A method for geosteering a horizontal well

Abstract

The application discloses a horizontal well geosteering method, comprising the following steps: acquiring basic data of adjacent wells around a to-be-drilled horizontal well; comparing target reservoirs to obtain the numerical values of the top depth and the bottom depth of the target reservoirs of the adjacent wells and the predicted values of the top depth and the bottom depth of the to-be-drilled horizontal well; comparing X-ray element data to predict the sandstone types of the target reservoirs and the reaction characteristics of the X-ray element data; obtaining the reservoir thicknesses of each adjacent well and the to-be-drilled horizontal well, and establishing a target reservoir thickness model; when the to-be-drilled horizontal well is under construction, drilling to a target point, analyzing and judging whether the actual sandstone type of a drilled formation is the predicted sandstone type, analyzing whether the actual sandstone type is consistent with the predicted value, and when the results are all yes, determining that the model is correct, and continuing to perform horizontal well geosteering. The method can timely correct the prediction result of a seismic inversion reservoir, provide a basis for trajectory adjustment of horizontal well construction, improve the drilling rate of the reservoir, and improve the success rate of trajectory adjustment.

Description

Technical Field

[0001] This invention belongs to the field of geological exploration technology, and in particular relates to a horizontal well geological steering method. Background Technology

[0002] Geological steering is an important construction step in horizontal well drilling operations. On-site geological steering engineers need to establish accurate geological models to predict the development of strata in the horizontal section. Currently, there are two commonly used methods: one is to use seismic data, using inverted seismic body models or seismic-based 3D geological models for geological steering; the other is to use logging data, using logging-while-drilling data, including but not limited to logging-while-drilling gamma, logging-while-drilling azimuth gamma, electromagnetic resistivity, and azimuth gamma imaging logging methods for geological steering.

[0003] However, there are some problems with using seismic data for geological guidance. The seismic inversion results are uncertain, and there are multiple solutions when converting the seismic inversion results into geological understanding. At the same time, during the conversion of the seismic body from the time domain to the depth domain, there are certain systematic errors between the time-depth conversion and the depth at the construction site due to factors such as synthetic records and wavelet selection. The disadvantage of using well logging data for geological guidance is that the depth returned by the well logging data is inconsistent with the actual drilling depth. The lag depth is determined by different well logging instruments. When drilling encounters non-reservoir information, the lagging data cannot provide timely decision support for geological guidance. Summary of the Invention

[0004] To address the aforementioned issues, this invention provides a horizontal well geological steering method that can promptly correct seismic inversion predictions of reservoirs, providing a basis for trajectory adjustment during horizontal well construction, thereby increasing both the reservoir encounter rate and the success rate of trajectory adjustment.

[0005] The present invention provides a horizontal well geological steering method comprising:

[0006] Acquire basic data from neighboring wells surrounding the horizontal well to be drilled, including lithological data, total hydrocarbon data, X-ray elemental data, and directional data;

[0007] Using the directional data, the depth of the adjacent wells is corrected from the inclined depth to the vertical depth. Then, the target reservoirs of each adjacent well are compared to obtain the values ​​of the top and bottom depths of the target reservoirs of the adjacent wells, as well as the predicted values ​​of the top and bottom depths of the target reservoirs of the horizontal well to be drilled.

[0008] By analyzing and comparing the X-ray elemental data, the target reservoir sandstone type and X-ray elemental data response characteristics of the area where the horizontal well to be drilled and the surrounding adjacent wells are located can be predicted.

[0009] The difference between the top and bottom depths of the target reservoir in the adjacent wells and the predicted difference between the top and bottom depths of the target reservoir in the horizontal well to be drilled are calculated to obtain the reservoir thickness of each adjacent well and the horizontal well to be drilled. A target reservoir thickness model is then established. Simultaneously, based on the values ​​of the top and bottom depths of the target reservoir in the adjacent wells and the predicted values ​​of the top and bottom depths of the target reservoir in the horizontal well to be drilled, a reservoir top structure model and a reservoir bottom structure model are established. Using the projection of the trajectory of the horizontal well to be drilled onto the target reservoir thickness model, the reservoir top structure model, and the reservoir bottom structure model, the horizontal reservoir thickness is predicted. The changes in reservoir thickness and reservoir structure in the horizontal section are analyzed. A target point is set at preset intervals in the horizontal section. The coordinates of the target point are projected onto the target reservoir thickness model, the reservoir top structure model, and the reservoir bottom structure model to obtain the reservoir top depth, reservoir bottom depth, and reservoir lithology parameters at the target point. Based on the reservoir lithology parameters, the target reservoir sandstone type in the area where the horizontal well to be drilled and the surrounding adjacent wells are located, and the X-ray element data response characteristics, the predicted sandstone type and predicted X-ray element data response characteristics of this target point are obtained.

[0010] When drilling a horizontal well, lithological and total hydrocarbon data of the horizontal well are obtained at the target point. These data are compared with those of the adjacent well to analyze and determine whether the actual sandstone type of the encountered formation is the predicted sandstone type. At the same time, X-ray elemental analysis is used to obtain the measured values ​​of the X-ray elemental response characteristics of the sandstone and analyze whether they match the predicted values. If all the results are yes, the target reservoir thickness model, the reservoir top structure model, and the reservoir bottom structure model are determined to be correct models, and the horizontal well geological steering is continued based on these models.

[0011] Preferably, the above-mentioned horizontal well geological steering method further includes:

[0012] If at least one of the lithological data, total hydrocarbon data, and measured values ​​of X-ray elemental reaction characteristics of the cuttings of the horizontal well to be drilled does not conform to the prediction results of the target reservoir thickness model, the reservoir top structure model, and the reservoir bottom structure model, then the reservoir sandstone variation is analyzed based on the lithological data of the horizontal well to be drilled, and the target reservoir thickness model, the reservoir top structure model, and the reservoir bottom structure model are updated and corrected until the predicted values ​​match the actual drilling results. Geological steering construction continues based on the corrected target reservoir thickness model, the reservoir top structure model, and the reservoir bottom structure model.

[0013] Preferably, the above-mentioned horizontal well geological steering method further includes:

[0014] When drilling horizontal wells, if non-reservoir mudstone is encountered, the mudstone cuttings are compared with the top and bottom mudstone of the reservoir in the adjacent well. X-ray elemental analysis is used to analyze the encountered reservoir cuttings. The results of this analysis are quantitatively compared with the elemental analysis results of the top and bottom mudstone of the reservoir in the adjacent well before drilling to determine whether the trajectory is top or bottom reservoir emergence or encountering non-reservoir mudstone interlayers developed within the reservoir. Based on the determination results, the target reservoir thickness model, the reservoir top structure model, and the reservoir bottom structure model are updated and corrected, and geological steering construction continues.

[0015] Preferably, in the above-mentioned horizontal well geological steering method, the lithological data includes whether it is sandstone or mudstone.

[0016] Preferably, in the above-mentioned horizontal well geological steering method, the X-ray elemental data includes elemental data of Si, Al, Fe, K, Na, Mg, and Ca.

[0017] Preferably, in the above-mentioned horizontal well geological steering method, the orientation data includes well depth, well inclination, and azimuth data.

[0018] Preferably, in the above-described horizontal well geological steering method, the prediction of the target reservoir sandstone type in the area where the horizontal well to be drilled and the surrounding adjacent wells are located includes:

[0019] Predict whether the target reservoir in the area where the horizontal well to be drilled and the surrounding adjacent wells are located is quartz sandstone, lithic quartz sandstone, or feldspar sandstone.

[0020] Preferably, in the above-mentioned horizontal well geological steering method, the X-ray elemental data response characteristics include:

[0021] The reaction characteristics of seven common elements (Si, Al, Fe, K, Na, Mg, and Ca) and the reaction characteristics of Si / Al and Fe / Al combination elements.

[0022] Preferably, in the above-mentioned horizontal well geological steering method, the preset interval is 50 meters, 100 meters or 150 meters.

[0023] As described above, the horizontal well geological steering method provided by this invention includes: acquiring basic data from neighboring wells surrounding the horizontal well to be drilled, including lithological data, total hydrocarbon data, X-ray elemental data, and directional data; using the directional data to correct the depth of the neighboring wells from oblique depth to vertical depth; comparing the target reservoirs of each neighboring well to obtain the numerical values ​​of the top and bottom depths of the target reservoirs in the neighboring wells and the predicted values ​​of the top and bottom depths of the target reservoirs in the horizontal well to be drilled; analyzing and comparing the X-ray elemental data to predict the sandstone type and X-ray elemental response characteristics of the target reservoirs in the area where the horizontal well to be drilled and the surrounding neighboring wells are located; and calculating... Calculate the difference between the top and bottom depths of the target reservoir in the adjacent wells and the predicted difference between the top and bottom depths of the target reservoir in the horizontal well to be drilled, to obtain the reservoir thickness of each adjacent well and the horizontal well to be drilled, and establish a target reservoir thickness model. Simultaneously, based on the values ​​of the top and bottom depths of the target reservoir in the adjacent wells and the predicted values ​​of the top and bottom depths of the target reservoir in the horizontal well to be drilled, establish a reservoir top structure model and a reservoir bottom structure model. Using the projection of the horizontal well trajectory onto the target reservoir thickness model, the reservoir top structure model, and the reservoir bottom structure model, predict the changes in reservoir thickness and reservoir structure in the horizontal section. Divide the horizontal section into sections at intervals... A target point is set at a preset interval. The target point coordinates are projected onto the target reservoir thickness model, the reservoir top structure model, and the reservoir bottom structure model to obtain the reservoir top depth, reservoir bottom depth, and reservoir lithology parameters at the target point. Based on the reservoir lithology parameters and the target reservoir sandstone type and X-ray elemental data response characteristics of the area where the horizontal well to be drilled and the surrounding adjacent wells are located, the predicted sandstone type and predicted X-ray elemental data response characteristics of this target point are obtained. When drilling the horizontal well to be drilled, the lithology data and total hydrocarbon data of the horizontal well to be drilled are obtained at the target point and compared with the lithology data and total hydrocarbon data of the adjacent wells. By comparing and analyzing the actual sandstone type of the drilled strata, it is determined whether the actual sandstone type is the predicted sandstone type. At the same time, X-ray elemental analysis is used to obtain the measured values ​​of the X-ray elemental response characteristics of the sandstone, and it is analyzed whether they are consistent with the predicted values ​​of the X-ray elemental response characteristics. When the results are all yes, the target reservoir thickness model, the reservoir top structure model, and the reservoir bottom structure model are determined to be the correct models, and horizontal well geological guidance is continued based on them. Therefore, the seismic inversion prediction of reservoir results can be corrected in a timely manner, providing a basis for adjusting the trajectory of horizontal well construction, improving the reservoir drilling rate, and improving the success rate of trajectory adjustment. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of an embodiment of a horizontal well geological steering method provided by the present invention;

[0026] Figure 2 A model diagram of sand body thickness in well JPH-428;

[0027] Figure 3 This is a cross-sectional view of the sand body structure model of the target layer in well JPH-428;

[0028] Figure 4 Geological steering trajectory diagram of well JPH-428 during actual drilling;

[0029] Figure 5 A schematic diagram illustrating the interpretation of quartz sandstone at point A of well JPH-428 using elemental analysis techniques;

[0030] Figure 6 A schematic diagram illustrating the interpretation of lithic sandstone using elemental analysis techniques in well JPH-325;

[0031] Figure 7 A schematic diagram of the cyclic characteristics of sand bodies;

[0032] Figure 8 A schematic diagram showing the characteristics of sedimentary facies;

[0033] Figure 9 This is a revised sand body thickness model diagram for well JPH-428.

[0034] Figure 10 This is the revised geological steering trajectory diagram of well JPH-428 after actual drilling.

[0035] Figure 11 Elemental logging diagram of the horizontal section of well JPH-428. Detailed Implementation

[0036] The core of this invention is to provide a horizontal well geological steering method that can promptly correct the results of seismic inversion prediction of reservoirs, provide a basis for adjusting the trajectory of horizontal well construction, and improve the reservoir drilling rate while increasing the success rate of trajectory adjustment.

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] An example implementation of the horizontal well geological steering method provided by this invention. Figure 1 As shown, Figure 1 This is a schematic diagram of an embodiment of a horizontal well geological steering method provided by the present invention, which may include the following steps:

[0039] S1: Obtain basic data from neighboring wells around the horizontal well to be drilled, including lithological data, total hydrocarbon data, X-ray elemental data, and directional data;

[0040] Specifically, the lithological data can include whether it is sandstone or mudstone, the total hydrocarbon data is the total hydrocarbon data while drilling, and drilling time data can also be collected. The X-ray elemental data can include, but is not limited to, Si, Al, Fe, K, Na, Mg, and Ca elemental data, and the directional data can include, but is not limited to, well depth, well inclination, and azimuth data. Of course, these acquisition parameters can be adjusted according to actual needs, and there are no restrictions here.

[0041] S2: Using directional data, the depth of adjacent wells is corrected from oblique depth to vertical depth. Then, the target reservoirs of each adjacent well are compared to obtain the values ​​of the top and bottom depths of the target reservoirs of the adjacent wells, as well as the predicted values ​​of the top and bottom depths of the target reservoirs of the horizontal well to be drilled.

[0042] It should be noted that the top and bottom depths of the target reservoir in the adjacent well are sandstone burial depth data. This comparison yields the actual values ​​of the target reservoir in the adjacent well, and at the same time, it provides the predicted values ​​of the target reservoir in the horizontal well to be drilled. These predicted values ​​are used to add this data point of the horizontal well to be drilled when building the thickness model and structural model later.

[0043] S3: Analyze and compare X-ray elemental data to predict the target reservoir sandstone type and X-ray elemental data response characteristics of the area where the horizontal well to be drilled and the surrounding adjacent wells are located;

[0044] Specifically, it can be analyzed which type of sandstone the target reservoir is: quartz sandstone, feldspar sandstone, or lithic sandstone.

[0045] S4: Calculate the difference between the top and bottom depths of the target reservoir in adjacent wells and the difference between the predicted values ​​of the top and bottom depths of the target reservoir in the horizontal well to be drilled, to obtain the reservoir thickness of each adjacent well and the horizontal well to be drilled, and establish a target reservoir thickness model. Simultaneously, based on the numerical values ​​of the top and bottom depths of the target reservoir in adjacent wells and the predicted values ​​of the top and bottom depths of the target reservoir in the horizontal well to be drilled, establish a reservoir top structural model and a reservoir bottom structural model; utilize the projection of the trajectory of the horizontal well to be drilled onto the target reservoir thickness model, the reservoir top structural model, and the reservoir bottom structural model. The method predicts the changes in reservoir thickness and structure in the horizontal section. A target point is set at preset intervals in the horizontal section, and the target point coordinates are projected onto the target reservoir thickness model, the reservoir top structure model, and the reservoir bottom structure model to obtain the reservoir top depth, reservoir bottom depth, and reservoir lithology parameters at the target point. Based on the reservoir lithology parameters, the target reservoir sandstone type in the area where the horizontal well to be drilled and the surrounding adjacent wells are located, and the X-ray element data response characteristics, the predicted sandstone type and X-ray element data response characteristics of this target point are obtained.

[0046] The preset interval can be, but is not limited to, 50 meters, 100 meters, or 150 meters. Taking 100 meters as an example, the horizontal segment is divided into target points every 100 meters, named A0, A1, A2, etc. The wellhead coordinates of the target points are projected into the model to obtain the top depth, bottom depth, and lithological parameters of the target layer at target points A0, A1, A2, etc. Then, the X-ray elemental characteristics T0, T1, T2, etc. at this location are inferred based on the lithology.

[0047] S5: When drilling a horizontal well, obtain lithological and total hydrocarbon data of the horizontal well to be drilled at the target point. Compare the lithological and total hydrocarbon data of the adjacent well to analyze and determine whether the actual sandstone type of the encountered formation is the predicted sandstone type. At the same time, use X-ray elemental analysis to obtain the measured values ​​of the X-ray elemental response characteristics of the sandstone and analyze whether they are consistent with the predicted values ​​of the X-ray elemental response characteristics. If the results are all yes, the target reservoir thickness model, reservoir top structure model and reservoir bottom structure model are determined to be the correct models, and the horizontal well geological steering is continued based on them.

[0048] Specifically, during horizontal drilling operations, based on the reservoir sandstone cuttings obtained from the actual drilling logs, the first step is to determine, using conventional lithology methods, including color, grain size, and total hydrocarbon data during drilling, whether the encountered formation cuttings are the reservoir sandstone cuttings predicted before drilling. Then, X-ray elemental analysis is used to confirm the lithological characteristics of the encountered cuttings, determining whether they are quartz sandstone, rock fragment quartz sandstone, or feldspathic sandstone. If the conventional cuttings assessment and the rock fragment elemental analysis characteristics match the prediction results of the pre-drilling model, the original model is considered correct and can continue to guide the next step of horizontal geological steering construction.

[0049] As described above, the embodiments of the horizontal well geological steering method provided by the present invention include: acquiring basic data of neighboring wells around the horizontal well to be drilled, including lithological data, total hydrocarbon data, X-ray elemental data, and directional data; using the directional data to correct the depth of the neighboring wells from oblique depth to vertical depth; comparing the target reservoirs of each neighboring well to obtain the numerical values ​​of the top and bottom depths of the target reservoirs of the neighboring wells and the predicted values ​​of the top and bottom depths of the target reservoirs of the horizontal well to be drilled; and analyzing and comparing the X-ray elemental data to predict the sandstone type and X-ray elemental data of the target reservoirs in the area where the horizontal well to be drilled and the surrounding neighboring wells are located. The study analyzes the characteristics of the target reservoir. It calculates the difference between the top and bottom depths of the target reservoir in adjacent wells and the predicted difference between the top and bottom depths of the target reservoir in the horizontal well to be drilled, obtaining the reservoir thickness of each adjacent well and the horizontal well to be drilled. A target reservoir thickness model is then established. Simultaneously, based on the numerical values ​​of the top and bottom depths of the target reservoir in adjacent wells and the predicted values ​​of the top and bottom depths of the target reservoir in the horizontal well to be drilled, a reservoir top structure model and a reservoir bottom structure model are established. Using the projection of the horizontal well trajectory onto the target reservoir thickness model, the reservoir top structure model, and the reservoir bottom structure model, the study predicts the changes in reservoir thickness and structure in the horizontal section. The process involves setting a target point at preset intervals along the horizontal section, projecting the target point coordinates onto the target reservoir thickness model, reservoir top structure model, and reservoir bottom structure model to obtain the reservoir top depth, reservoir bottom depth, and reservoir lithology parameters at the target point. Based on the reservoir lithology parameters, the target reservoir sandstone type in the area where the horizontal well to be drilled and surrounding wells are located, and the X-ray element data response characteristics, the predicted sandstone type and predicted X-ray element data response characteristics of this target point are obtained. During the drilling of the horizontal well to be drilled, the lithology data and total hydrocarbon data of the horizontal well to be drilled are obtained at the target point and compared with the lithology data and total hydrocarbon data of adjacent wells. By comparing and analyzing the actual sandstone type encountered in the drilling strata with the predicted sandstone type, and using X-ray elemental analysis to obtain the measured values ​​of the X-ray elemental response characteristics of the sandstone, it is analyzed whether they match the predicted values ​​of the X-ray elemental response characteristics. When the results are all yes, the target reservoir thickness model, reservoir top structure model, and reservoir bottom structure model are determined to be the correct models, and horizontal well geological guidance is continued based on them. Therefore, it is possible to correct the seismic inversion prediction of reservoir results in a timely manner, provide a basis for adjusting the trajectory of horizontal well construction, improve the reservoir encounter rate, and improve the success rate of trajectory adjustment.

[0050] In a specific embodiment of the above-described horizontal well geological steering method, the following steps may also be included:

[0051] If at least one of the measured values ​​of lithological data, total hydrocarbon data, and X-ray elemental reaction characteristics of cuttings in the horizontal well to be drilled does not conform to the prediction results of the target reservoir thickness model, reservoir top structure model, and reservoir bottom structure model, then the changes in reservoir sandstone will be analyzed based on the lithological data of the horizontal well to be drilled, and the target reservoir thickness model, reservoir top structure model, and reservoir bottom structure model will be updated and corrected until the predicted values ​​match the actual drilling results. Based on the corrected target reservoir thickness model, reservoir top structure model, and reservoir bottom structure model, geological steering construction will continue.

[0052] In other words, if the characteristics of conventional reservoir sandstone cuttings identification and cuttings element analysis do not match or do not match the pre-drilling model predictions, it is necessary to analyze the changes in reservoir sandstone based on the actual drilling logging cuttings, and update and correct the reservoir sandstone thickness model and structural model in a timely manner until they match the actual drilling results. Then, the corrected reservoir sandstone steering model and reservoir sandstone structure will continue to guide the next step of geological steering construction.

[0053] In another specific embodiment of the above-described horizontal well geological steering method, the following steps may also be included:

[0054] When drilling horizontal wells, if non-reservoir mudstone is encountered, the mudstone cuttings are compared with the top and bottom mudstone of the reservoir in adjacent wells. X-ray elemental analysis is used to analyze the encountered reservoir cuttings. The results of this analysis are quantitatively compared with the elemental analysis results of the top and bottom mudstone of the reservoir in adjacent wells before drilling to determine whether the trajectory is top or bottom reservoir emergence or non-reservoir mudstone interlayers developed inside the reservoir. Based on the judgment results, the target reservoir thickness model, reservoir top structure model and reservoir bottom structure model are updated and corrected, and geological steering construction continues.

[0055] Specifically, during horizontal drilling, if non-reservoir mudstone is encountered, the mudstone cuttings are first qualitatively compared and judged with the top and bottom surrounding rocks of the reference well based on factors such as color, brittleness, water absorption, plasticity, and total hydrocarbons during drilling. Secondly, X-ray elemental analysis is used to analyze the encountered reservoir cuttings, and the results of the analysis are quantitatively compared and judged with the elemental analysis results of the surrounding rocks before drilling. Both qualitative and quantitative approaches are used to determine whether the trajectory is from the top or bottom of the reservoir or from non-reservoir mudstone interlayers developed within the reservoir. Based on the judgment results, the reservoir sandstone thickness model and structural model are updated and corrected in a timely manner to guide the geological steering construction of the horizontal section.

[0056] In another specific embodiment of the above-mentioned horizontal well geological steering method, predicting the target reservoir sandstone type in the area where the horizontal well to be drilled and the surrounding adjacent wells are located may include:

[0057] Predict whether the target reservoir in the area where the horizontal well to be drilled and the surrounding adjacent wells are located is quartz sandstone, lithic quartz sandstone, or feldspar sandstone. Specifically, sandstone is classified according to its composition: if quartz content > feldspar content and lithic fragment content, the sandstone is defined as quartz sandstone; if feldspar content > quartz content and lithic fragment content, the sandstone is defined as feldspar sandstone; if lithic fragment content > feldspar content and quartz content, the sandstone is defined as lithic sandstone.

[0058] In a preferred embodiment of the above-mentioned horizontal well geological steering method, the X-ray elemental data response characteristics can include: conventional response characteristics of seven elements (Si, Al, Fe, K, Na, Mg, and Ca) and Si / Al and Fe / Al combined elemental response characteristics. Specifically, based on the sandstone classification and elemental data of wells already drilled in the work area, the X-ray elemental characteristics of three types of sandstone can be summarized.

[0059] The following is a specific example to illustrate the above method:

[0060] (1) Taking JPH-428 well as an example, before drilling, we collected and studied the logging data of sandstone, mudstone, drilling time, and total hydrocarbons of neighboring wells (Jin112 well, JPH-325 well, JPH-381 well, JPH-435 well, etc.);

[0061] (2) Simultaneously collect elemental data from adjacent wells of JPH-428 (Jin 112, JPH-325, JPH-381, JPH-435, etc.);

[0062] (3) X-ray elemental analysis was used to analyze that the target reservoir sandstone in the horizontal section of the well is lithic quartz sandstone-quartz sandstone. Among the seven conventional element data, the Si content is high in the target layer, while the Fe and Al values ​​are low. The Si / Al and Fe / Al ratios of the combined elements vary greatly in the reservoir and less in unfavorable reservoirs and non-reservoirs.

[0063] (4) The collected data were routinely analyzed and the target reservoir was predicted to be light gray medium- to coarse-grained sandstone with good homogeneity. The total hydrocarbons were predicted to be high after drilling into the predicted reservoir.

[0064] (5) Based on the collected burial depth data of the target reservoir sandstone in adjacent wells, the burial depth data of the target reservoir sandstone are analyzed and compared to determine the burial depth range of the target reservoir sandstone. The burial depth of the target reservoir sandstone is corrected in conjunction with the collected directional data to obtain the vertical and elevation burial depth data of the reservoir sandstone. Based on this, a reservoir sandstone thickness model and a reservoir sandstone structural model for the well area where the target well is located are established, as shown below. Figure 2 and Figure 3 As shown, Figure 2 This is a model diagram of the sand body thickness in well JPH-428. Figure 3This is a cross-sectional view of the target layer sandstone structure model in well JPH-428. According to the reservoir sandstone thickness model, the thickness of the target layer sandstone in the horizontal section is predicted to be stable from point A to point B. According to the reservoir structure model, the reservoir structure characteristics in the horizontal section are predicted to show a low-amplitude downdip trend from point A to point B.

[0065] (6) During the horizontal section drilling operation, based on the actual drilling cuttings from the 0-500m section, conventional analysis showed that the drilled reservoir was light gray medium sandstone with coarse sandstone strength and high total hydrocarbon value during drilling. X-ray elemental analysis was used to analyze the drilled reservoir sandstone. The Si element was high, the Fe and Al element values ​​were low, and the combined element Si / Al ratio was high. The analysis and judgment indicated that the well trajectory was located in a favorable position in the reservoir. The characteristics of the drilled reservoir sandstone were consistent with the sand body thickness model. The model was judged to be correct and could guide the subsequent geological steering construction of the horizontal section.

[0066] (7) During the horizontal section drilling operation, when the horizontal section reached 550 meters, the actual drilling logging showed that the cuttings were non-reservoir gray mudstone, such as... Figure 4 As shown, Figure 4 The geological steering trajectory diagram of well JPH-428, which was actually drilled, does not conform to the sandstone thickness model and requires model correction. The reservoir sandstone thickness and structural model will be corrected and verified through both qualitative and quantitative analysis.

[0067] ① The total hydrocarbon data during drilling in the horizontal section is between 0 and 500 meters. The total hydrocarbon value during drilling gradually decreases, which is considered to be a transition from a favorable area to an unfavorable area of ​​the reservoir.

[0068] ② The sandstone grain size of the reservoir in the horizontal section gradually decreases from medium-grained sandstone to fine-grained sandstone in the 0-500 meter range, and the lithology gradually changes from medium sandstone to fine sandstone.

[0069] ③ X-ray elemental analysis: The actual drilled reservoir sandstone at point A of well JPH-428 is light gray medium sandstone, and lithological elemental analysis evaluates it as quartz sandstone, such as... Figure 5 As shown, Figure 5 This is a schematic diagram illustrating the interpretation of quartz sandstone at point A of well JPH-428 using elemental analysis techniques. The target reservoir sandstone of the adjacent well JPH-325, located towards point B, is light gray medium sandstone. Lithological elemental analysis data classifies it as lithic sandstone. Figure 6 As shown, Figure 6 A schematic diagram illustrating the interpretation of lithic sandstone using elemental analysis techniques in well JPH-325;

[0070] ④ Analysis of mudstone and surrounding rock encountered during drilling: At target point A of well JPH-428, the actual surrounding rock at the top of the reservoir was brownish-brown mudstone. This mudstone is hard and brittle, with poor water absorption and plasticity. At target point B, the reference well JPH-435 also encountered brownish-brown mudstone at the top of its corresponding reservoir. This mudstone is hard, with poor water absorption and plasticity. Well JPH-428 encountered non-reservoir mudstone at 550m in the horizontal section. This mudstone was gray in color, relatively soft, and had good water absorption and plasticity. Conventional analysis suggests that the well trajectory did not penetrate the top of the reservoir. At target point B, the reference well JPH-435 also encountered gray mudstone at the bottom of its corresponding reservoir. This mudstone is relatively soft, with good water absorption and plasticity. Conventional analysis suggests that the mudstone encountered at the bottom of the horizontal section may be the bottom mudstone of the reservoir, and the well trajectory has reached the bottom of the reservoir.

[0071] ⑤ Sedimentary facies cycle characteristics: In the horizontal section at point A, the sandstone of the target layer in the adjacent well Jin 112 generally exhibits a reverse cyclic sedimentary characteristic, with the grain size decreasing from fine to coarse from top to bottom. In the horizontal section at point B, the sandstone of the target layer in the adjacent well JPH-325 generally exhibits a positive cyclic sedimentary characteristic, with the grain size decreasing from coarse to fine from top to bottom. Figure 7 As shown, Figure 7 This is a schematic diagram of the cyclic characteristics of sand bodies.

[0072] ⑥ Lithofacies characteristics: The target sandstone layer in adjacent wells J58-5-2, JPH-325 (guide well), and JPH-435A has a stable east-west thickness. The logging lithology of all three is light gray medium sandstone, and the total hydrocarbon evaluation during drilling indicates they are gas-bearing layers. The sandstone logging characteristics are similar. However, in the southern well JPH-435 (guide well), and in the same well site JPH-435A (guide well), the target sandstone layer lithology is light gray medium sandstone, but the mudstone interlayers within the target sandstone layer of JPH-435 (guide well) are very well-developed, and the sandstone grains are finer, consisting of light gray fine sandstone. Figure 8 As shown, Figure 8 This is a schematic diagram of sedimentary facies characteristics.

[0073] Therefore, it is determined that the J58-5-2~JPH-435D~JPH-435A sections along the near-east-west direction belong to the same period of core bar deposition, and are not part of the same period of core bar deposition as the Jin 112 well and the JPH-435 pilot well. Thus, the sandstone at point A and point B of the JPH-428 well is considered to be discontinuous sandstone. The mudstone section encountered at 550 meters in the horizontal section of this well is the lateral retaining rock after the pinch-out of this sandstone. The actual downhole conditions did not match the pre-drilling geological understanding and structural model. The target layer sandstone thickness model and the geological steering model were promptly revised based on the new geological understanding, as shown below. Figure 9 and Figure 10 As shown, Figure 9 This is a revised sand body thickness model diagram for well JPH-428. Figure 10 This is the revised geological steering trajectory map of well JPH-428, which will guide the geological steering construction of horizontal wells.

[0074] (6) In the horizontal section from 600 to 800 meters, the geological guidance construction was guided by the corrected sandstone thickness and geological guidance model. Actual drilling encountered sandstone. The corrected sandstone thickness model was correct, and according to the sandstone elemental data analysis during drilling, the sandstone encountered in the horizontal section from 600 to 800 meters was light gray medium sandstone, but the elemental evaluation identified it as lithic quartz sandstone. (Refer to...) Figure 11 , Figure 11 The elemental logging chart of the horizontal section of well JPH-428 is inconsistent with the quartz sandstone at target point A and the quartz sandstone encountered in the first 600m of the horizontal section of this well, further verifying the correctness of the previous geological understanding.

[0075] In summary, the method provided in this application utilizes logging data, including lithology and X-ray elemental logging data, to promptly verify and correct the results of seismic inversion prediction of reservoir target layers before and during drilling. During drilling, it uses lithological information and X-ray elemental logging data to analyze and evaluate the downhole reservoir conditions in real time. Based on the analysis and judgment of real-time drilling conditions, it promptly reviews and corrects the distribution characteristics of the target layer and the geological steering model to guide the geological steering construction of the horizontal section.

[0076] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A horizontal well geological steering method, characterized in that, include: Acquire basic data from neighboring wells surrounding the horizontal well to be drilled, including lithological data, total hydrocarbon data, X-ray elemental data, and directional data; Using the directional data, the depth of the adjacent wells is corrected from the inclined depth to the vertical depth. Then, the target reservoirs of each adjacent well are compared to obtain the values ​​of the top and bottom depths of the target reservoirs of the adjacent wells, as well as the predicted values ​​of the top and bottom depths of the target reservoirs of the horizontal well to be drilled. By analyzing and comparing the X-ray elemental data, the target reservoir sandstone type and X-ray elemental data response characteristics of the area where the horizontal well to be drilled and the surrounding adjacent wells are located can be predicted. The difference between the top and bottom depths of the target reservoir in the adjacent wells and the predicted difference between the top and bottom depths of the target reservoir in the horizontal well to be drilled are calculated to obtain the reservoir thickness of each adjacent well and the horizontal well to be drilled. A target reservoir thickness model is then established. Simultaneously, based on the values ​​of the top and bottom depths of the target reservoir in the adjacent wells and the predicted values ​​of the top and bottom depths of the target reservoir in the horizontal well to be drilled, a reservoir top structure model and a reservoir bottom structure model are established. Using the projection of the trajectory of the horizontal well to be drilled onto the target reservoir thickness model, the reservoir top structure model, and the reservoir bottom structure model, the horizontal reservoir thickness is predicted. The changes in reservoir thickness and reservoir structure in the horizontal section are analyzed. A target point is set at preset intervals in the horizontal section. The coordinates of the target point are projected onto the target reservoir thickness model, the reservoir top structure model, and the reservoir bottom structure model to obtain the reservoir top depth, reservoir bottom depth, and reservoir lithology parameters at the target point. Based on the reservoir lithology parameters, the target reservoir sandstone type in the area where the horizontal well to be drilled and the surrounding adjacent wells are located, and the X-ray element data response characteristics, the predicted sandstone type and predicted X-ray element data response characteristics of this target point are obtained. When drilling a horizontal well, lithological and total hydrocarbon data of the horizontal well to be drilled are obtained at the target point. These data are compared with the lithological and total hydrocarbon data of the adjacent well to analyze and determine whether the actual sandstone type of the encountered formation is the predicted sandstone type. At the same time, X-ray elemental analysis is used to obtain the measured values ​​of the X-ray elemental response characteristics of the sandstone and analyze whether they match the predicted values ​​of the X-ray elemental response characteristics. If all the results are yes, the target reservoir thickness model, the reservoir top structure model, and the reservoir bottom structure model are determined to be correct models, and the horizontal well geological steering is continued based on these models. Also includes: If at least one of the measured values ​​of the lithological data, total hydrocarbon data, and X-ray elemental data of the cuttings of the horizontal well to be drilled does not conform to the prediction results of the target reservoir thickness model, the reservoir top structure model, and the reservoir bottom structure model, then the reservoir sandstone variation is analyzed based on the lithological data of the horizontal well to be drilled, and the target reservoir thickness model, the reservoir top structure model, and the reservoir bottom structure model are updated and corrected until the predicted value matches the actual drilling results. Geological steering construction continues based on the corrected target reservoir thickness model, the reservoir top structure model, and the reservoir bottom structure model.

2. The horizontal well geological steering method according to claim 1, characterized in that, Also includes: When drilling horizontal wells, if non-reservoir mudstone is encountered, the mudstone cuttings are compared with the top and bottom mudstone of the reservoir in the adjacent well. X-ray elemental analysis is used to analyze the encountered reservoir cuttings. The results of this analysis are quantitatively compared with the elemental analysis results of the top and bottom mudstone of the reservoir in the adjacent well before drilling to determine whether the trajectory is top or bottom reservoir emergence or encountering non-reservoir mudstone interlayers developed within the reservoir. Based on the determination results, the target reservoir thickness model, the reservoir top structure model, and the reservoir bottom structure model are updated and corrected, and geological steering construction continues.

3. The horizontal well geological steering method according to any one of claims 1-2, characterized in that, The lithological data includes sandstone and mudstone.

4. The horizontal well geological steering method according to any one of claims 1-2, characterized in that, The X-ray elemental data includes elemental data for Si, Al, Fe, K, Na, Mg, and Ca.

5. The horizontal well geological steering method according to any one of claims 1-2, characterized in that, The orientation data includes well depth, well inclination, and azimuth data.

6. The horizontal well geological steering method according to any one of claims 1-2, characterized in that, The target reservoir sandstone type predicted for the area where the horizontal well to be drilled and the surrounding adjacent wells are located includes: Predict whether the target reservoir in the area where the horizontal well to be drilled and the surrounding adjacent wells are located is quartz sandstone, lithic quartz sandstone, or feldspar sandstone.

7. The horizontal well geological steering method according to any one of claims 1-2, characterized in that, The X-ray elemental data response characteristics include: The reaction characteristics of seven common elements (Si, Al, Fe, K, Na, Mg, and Ca) and the reaction characteristics of Si / Al and Fe / Al combination elements.

8. The horizontal well geological steering method according to any one of claims 1-2, characterized in that, The preset interval is 50 meters, 100 meters, or 150 meters.

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