Method for researching technical boundary of thin-layer horizontal well deployment

Abstract

The invention discloses a method for researching the technical boundary of thin-layer horizontal well deployment, belongs to the technical field of geological characteristic research and application, and aims to develop well position deployment research by utilizing a thin-layer horizontal well mining method so as to increase storage and yield and improve the utilization degree of difficult-to-exploit reserve blocks. The production condition, the geological condition and the oil production condition of the drilled horizontal well of the small-lying oil field are analyzed, economic benefit factors and technical feasibility are considered for deployment boundary analysis, the former is measured by accumulated oil production, and the latter is measured by sand body drilling encounter rate. According to the method, the oil layer is re-evaluated by utilizing the thin-layer horizontal well deployment technical boundary, and the previous poor part is changed into a good part, so that the reserve utilization degree of a deployment area is greatly improved. For example, the average thickness of the east three sections of the side parts of 38 hollow blocks is 3.7-4.26 m, and the three sections cannot be effectively used. Through thin-layer horizontal well deployment technology research, five thin-layer horizontal wells are deployed at the position, and the reserve utilization degree of a deployment area is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of geological feature research and application, and specifically relates to a method for studying the technical limits of thin-layer horizontal well deployment. Background Art

[0002] Previously, the Xiaowa Oilfield generally selected favorable blocks with large thickness and good physical properties for well deployment, and horizontal wells could not be deployed in the remaining edges or areas with thin oil layers, resulting in low utilization of difficult-to-recover areas. By using the technical limits of thin-layer horizontal well deployment to re-evaluate the oil layers, the once "bad" areas have been turned into "good" areas, greatly improving the utilization of reserves in the deployment areas. Summary of the invention

[0003] In order to solve the above-mentioned problems, the present invention proposes: a method for studying the technical limits of thin-layer horizontal well deployment, using the thin-layer horizontal well exploitation method to carry out well site deployment research to increase reserves and production, and improve the utilization level of difficult-to-recover reserve blocks. In the process of deployment boundary analysis, the production situation, geological conditions and oil production of the drilled horizontal wells in Xiaowa Oilfield are analyzed. For the deployment boundary analysis, economic benefit factors and technical feasibility are considered. The former is measured by cumulative oil production, and the latter is measured by sand body drilling rate.

[0004] Furthermore, firstly, for thin-layer horizontal wells, thicker oil layers not only have high oil abundance, but also good sedimentary facies and physical properties. Horizontal wells with cumulative production of more than 10 rounds in the East Third Section of Xiaowa Oilfield were selected to conduct an intersection analysis of sand body single-layer thickness and cumulative oil production in 10 cycles. This analysis did not take into account the differences in horizontal section lengths of different horizontal wells. Further, an intersection diagram of sand body single-layer thickness and cumulative oil production per meter in 10 cycles was drawn to avoid the influence of horizontal section differences on oil production. There is a positive correlation between single-layer thickness and cumulative oil production. Therefore, under the premise that conditions permit, areas with thicker single sand body development are selected for horizontal well deployment.

[0005] Furthermore, the drilling rate of the completed horizontal wells in the East Section 3 of the work area was statistically analyzed. Through the intersection analysis of the drilling rate and the sand body thickness, it was found that when the sand body thickness is greater than 5m, the sand body drilling rate of the horizontal well is higher than 80%, but as the sand body becomes thinner, the drilling rate decreases significantly, and the two have a good correlation. According to statistics, when the sand body thickness is less than 3m, the drilling rate will be less than 50%. Therefore, based on the above analysis, the lower limit of the single-layer sand body thickness is set to 3m.

[0006] Furthermore, the influence of reservoir physical property limits on the oil production of horizontal wells is analyzed. Physical properties include porosity and permeability. Porosity affects the oil storage capacity of the reservoir, while permeability determines the seepage capacity of the reservoir. Horizontal wells with a cumulative production of more than 10 rounds in the East Third Section of Xiaowa Oilfield were selected for cross-analysis of sand body porosity, permeability and cumulative oil production in 10 cycles. It was found that the cumulative oil production increased regularly with the increase of porosity and permeability, and the physical properties were correlated with the cumulative oil production. The production capacity of newly deployed horizontal wells was considered to be predicted based on the physical properties.

[0007] Furthermore, the influence of the single controlled reserve limit on the oil production of horizontal wells was analyzed. The horizontal section length and well spacing were included in the single controlled reserves for comprehensive analysis. The horizontal wells with more than 10 rounds of cumulative production in the East Third Section of Xiaowa Oilfield were selected for cross analysis of single controlled reserves and 10-cycle cumulative oil production. It can be seen that the cumulative oil production increases regularly with the increase of single controlled reserves. According to statistics, when the single controlled reserves of the oil well reach 1.5×10 4 t, and its cumulative oil production in 10 cycles will reach 7,000t.

[0008] Furthermore, when executing thin-layer horizontal well deployment, several parameters such as reservoir thickness, porosity, permeability and single controlled reserves are comprehensively considered.

[0009] Furthermore, considering the technical limit of horizontal well drilling, the oil layer thickness is greater than 3m.

[0010] Furthermore, considering the cumulative oil production, the area with higher porosity and permeability is selected for deployment, and the appropriate length of the horizontal section is designed to make the single controlled reserves greater than 1.5×10 4 t.

[0011] The beneficial effects of the present invention are as follows: Previously, the well site deployment of Xiaowa Oilfield generally preferred favorable blocks with large thickness and good physical properties, and the remaining edges or areas with thin oil layers could not deploy horizontal wells, resulting in a low degree of utilization of difficult-to-recover areas. The oil layers are re-evaluated using the technical boundaries of thin-layer horizontal well deployment, turning the once "bad" areas into "good" areas, greatly improving the degree of reserve utilization in the deployment area. For example, at the edge of Block 38 of Wa, the average thickness of the East Third Section is 3.7 to 4.26m, which has not been effectively utilized. Through the research on the deployment technology of thin-layer horizontal wells, 5 thin-layer horizontal wells were deployed in this area to improve the degree of reserve utilization in the deployment area. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Attached Figure 1 It is a cross-plot of single sand body thickness and cumulative oil production of the present invention;

[0013] Attached Figure 2 It is a cross-plot of single sand body thickness and cumulative oil production per meter of the present invention;

[0014] Attached Figure 3 It is a cross-plot of sand body thickness and drilling rate of the horizontal well of the East Section 3 of the present invention;

[0015] Attached Figure 4 It is the cross-plot of porosity and cumulative oil production of the present invention;

[0016] Attached Figure 5 is a cross-plot of permeability and cumulative oil production according to the present invention;

[0017] Attached Figure 6 It is a cross-plot of single controlled reserves and cumulative oil production of the present invention;

[0018] Attached Figure 7 This is the deployment map of the d3Ⅱ1-2 sand body in Xiaowa Oilfield;

[0019] Attached Figure 8 This is the deployment map of the sand body d3Ⅱ2-1 in Xiaowa Oilfield;

[0020] Attached Fig. 9 This is the actual drilling trajectory map of the Hai C13-17CH well. DETAILED DESCRIPTION

[0021] A method for studying the technical limits of thin-layer horizontal well deployment. Conducting well location deployment research using thin-layer horizontal well technology is one of the important means to increase reserves and production, and improve the utilization of difficult-to-recover reserve blocks.

[0022] Horizontal well technology has been widely used in oil and gas layer exploitation at home and abroad, but thin-layer horizontal well technology is mainly used in the expansion of old oil reservoirs and the secondary evaluation of undeveloped reserves, which has become an important part of the capacity construction of new areas (especially those difficult-to-use oil reservoirs in the past due to thin oil layers, low permeability oil reservoirs, and poor vertical well exploitation efficiency). By adopting thin-layer horizontal well technology, the secondary evaluation and secondary development of difficult-to-use oil fields have become one of the important means to increase reserves and production in old oil fields. To achieve efficient development of thin layers, two key problems need to be solved. One is that the edge reservoir is thin, the well control area is small, and the prediction is difficult; the other is the unclear technical boundaries of thin-layer horizontal well deployment. Regarding the deployment boundaries, it mainly involves parameters such as the physical properties of different oil layer thicknesses, the length of the horizontal section, the spacing, and the position in the plane and vertical direction.

[0023] In the process of deployment boundary analysis, the production situation, geological conditions and oil production of the drilled horizontal wells in Xiaowa Oilfield were analyzed in detail. For deployment boundary analysis, the main considerations are economic benefit factors and technical feasibility, the former is measured by cumulative oil production, and the latter is measured by sand body drilling rate.

[0024] First, for thin-layer horizontal wells, the thickness of the oil layer has a great influence on the oil production. Thicker oil layers not only have higher oil abundance, but also generally mean better sedimentary facies and physical properties. Figure 1As shown in the figure, horizontal wells with more than 10 cumulative production cycles in the East Section of Xiaowa Oilfield were selected for cross-analysis of sand body single layer thickness and 10-cycle cumulative oil production. It can be seen that the cumulative oil production increases with the increase of single layer thickness, and the correlation coefficient between the two is greater than 0.8. Of course, this analysis does not take into account the differences in the length of horizontal sections of different horizontal wells, so this study further draws a cross-plot of sand body single layer thickness and 10-cycle cumulative oil production per meter ( Figure 2 ), the influence of horizontal section differences on oil production is avoided at this time, and it can be seen that the positive correlation between single layer thickness and cumulative oil production is objective. Therefore, under the premise of conditions permitting, horizontal well deployment should be selected in areas with thicker single sand bodies.

[0025] In addition to affecting oil production, the thickness of a single sand body also has an important impact on the drilling rate of the sand body in horizontal wells. Under the same formation conditions, when the thickness of a single sand body becomes thinner, it will bring greater difficulties to the construction of horizontal wells. What is the specific situation of the drilling rate of horizontal wells in Xiaowa Oilfield? This study conducted a statistical analysis of the drilling rate of the completed horizontal wells in the East Section 3 of the work area. Through the intersection analysis of the drilling rate and the sand body thickness, it can be seen that ( Figure 3 ), when the sand body thickness is greater than 5m, the sand body drilling rate of the horizontal well is generally higher than 80%, but as the sand body becomes thinner, the drilling rate decreases significantly, and the two have a good correlation. According to statistics, when the sand body thickness is less than 3m, the drilling rate will be less than 50%, which is obviously unsatisfactory. Therefore, after the above analysis, the lower limit of the single-layer sand body thickness is set to 3m.

[0026] 1. Analysis of physical property boundaries of oil layers

[0027] In addition to the thickness of the single layer, physical properties also have a direct impact on the oil production of horizontal wells. Physical properties mainly include porosity and permeability. Porosity affects the oil storage capacity of the reservoir, while permeability determines the seepage capacity of the reservoir. Figure 4 , 5 As shown in the figure, horizontal wells with cumulative production of more than 10 rounds in the East Section of Xiaowa Oilfield were selected for cross-analysis of sand body porosity, permeability and cumulative oil production in 10 cycles. It can be seen that the cumulative oil production increases regularly with the increase of porosity and permeability. The correlation between physical properties and cumulative oil production is very strong, so it is possible to consider using physical properties as a basis for capacity prediction of newly deployed horizontal wells.

[0028] 2. Analysis of single controlled reserves limit

[0029] For horizontal well deployment, in addition to reservoir thickness, physical properties, and structure, other factors should also be considered, such as horizontal section length and well spacing. Considering that there are few sample points of completed horizontal well data (currently only 7 wells have produced more than 10 cycles), we will temporarily include horizontal section length and well spacing in the single controlled reserves for comprehensive analysis. Figure 6-Figure 8As shown in the figure, horizontal wells with more than 10 cycles of cumulative production in the East Section of Xiaowa Oilfield were selected for single-controlled reserves and 10-cycle cumulative oil production. It can be seen that the cumulative oil production increases regularly with the increase of single-controlled reserves. According to statistics, when the single-controlled reserves of an oil well reach 1.5×10 4 t, and its cumulative oil production in 10 cycles will reach 7,000t.

[0030] In summary, when deploying thin-layer horizontal wells, the oil layer thickness, porosity, permeability and single controlled reserves should be considered. Considering the technical limit of horizontal well drilling, the oil layer thickness should be greater than 3m. In addition, considering the cumulative oil production, areas with higher porosity and permeability should be selected as much as possible for deployment, and the appropriate horizontal section length should be designed to make the single controlled reserves greater than 1.5×10 4 t.

[0031] like Fig. 9 As shown, the oil production plant used the technical boundaries of thin-layer horizontal well deployment to re-evaluate the oil layer. Based on the accurate identification of the 3m thin layer, the oil production plant deployed the Hai C13-17CH well. During the drilling process, the well trajectory was tracked and adjusted in real time according to the seismic data to accurately grasp the target layer. The daily oil production capacity is expected to be 5 tons.

[0032] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for studying the technical limits of thin-layer horizontal well deployment, characterized in that: Well deployment research is carried out using thin-layer horizontal wells to increase reserves and production, and to improve the utilization of difficult-to-recover reserve blocks. In the process of deployment boundary analysis, the production, geological conditions and oil production of the drilled horizontal wells in Xiaowa Oilfield are analyzed. For the deployment boundary analysis, economic benefit factors and technical feasibility are considered. The former is measured by cumulative oil production, and the latter is measured by sand body drilling rate.

2. The method for studying the technical limits of thin-layer horizontal well deployment according to claim 1, characterized in that: First, for thin-layer horizontal wells, thicker oil layers not only have high oil abundance, but also good sedimentary facies and physical properties. Horizontal wells with cumulative production of more than 10 rounds in the East Third Section of Xiaowa Oilfield were selected to conduct an intersection analysis of sand body single-layer thickness and cumulative oil production in 10 cycles. This analysis did not take into account the differences in horizontal section lengths of different horizontal wells. Further, an intersection diagram of sand body single-layer thickness and cumulative oil production per meter in 10 cycles was drawn to avoid the impact of horizontal section differences on oil production. There is a positive correlation between single-layer thickness and cumulative oil production. Therefore, if conditions permit, areas with thicker single sand body development are selected for horizontal well deployment.

3. The method for studying the technical limits of thin-layer horizontal well deployment according to claim 1, characterized in that: The drilling rate of the completed horizontal wells in the East Section 3 of the work area was statistically analyzed. Through the intersection analysis of the drilling rate and the sand body thickness, it was found that when the sand body thickness is greater than 5m, the sand body drilling rate of the horizontal well is higher than 80%, but as the sand body becomes thinner, the drilling rate decreases significantly, and the two have a good correlation. According to statistics, when the sand body thickness is less than 3m, the drilling rate will be less than 50%. Therefore, based on the above analysis, the lower limit of the single-layer sand body thickness is set to 3m.

4. The method for studying the technical limits of thin-layer horizontal well deployment according to claim 1, characterized in that: The influence of reservoir physical property limits on the oil production of horizontal wells is analyzed. Physical properties include porosity and permeability. Porosity affects the oil storage capacity of the reservoir, while permeability determines the seepage capacity of the reservoir. Horizontal wells with cumulative production of more than 10 rounds in the East Third Section of Xiaowa Oilfield are selected for cross-analysis of sand body porosity, permeability and cumulative oil production in 10 cycles. It is found that the cumulative oil production increases regularly with the increase of porosity and permeability, and the physical properties are correlated with the cumulative oil production. The production capacity of newly deployed horizontal wells is considered to be predicted based on physical properties.

5. The method for studying the technical limits of thin-layer horizontal well deployment according to claim 1, characterized in that: The influence of single controlled reserves limit on horizontal well oil production was analyzed. The horizontal section length and well spacing were included in the single controlled reserves for comprehensive analysis. The horizontal wells with cumulative production of more than 10 rounds in the East Section of Xiaowa Oilfield were selected for single controlled reserves and 10-cycle cumulative oil production intersection analysis. It can be seen that the cumulative oil production increases regularly with the increase of single controlled reserves. According to statistics, when the single controlled reserves of the oil well reach 1.5×10 4 t, and its cumulative oil production in 10 cycles will reach 7,000t.

6. The method for studying the technical limits of thin-layer horizontal well deployment according to claim 5, characterized in that: When executing thin-layer horizontal well deployment, several parameters such as reservoir thickness, porosity, permeability and single controlled reserves are comprehensively considered.

7. The method for studying the technical limits of thin-layer horizontal well deployment according to claim 6, characterized in that: Considering the technical limit of horizontal well drilling, the oil layer thickness is greater than 3m.

8. The method for studying the technical limits of thin-layer horizontal well deployment according to claim 7, characterized in that: Considering the cumulative oil production, select areas with high porosity and permeability for deployment, and design an appropriate horizontal section length to make the single controlled reserves greater than 1.5×10 4 t.

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