A method for optimizing the completion of the mining section of a sandstone geothermal well

Abstract

A method for optimizing completion of the mining section of a sandstone geothermal well includes: obtaining the production capacity of different layers of a sandstone thermal reservoir; formulating a mixed plan for solid pipes and water filter pipes based on the production capacity of different layers; obtaining data on the particle size of sand particles in the layer section where the water filter pipe is lowered; and determining the specifications of the water filter pipe that matches the data on the particle size of sand particles based on the data. According to the production capacity of different layers of a sandstone thermal reservoir, a mixed plan for solid pipes and water filter pipes is formulated, and solid pipes are lowered into layers with low production capacity, and water filter pipes are lowered into layers with high production capacity. This mixed method of solid pipes and water filter pipes can effectively save costs; for the layer section where the water filter pipe is lowered, the data on the particle size of sand particles is obtained, and then the water filter pipe that matches the data on the particle size of sand particles is further matched. Therefore, the present invention can effectively improve the problems of thermal reservoir blockage and easy sand production caused by the use of water filter pipes of the same specifications in each layer section of the mining section in the prior art.

Description

Technical Field

[0001] The present invention belongs to the field of geothermal wells, and more specifically, relates to a method for optimizing the completion of a mining section of a sandstone geothermal well. Background Art

[0002] At present, most of the sandstone geothermal well completion methods adopt the completion technology combining open hole hanging filter pipe and gravel filling outside the pipe, which is mainly suitable for relatively shallow vertical wells; for medium and deep layers and directional wells, the open hole hanging filter pipe completion method is adopted, that is, cement cementing or water stopper is used to seal the upper part of the mining layer, and a filter pipe of a certain specification and model is hung in the open hole of the thermal reservoir section for completion. The main defects of the open hole hanging filter pipe completion method are: 1. Due to the high production capacity requirements of sandstone geothermal wells, the mining section is relatively long, reaching hundreds or even thousands of meters. The formations that produce water have large differences in physical properties, resulting in small contributions to the production capacity of some formations, making the open hole section longer and the drilling and completion filter pipe costs higher. In addition, the thermal reservoir section of sandstone geothermal wells is mostly interlayered with sand and mudstone. The use of filter pipes to complete the well in the mudstone section is likely to cause the mudstone section to collapse and fall off, and the geothermal water containing mud is likely to cause the thermal reservoir to be blocked when it is reinjected, reducing the reinjection capacity; 2. The interlayer physical properties of the main mining section are very different. The same specification and model of filter pipes are used in the whole well, resulting in the sand control accuracy of the filter pipe not matching the particle size and cementation degree of the formation sand. On the one hand, it affects the water production effect, and on the other hand, it is very easy to produce sand during the production process, and after sand production, it will cause the cost of formation sand removal equipment to increase and the production capacity to decrease.

[0003] Therefore, it is expected to invent a sandstone geothermal well mining section optimization completion method, which can effectively improve the problems of thermal reservoir blockage and easy sand production caused by using the same specification of water filter pipes in each layer of the mining section in the prior art. Summary of the invention

[0004] The purpose of the present invention is to provide a sandstone geothermal well mining section optimization completion method to improve the prior art due to the use of the same specification of filter pipes in each layer of the mining section caused by the thermal reservoir blockage and easy sand production problems.

[0005] In order to achieve the above object, the present invention provides a method for optimizing the completion of the mining section of a sandstone geothermal well, comprising:

[0006] Obtaining the productivity of different layers of sandstone thermal reservoirs;

[0007] Based on the production capacity of different layers, a mixed plan of solid pipe and filter pipe is formulated;

[0008] Acquiring the particle size data of the sand particles lowered into the water filter pipe layer section;

[0009] Based on the data, the water filter pipe specifications matching the sand particle size data are determined.

[0010] Optionally, obtaining the productivity of different layers of the sandstone thermal reservoir includes:

[0011] The logging data and productivity test data of the geothermal well development area and adjacent wells are analyzed, and the productivity of different layers of the sandstone thermal reservoir is determined based on the logging data and the productivity test data.

[0012] Optionally, the formulating of a mixed plan of solid pipes and filter pipes based on the production capacities of the different layers includes:

[0013] Based on the production capacity of the different layers, each layer is divided into a real pipe target layer and a filter pipe target layer. The real pipe target layer is used for lowering the real pipe, and the filter pipe target layer is used for lowering the filter pipe.

[0014] Optionally, the layer section with a production capacity less than a first threshold value is divided into a real pipe target layer, and the layer section with a production capacity greater than the first threshold value is divided into a filter pipe target layer.

[0015] Optionally, determining the water filter pipe specifications that match the sand particle size data based on the data includes:

[0016] Obtaining the corresponding relationship between the median of the sand particle size and the pore size of the water filter pipe, the corresponding relationship formula is y=f(x), wherein x is the median of the sand particle size, and y is the pore size of the water filter pipe;

[0017] Calculate the median value of the sand particle size in the layer section entering the filter pipe;

[0018] According to the calculated median value and the corresponding relationship, a water filter pipe matching the data of the sand particle size is determined.

[0019] Optionally, it also includes:

[0020] After determining the water filter pipe specifications that match the data of the sand particle size, a real pipe is placed in each real pipe target layer, and a water filter pipe with a matching aperture is placed in each water filter pipe target layer.

[0021] Optionally, it also includes: a water stopper is arranged on the solid pipe.

[0022] The beneficial effects of the present invention are:

[0023] According to the production capacity of different layers of the sandstone thermal reservoir, a plan for mixing solid pipes and filter pipes is formulated. Solid pipes are lowered into layers with low production capacity, and filter pipes are lowered into layers with high production capacity. This method of mixing solid pipes and filter pipes can effectively save costs. For the layers where the filter pipes are lowered, the data of sand particle size is obtained, and then a filter pipe that matches the sand particle size data is further lowered. Since the physical properties between the layers of the mining section are quite different, if the filter pipes of the same specification are used, the sand prevention accuracy of the filter pipe will not match the sand particle size of the formation, which will not only easily cause blockage of the thermal reservoir and affect the water production effect, but also easily cause sand production during the production process, increasing operating costs. Therefore, the mining section optimization completion method of the present invention can effectively improve the problems of thermal reservoir blockage and easy sand production caused by the use of filter pipes of the same specification in each layer of the mining section in the prior art.

[0024] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present invention.

[0026] Figure 1 A flow chart of a method for optimizing completion of a production section of a sandstone geothermal well according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0027] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0028] A method for optimizing completion of a production section of a sandstone geothermal well according to the present invention comprises:

[0029] Obtaining the productivity of different layers of sandstone thermal reservoirs;

[0030] Based on the production capacity of different layers, formulate a mixed plan of solid pipe and filter pipe;

[0031] Obtain data on the particle size of sand entering the filter pipe layer;

[0032] Based on the data, determine the filter pipe specifications that match the sand particle size data.

[0033] Specifically, according to the production capacity of different layers of the sandstone thermal reservoir, a plan for mixing solid pipes and filter pipes is formulated. Solid pipes are lowered into layers with low production capacity, and filter pipes are lowered into layers with high production capacity. This method of mixing solid pipes and filter pipes can effectively save costs. For the layers where the filter pipes are lowered, the data of sand particle size is obtained, and then a filter pipe that matches the sand particle size data is further lowered. Since the physical properties between the layers of the mining section are quite different, if the filter pipes of the same specification are used, the sand prevention accuracy of the filter pipe will not match the sand particle size of the formation, which will not only easily cause blockage of the thermal reservoir and affect the water production effect, but also easily cause sand production during the production process, increasing operating costs. Therefore, the mining section optimized completion method of the present invention can effectively improve the problems of thermal reservoir blockage and easy sand production caused by the use of filter pipes of the same specification in each layer of the mining section in the prior art.

[0034] In one example, obtaining the productivity of different intervals of a sandstone thermal reservoir includes:

[0035] Analyze the logging data and productivity test data of the geothermal well development area and adjacent wells, and determine the productivity of different layers of the sandstone thermal reservoir based on the logging data and productivity test data.

[0036] Specifically, the formation and thermal reservoir conditions in the same area of ​​the sandstone thermal reservoir are relatively stable, and the connectivity between the small layers of each well is strong, so the data of the adjacent wells can effectively guide the development of new wells. In the geothermal development area, a typical geothermal well is selected to carry out a production profile test, and a horizontal comparative study is carried out in combination with conventional logging and logging data to clarify the production capacity of each small layer. According to the production capacity, the drilling footage can be optimized and the completion plan can be guided. This method of determining the production capacity of different layers of the sandstone thermal reservoir based on logging data and production capacity test data is an existing technology and can be easily obtained by those skilled in the art.

[0037] In one example, based on the production capacities of the different layers, formulating a mixed plan of solid pipes and filter pipes includes:

[0038] Based on the production capacity of different layers, each layer is divided into a solid pipe target layer and a filter pipe target layer. The solid pipe target layer is used for lowering the solid pipe, and the filter pipe target layer is used for lowering the filter pipe.

[0039] In one example, a layer section with a production capacity less than a first threshold is divided into a solid pipe target layer, and a layer section with a production capacity greater than the first threshold is divided into a filter pipe target layer.

[0040] Specifically, the sandstone thermal reservoir development well section is generally long, and large-scale screen pipe completion is not only costly, but also very likely to cause sand production risks, affecting the reinjection and service life of the geothermal well. In contrast, the layers with lower production capacity are generally mudstone and thin layers of fine sandstone, corresponding to the layers prone to sand production. Therefore, the layers with production capacity less than the first threshold are divided into solid pipe target layers. The solid pipe target layer is used to run solid pipes, which can effectively avoid the scouring of mudstone and fine sandstone by water layers and reduce the risks of mudstone collapse and fine sandstone sand production.

[0041] In one example, based on the data, determining a water filter specification that matches the sand particle size data includes:

[0042] Obtain the corresponding relationship between the median of the sand particle size and the pore size of the water filter pipe, the corresponding relationship formula is y=f(x), where x is the median of the sand particle size and y is the pore size of the water filter pipe;

[0043] Calculate the median particle size of the sand in the layer entering the filter pipe;

[0044] According to the calculated median value and the corresponding relationship, the filter pipe that matches the sand particle size data is determined.

[0045] Specifically, sandstone reservoirs with high production capacity are generally thicker, coarser in lithology, and better in physical properties, but there is also heterogeneity between the layers, and some single-layer sandstones also have small particles, which also have the risk of sand production and reinjection into the formation, thereby blocking the formation. For the layer section where the filter pipe is lowered, cores are taken at the upper, middle, and lower water intake sections during the drilling process, and the rock cementation degree and the median of the sand particle size of the section are analyzed and tested. The relationship between the rock cementation degree and the pore size of the filter pipe and the relationship between the median of the sandstone particle size and the pore size of the filter pipe are established. Among them, the rock cementation degree includes good, medium, and poor. In practical applications, the correspondence between the median of the sand particle size and the pore size of the filter pipe is selected, and the accuracy of the filter pipe is scientifically and reasonably matched to achieve graded optimization of the filter pipe, so as to prevent the use of filter pipes of the same specification in the entire well section and avoid the use of high-precision filter pipes in coarse sand or even gravel sections.

[0046] In one example, the method for optimizing completion of a production section of a sandstone geothermal well further includes:

[0047] After determining the filter pipe specifications that match the sand particle size data, a real pipe is placed in each real pipe target layer, and a filter pipe with a matching aperture is placed in each filter pipe target layer.

[0048] In one example, the method for optimizing completion of the production section of a sandstone geothermal well further includes: setting a water stopper on the solid pipe.

[0049] Example

[0050] like Figure 1As shown, a method for optimizing completion of a production section of a sandstone geothermal well comprises:

[0051] Obtaining the productivity of different layers of sandstone thermal reservoirs;

[0052] Based on the production capacity of different layers, formulate a mixed plan of solid pipe and filter pipe;

[0053] Obtain data on the particle size of sand entering the filter pipe layer;

[0054] Based on the data, determine the filter pipe specifications that match the sand particle size data.

[0055] Capturing the productivity of different intervals of sandstone thermal reservoirs includes:

[0056] Analyze the logging data and productivity test data of the geothermal well development area and adjacent wells, and determine the productivity of different layers of the sandstone thermal reservoir based on the logging data and productivity test data.

[0057] Based on the production capacity of different layers, the mixed plan of solid pipe and filter pipe is formulated, including:

[0058] Based on the production capacity of different layers, each layer is divided into a solid pipe target layer and a filter pipe target layer. The solid pipe target layer is used for lowering the solid pipe, and the filter pipe target layer is used for lowering the filter pipe.

[0059] Among them, the layer section with a production capacity less than the first threshold is divided into a real pipe target layer, and the layer section with a production capacity greater than the first threshold is divided into a water filter pipe target layer.

[0060] Based on the data, the filter pipe specifications that match the sand particle size data include:

[0061] Obtain the corresponding relationship between the median of the sand particle size and the pore size of the water filter pipe, the corresponding relationship formula is y=f(x), where x is the median of the sand particle size and y is the pore size of the water filter pipe;

[0062] Calculate the median particle size of the sand in the layer entering the filter pipe;

[0063] According to the calculated median value and the corresponding relationship, the filter pipe that matches the sand particle size data is determined.

[0064] The optimized completion method for the production section of sandstone geothermal wells also includes:

[0065] After determining the filter pipe specifications that match the sand particle size data, a real pipe is placed in each real pipe target layer, and a filter pipe with a matching aperture is placed in each filter pipe target layer.

[0066] The method for optimizing the completion of the mining section of a sandstone geothermal well also includes: setting a water stopper on the solid pipe.

[0067] To summarize, according to the production capacity of different layers of the sandstone thermal reservoir, a mixed plan for lowering solid pipes and filter pipes is formulated. Solid pipes are lowered into layers with low production capacity, and filter pipes are lowered into layers with high production capacity. This mixed method of lowering solid pipes and filter pipes can effectively save costs. For the layers where filter pipes are lowered, data on sand particle size is obtained, and then filter pipes that match the data on sand particle size are further matched. Since the physical properties between layers of the mining section are quite different, if filter pipes of the same specification are used, the sand prevention accuracy of the filter pipes will not match the sand particle size of the formation, which will not only easily cause blockage of the thermal reservoir and affect the water production effect, but also easily cause sand production during the production process, increasing operating costs. Therefore, the mining section optimized completion method of the present invention can effectively improve the problems of thermal reservoir blockage and easy sand production caused by the use of filter pipes of the same specification in each layer of the mining section in the prior art.

[0068] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A method for optimizing the completion of the mining section of a sandstone geothermal well, characterized in that: include: Obtaining the productivity of different layers of sandstone thermal reservoirs; Based on the production capacity of different layers, a mixed plan of solid pipe and filter pipe is formulated; Acquiring sand particle size data of the layer section lowered into the water filter pipe; Based on the data, determining the water filter pipe specifications that match the sand particle size data; The above-mentioned plan for mixing solid pipes and filter pipes based on the production capacity of different layers includes: Based on the production capacity of the different layers, each layer is divided into a real pipe target layer and a filter pipe target layer, wherein the real pipe target layer is used to lower the real pipe, and the filter pipe target layer is used to lower the filter pipe; The layer section with a production capacity less than the first threshold is divided into a solid pipe target layer, and the layer section with a production capacity greater than the first threshold is divided into a filter pipe target layer; Determining the water filter pipe specifications that match the sand particle size data based on the data includes: Obtaining the corresponding relationship between the median of the sand particle size and the pore size of the water filter pipe, the corresponding relationship formula is y=f(x), wherein x is the median of the sand particle size, and y is the pore size of the water filter pipe; Calculate the median value of the sand particle size in the layer section entering the filter pipe; According to the calculated median value and the corresponding relationship, a water filter pipe matching the data of the sand particle size is determined.

2. The method for optimizing the completion of the mining section of a sandstone geothermal well according to claim 1, characterized in that: The production capacity of different layers of the sandstone thermal reservoir is obtained by: The logging data and productivity test data of the geothermal well development area and adjacent wells are analyzed, and the productivity of different layers of the sandstone thermal reservoir is determined based on the logging data and the productivity test data.

3. The method for optimizing the completion of the mining section of a sandstone geothermal well according to claim 1, characterized in that: Also includes: After determining the water filter pipe specifications that match the data of the sand particle size, a real pipe is placed in each real pipe target layer, and a water filter pipe with a matching aperture is placed in each water filter pipe target layer.

4. The method for optimizing the completion of the mining section of a sandstone geothermal well according to claim 1, characterized in that: Also includes: A water stopper is arranged on the solid pipe.

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