Method and system for identifying position and crossing trend of well trajectory in stratum

Abstract

The invention discloses a method and a system for identifying the position and the layer passing trend of a well trajectory in a stratum, belongs to the technical field of petroleum engineering, and is suitable for well trajectory evaluation of conventional reservoirs and complex fault block low-porosity low-permeability thin interbeds. And according to the characteristics of the upper and lower natural gamma logging curves, the logging data and the gas logging data, and according to the change of the characteristics of the upper and lower natural gamma logging curves, identifying the stratum position and the stratum passing trend of the well trajectory. According to the method, the position and the layer passing trend of the well track in the stratum can be rapidly and accurately recognized, the upcut stratum or the undercut stratum and the future direction are defined, timely optimization and adjustment while drilling are guided, and the drilling encounter rate and the drilling success rate of an oil and gas well reservoir are guaranteed.

Description

Technical Field

[0001] The present invention relates to the field of petroleum engineering technology, and in particular to a method and system for identifying the position of a well trajectory in a formation and a layer-crossing trend. Background Art

[0002] With the deepening of oil and gas field exploration and development, it is becoming increasingly difficult to find high-quality oil and gas reservoirs. The field of exploration and development has gradually expanded to complex oil and gas reservoirs and unconventional oil and gas reservoirs. The evaluation of complex reservoirs such as "complex fault blocks, low porosity and low permeability, and thin interlayers" is particularly important, especially in the process of drilling tracking research on strata with rich development of thin interlayers and interlayers. Due to the large structural amplitude changes and rapid formation changes, the accuracy and speed of evaluation are crucial. It is necessary to evaluate the complex structure and reservoir changes in real time, quickly and accurately, identify the position and layer-crossing trend of the well trajectory in the formation, and guide timely optimization and adjustment while drilling.

[0003] In view of the large errors in the geophysical methods mainly used in the evaluation of thin interbeds and interlayers, it is difficult to accurately identify the distribution and changes of thin interbeds and interlayers, let alone to quickly and accurately identify thin interbeds and interlayers in real time while drilling. It is difficult to identify the well trajectory position, layer-crossing trend and future direction, and it is impossible to guide real-time optimization and adjustment while drilling, which increases the difficulty and proportion of wrong judgments in real-time decision-making while drilling for oil and gas wells, directly affects the implementation effect of oil and gas wells while drilling, affects the reservoir encounter rate and drilling success rate of oil and gas wells, and wrong judgments lead to erroneous understanding of structural reservoirs, which in turn affects the success or failure of the entire oil and gas field development. Summary of the invention

[0004] In order to solve the above problems, the purpose of the present invention is to design a method for identifying the position of well trajectory in the formation and the cross-layer trend, aiming to use natural gamma logging data in exploration wells, evaluation wells or development wells to quickly identify the position of well trajectory in the formation and the cross-layer trend, so that the method is suitable for conventional reservoir evaluation and for complex reservoirs such as complex fault blocks with low porosity and low permeability thin interlayers.

[0005] In order to achieve the above technical objectives, the present application provides a method for identifying the position and inter-layer trend of a well trajectory in a formation, which is applicable to the evaluation of well trajectories in conventional reservoirs and thin interlayers of low porosity and low permeability in complex fault blocks, and includes the following steps:

[0006] Based on the distribution of interlayers in the formation, according to the characteristics of the upper and lower natural gamma logging curves, logging data and gas logging data, and according to the changes in the characteristics of the upper and lower natural gamma logging curves, the formation position and the cross-layer trend of the well trajectory are identified.

[0007] Preferably, in the process of obtaining the distribution of interlayers, the distribution of interlayers is obtained based on upper natural gamma data, lower natural gamma data, well deviation data and logging data of the formation.

[0008] Preferably, in the process of identifying the well trajectory in the formation position and the cross-layer trend, based on the distribution of interlayers in the formation and according to the characteristics of the upper and lower natural gamma logging curves, the first lithology data of the upper natural gamma and the lower natural gamma are obtained to identify the well trajectory in the formation position and the cross-layer trend.

[0009] Preferably, in the process of identifying the well trajectory in the formation and the trend of crossing the layer, based on the first lithology data, according to the logging data and gas logging data, the second lithology data within a certain time interval before and after is obtained to identify the well trajectory in the formation and the trend of crossing the layer.

[0010] Preferably, in the process of identifying the well trajectory's position in the formation and its cross-layer trend, the well trajectory's position in the formation and its cross-layer trend are identified based on the second lithology data and the time difference in the characteristic changes of the upper and lower natural gamma logging curves, including whether the well trajectory cuts into the upper formation or the lower formation and the future direction of the well trajectory.

[0011] The present invention discloses a system for identifying the position and inter-layer trend of a well trajectory in a formation, which is applicable to the evaluation of well trajectories in conventional reservoirs and thin interlayers of low porosity and low permeability in complex fault blocks, and includes:

[0012] Data collection module, used to obtain upper and lower natural gamma logging curve characteristics, logging data and gas logging data;

[0013] The analysis and identification module is used to identify the position of the well trajectory in the formation and the trend of the well trajectory in the formation based on the distribution of interlayers in the formation, according to the characteristics of the upper and lower natural gamma logging curves, logging data and gas logging data, and according to the changes in the characteristics of the upper and lower natural gamma logging curves.

[0014] Preferably, the analysis and identification module is also used to obtain the distribution of interlayers based on the upper natural gamma data, the lower natural gamma data, the well deviation data and the logging data of the formation.

[0015] Preferably, the analysis and identification module is also used to obtain the first lithology data of upper natural gamma and lower natural gamma based on the distribution of interlayers in the formation and according to the characteristics of upper and lower natural gamma logging curves, so as to identify the position of the well trajectory in the formation and the cross-layer trend.

[0016] Preferably, the analysis and identification module is also used to obtain second lithology data within a certain time interval based on the first lithology data, according to the logging data and the gas logging data, so as to identify the formation position and the layer-crossing trend of the well trajectory.

[0017] Preferably, the analysis and identification module is also used to identify the formation position and layer-crossing trend of the well trajectory based on the second lithology data and the time difference in the characteristic changes of the upper and lower natural gamma logging curves, including whether the well trajectory cuts into the upper or lower formation and the future direction of the well trajectory.

[0018] The present invention discloses the following technical effects:

[0019] Since the present invention adopts the logging method to quickly identify the position of the well trajectory and the trend of crossing layers, it has the advantages of being fast and accurate. It can quickly and accurately identify the position of the well trajectory in the formation and the trend of crossing layers, clarify whether it is cutting up or down the formation and the future direction, guide timely optimization and adjustment while drilling, and ensure the reservoir drilling rate and drilling success rate of oil and gas wells. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 is a schematic diagram of an upper-cut stratum model according to an embodiment of the present invention;

[0022] Figure 2 is a schematic diagram of a downcut formation model according to an embodiment of the present invention;

[0023] Figure 3 The well trajectory of the embodiment of the present invention is a gamma logging curve and a formation pattern diagram of the upper and lower formations;

[0024] Figure 4 The well trajectory described in the embodiment of the present invention is a gamma logging curve and a formation pattern diagram of the formation below;

[0025] Figure 5 is a schematic diagram of the method flow of the embodiment of the present invention;

[0026] In the figure, 1 is the upper gamma curve, 2 is the lower gamma curve, 3 is the well trajectory, 4 is the drill pipe, 5 is the drill bit, 6 is the upper gamma tool, 7 is the lower gamma tool, 8 is the upper mudstone, 9 is the sandstone, and 10 is the lower mudstone. DETAILED DESCRIPTION

[0027] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0028] like Figure 1-5 As shown, the present invention provides a method for identifying the position and layer-crossing trend of a well trajectory in a formation, which is applicable to the evaluation of well trajectories in conventional reservoirs and thin interlayers of low porosity and low permeability in complex fault blocks, and includes the following steps:

[0029] Based on the distribution of interlayers in the formation, according to the characteristics of the upper and lower natural gamma logging curves, logging data and gas logging data, and according to the changes in the characteristics of the upper and lower natural gamma logging curves, the formation position and the cross-layer trend of the well trajectory are identified.

[0030] Further preferably, the method for identifying the position of the well trajectory in the formation and the cross-layer trend provided by the present invention, in the process of obtaining the distribution of interlayers, obtains the distribution of interlayers based on the upper natural gamma data, lower natural gamma data, well inclination data and logging data of the formation.

[0031] Further preferably, the method for identifying the position of the well trajectory in the formation and the cross-layer trend provided by the present invention, in the process of identifying the position of the well trajectory in the formation and the cross-layer trend, based on the distribution of interlayers in the formation and according to the characteristics of the upper and lower natural gamma logging curves, obtains the first lithological data of the upper natural gamma and the lower natural gamma, which is used to identify the position of the well trajectory in the formation and the cross-layer trend.

[0032] Further preferably, the method for identifying the position of the well trajectory in the formation and the cross-layer trend provided by the present invention, in the process of identifying the position of the well trajectory in the formation and the cross-layer trend, based on the first lithology data, according to the logging data and the gas logging data, obtains the second lithology data at a certain time interval before and after, which is used to identify the position of the well trajectory in the formation and the cross-layer trend.

[0033] Further preferably, the method for identifying the position of the well trajectory in the formation and the cross-layer trend provided by the present invention, in the process of identifying the position of the well trajectory in the formation and the cross-layer trend, identifies the position of the well trajectory in the formation and the cross-layer trend according to the second lithological data and the time difference between the changes in the characteristics of the upper and lower natural gamma logging curves, including whether the well trajectory cuts into the upper formation or the lower formation and the future direction of the well trajectory.

[0034] The present invention discloses a system for identifying the position and inter-layer trend of a well trajectory in a formation, which is applicable to the evaluation of well trajectories in conventional reservoirs and thin interlayers of low porosity and low permeability in complex fault blocks, and includes:

[0035] Data collection module, used to obtain upper and lower natural gamma logging curve characteristics, logging data and gas logging data;

[0036] The analysis and identification module is used to identify the position of the well trajectory in the formation and the trend of the well trajectory in the formation based on the distribution of interlayers in the formation, according to the characteristics of the upper and lower natural gamma logging curves, logging data and gas logging data, and according to the changes in the characteristics of the upper and lower natural gamma logging curves.

[0037] Further preferably, the analysis and identification module of the system for identifying the position of the well trajectory in the formation and the cross-layer trend disclosed in the present invention is also used to obtain the distribution of interlayers based on the upper natural gamma data, lower natural gamma data, well deviation data and logging data of the formation.

[0038] Further preferably, the analysis and identification module of the system for identifying the position of the well trajectory in the formation and the cross-layer trend disclosed in the present invention is also used to obtain the first lithological data of the upper natural gamma and the lower natural gamma based on the distribution of interlayers in the formation and according to the characteristics of the upper and lower natural gamma logging curves, so as to identify the position of the well trajectory in the formation and the cross-layer trend.

[0039] Further preferably, the analysis and identification module of the system for identifying the position of the well trajectory in the formation and the cross-layer trend disclosed in the present invention is also used to obtain the second lithology data within a certain time interval before and after the first lithology data according to the logging data and the gas logging data, so as to identify the position of the well trajectory in the formation and the cross-layer trend.

[0040] Further preferably, the analysis and identification module of the system for identifying the position of the well trajectory in the formation and the cross-layer trend disclosed in the present invention is also used to identify the position of the well trajectory in the formation and the cross-layer trend according to the second lithological data and the time difference between the changes in the characteristics of the upper and lower natural gamma logging curves, including whether the well trajectory cuts into the upper formation or the lower formation and the future direction of the well trajectory.

[0041] Embodiment: The purpose of the present invention is to study a new method for quickly identifying the position and layer-crossing trend of the well trajectory in the formation by using natural gamma logging data in an exploration well, an evaluation well or a development well. The present invention is achieved by the following steps:

[0042] Step 1, collecting real-time upper natural gamma data, lower natural gamma data, well deviation data and logging data that meet the standards;

[0043] Step 2, establishing an interlayer distribution model;

[0044] Step 3, based on the characteristics of the upper and lower natural gamma logging curves, quickly determine the lithology of the upper and lower natural gamma;

[0045] Step 4, judging the lithology at a certain time interval based on the logging and gas logging data;

[0046] Step 5, calculating the time difference between the upper and lower natural gamma logging curve characteristic changes;

[0047] Step 6: Identify the position of the well trajectory in the formation and the trend of the well trajectory, and accurately determine whether it is cutting into the formation or the formation and the future direction.

[0048] Specifically, the upper and lower gamma logging curves and formation pattern diagrams of a well in a domestic oil field are shown in the attached Figure 3 During the drilling process of this well, the well logging curve and the well logging gas logging showed that the well trajectory entered the mudstone from the sandstone, with a well inclination of 88.6 degrees, but it was not certain whether it entered the upper mudstone or the lower mudstone. Using the upper and lower gamma curve characteristics and the reaction time difference, it was determined that the well trajectory cut through the formation and entered the upper mudstone.

[0049] Specifically, the upper and lower gamma logging curves and formation pattern diagrams of a well in a domestic oil field are shown in the attached Figure 4 During the drilling process of this well, the well logging curve and the well logging gas logging showed that the well trajectory entered the sandstone from the mudstone. Using the upper and lower gamma curve characteristics and the reaction time difference, it was judged that the well trajectory cut into the formation and entered the lower sandstone.

[0050] The present invention can quickly identify the position of the well trajectory in the formation and the trend of crossing the layer during the drilling process. When the well trajectory approaches the formation interface, it can quickly identify whether the well trajectory cuts the formation above or below, judge the future direction of the well trajectory, and guide the on-site drilling operation to optimize and adjust in real time accurately, so as to achieve the purpose of efficiently guiding the implementation of drilling and achieving the drilling objectives. The method adopted by this patent is to use the natural gamma logging data while drilling to identify the time difference between the upper natural gamma and the lower natural gamma to detect the interface, and combine the logging lithology data to quickly and accurately judge the trend of the well trajectory crossing the layer and the direction that has not been taken. This method can quickly, intuitively and accurately identify the trend of the well trajectory crossing the layer and the direction that has not been taken, and has significant application effect in drilling while drilling in domestic oil and gas fields.

[0051] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0052] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0053] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for identifying the position of a well trajectory in a formation and its tendency to pass through a formation, characterized in that: Applicable to conventional reservoirs and complex fault blocks with low porosity and low permeability thin interlayers. The evaluation includes the following steps: Based on the distribution of interlayers in the formation, according to the characteristics of the upper and lower natural gamma logging curves, logging data and gas logging data, and according to the changes in the characteristics of the upper and lower natural gamma logging curves, the formation position and the cross-layer trend of the well trajectory are identified.

2. The method for identifying the position and layer-crossing trend of a well trajectory in a formation according to claim 1, characterized in that: In the process of obtaining the distribution of interlayers, the distribution of interlayers is obtained according to the upper natural gamma data, the lower natural gamma data, the well deviation data and the logging data of the formation.

3. The method for identifying the position and layer-crossing trend of a well trajectory in a formation according to claim 2, characterized in that: In the process of identifying the well trajectory in the formation and the trend of crossing the layer, based on the distribution of interlayers in the formation and according to the characteristics of the upper and lower natural gamma logging curves, the first lithology data of the upper natural gamma and the lower natural gamma are obtained to identify the well trajectory in the formation and the trend of crossing the layer.

4. The method for identifying the position and layer-crossing trend of a well trajectory in a formation according to claim 3, characterized in that: In the process of identifying the well trajectory in the formation and the trend of crossing the layer, based on the first lithology data, according to the logging data and gas logging data, the second lithology data within a certain time interval before and after is obtained to identify the well trajectory in the formation and the trend of crossing the layer.

5. The method for identifying the position and layer-crossing trend of a well trajectory in a formation according to claim 4, characterized in that: In the process of identifying the well trajectory position in the formation and the trend of crossing the layer, based on the second lithology data and the time difference in the changes in the characteristics of the upper and lower natural gamma logging curves, the well trajectory position in the formation and the trend of crossing the layer are identified, including whether the well trajectory cuts into the upper formation or the lower formation and the future direction of the well trajectory.

6. A system for identifying the position of a well trajectory in a formation and its tendency to pass through a formation, characterized in that: Applicable to the well trajectory evaluation of conventional reservoirs and complex fault blocks with low porosity and low permeability thin interlayers, including: Data collection module, used to obtain upper and lower natural gamma logging curve characteristics, logging data and gas logging data; The analysis and identification module is used to identify the position of the well trajectory in the formation and the trend of the well trajectory in the formation based on the distribution of interlayers in the formation, according to the characteristics of the upper and lower natural gamma logging curves, logging data and gas logging data, and according to the changes in the characteristics of the upper and lower natural gamma logging curves.

7. The system for identifying the position and layer-crossing trend of a well trajectory in a formation according to claim 6, characterized in that: The analysis and identification module is also used to obtain the distribution of the interlayers according to the upper natural gamma data, the lower natural gamma data, the well deviation data and the logging data of the formation.

8. The system for identifying the position and layer-crossing trend of a well trajectory in a formation according to claim 7, characterized in that: The analysis and identification module is also used to obtain the first lithology data of upper natural gamma and lower natural gamma based on the distribution of interlayers in the formation and the characteristics of upper and lower natural gamma logging curves, so as to identify the position of the well trajectory in the formation and the trend of the well trajectory.

9. The system for identifying the position and layer-crossing trend of a well trajectory in a formation according to claim 8, characterized in that: The analysis and identification module is also used to obtain second lithology data at a certain time interval before and after based on the first lithology data, according to logging data and gas logging data, so as to identify the formation position and layer-crossing trend of the well trajectory.

10. The system for identifying the position and layer-crossing trend of a well trajectory in a formation according to claim 9, characterized in that: The analysis and identification module is also used to identify the formation position and layer-crossing trend of the well trajectory based on the second lithology data and the time difference in the changes in the characteristics of the upper and lower natural gamma logging curves, including whether the well trajectory cuts into the upper or lower formation and the future direction of the well trajectory.

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