Thin oil layer bottom edge water reservoir horizontal well accurate target entering method
By establishing geological models and modified profile models, calculating the vertical depth of the target point, and adjusting the construction trajectory, the problems of trajectory design lag and parameter complexity of horizontal wells in thin oil layer bottom water reservoirs were solved, and precise target entry was achieved.
Patent Information
- Application Number
- CN202411106131.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-13
- Publication Date
- 2026-02-13
AI Technical Summary
Existing technologies for trajectory design and target prediction in horizontal wells in thin oil-bearing reservoirs with edge and bottom water suffer from apparent dip angle lag, complex parameter selection, and difficulty in combining well logging judgment, leading to difficulties in accurate target entry.
A geological model is established by collecting data from surrounding control wells, marker layers are selected, structural maps and well logging sequence models are generated, the profile geological model is corrected, the vertical depth of the target point is calculated, and the construction trajectory is adjusted to achieve precise target entry.
It improves the actual drilling control accuracy of horizontal wells, ensures the accuracy of well inclination angle and trajectory deviation, avoids drilling through or failure to land in time, and achieves precise target entry into thin oil layers.
Smart Images
Figure CN121519918A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of oilfield development, specifically relating to a method for precise target entry into horizontal wells in thin oil-bearing reservoirs with bottom edge water. Background Technology
[0002] Because the average oil layer thickness in thin-layer, edge-bottom-water reservoirs is only 0.7m-5m, while the edge-bottom-water thickness reaches 10m, the trajectory design, which is only 0.5m from the top of the oil layer, is crucial for controlling the advance velocity of the edge-bottom-water ridge, requiring high precision in actual drilling trajectory control. Yang Jiaxiang's patent CN 114991753 A, "A Target Prediction Method for Horizontal Well Geological Steering under Variable Azimuth Conditions," can predict the vertical depth of the target point to a certain extent, providing a basis for accurate target entry. However, in practice, the following shortcomings remain: ① The apparent dip angle often requires drilling horizontally until the marker layer is encountered, or it can be derived solely from adjacent control wells based on the vertical thickness and planar distance of the marker layer. The apparent dip angle calculation is often delayed or has poor accuracy. ② The selection of relevant parameters in the target point vertical depth formula is complex, making it difficult to meet the needs of fast-paced field operations. ③ Without combining well logging judgment, it is difficult to truly achieve accurate target entry in horizontal wells. Summary of the Invention
[0003] The purpose of this invention is to provide a method for precise target entry of horizontal wells in thin oil layer bottom water reservoirs, so as to correct the actual drilling target layer structure and target depth in a timely manner, ensure precise landing and accurate target entry of horizontal wells, and avoid situations where the well inclination angle is too large and the landing is not timely; or the well inclination angle is too small and the trajectory is too low or the target layer is drilled through.
[0004] The objective of this invention is achieved through the following technical means: a method for precise target entry into a horizontal well in a thin oil layer bottom-edge water reservoir, comprising the following steps:
[0005] Collect data on the wellhead coordinates, core elevation, well trajectory, completion logging, and oil-water layer data of the control wells surrounding the horizontal well to be drilled, and establish a geological model of the area surrounding the well.
[0006] Based on the surrounding geological model, select a marker layer above the target oil layer;
[0007] Based on the data of the marker layer and the target oil layer, a structural contour map of the top surface of the marker layer and the target oil layer is established. A structural map of the top surface of the layer is generated from the contour map, and a well logging sequence model is generated from the structural map of the top surface of the layer.
[0008] A profile geological model of the designed horizontal well was established based on the well logging sequence model;
[0009] Actual construction was carried out, and the stratigraphic profile was corrected based on the depth of the marker layer encountered during the actual construction process, and the dip angle θ of the marker layer was obtained.
[0010] According to the marker bed stratum dip angle θ, the predicted target point vertical depth is calculated;
[0011] According to the comparison between the predicted target point vertical depth and the designed target point vertical depth, specific data of stratum pushback or advance are obtained, according to the specific data of stratum pushback or advance, the middle target trajectory is redesigned, the subsequent middle target construction is guided, and thus the precise target entry is realized.
[0012] The multiple sets of drilling peripheral geologic models are established according to the surrounding control well wellhead coordinates of the to-be-drilled horizontal well, the crown block altitude, the well trajectory, the completion well logging and the oil-water layer data;
[0013] Corresponding marker beds are obtained for each set of drilling peripheral geologic models, if the error of each marker bed is less than 50% of the thickness of the target oil layer, the final predicted target point vertical depth is accurate.
[0014] The marker bed is vertically not more than 30m away from the target oil layer.
[0015] From the multiple sets of marker beds, a set of marker beds closest to the target oil layer is selected, contour maps, layer top surface structure maps and well logging sequence models are upgraded, and the profile geologic model passing the designed horizontal well is established.
[0016] When drilling, the speed is reduced from 6m / min to 1min / m~5min / m; the cuttings are changed from mudstone to fine sandstone and medium sandstone; the gas logging value is increased; when the total amount of the oil layer full hydrocarbon is 5 times or more higher than that of the top non-reservoir, it is indicated that the target entry has been realized.
[0017] The predicted target point vertical depth h2=h0+h1±L*tanθ, if the designed well construction trajectory is opposite to the stratum structure trend, it is -, and if the same, it is +, wherein, h0 is the actual drilled marker bed vertical depth of the positive drilling horizontal well; h1 is the thickness of the marker bed; L is the horizontal distance between the actual drilled marker bed of the positive drilling horizontal well and the designed target point of the horizontal well; and θ is the marker bed stratum dip angle;
[0018] The present application has the beneficial effects that: through the data of the existing well, the well logging sequence model and the profile geologic model passing the designed horizontal well are constructed, the model is corrected according to the drilled marker bed depth on site, more accurate parameters are obtained, the stratum pushback or advance amount is further predicted, the parameters involved in the calculation and correction are less, it is more suitable for the fast rhythm on site, and the accuracy is enough, which provides guidance for the precise target entry trajectory after the marker bed. BRIEF DESCRIPTION OF DRAWINGS
[0019] Figure 1 The flow chart of the thin oil layer bottom edge water reservoir horizontal well precise target entry method;
[0020] Figure 2 The corrected stratum model diagram;
[0021] The application will be described in further detail below in conjunction with the accompanying drawings and embodiments. DETAILED DESCRIPTION
[0022] Embodiment 1
[0023] As shown in the drawings, a thin oil layer bottom edge water reservoir horizontal well precise targeting method comprises the following steps: Figure 1
[0024] Collecting wellhead coordinates of control wells around the to-be-drilled horizontal well, compensation elevation, well trajectory, completion well logging, and oil and water layer data, and establishing a drilling surrounding geological model;
[0025] Collecting basic data of surrounding wells to conduct geological modeling of the region, so as to obtain subsequent marker layer division according to the geological modeling;
[0026] Selecting a marker layer above the target oil layer according to the surrounding geological model;
[0027] The marker layer is not more than 30m vertically away from the target oil layer.
[0028] According to the characteristics of the stable development of the marker layer in the whole region, two or more marker layers above the target oil layer are selected, and the marker layer is preferably not more than 30m vertically away from the target oil layer.
[0029] According to the marker layer and the target oil layer data, a structure contour map of the top surface of the marker layer and the target oil layer is established, a layer top surface structure map is generated from the contour map, and a well logging sequence model is generated from the layer top surface structure map.
[0030] According to the marker layer and the target oil layer data of the surrounding control wells, a structure contour map of the top surface of each marker layer and the target oil layer is established, a layer top surface structure map is generated from the contour map, and a well logging sequence model is generated from the layer top surface structure map.
[0031] A cross-section geological model of the designed horizontal well is established according to the well logging sequence model;
[0032] The cross-section geological model of the designed horizontal well, that is, on the basis of the previous overall model, a part of the to-be-drilled well, that is, the designed horizontal well, is selected to make a cross-section, and a cross-section geological model of the designed horizontal well is obtained.
[0033] Actual construction is carried out, and the cross-section stratum model is corrected according to the marker layer depth drilled during the actual construction process, and a marker layer stratum dip angle θ is obtained.
[0034] According to the previous marker layer data, actual construction is carried out to obtain the actual marker layer depth. Since the distance between the previously selected marker layer and the target oil layer is 0-30m, the thin oil layer will not be drilled at this time.
[0035] According to the actual drilling marker layer depth, the profile stratigraphic model is corrected, and the marker layer stratigraphic dip angle θ is obtained by using the stratigraphic dip angle calculation formula provided by the software.
[0036] According to the actual data of the field construction, the model parameters are corrected, and the marker layer stratigraphic dip angle θ is calculated by using the existing software.
[0037] According to the marker layer stratigraphic dip angle θ, the vertical depth of the predicted target point is calculated.
[0038] The vertical depth h2 of the predicted target point is h0+h1±Lxtanθ, if the design well construction trajectory is opposite to the stratigraphic structure trend, then it is -, and if it is the same, then it is +, wherein, h0 is the vertical depth of the actual drilling marker layer of the vertical drilling horizontal well; h1 is the thickness of the marker layer; L is the horizontal distance between the actual drilling marker layer of the vertical drilling horizontal well and the design target point of the horizontal well; and θ is the stratigraphic dip angle of the marker layer.
[0039] When the design well construction trajectory is opposite to the stratigraphic structure trend, h2=h0+h1-Lxtanθ, and when it is the same, h2=h0+h1+Lxtanθ.
[0040] h2 is the vertical depth of the predicted target point, h0 is the vertical depth of the actual drilling marker layer of the vertical drilling horizontal well, h1 is the thickness of the marker layer, L is the horizontal distance between the actual drilling marker layer of the vertical drilling horizontal well and the design target point of the horizontal well, and θ is the stratigraphic dip angle of the marker layer.
[0041] According to the comparison between the vertical depth of the predicted target point and the design target point, the specific data of the stratigraphic pushback or advance is obtained, and according to the specific data of the stratigraphic pushback or advance, the middle target trajectory is redesigned to guide the subsequent middle target construction, so as to realize accurate targeting.
[0042] According to the difference between the vertical depth of the predicted target point and the design target point, it can be known whether the stratigraphic layer is pushed back or advanced, and the specific amount of pushback or advance, and through the pushback or advance, the subsequent middle target trajectory is corrected, and combined with the display characteristics of the oil and gas layer, accurate targeting is realized.
[0043] Specifically, as shown in Figure 2 According to the actual drilling marker layer depth, the profile stratigraphic model is corrected, and the marker layer stratigraphic dip angle θ is obtained by using the stratigraphic dip angle calculation formula provided by the software.
[0044] The following formula is established in EXCEL: h2 = h0 + h1 + L x tan θ wherein: h2 is the predicted target vertical depth = 1558.53, unit m; h0 is the vertical depth of the actual drilled marker layer of the vertical well = 1548.96, unit m; h1 is the thickness of the marker layer = 9.45, unit m; L is the horizontal distance between the actual drilled marker layer of the vertical well and the design target of the horizontal well = 37.78, unit m; and θ is the dip angle of the marker layer = 0.2 (downdip), unit degree. The design target vertical depth is 1557.05 m. It is predicted that the stratum is pushed back by 1.48 m.
[0045] During the construction process, the logging display characteristics of the exposed oil and gas layer are accurately grasped. ① When the depth is 1626, the drilling time (m / min) is reduced from 6 min / m and above to 1 min / m~5 min / m; ② The cuttings change from mudstone to fine sandstone and medium sandstone; the gas logging value increases; the total amount of whole hydrocarbon of the exposed oil layer is 5 times higher than that of the top non-reservoir, and the component is at least C4 and above. It is indicated that the target has been achieved at this time.
[0046] The actual oil top and target point (i.e. point A in the figure) are at the depth of 1626 and the vertical depth of 1557.87, which is very close to the design target vertical depth of 1557.05.
[0047] According to the comparison between the predicted target vertical depth and the design target vertical depth, it is judged that the stratum is pushed back by 1.48 m, and the trajectory is adjusted in time on site, as shown in Figure 2 The accurate target is judged in combination with the display characteristics of the exposed oil and gas layer. From the actual drilling, the actual oil top vertical depth is 1556.55 m, the design oil top vertical depth is 1557.87 m, and the vertical depth is pushed back by about 1.32 m (design oil top vertical depth-actual oil top vertical depth).
[0048] According to the wellhead coordinates of the surrounding control well, the elevation of the supplement core, the well trajectory, the completion logging, and the oil and water layer data of the horizontal well to be drilled, a plurality of sets of drilling surrounding geological models are established;
[0049] For each set of drilling surrounding geological model, a corresponding marker layer is obtained. If the error of each marker layer is less than 50% of the thickness of the target oil layer, the final predicted target vertical depth is accurate.
[0050] From the plurality of marker layers, a set of marker layers closest to the target oil layer is selected, contour maps, layer top surface structure maps, and logging sequence models are upgraded, and a profile geological model passing through the design horizontal well is established.
[0051] When the drilling time is reduced from 6 m / min to 1 min / m~5 min / m; the cuttings change from mudstone to fine sandstone and medium sandstone; the gas logging value increases; the total amount of whole hydrocarbon of the exposed oil layer is 5 times higher than that of the top non-reservoir, and the component is at least C4 and above, it is indicated that the target has been achieved.
[0052] According to the wellhead coordinates of the control well around the horizontal well to be drilled, the elevation of the backup core, the well trajectory, the completion logging, and the oil-water layer data, multiple sets of drilling surrounding geological models can be established.
[0053] On the basis of the drilling surrounding geological model, the subsequent marker layer, contour map, layer top surface structure map, logging sequence model, and cross-section geological model of the designed horizontal well are also multiple sets.
[0054] According to the error of each set of marker layers, the accuracy of this prediction is first estimated for reference.
[0055] Specifically, the error range of the marker layer is compared with the thickness of the target oil layer. If the error range exceeds 50% of the thickness of the target oil layer, it can be considered that the prediction error may be large, and if it does not exceed 50%, it can be considered that the prediction result is accurate.
[0056] For example, the thickness of the target oil layer is only 1m, and the thickness of the marker layer is 1m and 2m. Therefore, it can be considered that the final prediction result error may be large.
[0057] In actual use, most of the standard layer positions are close, for example, within 5m range 0.5m, and there will be no large error, and the prediction is accurate.
[0058] This step only provides a reference for construction personnel, and in actual use, it can not be used, and the main construction is still based on the comparison of the predicted target vertical depth and the designed target vertical depth.
[0059] Due to multiple sets of standard layers, when calculating the predicted target vertical depth, the nearest set of standard layers to the target oil layer is selected to generate the structure contour map, layer top surface structure map, and logging sequence model, and further calculate the predicted target vertical depth.
[0060] A computing device includes a processing component and a storage component: the storage component stores one or more computer instructions, the one or more computer instructions are executed by the processing component to realize a thin oil layer bottom edge water oil reservoir horizontal well accurate targeting method.
[0061] A computer storage medium stores a computer program, and when the computer program is executed by a computer, a thin oil layer bottom edge water oil reservoir horizontal well accurate targeting method is realized.
Claims
1. A method for precise target insertion in horizontal wells of thin oil-bearing reservoirs with bottom-edge water, characterized in that, Includes the following steps: Collect data on the wellhead coordinates, core elevation, well trajectory, completion logging, and oil-water layer data of the control wells surrounding the horizontal well to be drilled, and establish a geological model of the area surrounding the well. Based on the surrounding geological model, select a marker layer above the target oil layer; Based on the data of the marker layer and the target oil layer, a structural contour map of the top surface of the marker layer and the target oil layer is established. A structural map of the top surface of the layer is generated from the contour map, and a well logging sequence model is generated from the structural map of the top surface of the layer. A profile geological model of the designed horizontal well was established based on the well logging sequence model; Actual construction was carried out, and the stratigraphic profile was corrected based on the depth of the marker layer encountered during the actual construction process, and the dip angle θ of the marker layer was obtained. Calculate the predicted vertical depth of the target point based on the dip angle θ of the marker layer; By comparing the predicted vertical depth of the target point with the designed vertical depth of the target point, specific data on whether the strata are pushed back or advanced are obtained. Based on the specific data on whether the strata are pushed back or advanced, the target trajectory is redesigned to guide subsequent target-hitting construction, thereby achieving accurate target entry.
2. The method for precise target entry into a horizontal well in a thin oil layer bottom-edge water reservoir according to claim 1, characterized in that: Based on the wellhead coordinates of the control wells around the horizontal well to be drilled, the core elevation, the well trajectory, the completion logging, and the oil and water layer data, multiple geological models around the well are established. For each set of geological models around the well, corresponding marker layers are obtained. If the error of each marker layer is less than 50% of the thickness of the target oil layer, the final predicted vertical depth of the target point is accurate.
3. A method for precise target entry into a horizontal well in a thin oil layer bottom-edge water reservoir according to claim 1 or 2, characterized in that: The vertical distance between the marker layer and the target oil layer is no more than 30m.
4. The method for precise target entry into a horizontal well in a thin oil layer bottom-edge water reservoir according to claim 2, characterized in that: From multiple sets of marker layers, the set that is closest to the target oil layer is selected, and contour maps, top surface structural maps, and well logging sequence models are generated. A cross-sectional geological model of the designed horizontal well is also established.
5. The method for precise target entry into a horizontal well in a thin oil layer bottom-edge water reservoir according to claim 1, characterized in that: When the drilling speed decreases from 6 m / min to 1 min / m to 5 min / m; the cuttings change from mudstone to fine sandstone and medium sandstone; the gas measurement value increases; and the total hydrocarbon content of the oil layer is 5 times or more higher than that of the top non-reservoir, it indicates that the target has been successfully hit.
6. The method for precise target entry into a horizontal well in a thin oil layer bottom-edge water reservoir according to claim 1, characterized in that: The predicted vertical depth of the target point is h2 = h0 + h1 ± L × tanθ. If the design well construction trajectory is opposite to the formation structure trend, it is -; if they are the same, it is +. Where h0 is the vertical depth of the actual drilled marker layer in the horizontal well; h1 is the thickness of the marker layer; L is the horizontal distance between the actual drilled marker layer in the horizontal well and the design target point of the horizontal well; and θ is the dip angle of the marker layer formation.