New well yield limit determination method and device based on divided development oil fields

Abstract

The invention relates to the field of oil and gas field development, in particular to a new well yield limit determination method and device based on divided development oil fields. The method mainly solves the problem that an existing new well yield limit calculation method cannot be used for guiding calculation of an overseas oil field new well yield limit under a yield division contract. Comprising the following steps: determining the content of a divided contract and an internal return rate specified value; collecting to-be-measured oil field data; the total yield in the new well income period is calculated; the total income in the new well development period is calculated; the total expenditure in the new well development period is calculated; constructing an oil field internal yield rate model under yield classification; according to the conditions of different well depths and oil prices, the initial yield of a single well is subjected to trial calculation, and when the trial calculation internal yield of a new well is the same as the internal yield specified value, the result is the single well yield limit. The method can judge whether the single well yield reaches the economic and effective development limit or not in the oilfield development process and judge whether the potential well site can be developed or not, and has guiding significance for economic and effective development of an oilfield.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of oil and gas field development, in particular to a new well production limit determination method and device based on shared development oil field. BACKGROUND

[0002] The new well production limit refers to the minimum value of the required rate of return that should be reached when the benefits obtained by a newly drilled development well in the economic life period are equal to the total investment, oil production operation cost and tax under the existing oil field development technology and fiscal system. The new well economic limit is a yardstick for measuring whether the investment is economically feasible and is an important reference standard for optimizing investment decisions.

[0003] The calculation of the new well production limit in domestic oil fields is mainly based on the profit break-even analysis method, which determines the initial daily oil production of the new well, i.e. the initial daily oil production limit of the new well, through comprehensive analysis of the new well fixed cost, variable cost, crude oil production and sales volume, tax and rate of return.

[0004] However, if this method is used to calculate the initial production limit of the new well in overseas oil fields under the production sharing contract, it does not take into account the differences between overseas oil fields and domestic oil fields, neither does it consider the production sharing ratio of the contract holder and the host country of the production sharing contract oil field, nor does it consider the development period of the contract and the mineral tax system of the host country, so this method cannot be used to guide the calculation of the new well production limit in overseas oil fields under the production sharing contract. SUMMARY

[0005] In order to overcome the shortcomings of the existing new well production limit calculation method that cannot be used to guide the calculation of the new well production limit in oil fields under the production sharing contract, the present application provides a new well production limit determination method and device based on shared development oil field, which can determine whether the single well production in the oil field development process can reach the economically effective development limit and whether the potential well site can be developed, which has important guiding significance for the economic and effective development of overseas oil fields and the protection of oil field benefits.

[0006] The technical solution of the present application is: a new well production limit determination method based on shared development oil field, comprising the following steps:

[0007] S1, determining the development period of the new well, the contract specified mineral tax, the production sharing ratio, and the internal rate of return specified value;

[0008] S2, collecting data of the oil field to be tested;

[0009] S3, calculating the total production in the new well benefit period;

[0010] S4, calculating the total income in the development period of the new well;

[0011] S5, calculate the total expenditure in the new well development period;

[0012] S6, build an oilfield internal rate of return model under production sharing;

[0013] S7, according to different well depth and oil price conditions, the initial production of single well is calculated, when the internal rate of return of new well and the internal rate of return of the prescribed value are the same, it is the single well production limit.

[0014] Further, the development period in step S1 includes construction period, stable production period and production decline period.

[0015] Further, the data of the oilfield to be measured in S2 includes crude oil price, exchange rate, crude oil commodity rate, operating cost, annual production rate, production rate, discount rate, natural decline rate.

[0016] Further, the total production in the new well yield period in S3 is calculated as:

[0017]

[0018] In the formula:

[0019] Q-the total production in the new well yield period, unit tons, 10 4 t;

[0020] γ-yearly production rate, unit day, d;

[0021] q0-new well initial daily oil production, unit tons, t;

[0022] S0-production rate, unit percentage, %;

[0023] t-cash flow calculation year, unit year, a;

[0024] i0-discount rate, unit percentage, %;

[0025] D0-natural decline rate, unit percentage, %;

[0026] N1-construction period, or production period, unit year, a;

[0027] N2-stable production period, unit year, a;

[0028] N3-production decline period, unit year, a.

[0029] Further, the total income in the new well development period in step S4 is:

[0030]

[0031] In the formula:

[0032] R s Total income during the development period of the new well, in RMB 10 4 thousands;

[0033] C r Crude oil commodity rate, in percentage, %;

[0034] P0—Crude oil price, in $ / bbl;

[0035] μ—Exchange rate, in percentage, ￥ / $;

[0036] η—Production sharing ratio, in percentage, %.

[0037] Further, the total expenditure during the development period of the new well in step S5 is:

[0038]

[0039] wherein:

[0040] Z D Total investment, in RMB 10 4 thousands;

[0041] I D Total investment of drilling, in percentage, %;

[0042] E o Annual operating cost of single well, in RMB 10 4 thousands;

[0043] P t Development period, in a;

[0044] K s Contractual royalty, in RMB 10 4 thousands.

[0045] Further, the development period Pt in formula (3) is:

[0046] P t = N1+N2+N3 (4)

[0047] Further, the oilfield internal rate of return model under the production sharing contract in step S6 is:

[0048]

[0049] wherein:

[0050] IRR—Internal rate of return, in percentage, %.

[0051] A device for determining the new well production limit of a split development oilfield, comprising a processor, a memory,

[0052] The processor is used for executing the steps of the method for determining the new well production limit of a split development oilfield;

[0053] The memory is used for storing the instructions executed by the processor.

[0054] The present application has the following beneficial effects: due to the above-mentioned scheme, the overseas oilfield new well initial production limit calculation method combines the split proportion of crude oil, the mineral tax and the decline law of the oilfield to jointly determine the initial production limit of the overseas oilfield new well, which, compared with the traditional method, not only considers the properties of the oilfield (including the decline law of the oilfield, the length of the stable production period, etc.), but also considers the particularity of the overseas oilfield, and takes the mineral tax system of the host country and the signed production split contract as factors that jointly affect the new well production limit, so that the calculation of the initial production of the overseas oilfield new well is more practical, the decision basis for the development of the overseas oilfield is improved, the development of the overseas oilfield is ensured to be profitable, and the market competitiveness of the enterprise is improved. BRIEF DESCRIPTION OF DRAWINGS

[0055] Figure 1 is a flowchart of the present application;

[0056] Figure 2 is the initial limit of a vertical well corresponding to different well depths at different oil prices;

[0057] Figure 3 is the initial limit of a horizontal well corresponding to different well depths at different oil prices. DETAILED DESCRIPTION

[0058] The present application will be described in detail below with reference to the accompanying drawings and embodiments, and the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0059] As shown in Figure 1 , a method for determining the new well production limit of a split development oilfield comprises the following steps:

[0060] S1, determining the content of the production split contract: including the development period, the mineral tax system, the production split proportion, etc., and determining the internal rate of return specified value;

[0061] S2, collecting the to-be-tested oilfield data, the to-be-tested oilfield data including crude oil price, exchange rate, crude oil commodity rate, operation cost, annual production rate, yield increase rate, discount rate, natural decline rate, etc.

[0062] S3, calculating the total yield in the new well yield period, considering the length of the yield increase period, the stable yield period and the decline period, and the yield increase rate in the yield increase period and the yield decline rule in the decline period, the total yield in the new well yield period is:

[0063]

[0064] In the formula:

[0065] Q—total yield in the new well yield period, unit: ten thousand tons, 10 4 t;

[0066] γ—annual production rate, unit: day, d;

[0067] q0—initial daily oil production of new well, unit: ton, t;

[0068] S0—yield increase rate, unit: percentage, %;

[0069] t—cash flow calculation year, unit: year, a;

[0070] i0—discount rate, unit: percentage, %;

[0071] D0—natural decline rate, unit: percentage, %;

[0072] N1—construction period, or yield increase period, unit: year, a;

[0073] N2—stable yield period, unit: year, a;

[0074] N3—yield decline period, unit: year, a.

[0075] Among them, the annual production rate γ is determined according to the average production rate of the production block, generally 300-330 days for oilfield; the yield increase rate S0 is determined by referring to the yield increase rate of similar oilfields; the discount rate i0 is the investment financial internal rate of return expected by the project investor, generally 6%-15%; the natural decline rate D0 is determined according to the average yield decline rate of similar oilfields; the construction period N1 is determined by the project investor; the stable yield period N2 is determined by referring to the stable yield time of similar oilfields; the yield decline period N3 is determined by comprehensively considering the stable yield time of similar oilfields and the contract time of the production block.

[0076] S4, calculating the total income in the new well development period, considering the cost oil recovery and the proportion of remaining oil in the development of the overseas oilfield under the contract, the total income in the new well development period is:

[0077]

[0078] wherein:

[0079] R s Total revenue of the new well during the development period, in RMB 10 4 thousands;

[0080] C r Crude oil commodity rate, in percentage, %;

[0081] P0Crude oil price, in $ / bbl;

[0082] μExchange rate, in percentage, ￥ / $;

[0083] ηYield sharing ratio, in percentage, %.

[0084] wherein the crude oil commodity rate C r is between 98.5% and 99.9% of the average value of similar oil fields.

[0085] S5, calculate the total expenditure of the new well during the development period, including the drilling and construction of the new well, the operating cost of the crude oil, and the mining tax and other expenditures. The total expenditure of the new well during the development period is:

[0086]

[0087] wherein:

[0088] Z D Total investment, in RMB 10 4 thousands;

[0089] I D Total drilling investment, in percentage, %;

[0090] E0Annual operating cost of a single well, in RMB 10 4 thousands;

[0091] P t Development period, in years, a;

[0092] K s Contractual mining tax, in RMB 10 4 thousands.

[0093] wherein the annual operating cost of a single well E0is determined according to the price level of the country where the contract block is located and the contract content.

[0094] The development period Ptis:

[0095] P t= N1+N2+N3 (4)

[0096] S6, constructing an internal rate of return model of the oilfield under the production sharing contract;

[0097]

[0098] In the formula:

[0099] IRR - internal rate of return, unit: percentage, %.

[0100] S7, according to different well depth and oil price conditions, the initial production of single well is calculated, when the internal rate of return of the new well is equal to the specified value of the internal rate of return, the single well production limit is obtained, wherein the specified value of the internal rate of return is determined by the investor.

[0101] A device for determining the production limit of a new well in a production-sharing development oilfield, comprising a processor and a memory, wherein the processor is configured to perform the steps of the method for determining the production limit of a new well in a production-sharing development oilfield, and the memory is configured to store instructions for execution by the processor.

[0102] The method for calculating the initial production limit of a new well in an overseas oilfield combines the production sharing ratio, the mineral tax and the decline rule of the oilfield to determine the initial production limit of a new well in an overseas oilfield. Compared with the traditional method, this method not only considers the properties of the oilfield (including the decline rule of the oilfield, the length of the stable production period, etc.), but also considers the special nature of the overseas oilfield, taking the mineral tax system of the host country and the production sharing contract into account as factors affecting the production limit of a new well, so that the calculation of the initial production limit of a new well in an overseas oilfield is more practical, and the development of an overseas oilfield is more likely to be profitable, and the market competitiveness of the enterprise is improved.

[0103] Embodiment:

[0104] T oilfield in M country is an overseas development oilfield acquired by China, and a production sharing contract is signed. This paper takes this oilfield as an example to introduce a method for determining the production limit of a new well in an overseas oilfield developed based on a production sharing contract, which mainly includes the following steps:

[0105] S1, determine the content and required internal rate of return of the production sharing contract:

[0106] The production sharing contract of T oilfield stipulates that the production sharing ratio of China's refined oil is 45.8%, the mineral tax is 8.5%, and the development period is 10 years. The required internal rate of return is 10%.

[0107] S2, data collection and determination:

[0108] According to the actual situation of T oilfield and the relevant policies of foreign countries, the actual evaluation parameters of the oilfield are calculated, and the main evaluation parameters are as follows: the drilling cost of vertical well is 2600 yuan / m, the drilling cost of horizontal well is 10050 yuan / m, the capital construction cost is 1.8 million yuan per well, the transportation cost is 5.8 dollars per barrel, the operation cost is 32 dollars per barrel, the exchange rate is 6.9 yuan per dollar, the calculated oil price is 50-100 dollars per barrel, and the evaluation period is 10 years.

[0109] S3, according to formula (1), the total production in the yield period of the new well is calculated, and the total production in the yield period of the new well is calculated taking the well depth of 2200m and the well depth of 3000m as examples:

[0110]

[0111] Using the parameters of the above T oilfield for calculation, under the condition of well depth of 2200m and oil price of 60 dollars per barrel, the initial production of the new well is 8.03 tons per day, the evaluation period is 7 years, the stable production period is 1 year, the hyperbolic decline mode is adopted, the decline index is 0.5, and the initial decline rate is 18%, and the total production is 46.7 tons.

[0112] Using the parameters of the above T oilfield for calculation, under the condition of well depth of 3000m and oil price of 80 dollars per barrel, the initial production of the new well is 5.88 tons per day, the evaluation period is 7 years, the stable production period is 1 year, the hyperbolic decline mode is adopted, the decline index is 0.5, and the initial decline rate is 18%, and the total production is 34.2 tons.

[0113] S4, according to formula (2), the total income of the new well in the development period under different oil prices is calculated,

[0114]

[0115] Using the parameters of the above T oilfield for calculation, under the condition of well depth of 2200m and oil price of 60 dollars per barrel, the initial production of the new well is 8.03 tons per day, the evaluation period is 7 years, the stable production period is 1 year, the hyperbolic decline mode is adopted, the decline index is 0.5, and the initial decline rate is 18%, and the total production is 46.7 tons, and the total income of the project investor is 6431.7 million yuan.

[0116] Using the above parameters for calculation, under the condition of well depth of 3000m and oil price of 80 dollars per barrel, the initial production of the new well is 5.88 tons per day, the evaluation period is 7 years, the stable production period is 1 year, the hyperbolic decline mode is adopted, the decline index is 0.5, and the initial decline rate is 18%, and the total production is 34.2 tons, and the total income of the project investor is 6604.3 million yuan.

[0117] S5, according to formula (3), the total expenditure in the development period of different well depths, different well types and different development costs is calculated,

[0118]

[0119] Based on the parameters of the T oilfield mentioned above, with a well depth of 2200m and an oil price of $60 / barrel, the initial production of the new well is 8.03 tons / day, the evaluation period is 7 years, the stable production period is 1 year, and with the hyperbolic decline model, a decline index of 0.5, and an initial decline rate of 18%, the total production is 46,700 tons, and the total expenditure of the project investor is 55.593 million yuan.

[0120] Based on the parameters of the T oilfield mentioned above, with a well depth of 3000m and an oil price of $80 / barrel, the initial production of the new well is 5.88 tons / day, the evaluation period is 7 years, the stable production period is 1 year, and with the hyperbolic decline model, a decline index of 0.5, and an initial decline rate of 18%, the total production is 34,200 tons, and the total expenditure of the project investor is 54.329 million yuan.

[0121] S6. Based on formula (5), calculate the production limits for new vertical and horizontal wells at oil prices of $50 / bbl-100 / bbl for well depths of 2200m-3800m.

[0122]

[0123] The calculation results are shown in Appendix 1 and Figure 2 , Figure 3 .

[0124] Table 1 Initial Production Limits for New Wells under Different Well Depths and Oil Prices (Unit: tons / day)

[0125]

[0126] S7. Calculate the internal rate of return for various single-well production rates under different well depths and oil prices, taking well depths of 2200m and 3000m as examples.

[0127] Based on the parameters of the T oilfield mentioned above, with a well depth of 2200m and an oil price of $60 / barrel, the initial production of the new well is 8.03 tons / day, the evaluation period is 7 years, the stable production period is 1 year, and using a hyperbolic decline model with a decline index of 0.5 and an initial decline rate of 18%, the total production is 46,700 tons. The total revenue for the project investor is 64.317 million yuan, the total expenditure is 55.593 million yuan, the development period is 4.8 years, and the internal rate of return is 10%.

[0128] Based on the parameters of the T oilfield mentioned above, with a well depth of 3000m and an oil price of $80 / barrel, the initial production of the new well is 5.88 tons / day, the evaluation period is 7 years, the stable production period is 1 year, and using a hyperbolic decline model with a decline index of 0.5 and an initial decline rate of 18%, the total production is 34,200 tons. The total revenue for the project investor is 66.043 million yuan, the total expenditure is 54.329 million yuan, the development period is 5.0 years, and the internal rate of return is 10%.

[0129] The production rate of a single well when the calculated internal rate of return is the same as the specified internal rate of return is the production limit for a new well.

[0130] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for determining the production limit of new wells in a segmented development oilfield, characterized in that... Includes the following steps: S1. Determine the development period for the new well, the mineral resources stipulated in the contract, the production sharing ratio, and the stipulated value of the internal rate of return; S2. Collect data from the oilfield to be tested; S3. Calculate the total output during the new well's revenue period; S4. Calculate the total revenue during the development period of the new well; S5. Calculate the total expenditure during the development period of the new well; S6. Construct an internal rate of return model for oilfields under production sharing; S7. Based on different well depths and oil price conditions, conduct trial calculations on the initial production of a single well. When the calculated internal rate of return of the new well is the same as the specified value of the internal rate of return, it is the production limit of the single well.

2. The method for determining the production limit of new wells based on the development of oilfields by division, as described in claim 1, is characterized in that: The development period in step S1 includes the construction period, the stable production period, and the production decline period.

3. The method for determining the production limit of new wells based on the development of oilfields by division, as described in claim 2, is characterized in that: The oilfield data to be tested in S2 includes: crude oil price, exchange rate, crude oil commodity rate, operating cost, annual production hour rate, production growth rate, discount rate, and natural decline rate.

4. The method for determining the production limit of new wells based on the development of oilfields by division, as described in claim 3, is characterized in that: The total production during the new well's revenue period is calculated in S3 as follows: In the formula: Q – Total production during the new well's revenue period, in tens of thousands of tons. 4 t; γ — Annual production time rate, in days (d); q0 — Initial daily oil production of a new well, in tons (t); S0 – Production increase rate, in percentage (%); t — Cash flow calculation year, unit is year, a; i0 — Discount rate, in percentage (%); D0—Natural decline rate, in percentage (%); N1—Construction period, or production period, in years (a); N2 — Stable production period, in years (a); N3 – Decline in production period, in years, a.

5. The method for determining the production limit of new wells based on the development of oilfields by division, as described in claim 4, is characterized in that: The total revenue during the new well development period in step S4 is: In the formula: R s —Total revenue during the development period of the new well, in ten thousand yuan. 4 RMB; C r —Crude oil commodity rate, in percentage (%); P0 – Crude oil price, in US dollars per barrel, $ / bbl; μ — Exchange rate, in percentages, ¥ / $; η – Production share percentage, expressed as a percentage (%).

6. The method for determining the production limit of new wells based on the development of oilfields by division, as described in claim 5, is characterized in that: The total expenditure during the new well development period in step S5 is: In the formula: Z D —Total investment, in ten thousand yuan, 10 4 RMB; I D —Total investment in drilling, expressed as a percentage (%); E o —Annual operating cost per well, in ten thousand yuan, 10 4 RMB; P t —Development period, in years, a; K s —The mining tax stipulated in the contract is in ten thousand yuan (10 4 RMB).

7. The method for determining the production limit of new wells based on the development of oilfields by division, as described in claim 6, is characterized in that: The development period P in formula (3) t for: P t =N1+N2+N3 (4) 8. The method for determining the production limit of new wells based on the development of oilfields by division, as described in claim 7, is characterized in that: The internal rate of return model for the oilfield under the production sharing contract in step S6 is as follows: In the formula: IRR – Internal Rate of Return, expressed as a percentage (%).

9. A device for determining the production limit of new wells in a divided development oilfield, characterized in that: Including processor, memory, The processor is configured to perform the steps of the new well production limit method based on any one of claims 1-8; The memory is used to store the instructions executed by the processor.

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