How to properly configure drilling fluid mud purification system
Release time: 2016/04/19 Ai Yi NewsViews : 2124
Abstract: With the continuous development of drilling technology, the performance control requirements of drilling fluids are becoming higher and higher. Therefore, the drilling fluid circulation system process and equipment configuration must meet the requirements of drilling processes. This article has scientifically divided the process system of the drilling fluid circulation system, analyzed and explained the main role, basic requirements and reasonable configuration of each process system. The ultimate goal is to use the circulation system and solid control equipment to achieve the technical parameters of drilling fluid Reasonable control to provide high-quality drilling fluids for drilling operations, and to meet the drilling fluid performance requirements of different drilling process technologies.
Keywords: drilling fluid; circulation system; mud purification system; solid control equipment; drilling fluid shaker; drilling fluid centrifuge; sand remover; mud remover; equipment configuration
The research and exploration of drilling fluid circulation solid control system is mainly aimed at the scientific design of the process, and the flow is the main line to reasonably configure the solid control equipment. The ultimate goal is to better meet the needs of drilling operations. From the angle of view, secondly, it must meet the requirements of high efficiency, energy saving, and environmental protection. In addition, it must be easy to install, simple to operate, and reduce labor intensity.
2 Division of the process system
According to the requirements of drilling operations, we can divide the process of drilling fluid circulation system as follows:
① Drilling fluid tank volume system;
② Pulp distribution pipe 5 + X system;
③Drilling fluid solid control equipment flow system;
④ Drilling fluid mixing process system;
⑤ Suction system of drilling fluid pump;
⑥The conventional degassing system of drilling fluid;
计量 Drilling measurement tank and grouting system;
⑧Clear water irrigation and water system;
Radon invasion and discharge of liquid gas separator system;
⑩ Drilling fluid tank circuit system.
3 Research and insights on process systems
The flow system has relative independence in the entire drilling fluid circulation system, and its role is determined by the drilling process. In turn, it serves drilling and how to serve well. This requires the flow system to be scientific and reasonable.
3.1 Volume system of drilling fluid tank
Generally, the drilling fluid circulation system consists of five kinds of tanks according to their functions. The first is a solid control equipment tank, sometimes called a drilling fluid shaker tank, and the second is an intermediate tank, also called a transition tank. A centrifuge can be installed in this tank. Above, the third type is a slurry storage tank, the fourth type is a pump suction tank, and the rest are storage tanks. The metering tank is at the end of the solid control equipment tank with a volume of 10 to 16 m3. Each tank compartment is installed There are 7.5kw, 11kw, or 15kw mud mixers. Each compartment is set with a fixed scale, which can observe the drilling fluid volume in the tank in time. Each compartment also leaves the position of the drilling fluid volume sensor for installation. The entire tank group is connected by a steel mesh plate on the walkway. There are retractable railings on the side of the tank. There are connections between the railings. Three or more sets of tanks are placed at the drilling fluid shaker, pump room, and slurry. ladder.
3.2 5 + X system of slurry distribution pipe
After the drilling fluid returns from the wellhead, it is connected to the drilling fluid distribution pipe via the elevated groove. The 5 + X system distribution pipe interface and function are as follows:
① Inflow interface for drilling fluid shaker, there are several interfaces for several drilling fluid shakers, which can be assumed to be X;
②Elevated slot access;
③ The deaerator drilling fluid flows out of the interface after degassing;
④Return pulp connection of metering tank;
⑤ Drilling fluid is directly discharged into the tank interface;
⑥ The drilling fluid is directly discharged into the external pool interface.
3.3 Drilling fluid solid control equipment process system
Drilling fluid solid control is the core part of the drilling fluid circulation system. According to the solid control classification principle, the processing and placement procedures of the solid control equipment are drilling fluid shaker → sand remover → desilter → drilling fluid centrifuge (large, Medium displacement) → Mud centrifuge (high speed centrifuge). Drilling fluid vibrating screen is the first-level leading equipment of solid control, and it is the only full-flow treatment. Therefore, the reliability of drilling fluid vibrating screen is very important. The performance of the drilling fluid vibrating screen directly affects the working effects of the subsequent levels of solid control equipment. And the quality of the drilling fluid system. What is the good working performance of drilling fluid vibrating screen, that is, the processing of drilling fluid vibrating screen is large, the slurry discharge is smooth, it is suitable for high mesh screen, and it can reach more than 120 mesh in normal work. The currently used HYS280-3P drilling fluid vibrating screen has a processing capacity of 50L / s, and the maximum excitation force is 25KN × 2. After field use, the reflection effect is very good.
Table 1 Main technical parameters of drilling fluid shaker
|name||power||frequency||Explosion-proof grade||Screen area||amplitude||Vibration intensity||Tilt adjustment range|
|parameter||2.2 × 2Kw||23.4Hz||dIIBT4||3 × 0.833 × 1.15 cubic meters||5.8mm||7.2G||-1 ~ 3 degrees|
The sand remover is the second-level solid control equipment in the solid control equipment. Its working principle is the combination of the centrifugal separation of the cyclone and the gravity sand removal. The processing process is not full overcurrent, and the working power is 75kW. Provided by the sand pump, its separation point is about 74 microns (the separation point is through the work of the separation equipment, there is a kind of particles in the underflow and overflow 50% each, the particle size point is called the equipment's separation point) The underflow can also be used for drilling fluid recovery through the cleaner, and the overflow of the sand remover enters the next stage, which is used as the slurry input of the mud remover. The point is about 43 μm. In order to meet the drilling fluid's requirements for drilling fluid, the solid control system of the current circulation system adopts an integrated sand removal and mud removal machine, which can better ensure the control of the solid phase and the stability of the drilling fluid performance.
Table 2 Main technical parameters of drilling fluid cleaner
|name||Throughput||Working pressure||Desander cone||Desilter cone||Desander point||Desilter separation point||power||Vibration intensity|
|parameter||200 cubic meters / hour||0.25 ～ 0.45||250mm × 10 ″ × 2||100mm × 4 ″ × 16||40 ~ 70 microns||20 ～ 40 microns||2.2Kw × 2||7.2G|
The overflow slurry of the desilter can be used as the feed for the centrifuge. The working efficiency of the centrifuge is relatively high. The centrifuge was first introduced to oil drilling because the centrifuge can reduce the viscosity of the drilling fluid while reducing the viscosity, and can also save a lot of drilling fluid additives. After working in a high-speed centrifuge, the colloidal solid phase and ultra-fine solid phase overflow can be discharged to the tank, and the solid phase containing relatively large particles or the underflow containing barite can be recovered into a specific tank and a certain Water and pharmaceuticals synthesize high-quality drilling fluids. After processing, the entire drilling fluid system can maintain reasonable control of drilling fluid density and viscosity, which can greatly save drilling fluid costs.
Table 3 Main technical parameters of sedimentation drilling fluid centrifuge
|name||Throughput||Separation factor||main motor power||Auxiliary motor power||Drum diameter||Drum length||Separation point|
|parameter||50 m3 / h||717||30Kw||7.5Kw||500mm||1000mm||10 microns|
3.4 Drilling fluid mixing process system
The drilling fluid mixing process consists of two sets of mixers, two mixing sand pumps and one shear pump. The process has the following characteristics:
① 2 sand pumps can pump drilling fluid in any tank other than the solid control equipment tank and in the compartment, and mix the slurry through any of 2 sets of mixers;
② The mixed drilling fluid can be placed in the storage tank or in any tank and compartment except the solid control equipment tank;
③ For high-viscosity materials, they can be mixed by any mixer and then cyclic sheared by a shear pump. After full penetration and hydration, any slurry pump can be sent to any tank and compartment;
④ 2 mixing pumps can provide power for low-pressure circulating drilling fluid guns;
⑤ The drilling fluid in any tank and compartment can be sent to any tank and compartment by any slurry sand pump, and the drilling fluid in the suction tank and compartment can be emptied.
3.5 Suction system for drilling fluid pump
There are usually two drilling and drilling fluid pumps. The process of the suction system allows each pump to suck the drilling fluid in any tank except the solid control equipment tank and the compartment. The tank and the compartment can communicate and block. It is controlled by the tank bottom valve, so that it can deal with the downhole emergency such as well leakage, well surge, etc. at the fastest speed. It can be equipped with plugging and increasing drilling fluid. After the pump sucks directly from the distribution tank, Drive into the well. In addition, drilling fluid can be matched according to the depth of the well. If wells of 5000m to 6,000m are normally constructed, a 5 + X circulation system can be used to equip drilling fluids to meet drilling requirements. However, for wells with special requirements of 3,000m, the volume of drilling fluid can be adjusted to a depth of 3,000m by closing some compartments of the transition tank and the suction tank, instead of matching the drilling fluid with the rated capacity of the circulating tank, which can reduce the Cost and improve economic benefits.
3.6 Degassing system for drilling fluid
During the drilling production process, drilling fluids are susceptible to gas invasion whenever they encounter oil and gas formations. In addition, due to the use of certain drilling fluid additives, drilling fluids can also generate bubbles. Generally, bubbles with diameters less than 0.8mm will appear in drilling fluid. The bubbles are trapped in the drilling fluid due to the effect of surface tension. After the drilling fluid gas invades, its performance will be destroyed, which will bring great damage to drilling production. harm.
From this point of view, to expose the bubbles, the first is to cause the bubbles to escape to the surface like a turbulent flow of a thin layer of drilling fluid. The second is to make the drilling fluid impact the tank wall to form a thin layer and bring bubbles to the surface (see Figure 1). These two points are the function and principle of the deaerator. That is, after the bubbles are degassed in a vacuum, the diameter of the bubbles increases by 0290 / 0.254 = 1.114 times. If the surface tension of the liquid is large and the viscosity is high, the bubbles may not escape from the liquid quickly and rupture. Therefore, under normal circumstances, the liquid entering the vacuum degasser should be designed to impact the tank wall to form a thin layer of turbulent liquid structure. Through the work of the degasser, the degassed drilling fluid is directly discharged to the next compartment to achieve the purpose of degassing.
Table 4 Main technical parameters of vacuum deaerator
|name||Throughput||Degree of vacuum||main motor power||Vacuum pump motor power||Outgassing efficiency|
|parameter||200 ～ 240 cubic meters / hour||280 ～ 350mmHg||15Kw||2.2Kw / 3Kw||≥95%|
3.7 Independent measurement tank and grouting system
The drilling fluid needs to be independently measured, observed, and alarmed when the drilling tool is started and drilled to prevent the occurrence of blowouts or leaks in the well when the drilling is started. The measuring tank is usually about 10-16m3, and there are two or one 11KW grouting pumps. The grouting pump outlet pipeline is connected with the overflow pipe, and the drilling fluid can be injected into the well. In the tank, the butterfly valve is installed at the interface. The metering system of the metering tank can be displayed by a floating ruler, and the volume of drilling fluid entering or exiting the well can be indicated by the electronic liquid crystal display of the floating ball sensor. The fixed alarm device will alarm.
3.8 Clean water tank and clean water process system
The clear water tank is very important in the drilling fluid circulation system. The clear water is not only the drilling fluid mother fluid, but also it must be continuously replenished. It is also required in cementing, and the cooling rig winch cleaning equipment requires clean water.
3.9 Liquid-gas separator nozzle system
When natural gas appears downhole to a certain degree, it will be throttled and ejected after the sealer is closed. At this time, the gas invasion drilling fluid contains natural gas, which needs to pass through the throttling manifold to enter the liquid-gas separator for degassing. After the “pipe line is drawn out, it will burn to the combustion pit. The degassed drilling fluid will enter the drilling fluid tank through the interface of the 10” line to the slurry distribution pipe system. The inlet and outlet are connected by flanges and equipped with butterfly valves.
3.10 Drilling fluid tank circuit system
The circuit of the circulation tank is more complicated, but the whole must be explosion-proof. The exposed cables must be protected by steel wires. When the sand pump is started, a step-down explosion-proof starter cabinet is provided. Each power appliance must have an explosion-proof switch and a closing lock mechanism. The light tube must be explosion-proof, and the light pole is movable, and it can be laid down when the equipment is moved.
4 Flow chart of typical solid control
Typical solid control flowchart (see Figure 2)
5 On-site use
Wells TK1083 and TP17, which were constructed by two well teams in Tahe Oilfield, Xinjiang, were equipped with the above-mentioned circulation system. After being used on site, the effect was good.
6 Conclusions and understanding
The process system of the above drilling fluid circulation system needs to be further improved, and the situation is more complicated in actual application, and each drilling operation area is different. Therefore, the drilling fluid circulation system process design and equipment configuration must be based on the needs of the drilling process, and exchange and research with drilling technicians in order to achieve more perfect results.
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