team (including geological guidance, downhole logging, directional wells, reservoirs, geophysics, and geology, etc.) is required to follow the well to issue operation instructions. Therefore, there are problems such as the difference in personnel experience affecting the prediction accuracy, resulting in poor landing trajectory morphology and affecting horizontal section operations.

[0004] This study proposed the use of analytical charts to analyze the landing operation process, and used algorithmic processes to achieve automatic analysis and prediction of the landing operation process, eliminating calculation errors caused by differences in personnel experience; it is convenient for analysts to intuitively obtain key information on the landing operation, thereby improving prediction accuracy, optimizing landing operations, improving analysis efficiency, and achieving process control of landing operations. Summary of the invention

[0005] The present invention overcomes the shortcomings of the prior art. The horizontal well landing operation process is affected by personnel experience, resulting in large prediction errors and low decision-making analysis efficiency. An analysis chart method for horizontal well landing is proposed. The method organically combines geological prediction and engineering implementation and displays them in an intuitive graphical form, making it convenient for operators with different professional backgrounds to quickly obtain key information on landing operations, realize process control of landing operations, and improve decision-making analysis efficiency.

[0006] The present invention is achieved through the following technical solutions:

[0007] A horizontal well landing analysis chart method is performed according to the following steps:

[0008] Step 1, performing logging curve comparison, comparing and analyzing the morphological characteristics of the logging curve of the active well and the logging curve of the adjacent well, and realizing the formation position correction of the active well curve relative to the adjacent well curve;

[0009] Step 2, dividing the marker layer into marker layer groups of the logging curve of the drilling well and the logging curve of the adjacent well;

[0010] Step 3: perform marker layer comparison and matching, and pair the marker layer groups of the drilling well and the adjacent wells;

[0011] Step 4, calculating the inclination angle of the target layer;

[0012] Step 5, calculate the landing window and obtain the vertical depths of the upper and lower boundaries of the landing window;

[0013] Step 6, predicting the vertical depth of the target layer;

[0014] Step 7: Display the results obtained in steps 5 and 6 through analysis charts. Technicians can obtain landing operation conditions and make decisions through intuitive graphic analysis.

[0015] In step 1, formation position correction refers to using the positive drilling curve as a template to find formations with similar logging response characteristics on the adjacent well curves;

[0016] In step 1, the stratigraphic correlation is performed using the Pearson correlation coefficient, which is as follows:

[0017]

[0018] In formula (1), x i With y i is the sample value of the discrete sequence of different logging curves, and N is the number of sequence samples.

[0019] In step 2, the marker layer refers to a stratum with obvious logging response characteristics and relatively stable sedimentary development in the block; it is identified and divided based on the logging response characteristics;

[0020] In step 2, the marker layer division adopts the curve activity calculation method, and the calculation formula is as follows:

[0021]

[0022] In formula (2), E(d) is the curve activity value, n is the window of activity analysis, x(i) is the sequence sample, is the mean of the sequence samples in the window. The five lines with the highest activity values ​​are selected as the division results of the marker layer, and the calculation results are shown as the black horizontal lines in Figure 1-b / c / d.

[0023] In step 3, marker layer pairing refers to associating strata with similar logging response characteristics as the same stratum;

[0024] In step 4, according to the marker layer pairing results, assuming that there are paired marker layers A and A`, the vertical depths corresponding to the marker layers can be obtained as TVD_A and TVD_A`, and the inclined depths as MD_A and MD_A` according to the trajectory parameters of the drilling well and the adjacent wells. The calculation formula for the formation apparent dip angle Dip is as follows:

[0025]

[0026] In step 5, the landing window is defined as shown in the attached Figure 2 , the solid line curve is the designed drilling trajectory, K is the trajectory inclination point, A is the designed landing point, B is the designed completion point, assuming that the current drill bit position is M, the shallowest and deepest vertical depths that the trajectory can reach are the upper boundary (landing point S) and lower boundary (landing point D) of the landing window respectively;

[0027] The calculation formula for the vertical depth of the upper boundary of the landing window is as follows:

[0028]

[0029] In formula (4), TVD_S is the vertical depth of the upper boundary S, TVD_M is the vertical depth of M, Dip is the formation dip, and BR is the slope increase rate. The slope increase rate is usually set by combining the tool build-up rate and the maximum curvature limit of the trajectory. The calculation formula for the vertical depth of the lower boundary of the landing window is as follows:

[0030]

[0031]

[0032] In formulas (5) and (6), TVD_D is the vertical depth of the lower boundary D, VSEC_A is the displacement of A, VSEC_S is the displacement of S, VSEC_M is the displacement of M, θ 1 is the well deviation M;

[0033] In step 6, the vertical depth of the target layer is predicted based on the marker layer pairing result obtained in step 3, assuming that the interval between the marker layer and the target layer of the adjacent well remains unchanged, so as to predict the vertical depth position of the target layer being drilled;

[0034] In step 7, as shown in the attached Figure 3 The method of drawing the analysis chart is to express the vertical depth range of the target layer using a box diagram, and the landing window range using a dotted line.

[0035] The advantages and beneficial effects of the present invention are as follows: the present invention realizes automatic analysis and prediction of horizontal well landing operations through a series of algorithms, thereby reducing calculation errors caused by differences in personnel experience; the present invention adopts multi-neighboring well marker layer comparison to predict the location of the target layer being drilled, thereby improving the prediction accuracy of the target layer location; the present invention proposes a landing window calculation method, which quantitatively calculates the drilling trajectory control by calculating the upper and lower boundary vertical depths; the present invention proposes an analysis chart method for horizontal well landing operations, which organically combines geological prediction analysis with engineering operation implementation, facilitates operators with different professional backgrounds to quickly obtain key information on landing operations, realizes process control of landing operations, and improves decision-making analysis efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a schematic diagram of the comparison division of the marker layer.

[0037] Figure 2 This is a schematic diagram of the landing window.

[0038] Figure 3 Schematic diagram of the analysis plate.

[0039] Figure 4 It is a flow chart of the present invention.

[0040] For ordinary technicians in this field, other relevant drawings can be obtained based on the above drawings without any creative work. DETAILED DESCRIPTION

[0041] The technical solution of the present invention is further described below in conjunction with specific embodiments.

[0042] Example

[0043] A horizontal well landing analysis chart method is performed according to the following steps:

[0044] a. Comparison of logging curves

[0045] The morphological characteristics of the logging curve of the active well and the logging curve of the adjacent well are compared and analyzed to realize the formation position correction of the active well curve relative to the adjacent well curve. The logging curve is not limited to a specific logging project. In this case, the gamma logging curve is used for comparison. Figure 1 a is the adjacent well curve, Figure 1 d is the positive drilling curve. Taking the positive drilling logging curve as a sample, we traverse the different depth positions of the adjacent wells for similarity search and comparison, and calculate the Pearson correlation coefficient of the two curves (Formula 1). i With y i is the sample value of the discrete sequence of different logging curves, and N is the number of sequence samples. The PCC value range is [-1,1]. The result of 1 indicates that the two sequences are most strongly correlated, and -1 indicates that the two sequences are least correlated.

[0046]

[0047] We can get two possible comparison conclusions. After enlarging the vertical scale, Figure 1 The correlation coefficients of 1b and 1c are 0.91 and 0.62, respectively, indicating that the correlation of the results of comparison 1 is higher.

[0048] b. Division of marker layer groups

[0049] Marker layers refer to strata with obvious logging response characteristics and relatively stable sedimentary development within the block; they are usually identified and divided by analysts based on logging response characteristics to identify the stratigraphic structure and sedimentary distribution between wells. The marker layer group of the drilling curve and the adjacent well curve is automatically divided, and the curve activity calculation method is adopted. The calculation formula is as follows:

[0050]

[0051] Where E(d) is the curve activity value, n is the window of activity analysis, x(i) is the sequence sample, is the sample mean of the sequence in the window. The five sequences with the highest activity values ​​are selected as the result sequence of the division of the marker layer, and the calculation results are shown as the black horizontal lines in Figure 1-b / c / d.

[0052] c. Marker layer comparison and matching

[0053] The Pearson matrix of the two marker layer sequences is established to achieve automatic pairing of the two marker layer sequences. Since there are multiple pairing possibilities between the two marker layer sequences, the matrix grid represents the Pearson coefficient values ​​between marker layers of different sequences as shown in Table 1. The best marker layer pairing scheme is obtained by comparing the cumulative Pearson coefficient values ​​of different combinations of marker layer comparisons, as shown in Table 1, which shows the best scheme of BB`-CC`-EE` (corresponding to the well logging curves 1b and 1d).

[0054] Table 1 Pearson matrix for automatic comparison of landmark layers

[0055] Table 1 Person Matrix used for Automatic Marker Correlation

[0056]

[0057] d. Calculation of target layer inclination

[0058] Calculate the formation dip. Assuming there are matching marker layers A and A`, their corresponding vertical depths are TVD_A and TVD_A`, and their oblique depths are MD_A and MD_A`, then the calculation formula for the apparent dip Dip is as follows:

[0059]

[0060] e. Landing window calculation

[0061] The calculation formula for the vertical depth of the upper boundary of the landing window is as follows:

[0062]

[0063] In formula (2), TVD_S is the vertical depth S, TVD_M is the vertical depth M, Dip is the formation dip, and BR is the slope increase rate. The slope increase rate is usually set by combining the tool build-up rate and the maximum curvature limit of the trajectory. The maximum curvature limit of the trajectory is obtained from the drilling design. For example, the horizontal section trajectory curvature requirement is <3deg·30m -1 .

[0064] The calculation formula for the vertical depth of the lower boundary of the landing window is as follows:

[0065]

[0066]

[0067] In formulas (3) and (4), VSEC_A is the A displacement, VSEC_S is the S displacement, VSEC_M is the M displacement, and θ 1 It is the M well inclination.

[0068] f. Prediction of vertical depth of target layer

[0069] Automatically predict the vertical depth range of the target layer. Using the marker layer comparison and matching results obtained in step c, the vertical depth of the target layer being drilled is predicted according to the interlayer spacing of the marker layers in the adjacent wells, that is, assuming that the interlayer spacing from the marker layer to the target layer in the adjacent wells remains unchanged. Because the predicted values ​​of different adjacent wells and different marker layers vary, the vertical depth distribution range of the target layer can be obtained after statistics.

[0070] g. Draw the analysis board

[0071] As attached Figure 3 As shown, the horizontal axis of the figure is the horizontal displacement of the trajectory, and the vertical axis is the vertical depth. First, the target layer prediction results are marked along the horizontal axis using the box plot method, where the red line of the box plot is the median value of the statistical results; secondly, the landing window prediction results are marked along the horizontal axis using the point-line diagram method, with the upper boundary in red and the lower boundary in blue. The thick black solid line in the figure is the actual drilling trajectory, and the thin blue solid line is the designed drilling trajectory. The analysis conclusions are as follows:

[0072] (1) During the landing operation, the error range of the target layer prediction reached 3 to 6 meters, but the median line of the box plot was close to the actual formation depth line, accurately indicating the depth of the target layer, indicating that the target layer prediction result obtained by comparing the marker layers of multiple adjacent wells was relatively accurate;

[0073] (2) During the landing decision-making process, the guidance team selected the top of the box data as the landing window, that is, the decision was made based on the comparison results of individual wells. At the horizontal displacement of 270m, it was decided to increase the inclination in advance. At 280m, the vertical depth of the target layer exceeded the upper boundary of the landing window, resulting in the failure of the first landing. Subsequently, the well inclination had to be lowered for a second landing to explore the target layer, and ultimately nearly 65m of horizontal displacement was wasted. The step-like trajectory morphology left hidden dangers for subsequent horizontal drilling and completion operations;

[0074] (3) By analyzing the chart, it can be found that the landing window of the overlying stratum segment is much larger than the predicted range of the target layer. It is not recommended to intervene in the guidance too early, but intervention too late will lose the best time for adjustment.

[0075] (4) The analysis chart shows that the current takeover plan is radical and prone to landing failure. In order to reduce operating costs, block operators usually require the guidance technical service team to intervene later. In this case, the guidance team took over the well at a well inclination of 80 degrees according to the operator's requirements. At a displacement of 260 meters (well inclination of 80 degrees), the predicted range of the target layer of the well was close to the lower boundary of the landing window, and there was little room for trajectory adjustment after taking over. As a reference for future wells to be drilled in the block, the takeover plan can be optimized as follows: advance the guidance takeover point to a displacement of 220 to 240 meters (well inclination of 72 to 76 degrees), that is, take over when the box chart is located in the middle of the landing window.

[0076] The present invention is described above by way of example. It should be noted that, without departing from the core of the present invention, any simple deformation, modification or other equivalent replacement that can be made by a person skilled in the art without inventive effort falls within the protection scope of the present invention.

Claims

1. A horizontal well landing analysis chart method, characterized in that: Follow the steps below: Step 1, performing logging curve comparison, comparing and analyzing the morphological characteristics of the logging curve of the active well and the logging curve of the adjacent well, and realizing the formation position correction of the active well curve relative to the adjacent well curve; Step 2, dividing the marker layer into marker layer groups of the logging curve of the drilling well and the logging curve of the adjacent well; Step 3: perform marker layer comparison and matching, and pair the marker layer groups of the drilling well and the adjacent wells; Step 4, calculating the inclination angle of the target layer; Step 5, calculate the landing window and obtain the vertical depths of the upper and lower boundaries of the landing window; in step 5, the solid line curve is assumed to be the designed drilling trajectory, K is the trajectory inclination point, A is the designed landing point, B is the designed drilling completion point, the current drill bit position is assumed to be M, the shallowest and deepest vertical depths that the trajectory can reach are the upper and lower boundaries of the landing window, respectively, the landing point of the upper boundary is S, and the landing point of the lower boundary is D; The calculation formula for the vertical depth of the upper boundary of the landing window is as follows: In formula (4), TVD_S is the vertical depth of the upper boundary S, TVD_M is the vertical depth of M, Dip is the formation dip, BR is the slope increase rate, and the slope increase rate is set based on the tool build rate and the maximum curvature limit of the trajectory. The calculation formula for the vertical depth of the lower boundary of the landing window is as follows: In formulas (5) and (6), TVD_D is the vertical depth of the lower boundary D, VSEC_A is the A displacement, VSEC_S is the S displacement, and VSEC_M is the M displacement; Step 6, predicting the vertical depth of the target layer; Step 7: Display the results obtained in steps 5 and 6 through analysis charts. Technicians can obtain landing operation conditions and make decisions through intuitive graphic analysis.

2. The horizontal well landing analysis chart method according to claim 1, characterized in that: In step 1, formation position correction refers to using the positive drilling curve as a template to find formations with similar logging response characteristics on the adjacent well curves.

3. The horizontal well landing analysis chart method according to claim 1, characterized in that: In step 1, the stratigraphic correlation is performed using the Pearson correlation coefficient, which is as follows: In formula (1), x i With y i is the sample value of the discrete sequence of different logging curves, and N is the number of sequence samples.

4. The horizontal well landing analysis chart method according to claim 1, characterized in that: In step 2, the marker layer refers to a stratum with obvious logging response characteristics and stable sedimentary development in the block; it is identified and divided based on the logging response characteristics.

5. The horizontal well landing analysis chart method according to claim 1, characterized in that: In step 2, the marker layer division adopts the curve activity calculation method, and the calculation formula is as follows: In formula (2), E(d) is the curve activity value, n is the window of activity analysis, x(i) is the sequence sample, and the five samples with the highest activity values ​​are selected as the division results of the marker layer.

6. The horizontal well landing analysis chart method according to claim 1, characterized in that: In step 3, marker layer pairing refers to associating strata with similar logging response characteristics as the same stratum.

7. The horizontal well landing analysis chart method according to claim 1, characterized in that: In step 4, according to the marker layer pairing results, paired marker layers A and A' are set. According to the trajectory parameters of the drilling well and the adjacent wells, the vertical depths of the marker layers are obtained as TVD_A and TVD_A', and the inclined depths are obtained as MD_A and MD_A'. The calculation formula of the formation apparent dip angle Dip is as follows:

8. The horizontal well landing analysis chart method according to claim 1, characterized in that: In step 6, the vertical depth of the target layer is predicted based on the marker layer pairing result obtained in step 3, assuming that the interlayer distance from the marker layer of the adjacent well to the target layer remains unchanged, so as to predict the vertical depth position of the target layer being drilled.

9. The horizontal well landing analysis chart method according to claim 1, characterized in that: In step 7, the method of drawing the analysis chart is to express the vertical depth range of the target layer using a box diagram and the landing window range using a dotted line.

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