In order to meet the requirements of drilling process technical measures and drilling construction quality, the solid control system during complex drilling construction operations was optimized. Solve the problems of drilling solid control system, high quality drilling fluid solid control system, improve the performance of solid control equipment, reduce the solid phase content in drilling fluid, improve the quality of cementing construction, and ensure that drilling construction meets the design quality standards.
Solid control system
Solid control system in complex drilling operations
For oil drilling operations, straight wells are the simplest drilling construction task. The directional and horizontal wells are difficult to drill and belong to complex drilling operations. For horizontal well drilling operations, vertical well sections, inclined well sections, stable inclined well sections, and horizontal well sections need to be drilled. Each well section needs to be matched to form a reasonable borehole trajectory and achieve the quality of horizontal well drilling construction. .
The solid control system for drilling construction is to meet the technical requirements for solid control of drilling fluids. Through solid control equipment, the solid phase content in drilling fluids can be reasonably controlled, and the purification of drilling fluids can be strengthened so that its performance can meet the technical requirements of complex drilling constructions. Reduce the cost of drilling construction as much as possible, improve the quality of oil drilling construction, and meet the needs of oil and gas field exploration and development.
The solid control system in the oil drilling process mainly realizes the control and separation of the solid phase and the liquid phase of the drilling fluid, and recycles the drilling fluid, which also belongs to the mud purification system. The solid control system is composed of several modular combined tanks to avoid the occurrence of sediment at the bottom of the mud tank . A mixing device is designed on the mud tank . Each tank of the entire circulation system is independent and connected to each other to form Certain technological processes meet the requirements of mud purification and meet the technical requirements of petroleum drilling construction.
Multiple purification equipment is designed in the system, and the supporting equipment includes vibrating screen, agitator and desilter, etc. to reduce the discharge of waste cement slurry, avoid environmental pollution accidents, improve the safety and environmental protection of oil drilling construction, and achieve need.
Analysis of complex drilling procedures
"Green drilling" refers to drilling that focuses on pollution prevention, minimizes consumption of raw materials and energy, reduces production costs, and reduces and prevents damage to the ecological environment during the drilling process.
In order to carry the broken cuttings of the bottom drill bit to the surface in time to continue drilling, and at the same time to cool the drill bit to protect the well wall and prevent drilling accidents such as well collapse, the rotary drilling rig is equipped with a circulation system. The circulation system includes drilling pumps, ground manifolds, mud tanks, mud purification equipment, etc. Among them, ground manifolds include high-pressure manifolds, risers, and water hoses, and mud purification equipment includes drilling fluid shakers , sand removers, desilter, Centrifuge, etc.
The drilling pump sucks the mud from the mud tank, and the mud pressurized by the drilling pump passes through the high-pressure manifold, riser, and water hose, enters the faucet, goes down to the bottom of the well through the hollow drilling tool, and is ejected from the water hole of the drill bit. Through the circular space between the wellbore and the drilling tool, rock debris is carried back to the ground, and the mud returned from the bottom of the well is passed through various levels of mud purification equipment to remove the solid content and then reused.
Drilling engineering is a field operation project in oil and gas exploration and development activities. The "waste slurry, waste water, waste oil" and the debris such as rock cuttings and production garbage during the drilling production process inevitably cause pollution and damage to the surrounding environment. Especially in sensitive ecologically fragile areas, the damage will be severe and difficult to repair once it occurs. Therefore, vigorously promoting clean production and actively realizing sustainable development "establish green awareness of environmental protection, control pollution from the source, and achieve green environmental protection of oil and gas exploration and development, has become the incumbent responsibility and obligation of today's oil and gas exploration and development enterprises.
Four-level solid control equipment drilling fluid circulation system can strengthen the solid phase control of drilling fluid; through rational use of solid control equipment such as vibrating screen, sand remover, desilter, swirl separator and drilling fluid cleaner, drilling fluid can be reduced Dilution and dosage of treatment agent; Closed drilling fluid circulation system can prevent drilling fluid from falling to the ground and avoid seepage pollution.
Keywords: deep well rig; solid control system; process flow; solid control equipment
In recent years, the development of medium and shallow wells in China has reached the middle and late stages. At present, the development of deep and ultra-deep well drilling rigs is concentrated, and higher requirements are imposed on the drilling fluid solid control system. The solid control system is from solid control equipment to drilling fluid circulation tank. Although the technology has been greatly improved and the process flow is becoming more reasonable, there are still many problems in the supporting of the solid control system, especially for the solid control of deep well and ultra-deep well rigs. The system is not mature enough. The author analyzes the advanced technology and development direction of the solid control system used in modern drilling, and combines the current status of the drilling fluid solid control system and the technical development status of the solid control equipment. Based on the actual process requirements of the drilling rig site, a set of research that can meet the production needs , And can produce better economic benefits of the 7000m deep well drilling control system.
1 Status and development of solid control equipment at home and abroad
1.1 Status of domestic solid control equipment
Domestic solid control technology was developed in the 1980s. In the past two decades, with the comprehensive implementation of jet drilling, optimized drilling, high-quality drilling fluids, and oil and gas layer protection technologies, the theoretical research and manufacturing processes of domestic drilling fluid solid-phase control equipment have been rapidly developed, promoted, and popularized. In terms of performance and life, domestic solid control equipment still has a certain gap compared with foreign countries in terms of materials, processing technology, processing accuracy and quality of supporting general-purpose equipment. At present, the mainstream configuration of domestic solid control is mainly based on 5-level solid phase control (screening-degassing-sand removal-mud removal-centrifugation).
1.2 Status of foreign solid control equipment
Foreign solid control equipment is represented by American companies such as BRANDT, SWACO, DERRICK, etc. The solid control equipment produced by them not only has good performance, stable work and long life, but also realizes equipment standardization, serialization and specialization. Quality and performance are first in the world. Foreign countries are equipped with solid control system equipment, focusing on optimized configuration and efficiency evaluation, and thus developed a drilling fluid solid phase control expert system. For example, a solid control system composed of 4 drilling fluid shakers and 2 dryers in the United States increases the processing capacity by 70% and is not easy to block. The separated solid particles are dehydrated by a dryer, and the dried particles are discharged. Dropped and recovered liquid is effective.
1.3 Development Direction of Solid Control Equipment
At present, foreign solid control equipment has matured, and standardized, serialized and specialized equipment types have been formed. Compared with foreign countries, the overall technical level of domestic solid control equipment still has a certain gap, and it is necessary to focus on the development of solid control equipment types, solid control equipment performance, life, and efficiency evaluation of the entire solid control system. In the future, the development requirements of international solid control equipment: energy saving, consumption reduction, safety and environmental protection. It mainly develops from the following six aspects: simplification and optimization of the solid control system; degassing and then screening; changing part of the processing to full processing; selective solid phase control technology; on-line drilling cuttings processing technology; drilling fluid repetition Use technology.
2 Design of deep well rig solid control system
With the deepening of oil and gas resources exploration and development, the definition of deep wells is also constantly changing. The current well depth of 6000 to 9000 meters is the category of deep wells. Here, a deep-well drilling rig for the exploration and development of oil and gas wells within a depth of 7000 meters of land drilling is developed from the main technical parameters of the solid control system, the configuration of the solid control equipment, and the process flow of the solid control system. Meter rig's solid control system.
2.1 Main technical parameters
(1) Determination of effective volume of drilling fluid circulation tank.
The effective volume of the drilling fluid circulation tank is the main technical parameter of the solid control system of the drilling rig. The finished drilling volume method is based on the volume of drilling fluid required to fill the borehole after completion of drilling as the minimum volume required for the drilling fluid system. This method assumes that no mud collection device is used and all drilling fluid is lost in the drill.
The nominal drilling depth capacity is 7000m, and the volume of the drilling fluid system supported by the drilling rig combined with Ф127mm (5in) drill pipe and 36T drill bit to reach the bottom of the well.
7000m × O.O127m3 / m = 88.9m³
36000kg ÷ 7754kg / m3 = 4.6m3
88.9m³ + 4.6m3 = 93.5m3
In the formula:
7754kg / m³—Density of drilling tool
O.O127m3 / m—Ф127mm (5in) drill pipe per meter of external volume fills the minimum volume of drilling fluid required for the wellbore to be 93.5m3, and an additional 50% is used as a safe volume, that is, 46.75m3, which is the minimum in use The volume is about 140m3, plus the reserve volume, usually the reserve volume is similar to the in-use volume, so the effective volume of the entire drilling fluid system is about 280m3, plus a 20m3 weighting bin, the total effective volume is 300m³. Requirement in "SYT6223-2005 Drilling fluid purification equipment supporting installation and use and maintenance"
The volume of drilling fluid circulation tank of 7000m rig is not less than 270m³, which fully meets the requirements.
(2) Main technical parameters:
Total volume: 353m3
Effective volume: 300m3 (excluding sand silo, etc.)
Mud tank body size (length × width × height): 11000 × 2800 × 2300mm (including skid height 300mm)
Transport size of mud tank (length × width × height): 13500 × 3000 × 2800mm
Number of mud tanks: 6 (inclined bottom structure)
Medicine tank: 1
Total installed power: ~ 650kw
2.2 Process flow of solid control system
2.2.1 Flow chart of drilling fluid purification process.
During the drilling process, the drilling fluid purification treatment is a solid-liquid separation of the drilling fluid by the purification equipment. It is currently divided into five levels, usually called five-level purification: vibrating screen → sand remover → desilter → mud centrifuge Machine → deaerator. For deep well drilling rigs, drilling fluids are all purified in five stages. After the mud returned from the wellhead is purified by a five-stage purification equipment, it is repeatedly pumped into the well for recycling by a drilling pump. The following is a typical process flow chart of a 7000m drilling rig solid control system (wherein from left to right, and from top to bottom are 5, 6, 1, 2, 3, and 4 tanks).
2.2.2 Main supporting solid control equipment.
The main supporting solid control equipment is shown in Table 1.
|Vacuum deaerator||1 set||null|
|Drilling fluid shaker||3 sets||null|
|Drilling fluid centrifuge||1||LW450 × 1000N2|
|Sand pump||6 units||55Kw|
|Shear pump||1 set||55Kw|
|No pump||1 set||11Kw|
|Jet mixing funnel||3 sets||Barite feeding: 300kg / min|
|Swirl mixing funnel||1 set||Bentonite feed: 150KG / min|
|Mud Mixer||11 units||15Kw|
|Mud Mixer||3 sets||7.5Kw|
|Mud Mixer||1 set||5.5Kw|
|Mud gun||14 only||Pressure: 6.4Mpa|
2.2.3 Composition of drilling fluid purification cycle process.
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主要用于清除钻屑等有害固相及回收重晶石等有用固相。 The drilling fluid solid control system is mainly used to remove harmful solid phases such as drilling cuttings and recover useful solid phases such as barite. The solid control system is mainly composed of mud tanks, drilling fluid shakers, sand removers, desilters, drilling fluid centrifuges and other major equipment, as well as auxiliary equipment such as sand pumps, slurry mixing devices, and vacuum degassers.
The mud tank is mainly used to store the mud and the carrier of the solid control equipment. The mud purified by the solid control equipment enters the various chambers of the mud tank and is processed according to different equipment to achieve the removal of solid particles and recovery of barite and purification of the mud. purpose.
General process of solid control system:
Drilling fluid vibrating screen is the first-level processing equipment in the solid control system, which can remove larger solid phases in drilling fluid, and can remove solid phase particles above 74 μm. It is an indispensable device in the solid control system and a leader in subsequent equipment.
用于清除泥浆中的气体，是固控系统中的第2及固控设备，它能够迅速、有效地清除泥浆中所含的气体，除气器对于恢复泥浆密度，防止潜在井喷、井塌危险的发生其有重要作用。 The vacuum deaerator is used to remove the gas in the mud. It is the second and solid control equipment in the solid control system. It can quickly and effectively remove the gas contained in the mud. The deaerator is used to restore the density of the mud and prevent potential blowouts. The occurrence of well collapse risk plays an important role.
The solid control equipment ranked in the third stage is a drilling fluid sand remover. The mud processed by the vacuum deaerator is conveyed into the sand remover by a sand pump. The sand remover sends the larger sand particles (grain size 44μm-74μm). )separate from.
After the sand remover is a drilling fluid desilter, which can be used to remove the solid phase of 15 ~ 44μm, which can further ensure the performance of the drilling fluid.
In some solid control systems that need to save space, a sand remover, a desilter, and an underflow screen can be combined into a drilling fluid cleaner. The drilling fluid cleaner can effectively remove solid particles larger than 15 μm. In some uncomplicated drilling platforms, it can completely replace the sand remover and desilter.
The final processing equipment of the solid control system is a drilling fluid centrifuge, which is mainly used to remove solid particles smaller than 7 μm and to recover barite. The recovery rate is 95 ~ 97%.
全部采用主要用干复杂井况和要求较高的井况，在实际应用过程中，可以跟据钻井作业的需要，采用其中的一级成几级泥浆固控流程。 The solid control equipments are mainly used in dry complex conditions and well-required well conditions. In the actual application process, according to the needs of the drilling operation, one of the mud solid control processes can be adopted.Read More »
是整套钻机系统中最为重要的部分之一,被称为钻井“血液”的过滤器。 The mud solid control system is one of the most important parts of the entire drilling rig system, and it is called a "blood" filter for drilling. Reasonable solid control system can effectively control the solid phase content of drilling fluid, reduce the complexity of the drilling process and the probability of accidents, and is an important technical means to achieve safe, efficient and economical drilling.
、除砂器、除泥器、钻井液清洁器、离心机、钻井液罐等设备组成的,一旦某一设备发生故障或整体配套不合适将直接影响整套钻机性能,增大钻井施工过程中发生事故的风险。 The solid control system is composed of equipment such as vibrating screen , sand remover, desilter, drilling fluid cleaner, centrifuge, drilling fluid tank and other equipment. Once a certain equipment fails or the overall matching is not suitable, it will directly affect the performance of the entire rig Increase the risk of accidents during drilling construction. Therefore, the performance of the solid control system has important practical significance for drilling engineering.
Understand the performance and main characteristics of the solid control equipment, and choose a solid control equipment that satisfies the requirements based on the characteristics of formation cuttings and drilling fluid properties.
故障会引发的钻井施工过程中的事故风险,并作出相应的调控措施。 Through the analysis and evaluation of the overall performance of the solid control system, the potential safety hazards and causes of the solid control system were identified, including the hidden dangers of equipment components at all levels and the accident risk during the drilling construction process caused by the failure of the solid control system And make corresponding control measures. Thereby reducing the risk of accidents during drilling construction and increasing the drilling speed of safe drilling.Read More »