Well drilling and completion operation sequence design method considering heavy oil thermal recovery and heat injection period

Abstract

The invention provides a drilling and completion operation sequence design method considering a heavy oil thermal recovery heat injection period, and belongs to the field of drilling and completion of heavy oil thermal recovery, and the method comprises the following steps: customizing target point coordinates according to the actual demand of an oil reservoir, inputting the target point coordinates of two wells of which the relative distance needs to be calculated at the same layer, and calculating the target point coordinates; the projection intersection point distance of the target spot of the target well on the well track of the other well and the relative distance of each target spot are calculated, the result that the target spot and the projection distance are located on the extension line of the well track is excluded, and after the result is optimized, a minimum distance matrix is formed; according to actual requirements, a well is selected as the first heat injection well, and according to the distance matrix calculation result, the well with the farthest distance is selected to conduct well drilling and completion operation in the same period; and subsequently, according to the actual operation progress, the well for heat injection operation and the well for drilling and completion operation are alternately selected according to the farthest distance principle. According to the method, the time utilization rate can be increased to the maximum extent, and synchronous operation of heat injection and well drilling and completion is achieved under the condition that safety is guaranteed.

Description

Technical Field

[0001] The invention relates to the field of heavy oil thermal recovery drilling and completion, and in particular to a drilling and completion operation sequence design method considering heavy oil thermal recovery heat injection cycle. Background Art

[0002] Offshore resources are abundant, and the development of heavy oil is crucial to offshore oil fields. However, heavy oil has high viscosity and poor fluidity in the wellbore, so the production efficiency of traditional oil and gas development methods is low. In order to reduce the viscosity of heavy oil and improve its fluidity, injecting high-temperature thermal fluids is a common method for such heavy oil reservoirs.

[0003] Unlike onshore heavy oil fields, offshore heavy oil production platforms are limited by site size, and the heat injection operations of development wells and the drilling and completion operations of new wells have a great impact on each other. In order to ensure the production safety of offshore platforms, the initial stage of offshore heavy oil development requires that drilling and completion operations related to the same reservoir section be stopped during the heat injection process. This practice not only has low time utilization but is also not conducive to the efficient development of heavy oil reservoirs. With the increase of experience in offshore heavy oil heat injection operations, people gradually realize that the impact of heat injection operations on the same reservoir section is limited, and it is feasible to carry out heat injection and drilling and completion in the same layer at the same time. However, there is currently no method for designing the sequence of drilling and completion operations that comprehensively considers the heat injection operation cycle.

[0004] If the minimum heat injection operation influence range is taken as a constraint condition, and the problem is considered from the perspective of the easiest drilling and completion, it is believed that all areas outside this range can be freely drilled and completed, which can maximize the selection range of drilling and completion operation areas. However, the method based on the minimum influence range of heat injection operation has the following three defects: First, the distance between different wells usually needs to be calculated by professional software using detailed wellbore trajectory data. However, in the early stage of drilling and completion design, the wellbore trajectory plan is usually not determined, and only the target coordinate data is available. At present, there is a lack of methods that rely solely on target data to calculate the shortest distance between different wells; secondly, the heat injection influence range of different heavy oil blocks is different, and is greatly affected by local differences in the formation. Therefore, it is difficult to quantify the heat injection influence area, which poses a great safety hazard. Therefore, it is difficult to confirm the minimum heat injection operation influence range; thirdly, when the minimum range principle is used to design the drilling and completion operation sequence, when the number of drilling and completion wells is large, there may be a situation where the heat injection ranges overlap with each other and there is no safe drilling and completion area, that is, the convergence guarantee of the design results using this principle is low.

[0005] At present, offshore platform drilling technology is relatively complete, but heat injection operations are greatly limited by the platform boiler capacity. If drilling and completion operations are abandoned during heat injection operations according to current practices, the time utilization rate of operations will be extremely low. However, it is difficult to obtain reliable values ​​by mainly considering the difficulty of drilling and completion and relying on the minimum impact range of heat injection operations. Therefore, it is urgent to establish a drilling and completion operation sequence method that mainly considers heat injection operations to improve the time utilization rate of field operations. Summary of the invention

[0006] In view of this, the present invention aims to propose a drilling and completion operation sequence design method considering the heat injection cycle of heavy oil thermal recovery, adopting the principle of maximum distance, aiming to ensure the safety of operations while achieving the synchronization of heat injection and drilling and completion operations, thereby improving the time utilization of field operations.

[0007] To achieve the above object, the technical solution of the present invention is implemented as follows: a drilling and completion operation sequence design method considering the heavy oil thermal recovery and heat injection cycle, comprising the following steps:

[0008] Based on reservoir characteristics, target information is formulated according to reservoir characteristics and reservoir development requirements. According to reservoir data, the target coordinates of two wells in the same layer whose relative distance needs to be calculated are input. At the same time, according to the target coordinates of the two wells, the corresponding wellbore trajectory straight line expressions are compiled;

[0009] Based on the target point coordinates of the target well and the straight line expression of the wellbore trajectory of another well, the projection intersection point of the target point of the target well on the wellbore trajectory of another well is calculated, and the distance between the target point and the projection intersection point is calculated;

[0010] According to the target coordinates of the target well and the target coordinates of another well, the relative distances of the respective targets are calculated, and the distance results calculated for the two wells are optimized to exclude the results where the target and the projected distance are on the extension line of the wellbore trajectory;

[0011] After the optimization results, the minimum distance value is extracted as the calculation result of the distance between the two wells. The same method is used to calculate the shortest distance of all wells in the entire area to form a minimum distance matrix;

[0012] According to actual needs, a well is selected as the first heat injection well, and based on the distance matrix calculation results, the farthest distance principle is adopted to select the farthest well for simultaneous drilling and completion operations;

[0013] Subsequently, based on the actual operation progress, wells for heat injection operations and drilling and completion operations are selected alternately according to the principle of maximum distance.

[0014] Furthermore, the distance between the two wells is calculated by obtaining the target point data of the two wells.

[0015] Furthermore, when calculating the relative distance between the target well point and another well point, a total of eight distance calculation results can be obtained.

[0016] Furthermore, the minimum distance matrix excludes the results where the distance between the target point and the projection is on the extension line of the wellbore trajectory, which is the accurate wellbore trajectory distance.

[0017] Furthermore, if after the heat injection or drilling completion operation is completed, the wells in the corresponding area have not yet completed the operation, you can choose to wait for the operation in the current area to end and exchange the operation position according to actual needs, or continue to select the target position with the second longest distance in the corresponding area to operate.

[0018] Compared with the prior art, the method for designing the sequence of drilling and completion operations taking into account the heavy oil thermal recovery heat injection cycle described in the present invention has the following advantages: the method described in the present invention can calculate the minimum well spacing based on the target data before the wellbore trajectory is determined, which weakens the dependence on the minimum heat injection operation impact range data and improves the convergence of the selection method. If the farthest distance well is also affected by the heat injection on-site monitoring, then other wells will definitely be affected, taking into account safety considerations at the same time. Therefore, while ensuring safety, the platform's heat injection capacity and drilling and completion operation capacity can be comprehensively considered, which greatly improves time utilization and realizes the synchronous operation of heat injection and drilling and completion. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0020] Figure 1 Calculate the flow chart for the shortest distance between two wells;

[0021] Figure 2 It is a schematic flow chart of a method for designing a drilling and completion operation sequence considering a heavy oil thermal recovery and heat injection cycle according to an embodiment of the present invention;

[0022] Figure 3 This is the final operation sequence diagram of the NB35-2 block. DETAILED DESCRIPTION

[0023] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0024] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0025] like Figure 1-Figure 3 As shown, the present invention is a drilling and completion operation sequence design method considering the heavy oil thermal recovery and heat injection cycle, which can greatly improve the operation time utilization rate and shorten the overall operation period, including the following steps:

[0026] Based on reservoir characteristics, target information is formulated according to reservoir characteristics and reservoir development requirements. According to reservoir data, the target coordinates of two wells in the same layer whose relative distance needs to be calculated are input. At the same time, according to the target coordinates of the two wells, the corresponding wellbore trajectory straight line expressions are compiled;

[0027] Based on the target point coordinates of the target well and the straight line expression of the wellbore trajectory of another well, the projection intersection point of the target point of the target well on the wellbore trajectory of another well is calculated, and the distance between the target point and the projection intersection point is calculated;

[0028] According to the target coordinates of the target well and the target coordinates of the other well, the relative distances of the respective targets are calculated. Combining the calculation results of the previous step, a total of 8 distance calculation results can be obtained. The 8 distance results calculated for the two wells are optimized to exclude the results where the target and the projection distance are on the extension line of the wellbore trajectory;

[0029] After the optimization results, the minimum distance value is extracted as the calculation result of the distance between the two wells. The same method is used to calculate the closest distance of all wells in the entire area to form a minimum distance matrix; the minimum distance matrix excludes the results where the target point and the projection distance are on the extension line of the wellbore trajectory, which is the accurate wellbore trajectory distance.

[0030] According to actual needs, a well is selected as the first heat injection well, and according to the calculation results of the distance matrix, the farthest distance principle is adopted to select the farthest well for the drilling and completion operations at the same time. If the heat injection or drilling and completion operations are completed, the wells in the corresponding area have not completed the operation, then according to actual needs, you can choose to wait for the current area operation to end and exchange the operation position, or continue to select the second farthest target position in the corresponding area to operate. According to the farthest distance principle, the two farthest wells are selected for operation, which can maximize the safety of heat injection and drilling and completion operations. It should be noted that selecting a well as the first heat injection well means selecting any well. If the logic cannot be arranged in order, just change another well and start the calculation again. The applicability of the farthest distance principle is not limited by region. Therefore, the method described in the present invention is not only suitable for offshore heavy oil fields, but also for terrestrial heavy oil fields.

[0031] Subsequently, based on the actual operation progress, wells for heat injection operations and drilling and completion operations are selected alternately according to the principle of maximum distance.

[0032] The distance between the two wells is calculated by requiring the target point data of the two wells, that is, the calculation of the distance between the two wells only requires the target point data of the two wells, without relying on accurate well trajectory data.

[0033] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.

[0034] Step 1: Preliminary formulation of target information for each well based on reservoir characteristics and reservoir development requirements.

[0035] Step 2: For two wells (well A and well B) at any location, first collect the target locations of well A and well B at the same layer, which are (X A1 , Y A1 ), (X A2 ,Y A2 ) and (X B1 , Y B1 ), (X B2 ,Y B2 ).

[0036] Step 3: For well A and well B, no matter how their relative positions are, the minimum possible distance between the two wells must be one of the following eight values: 1. Well A (X A1 , Y A1 ) and the distance between the two endpoints of Well B; 2. Well A (X A2 ,Y A2 ) and the distance between the two endpoints of Well B; 3. Well A (X A1 , Y A1 ), (X A2 ,Y A2 ) and the vertical distance between well B; 4. well B (X B1 , Y B1 ), (X B2 ,Y B2 ) is the vertical distance from Well A.

[0037] Step 4: The distances S1, S2, S3, and S4 between the endpoints of well A and well B can be calculated using the following four formulas:

[0038]

[0039] Step 5, calculate the endpoint of well A (X A1 , Y A1 ), (X A2 ,Y A2 ) The distance from Well B requires first calculating the intersection of the endpoint of Well A and the vertical distance of Well B. For Well B, the straight line expression through its double target points is as follows:

[0040] y=K B x+Y B1 -K B X B1 ,in

[0041] Then the expressions of the perpendicular lines passing through the two end points of well A are:

[0042]

[0043] The intersection point of the closest distance between the endpoint of well A and well B is calculated as:

[0044]

[0045] and

[0046]

[0047] Then the endpoint of well A (X A1 , Y A1 ), (X A2 ,Y A2 ) and the distance between well B is as follows:

[0048]

[0049] Step 6, calculate the endpoint of well B (X B1 , Y B1 ), (X B2 ,Y B2 ) The distance from Well A requires first calculating the intersection of the endpoint of Well B and the vertical distance of Well A. For Well A, the straight line expression through its double target points is as follows:

[0050] y=K A x+Y A1 -K A X A1 ,in

[0051] Then the expressions of the perpendicular lines passing through the two end points of well B are:

[0052]

[0053] The intersection point of the closest distance between the endpoint of well B and well A is calculated as:

[0054]

[0055] and

[0056]

[0057] Then the endpoint of well A (X A1 , Y A1 ), (X A2 ,Y A2 ) and the distance between well B is as follows:

[0058]

[0059] Step 7, select the smallest distance S between S1 and S8 ABmin , where if S ABmin Appears between S1 and S4, no further judgment is required. ABmin If it appears between S5 and S8, it is necessary to further determine whether the intersection of the vertical lines is within the target range of the corresponding straight line, for example: S ABmin = S5, then we need to judge (X B3 , Y B3 ) is in (X B1 , Y B1 ), (X B2 ,Y B2 ), if so, then S ABmin = S5. If not, it means that the intersection point is located on the extension line of well B, and the next smallest distance needs to be re-judged. Repeat the above steps until the selected minimum distance S ABmin The result is that the distance intersection point is between S1 and S4 or is not on the extension line of the corresponding well.

[0060] Step 8, repeatedly calculate the distance results of all wells in the same layer to form the minimum distance matrix of all wells in the block. The overall calculation process is as follows: Figure 1 shown.

[0061] Step 9, according to actual needs, set the minimum safety distance as the termination condition, recorded as the termination distance. Enter the first batch of drilling coordinates, drilling and completion time and heat injection time. The heat injection start well should be selected from the first batch of drilling, and one well should be selected as the first heat injection well. The first batch of drilling coordinates refers to the batch of wells that need to be analyzed for heat injection and drilling and completion, that is, the coordinates of the batch of drillings whose distances have been calculated in the previous steps.

[0062] Step 10, based on the existing heat injection well positions, select the well farthest from the heat injection well to start a new drilling operation. After the operation is completed, activate the position of the new heat injection well.

[0063] Step 11: If the drilling is completed but the heat injection operation at the far end is not completed, then select the undrilled well farthest from the heat injection location to continue drilling.

[0064] Step 12: After the heat injection is completed, if the drilling operation is not completed, select the heat injection well farthest from the existing drilling position for heat injection.

[0065] Step 13: At the beginning of the operation, the selection of heat injection positions is narrow, and the distance between the heat injection well and the existing drilling well may be less than the set distance. In this case, it is necessary to wait until the well is drilled and completed before reselecting the heat injection position. The new drilling position can continue to be selected according to the principle of the farthest distance;

[0066] Step 14: In the middle of the operation, if the heat injection and drilling and completion are completed at the same time, any of the two wells can be used as the target well to restart the operation sequence selection;

[0067] Step 15, at the end of the operation, since the maximum distance approach will make the distance between the heat injection operation well and the well being drilled and completed closer and closer, it is possible that the undrilled area and the current heat injection operation area are less than the set end distance. At this time, the drilling and completion operation should be resumed after the heat injection operation is completed. The schematic diagram of all the flow charts of the drilling and completion operation sequence design method considering the heavy oil thermal recovery heat injection cycle is as follows Figure 2 shown.

[0068] Embodiment 1:

[0069] Taking the NB35-2 oilfield as an example, there is a steam drive well, B36M, in the area. In addition, six new heat injection wells need to be drilled, namely B28H1, B47H, B25H2, B48, B30H2, and B8H1. The relative target coordinates centered on B36M are shown in Table 1.

[0070] Table 1. Target information of heat injection wells in NB35-2 oilfield

[0071]

[0072] Based on the target data, the minimum distance matrix between different wells was calculated, and the termination distance was set to 250m. The drilling and completion cycle in this area was 10 days, and the heat injection cycle was 25 days.

[0073] Table 2 Minimum distance matrix of each heat injection well

[0074]

[0075] According to the principle of the longest distance, since B36M well is the original heat injection well, B8H1, B25H2 and B28H1 wells should be drilled first according to the distance. When B28H1 is drilled for 5 days, the heat injection of B36M is completed. At this time, the wells that can be injected with heat are B8H1 and B25H2, and the wells that can be drilled are B47H, B48, and B30H2.

[0076] According to the principle of the longest distance, when drilling well B28H1, well B25H2 should be injected with heat. During the injection of well B25H2, wells B28H1, B30H2 and B48 should be completed according to the principle of the longest distance. When well B48 is completed, wells that can be injected with heat are B8H1, B28H1, B30H2, and wells that can be drilled are well B47H.

[0077] Since the distance between B48 and B47H is 394m, which exceeds the set end distance, the drilling and completion operations of B47H can be continued. At this time, the heat injection of B8H1 should be carried out according to the principle of the longest distance. During the heat injection period of B8H1, the drilling and completion operations of all wells have been completed, so the subsequent heat injection operations are not restricted. Figure 3 As shown in the figure, the final operation sequence diagram of the NB35-2 block shows that while ensuring safety, heat injection operations and drilling and completion operations can be carried out simultaneously, greatly improving the utilization of operation time.

[0078] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for designing the sequence of drilling and completion operations considering the heavy oil thermal recovery and heat injection cycle, characterized in that: The following steps are involved: Based on reservoir characteristics, target information is formulated according to reservoir characteristics and reservoir development requirements. According to reservoir data, the target coordinates of two wells in the same layer whose relative distance needs to be calculated are input. At the same time, according to the target coordinates of the two wells, the corresponding wellbore trajectory straight line expressions are compiled; Based on the target point coordinates of the target well and the straight line expression of the wellbore trajectory of another well, the projection intersection point of the target point of the target well on the wellbore trajectory of another well is calculated, and the distance between the target point and the projection intersection point is calculated; According to the target coordinates of the target well and the target coordinates of another well, the relative distances of the respective targets are calculated, and the distance results calculated for the two wells are optimized to exclude the results where the target and the projected distance are on the extension line of the wellbore trajectory; After the optimization results, the minimum distance value is extracted as the calculation result of the distance between the two wells. The same method is used to calculate the shortest distance of all wells in the entire area to form a minimum distance matrix; According to actual needs, a well is selected as the first heat injection well, and based on the distance matrix calculation results, the farthest distance principle is adopted to select the farthest well for simultaneous drilling and completion operations; Subsequently, based on the actual operation progress, wells for heat injection operations and drilling and completion operations are selected alternately according to the principle of maximum distance.

2. The method for designing a drilling and completion operation sequence considering a heavy oil thermal recovery and heat injection cycle according to claim 1, characterized in that: The distance between two wells is calculated by requiring the target point data of the two wells.

3. The method for designing a drilling and completion sequence considering a heavy oil thermal recovery and heat injection cycle according to claim 2, characterized in that: When calculating the relative distance between the target well point and another well target point, a total of eight distance calculation results can be obtained.

4. The method for designing a drilling and completion operation sequence considering a heavy oil thermal recovery and heat injection cycle according to claim 3, characterized in that: The minimum distance matrix excludes the results where the distance between the target point and the projection is on the extension line of the wellbore trajectory, which is the accurate wellbore trajectory distance.

5. The method for designing a drilling and completion sequence considering a heavy oil thermal recovery and heat injection cycle according to claim 1, characterized in that: If the heat injection or drilling and completion operations are completed, the wells in the corresponding area have not been completed. If the job is completed, you can choose to wait for the current area job to end and exchange the job position according to actual needs. Or continue to select the target position with the second longest distance in the corresponding area to perform the operation.

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