(China Petrochemical Engineering Technology Research Institute, Beijing 100 10 1)
Air drilling has the advantages of improving ROP, reducing the complexity of downhole leakage and reducing material consumption, which is one of the important ways to speed up drilling in northeast Sichuan. Based on the actual effect of the application of air drilling, this paper analyzes and studies the manifestations of the economic benefits of air drilling, determines the cost and benefits of air drilling according to the principle of "whether there is comparison or not", defines the calculation scope and method of economic benefits, constructs the index system of comprehensive evaluation, and takes the application of Laojun 1 well as an example for calculation. The application of this method can provide a basis for the popularization and application of gas drilling technology in northeast Sichuan exploration area and the calculation of investment benefit.
Keywords:: economic benefit of penetration rate of air drilling machinery
Technical and Economic Evaluation of Air Drilling in Northeast Sichuan Basin
, Zhang
(China Institute of Petroleum Engineering, Beijing1001KLOC-0/,China)
According to the actual effect of air drilling and the principle of "comparison or not", this paper analyzes the economic benefits of air drilling, and determines the scope and method of economic benefit calculation. The benefit of air drilling in Laojun 1 well is calculated.
Keywords air drilling; Permeability; economic benefits
The reservoirs in northeast Sichuan are deeply buried, with high temperature, high pressure and high sulfur content. Terrestrial strata have strong abrasiveness, poor drillability and low ROP, and high and steep structural strata are prone to well deviation. Serious formation leakage, difficult plugging, serious formation collapse and unstable borehole wall make drilling face many problems, which seriously restricts the improvement of drilling speed. In order to accelerate the efficient, safe and rapid exploration and development in northeast Sichuan, China Petrochemical introduced gas drilling technology at the end of 2005, and achieved good results in its first well-Laojun 1. Created a new record of ROP in northeast Sichuan. Since then, air drilling technology has been widely used in northeast Sichuan, effectively solving the engineering problems in northeast Sichuan and finding a new way to improve the exploration and development speed in this area.
The popularization of air drilling has effectively promoted the progress of petroleum engineering technology in China Petrochemical Company, but what is the economic benefit? At present, there is no recognized and standardized evaluation method to meet the needs of exploration and development, improve the technical level of petroleum engineering of the group company, and achieve good economic benefits at the same time, so as to realize "speeding up and increasing efficiency". Based on the input-output characteristics of petroleum engineering technology, this paper discusses the method of economic benefit calculation and comprehensive evaluation produced by the application of new petroleum engineering technology.
1 input-output characteristics of petroleum engineering technology
1) The output of petroleum engineering is drilling footage or wellbore, and the drilling contractor and the oil company will settle the account with drilling consumption plus appropriate profit. Therefore, the output of petroleum engineering can't be profitable like other products, and its financial cash flow can't fully and truly reflect the economic value of its output.
2) For oil companies, petroleum engineering belongs to the cost center, which has the characteristics of only considering the cost, only being responsible for the controllable cost, and only assessing and controlling the responsibility cost.
The existence of the above two characteristics makes it impossible to evaluate the economic benefits of air drilling with the commonly used economic evaluation method with discounted cash flow as the core, but the economic benefits of air drilling technology application should focus on its impact on drilling costs.
The theoretical premise of technical and economic evaluation of petroleum engineering is the symmetrical relationship between cost and benefit, that is, the abandoned benefit is cost and the avoided cost is benefit. Defining the basic objectives is the basic premise of determining the costs and benefits. Revenue and cost are relative to the goal, revenue is the contribution to the goal, and cost is the price paid to achieve the goal. As far as the technical and economic evaluation of air drilling is concerned, the goal is to reduce costs and increase efficiency on the basis of improving the technical level. Cost refers to the increased expenditure due to the use of air drilling technology, and the benefit is the reduction of expenditure brought about by its use. The difference between them lies in the direct economic benefits of technology application.
2 air drilling technology and economic benefit evaluation
2. 1 Analysis of technical advantages of air drilling
The advantages of air drilling are:
1) has low air density, which can obviously reduce the pressure on the bottom formation, greatly improve the ROP and shorten the drilling cycle compared with conventional drilling fluid.
2) The conventional mud density is greater than 1.00g/cm3, and when the mud pressure is greater than the formation pressure, lost circulation is easy to occur. During gas drilling, the gas column pressure is much less than the formation pressure, which can effectively avoid the occurrence of lost circulation.
3) There is a negative pressure difference at the bottom of gas drilling. With a small WOB, the ROP can be greatly improved, the rock breaking efficiency of the bit is improved, and the service life of the bit is prolonged.
4) The pollution of drilling fluid in gas drilling operation is avoided, and the working environment becomes clean and sanitary. The air is inexhaustible, and most wells in northeastern Sichuan are located in mountainous areas, which makes water supply difficult, environmental protection difficult and cost high. Using air drilling technology can save water and reduce pollution, which is beneficial to environmental protection.
2.2 Drilling cost driver analysis
Cost drivers refer to important activities or events that determine the occurrence of costs. Generally speaking, cost drivers dominate cost behavior and determine the generation of costs, which can be used as a standard for allocating costs.
According to the motivation of cost occurrence, drilling engineering cost can be divided into four types:
1) Expenses related to the wellhead quantity, such as construction compensation, water and telecommunication engineering fees, equipment calibration fees, etc.
2) Material cost, characterized by the separation of energy and price, with large consumption and small consumption. The material cost of drilling engineering includes drill bit, mud, petroleum, other materials, casing, casing accessories, cement and cement additives. The amount of materials consumed by pre-drilling engineering and completion engineering is small, which is directly included in other material cost items.
3) Time-related expenses are characterized by increasing with time, such as the daily expenses of drilling rig and the increase of maneuvering time while drilling. The rig daily fee includes equipment depreciation, personnel cost, equipment repair cost, consumables freight, camp fee, third-party service fee, HSE fee, management fee, risk fee, drilling tool rental fee and well control equipment rental fee. The cost of drilling, standby, midway test and oil test is different for the same rig every day.
The sum of the above three items constitutes the direct cost of drilling.
4) Expenses accrued according to a certain proportion of direct expenses. For example, the shared enterprise management fee, scientific and technological progress fee and HSE fee are accrued according to 6%, 1.5% and 0.5% of the direct cost respectively, totaling 8%; The basis of risk profit accrual is the sum of direct cost, enterprise management fee, scientific and technological progress fee and HSE fee, and the total extraction ratio is 1 1%.
After this division, the economic benefits of new technology application can be calculated according to the principle of "comparison with or without" and through the changes of various cost drivers after the application of new technology. As long as we master the changes of the first three driving factors, we can calculate the benefits of technology application. The specific calculation formula is as follows:
Oil and gas accumulation theory and exploration and development technology: Proceedings of Postdoctoral Academic Forum of China Petrochemical Petroleum Exploration and Development Research Institute 20 1 1. 4
Where: mi0 is the consumption of the I-th material before adopting the new technology; Pi0 is the price of the first material before the new technology is used; Mi 1 is the consumption of the ith material after using the new technology; Pi 1 is the price of the first material after using the new technology.
Oil and gas accumulation theory and exploration and development technology: Proceedings of Postdoctoral Academic Forum of China Petrochemical Petroleum Exploration and Development Research Institute 20 1 1. 4
Where: △di is the time variation of item I service consumption; Ri is the rate of the first service.
Oil and gas accumulation theory and exploration and development technology: Proceedings of Postdoctoral Academic Forum of China Petrochemical Petroleum Exploration and Development Research Institute 20 1 1. 4
When accidents and complex engineering failures occur, the loss includes two parts: (1) drilling time from the accident to the delay of normal operation of the accident; (2) Special materials for handling accidents and direct loss of drilling tools.
Its calculation formula is:
Failure loss = cost of special materials for failure handling+average residual value of accident scrapped drilling tools+failure loss drilling cycle × daily cost of drilling rig.
2.3 Determination of cost-effectiveness of air drilling
2.3. 1 Air drilling cost increases
At present, the increased cost due to the use of air drilling mainly includes the following parts:
1) Equipment relocation fee;
2) Special wellhead equipment and technical service fee;
3) Daily fee for drilling rig operation:
Daily operating rate of drilling rig = working time of air drilling rig × daily operating rate of air drilling rig
4) Daily standby fee for air drilling equipment:
Daily standby rate of air drilling equipment = standby time of air drilling rig × standby daily rate of air drilling rig.
5) Fuel cost of air drilling equipment. In the current air drilling contract, the fuel cost of air drilling equipment is borne by the service provider according to the actual consumption.
Fuel cost = working hours of air drilling rig × daily fuel consumption × fuel price
6) The management fee increased due to the increase of the above items shall be calculated according to Formula (4).
2.3.2 Expenditure (income) reduced by air drilling
1) Benefits of shortening drilling cycle:
Benefit of shortening drilling cycle = drilling cycle shortened by air drilling compared with mud drilling × daily cost of mud drilling rig.
2) The benefits of reducing the use of drill bits:
The benefit of reducing the use of drill bit = the use of drill bit reduced by air drilling compared with mud drilling × the unit price of drill bit.
3) Prevent lost circulation and reduce the benefits brought by mud consumption: lost circulation during drilling is a world-class problem in drilling production. With the implementation of gas drilling, the drilling medium changed from drilling fluid to air, which solved the problem of lost circulation during drilling. The estimation of this part of benefit should be based on the investigation of lost circulation in the same horizon and approximate depth of air drilling interval in the nearby area, and the potential loss avoided by air drilling can be calculated by investigating the complex lost circulation probability and average lost circulation.
4) The reduction of indirect expenses shall be calculated according to Formula (4).
3 the establishment of comprehensive evaluation index system
From the demand of exploration and development for drilling engineering, it is necessary to drill to the target horizon according to the design requirements, provide qualified drilling holes, control the consumption of time and raw materials in the drilling process, maximize the benefits, and give consideration to the higher requirements of health, environmental protection and safety. These requirements are interrelated and mutually restricted, some of them fluctuate in the same direction, and some of them change, which determines the application effect of drilling technology. A multi-dimensional goal and effect system pursues the overall optimization of the effect, not the optimization of one or several indicators. The evaluation based solely on the effect of technology application or financial indicators cannot reflect the full effect of technology application. The comprehensive evaluation of the application of air drilling technology must be combined with the drilling needs of exploration and development, and the application effect of the technology must be investigated from all directions and angles.
Combined with the requirements of exploration and development for drilling technology, the following evaluation index system can be established to comprehensively evaluate the drilling construction process:
Oil and gas accumulation theory and exploration and development technology: Proceedings of Postdoctoral Academic Forum of China Petrochemical Petroleum Exploration and Development Research Institute 20 1 1. 4
The analytic hierarchy process (AHP) is used to determine the weight of subsystems and their components, and a number of evaluation index values are "synthesized" into a whole comprehensive evaluation value through a certain mathematical model to comprehensively evaluate the target technology.
Calculation of economic benefit of air drilling in Laojun 1 well
Laojun 1 Well is the first air drilling in China Petrochemical Company. The air drilling interval is 762.00 ~ 3253.70m, and the footage is 2491.7m. The air drilling stratum is Penglai Town Formation to Qianfoya Formation, and the working time of air drilling is 23d, and the drilling time is 219.08h. Compared with the same interval of adjacent wells, the average ROP of air drilling is 7 times higher than that of drilling fluid, and the drilling period of this interval is 7 times.
4. 1 Air drilling cost increases
1) Equipment removal fee: 220,000 yuan.
2) Special wellhead equipment and technical service fee for air drilling: 700,000 yuan.
3) Daily cost of drilling rig: φ 311~ φ 316 mm drilling, and daily cost of air drilling operation: 80,000 yuan/day (excluding fuel).
Air drilling for 23 days: 23×8 = 1.84 million yuan.
4) Daily fee for equipment standby: 40,000 yuan/day (normal time without footage during drilling is not counted as standby). Three drill collar fracture accidents occurred during air drilling, and the lost time was 74 hours.
74/24× 4 = 65438+200,000 yuan
5) Fuel cost: 23× 5.8× 4,700 = 630,000 yuan.
6) Management fee increased due to the above increase: 351× 0.08+351× (1+0.08) × 0.1= 697,800 yuan.
The total cost is 4,207,800 yuan.
4.2 Use air drilling to reduce costs
1) The daily operation cost of the 70d drilling rig is reduced due to the shortened drilling cycle.
10.65×105.14 =1197400 yuan.
According to the drilling rig quota standard of Northeast Sichuan issued by China Petrochemical Group Company in 2007, the daily cost quota of conventional drilling operation for conventional drilling fluid of 70d drilling rig is 10054 1.79 yuan. In fact, the consumption of most wells is much higher than this value, and the conservative data is 100500 yuan, plus the daily logging fee of 0.6 million yuan.
2) Bit cost:11× 4.33 = 476,000 yuan.
3) Reduce the cost of lost circulation: the geological structure in northeast Sichuan is complex. During drilling, the middle and upper strata are hard, the structure is steep, the strata are broken, there are many faults, fractures and pores are developed, and there are many pay zones. The pressure coefficient of the same open hole interval is quite different, and the lost circulation is frequent. All the drilled structures have lost circulation to varying degrees, and 98% of the completed structures have lost circulation. According to statistics, all layers from Shaximiao Formation to Carboniferous have different degrees of leakage, among which Shaximiao Formation, Xujiahe Formation, Feixianguan Formation and Changxing Formation have the most frequent leakage. Based on the statistical investigation of the complex lost circulation in this air drilling interval (Penglai Town Formation to Qianfoya Formation), the possible lost circulation when drilling without air is calculated by using the "with or without comparison method". Through the statistical investigation of 243 lost circulation in 8 1 well in northeast Sichuan, it is found that 9 of these 8 1 wells have no lost circulation in the investigated interval, with the probability of lost circulation of 9 1.9%, the probability of no lost circulation of 8. 1%, and the average lost circulation of the remaining 74 wells is 66.
According to the method of probability statistics, the potential mud consumption reduced by air drilling is: 611× 0.919+0 × 0.081= 561.5m3.
According to the density and cost price of mud commonly used in this formation, it is estimated as 1300 yuan /m3, and the mud leakage cost is:
561.5×1300 = 729950 yuan
The benefit of preventing lost circulation and reducing mud consumption is about 730,000 yuan.
Total of the above three items: 6,543,800 yuan+02,400,000 yuan.
4) Reduced expenses: calculated according to formula (4):1240× 0.08+1240× (1+0.08 )× 0.1= 2465200 yuan.
Total income is: 1, 486.55438+0,000 yuan.
4.3 Laojun 1 Net income from air drilling in well
The difference between income and cost:1486.5438+0-420.78 =10657300 yuan.
The index shows that the application of air drilling technology reduces the cost of Laojun 1 single well by 10657300 yuan.
Return on investment of air drilling = net income of air drilling application/increased expenditure of air drilling.
1065.73/420.78=2.53
4.4 Analysis of interest structure
By analyzing its economic benefits, it can be found that 90.3% of the economic benefits generated by air drilling come from the saving of daily expenses and 9.7% from the reduction of material consumption.
4.5 Benefit Sensitivity Analysis
According to the sensitivity analysis of the main factors affecting the economic benefits of air drilling technology, that is, ROP, daily output of air drilling and material price, it can be found that the most sensitive factor of economic benefits is ROP, followed by daily output of drilling, and less sensitive to the prices of drill bits and diesel oil. See table 1 to table 3 for the calculation results.
Table 1 Sensitivity analysis of economic benefits to ROP
Table 2 Sensitivity analysis of economic benefit to daily rate of drilling rig
Table 3 Sensitivity Analysis of Economic Benefit to Bit Price
In addition, the acceleration of drilling speed can save the investment of petroleum engineering, make the oilfield put into production ahead of schedule, and improve the final income of oilfield projects. Using the production curve and net cash flow method of the oilfield, the net income of the oilfield is calculated. It is found that16.234 million dollars before the speed increase and19.766 million dollars after the speed increase, which improves the final income.
5 Conclusion and understanding
By comparing the increase and decrease of air drilling technology, it is found that the use of air drilling not only greatly improves the penetration rate, but also produces good economic benefits, reduces the cost of a single well and realizes the speed increase and efficiency increase. Most of the economic benefits of air drilling come from the shortening of drilling cycle caused by the increase of drilling speed. Laojun 1 Well is the first well to use air drilling tools, and the BHA used in drilling is still in the exploration stage. There were three drill collar fracture accidents in the early stage, which complicated the treatment and reduced the drilling efficiency. With the gradual accumulation of air drilling experience, this complex situation will gradually decrease, and the net economic benefit is most sensitive to mechanical drilling speed and pure drilling efficiency. With these two,
Using this method to calculate the economic benefits of air drilling, the economic benefits can be calculated as long as the technical indicators are mastered, and the calculation is simple. The key to the application of this method is to scientifically determine the cost and benefit, and make a complete and comprehensive comparison between the cost and benefit on the basis of unified caliber.
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