Status and development trend of drilling fluid solid control system technology
Release time: 2016/04/21 Ai Yi NewsViews : 2296
Development of new drilling fluid shaker and variable frequency drilling fluid centrifuge
With the development of petroleum exploration and development work, the drilling depth has been increasing, and the formations encountered have become increasingly complex, especially the development of new drilling technologies at home and abroad (such as deep wells, ultra-deep wells, horizontal wells, and underbalanced drilling technologies). Drilling fluid purification and solid control have imposed stricter requirements. At present, China's existing drilling fluid solid control system is mainly a three-stage or four-stage purification system consisting of drilling fluid shaker, sand remover, desilter, drilling fluid centrifuge, etc., with a total weight of 50t and total power consumption. Close to 300kW. With the continuous progress of drilling process technology, the existing drilling fluid solid control system has not been able to meet the needs of the development of modern drilling technology, nor can it meet the needs of the increasingly competitive international drilling market. Develop new solid control equipment and build New solids control systems are needed. The author discusses the current status of solid control equipment technology and the development of new solid control systems, hoping to have a reference for the development and innovation of related domestic equipment .
1System technology status
At present, foreign solid control systems have a high level of theoretical and equipment research. Some manufacturers can change the solid control process based on indoor analysis data and computer calculation results, guide drilling fluid processing, and can automatically and quantitatively control various solid control equipment through computers. .
In the field of solid control equipment technology, Thomas Broadbent & Son's Ltd. of the United Kingdom and Derrick, Brandt and SWACO of the United States are relatively representative divisions. The drilling fluid solid control system of the British Broadbent company is 5 double-layer double-line linear drilling fluid vibrating screens (upper 8-80 mesh screen, lower 150 mesh screen mesh) and 1 variable-frequency speed-regulating large-throughput drilling fluid. Centrifuge (roller diameter 508mm). The new drilling fluid solid control system of the American SWACO company includes 4 drilling fluid shakers, 1 vacuum degasser , 1 drilling fluid cleaner, 2 drilling fluid centrifuges (1 medium-speed drilling fluid centrifuge, 1 high-speed drilling Liquid centrifuge, etc. The complete solid control system of the American Brandt company includes 2 ATL-CS fine-line linear drilling fluid shakers, 1 ATL-DRYER-16 / 2 dryer, 1DG10 deaerator, and 2 HS-3400 drilling rigs Liquid centrifuge, which can handle heavy or non-heavy drilling fluids. The solid control system introduced by Derrick includes drilling fluid distributors, 4 to 5 ultra-fine mesh linear drilling fluid shakers, 1 deaerator, and 2 drilling fluid centrifuges. machine.
It can be seen that the foreign solid control system has developed into a two-stage system with drilling fluid vibrating screen as the core, that is, a combination of multiple fine or ultra-fine linear drilling fluid vibrating screens and medium and high speed large displacement drilling fluid centrifuges. And it is very mature, replacing the traditional multi-level solid control system with high energy consumption, low system reliability and heavy maintenance workload.
Most of the domestic solid control systems are localized based on the introduction of foreign technologies, making them suitable for the needs of China's drilling technology. Each oil field also introduces unique solid control systems based on regional characteristics. At present, China is mainly based on the NG4 solid control system, which is mainly composed of drilling fluid shaker, sand remover, desilter and drilling fluid centrifuge. It can control the solid phase content in drilling fluid by 5% ~ 8%. At present, the following problems exist in such three-level or four-level solid control systems.
(1) The swirling sand remover with a nominal diameter of 200 ~ 300mm can only reach the screening effect of 80 ~ 120 mesh screen, and the swirling mud remover with a nominal diameter of 120 ~ 125mm can only reach a screen of 100 ~ 200 mesh screen effect. At the same time, since the fine mesh screen is easy to break, most of the low mesh number screens are used. 80% of the solid particles in the drilling fluid cannot be efficiently removed. The purification effect of the drilling fluid is greatly reduced, and the solid content is high, affecting subsequent equipment or Use of high-end instruments.
(2) The pressure exerted by the sand pump on the drilling fluid and the friction inside the cyclone cause the cuttings to be more refined and it is more difficult to remove them.
(3) The sand pump has high energy consumption, and the sand pump motor with a displacement of 200m3 / h is 55 ~ 75kW. If the sand remover and desilter are used at the same time, the energy consumption is greater than 100kW. In addition, the seal of the sand pump shaft is easy to damage, resulting in the loss of drilling fluid and inconvenient equipment management and maintenance.
(4) With the development of drilling technology, the existing multi-level solid control system cannot well meet new wells such as horizontal wells, underbalanced wells, extended reach wells, deep wells and ultra-deep wells with complex structure wells and special process wells. Need for craftsmanship.
(5) The consumable parts in the solid control system have a short life and frequent replacement, which not only increases the drilling cost, but also greatly affects the continuous and smooth progress of drilling construction, especially the drilling fluid shaker screen, cyclone screen, sand Compared with foreign countries, there are still large gaps in wearing parts such as pump shaft seals.
(6) The processing quality of solid control equipment is poor, and the reliability is not high. The series of solid control system products has not been standardized and standardized, and scientific research and design capabilities, especially theoretical research, still lag behind abroad.
2 new solid control equipment
2.1 New Linear Drilling Fluid Shaker
Drilling fluid shaker is the first-level conventional solid control equipment that returns drilling fluid from the wellhead. It is also the only solid-liquid separation equipment that can handle full flow and has the lowest energy consumption. At present, the shortcomings of most domestic drilling fluid vibrating screens are: the vibration mode is unreasonable, which affects the performance of the drilling fluid vibrating screen, especially the throughput, screen life and filtration accuracy, which cannot meet the development requirements of new drilling technology; The life of the mesh is short, it is inconvenient to replace, and it cannot meet the technical requirements of continuous drilling. The sieving ability is not strong, and the phenomenon of "paste sieve" and "running drilling fluid" is easy to occur. Solid phase particles still exist in the drilling fluid circulation system; the drilling fluid vibration screen vibration isolation device uses metal coil springs to isolate the vibration, the vibration isolation effect is not good, the whole machine is noisy, and the work is not stable; the adjustment and adaptability are poor, and the drilling fluid vibrates The slope angle and vibration force of the screen box cannot be adjusted according to the actual requirements of the drilling process; longer resonance times during startup and shutdown, which will cause greater damage to the machine, especially the wearing parts of the vibration isolation system; in China When bidding for rigs for construction abroad, the performance of domestic drilling fluid vibrating screens cannot be recognized by foreign contractors. Imported drilling fluid vibrating screens must be used, but their prices are high. Parts supply is not timely, the service is not in place, and even affect the further development of foreign markets. Based on this, using the advantages of China ’s drilling fluid drilling fluid vibration sieve theory research, the development of advanced domestic drilling fluid drilling fluid vibration sieve, especially the development of linear drilling fluid vibration with high reliability and strong processing capacity in line with modern drilling technology. Sieves are particularly urgent and important [2-3].
At present, a new type of drilling fluid linear drilling fluid vibrating screen developed by a certain unit adopts a dual-screening bin structure, which can clean the drilling fluid twice and separate solid-liquid. The upper screen mesh is generally 20-60 mesh, and the lower screen mesh. According to the well section and solid control requirements, 60-325 mesh fine, ultra-fine mesh with frame plate laminated bonding screen. The characteristics of the drilling fluid vibrating screen are: easy replacement of the screen, long service life, good screening effect, large processing capacity, which can replace imported products and meet the continuous drilling process requirements; the screen surface angle can be adjusted and the adjustment range is 5 °; with drilling fluid inlet buffer tank and geological instrument installation tank; can be quickly connected with the wellhead water outlet pipe; simple structure, easy installation, low noise, stable machine vibration; high reliability, suitable for domestic oil mine Field actual conditions [4-5], the main technical performance of this new type of double-layer double-layer linear drilling fluid shaker is as follows:
(1) Mode shape: straight line;
(2) Rated power: 1.5 × 4kW;
(3) Power supply frequency and voltage: 50Hz, 380V;
(4) Excitation frequency: 24.16Hz (1450r / min);
(5) Vibration intensity: 5.5g;
(6) Capacity: 50 ~ 80L / s;
(7) Excitation force: 63 × 2kN;
(8) Amplitude: 5mm;
(9) Upper screen: mesh number: 20 ~ 60 mesh, area: 1.1m × 2m;
(10) Lower screen (panel laminated composite screen): mesh number: 60 ~ 325 mesh, area: 2.4m × 2m;
(11) Overall dimensions (length × width × height): 4500mm × 2600mm × 1550mm;
(12) Mass: 5082kg.
2.2 Closed-loop control full-frequency drilling fluid drilling fluid centrifuge
The drilling fluid centrifuge is also one of the key equipment in the solid control system, and its performance directly affects whether the secondary solid control system can be realized. Although the drilling fluid vibrating screen can process the harmful solid phases in the drilling fluid at full flow, it cannot be completely removed. Some small solid phase colloids still need to be separated by a drilling fluid centrifuge. In addition, the drilling fluid centrifuge can recover barite. Drilling fluid centrifuge is the most complicated structure and the most difficult equipment in solid control system. Generally it is divided into 3 types according to the processing capacity, centrifugal force, separation point and speed:
① The barite recovery drilling fluid centrifuge mainly recovers the barite powder into the drilling fluid system, and excludes some low solid phase particles. The processing capacity is generally 38 ~ 151L / min, the speed is 1800r / min, the centrifugal force is 700g, and the low density solid Phase separation point 6 ~ 10μm, high density solid phase separation point 4 ~ 10μm;
② Large-capacity drilling fluid centrifuge mainly removes low-density solid phase, with a very large processing capacity. The speed is 1900 ~ 2200r / min, the centrifugal force is 800g, and the separation point is about 5 ~ 7μm (in unweighted drilling fluid);
③ The second drilling fluid centrifuge in the combination of high-speed drilling fluid centrifuge and dual drilling fluid centrifuge, mainly removes the low-density solid phase in the unweighted drilling fluid. The processing capacity is 151 ~ 453L / min, and the speed is 2500 ~ 3300r / min. , Centrifugal force 1200 ~ 2100g, separation point 2 ~ 5μm. The first barite was recovered when the dual drilling fluid centrifuge was combined.
GLW series closed-loop controlled full-frequency drilling fluid drilling fluid centrifuge. Compared with other drilling fluid centrifuges at home and abroad, due to the use of a special differential, the drum and auger are all driven by a main motor. The control is simple, reliable and easy to operate. The existing drilling fluid centrifuges in China use two main and auxiliary motors to drive the drum and auger, respectively. The whole machine adopts a set of full-frequency conversion and full-automatic closed-loop control, including the host and the pulp supply pump, which are AC frequency conversion control .
This drilling fluid centrifuge has the characteristics of large processing capacity, compact structure, long service life, reliable performance, etc. It is an ideal equipment for solid phase control of drilling fluid and liquid / solid phase separation. Adopting variable frequency speed regulation intelligent control and real-time data acquisition technology, it can automatically adjust the rotation speed, differential speed of the drilling fluid centrifuge drum and the displacement of the slurry pump according to the change of drilling fluid performance parameters to obtain the maximum slag discharge. And can achieve fault parking alarm, real-time remote display and control functions. And has a large aspect ratio, high separation factor, reasonable differential structure and long life. The separation midpoint can reach below 3μm, the processing capacity Q = 50m3 / h, and the slag transfer capacity G3 = 7200kg / h.
In addition, underflow and overflow regulation is easy. The wet and dry underflow of the drilling fluid centrifuge is adjusted by the overflow regulating plate at the large end of the drum. Can also be achieved by the depth of the inlet pipe.
(1) It has the ability to adapt to different drilling fluid performance parameters, implements an intelligent variable frequency speed regulation feedback control system, and realizes closed-loop control. The overall control system has explosion-proof and automatic protection functions. According to the actual conditions of the drilling process, the drilling torque of the drilling fluid centrifuge can be collected in real time for changes in the properties of the drilling fluid (including viscosity, density, solid content content) and slag discharge in different formations and different drilling processes. The actual parameters such as processing capacity and closed-loop control are achieved through inverters and automatic control systems, which can automatically change the operating parameters of drilling fluid centrifuges and automatically adjust the displacement of the slurry pump to ensure slag discharge when the performance parameters of drilling fluids change. Volume and processing capacity of drilling fluid centrifuge are always at the maximum state, and drilling fluid centrifuge is in the best working condition.
(2) It has a good self-control ability, when the equipment fails, it can automatically stop and alarm, and has a long-distance monitoring capability, which greatly improves the use efficiency of drilling fluid centrifuge and reduces the risk, so as to get the best treatment. effect.
(3) It can be matched with solid control equipment such as the new linear drilling fluid vibrating screen and medium-speed drilling fluid centrifuge successfully developed by our institute to form a new solid control system, thereby greatly improving the solid phase control level of drilling fluid and promoting the drilling technology. Development, increase drilling speed and reduce drilling costs. When the new linear drilling fluid vibrating screen and high and low speed drilling fluid centrifuge combined solid control system is adopted, the sand content of drilling fluid can be always controlled below 0.3%.
(4) The speed adjustment range is wide, and it can be used as both a medium-speed drilling fluid centrifuge and a high-speed drilling fluid centrifuge.
(5) Real-time temperature monitoring performance in the control system. A temperature sensor is provided in the control system to monitor the temperature of the control system in real time in order to manually control the startup and shutdown of the fan, so that the control system is in a good and optimal working state.
(6) The aspect ratio is large (k = 3), the separated solid phase is drier, the leakage of drilling fluid is reduced, and it is beneficial to protect the environment and the consumption of drilling fluid.
(7) From the aspects of design and manufacturing, the separation performance of the drilling fluid centrifuge has been comprehensively improved, making it more suitable for the development requirements of oilfield drilling processes, thereby improving the level of drilling fluid solid phase control.
3 Development Trend of Drilling Fluid Solid Control System
Looking at the technical status of drilling fluid solid control equipment and systems at home and abroad, the research and development direction should focus on improving the performance of drilling fluid shaker screens, increasing the drilling fluid centrifuge throughput and working speed, simplifying the existing solid control system, and striving to use more A two-stage solid control system consisting of a drilling fluid shaker and a drilling fluid centrifuge. The simplified solid control system can be divided into two steps: in the long run, the research uses a vacuum filtration and suction principle to directly perform primary filtration to achieve efficient solid-liquid separation. In one step, the solid control efficiency is higher and the cost is lower. The main direction of solid control equipment research and development in the future; the near-term goal is to study the multi-screen solid control system with large processing capacity, high reliability and good separation effect, remove the sand remover, desilter, and supply liquid for the sand remover and desilter Sand pump with high energy consumption and low efficiency, this new solid control system consists of 3 ~ 4 fine mesh screen linear drilling fluid vibrating screens, 1 full-frequency automatic intelligent control medium speed large displacement drilling fluid centrifuge (speed 1200 ~ 2000r / min), a full-frequency automatic intelligent control high-speed drilling fluid centrifuge (speed 1800 ~ 3400r / min) to form a two-level solid control system. Its advantages are mainly reflected in: simple structure, high system reliability, good separation performance of drilling fluid shaker and drilling fluid centrifuge, long wearing parts life, reduced energy consumption, high drilling fluid purification accuracy; simple equipment installation, convenient maintenance , Transportation and relocation are fast; able to adapt to the needs of foreign drilling markets .
4 recognition and suggestions
(1) Studying the new solid-liquid separation mechanism and developing new solid-control equipment are important ways to fundamentally improve and develop the solid-control system and improve the solid-liquid separation effect of drilling fluid.
(2) Simplify the structure of the existing solid control system, reduce the number of stages of the solid control system, reduce energy consumption, improve the overall reliability of the solid control system, reduce leakage of drilling fluid, and reduce environmental pollution. It is suggested that the current supporting scheme of the solid control system is a combination of 4 ~ 5 ultra-fine mesh drilling fluid shakers, a medium-speed drilling fluid centrifuge, and a high-speed drilling fluid centrifuge. The drilling fluid vibrating screen is mainly a linear sieve with a large processing capacity, and the screen mesh number is above 200 mesh. At the same time, the processing capacity and separation particle size of the drilling fluid centrifuge are improved, and 2 drilling fluid centrifuges can be used to meet the processing capacity and screen.分 结果。 The effect.
(3) Drilling fluid vibrating screen is the key equipment for the first stage full-flow processing drilling fluid. Therefore, it is necessary to deepen the theoretical study of drilling fluid vibrating screen and develop a new type of large displacement ultrafine mesh drilling fluid vibrating screen. Drilling fluid shaker research mainly includes deepening the working theory of drilling fluid shaker, reasonable vibration mode, solid phase particle movement law on the sieve surface, sieving effect, purification accuracy, etc., and continuously improving the control, adjustment, and vibration isolation of drilling fluid shaker. Performance, improve the life of plate-bonded laminated composite screen, and further improve the reliability of the whole machine and components.
(4) Develop intelligently controlled medium and high-speed large-displacement drilling fluid centrifuges. The processing capacity of a single drilling fluid centrifuge must be above 100m3 / h, the separation midpoint is 2 ~ 3μm, and the separated solid phase sediments can be transported. Investigate the particle size distribution of solid-liquid separation of drilling fluid centrifuge, and develop a recoverable drilling fluid centrifuge for barite.
(5) Strengthen environmental awareness, reduce environmental pollution, develop environmental protection equipment suitable for oilfield drilling fluids and drilling cuttings while drilling, effectively recover drilling fluids, reduce drilling costs, completely remove mud pools, and truly realize drilling fluids and cuttings The scene does not land .
(6) Strengthen the research on automatic metering and automatic control in the process of solid control of drilling fluids, on-line detection and analysis of drilling fluid performance parameters, develop an expert system for solids control of drilling fluids, and realize automation of the solid control system. Research and development of domestic solid control equipment evaluation calculation models, optimized configuration and efficiency evaluation of solid control systems, and promote the development of China's solid phase control process technology.
 Gong Weian. Solid phase control technology and equipment for drilling fluids [M]. Beijing: Petroleum Industry Press, 1995.
 Zhao Guozhen, Li Junyu. Development level of drilling fluid and drilling fluid vibrating screens at home and abroad [J]. Petroleum Machinery, 1992, 20 (12): 47-51.
 Dong Huairong, Zhang Huifeng, Wang Ping, et al. New B-type drilling fluid linear drilling fluid vibrating screen and its application [J]. Petroleum Machinery, 2002, 30 (12): 19-21.
 Dong Huairong, Cai Wenjun, Li Qin, et al. New type of drilling fluid vibration screen mesh bonding technology [J]. Bonding, 2000, 21 (1): 38-39.
 Dong Huairong. Improvement of bonding technology of plate laminated screens [J]. Bonding, 2003, 24 (1): 35-37.
 Dong Huairong, Wang Ping, Cai Wenjun. A fully automatic closed-loop control drilling fluid high-speed drilling fluid centrifuge [J]. Western Exploration Engineering, 2006, 18 (4): 209-211.
 Mou Shunquan, Dong Huairong, Ding Xijun, et al. Research on drilling-while-drilling treatment technology [J]. Western Exploration Engineering, 2012, 24 (6): 77-80.
Author: Dong Huairong *, Lizong Qing, Li Qin, Guo, Fu Guangmeng, Chen Zhili (Sinopec Shengli Petroleum Engineering Drilling Technology Research Institute)