Petroleum drilling fluids, properties of drilling fluids

It's best to be specific, but I'll give you a brief description of the treatment and application of drilling fluid in the event of a well leak, I hope it will help you

Drilling fluid process technology for well leakage treatment.

Definition of well leakage: During various downhole operations (drilling, cementing, testing or workover, etc.), various working fluids (including mud, cement slurry, completion fluid and other liquids, etc.) are present.

It is a complex downhole situation that leaks into the formation under the action of differential pressure.

Well leakage hazards: loss of drilling time and prolongation of drilling cycle; loss of a large amount of drilling fluid raw materials; Layer leakage will seriously damage the layer; Induce other underground accidents; Interference drilling.

normal maintenance of liquid properties; Interference with geological logging work.

The development of China's anti-well leakage plugging technology.

Features: vigorously develop plugging agents and corresponding process technologies (dozens of plugging materials in several categories); Began to pay attention to the prevention of well leakage; Geological characteristics of leakage layers, leakage mechanism and leakage testing methods.

Research began to take off; Leak plugging test equipment and tools have been studied.

Development history: the initial stage of plugging when leakage is seen, mainly plugging, and the plugging efficiency is low; The development stage of plugging technology, combining plugging and prevention, and preventing leakage and plugging technology; Precautionary Main

The combination of plugging and prevention, and the work of leakage prevention and plugging have entered the stage of scientific development.

Classification of well leakage (according to the shape of the leakage channel): permeability leakage, leakage velocity is small, generally in the formation with strong permeability and poor cementation; Fracture leakage, leakage velocity of several hundred square hours, generally in natural or man-made fractured formations; The cave leakage, often in but without exit, mostly occurs in the multi-cave limestone dolomite formation.

Prevention of well leakage:

Reasonable slurry density; Rational casing procedures; Use low-density, low-shear, low-viscosity slurries whenever possible; Prepare leakage plugging materials; Reduced pressure agitation (slow pump opening, slow drilling, segmented circulation.)

rings, etc.); Low return velocity with sand; Prevent annular blockage and diameter reduction; Improve the pressure bearing capacity of the formation.

Plugging method: drilling static plugging; Bridging material plugging method; temporary plugging method; High water loss slurry plugging method; Leakage plugging of flocs and colloids; Soft and hard plug plugging method; Composite plugging method.

forcibly drilling into the casing to seal the leakage layer; Injection of cement slurry; Nylon cement bag plugging karst cave leakage, etc.

The above is a brief list of some basic knowledge, I hope it will be helpful to you.

Drilling fluid is usually called mud Mainly, balancing the pressure of the real estate, lubricating the drill bit, the friction of the drill pipe, carrying underground rock particles, the specific situation is specific to the slurry, and the good drilling of a well also depends on whether the mud is well or not.

1. Density of drilling fluid:

Refers to the mass of drilling fluid per unit volume;

Drilling fluid density is a very important parameter to ensure safe and fast drilling and protection of oil and gas reservoirs. Through the change of drilling fluid density, the hydrostatic column pressure of drilling fluid in the wellbore can be adjusted to balance the formation pore pressure. It is also sometimes used to balance the structural stress of the formation to avoid the occurrence of well collapse.

Excessive density: It will cause a series of problems such as excessive thickening of drilling fluid, easy leakage loss, decrease in drilling rate, aggravation of damage to oil and gas reservoirs, and increase in drilling fluid costs.

Low density: It is easy to cause well surges and even blowouts, which can also cause well collapse, well diameter reduction and chip carrying capacity.

In general, the higher the density of the drilling fluid required, the lower the solid phase content, viscosity and shear force of the drilling fluid before the aggravation, and the addition of soluble inorganic salts is also a more commonly used method to increase the density.

2. Rheology of drilling fluid:

characteristics of drilling fluid flow and deformation;

The most commonly used rheological modes are Bingham and power-law modes. The parameters of the Bingham mode are plastic viscosity and dynamic shear force; The parameters of the power-law mode are the flow stress index and the consistency coefficient.

Because the rheology of drilling fluid is closely related to a series of drilling work such as rock bearing, borehole stability, increasing mechanical speed and calculating annular hydraulic parameters, it is one of the most important properties of drilling fluid.

3. Filtration and wall-building properties of drilling fluid:

In the drilling process, when the drill bit drills through the permeable formation, because the liquid column pressure of the drilling fluid is generally always greater than the formation hole pure clearance pressure, under the action of pressure difference, the liquid of the drilling fluid will seep into the formation, which is called the filtration of the drilling fluid.

Fourth, the pH value of drilling fluid:

Dispersion of drilling fluid in more than 10;

Lime calcium treatment drilling fluid in 11 12

Gypsum of calcium treatment drilling fluids in.

Polymer drilling fluids in.

5. Sand content of drilling fluid:

The general requirements are controlled as follows, and the sand content is too high to have the following hazards to drilling

1.The increase in the density of drilling fluid is not conducive to increasing the ROP.

2.The mud cake is soft, which leads to the increase of filtration loss, which is not conducive to the stability of the borehole and affects the cementing quality.

3.Increase the wear and tear of drill bits and drilling tools, shorten the service life;

4.It is easy to cause pressure difference jamming;

6. The solid phase content of the drilling fluid.

1.Cleaning the bottom of the well, carrying cuttings.

2.Cooling and lubrication of drill bits and drill strings.

3.Balance the pressure on the side of the rock on the borehole wall.

4.Suspended cuttings and weighting agents.

5.Efficient transfer of hydraulic power. Bureau.

6.Provides a wealth of information on the strata drilled.

7.Hydraulically crushing rocks.

8.Bear the gravity of the tungsan orange part of the drill pipe and casing.

9.Balance control formation pressure.

Mud is a widely used drilling fluid, which is mainly suitable for loose rock formations with unstable hole walls such as loose fracture development, easy to collapse and fall off blocks, and expansion and spalling when exposed to water.

In the early stage of rotary drilling, the main role of drilling fluid is to carry cuttings from the bottom of the well to the surface. At present, drilling fluids are recognized as having at least the following ten functions:

1. Clean the bottom of the well and carry cuttings. Keep the bottom of the old lead well clean, avoid repeated cutting of the drill bit, reduce wear and tear, and improve efficiency.

2. Cool and lubricate the drill bit and drill string. Reduce the temperature of the drill bit, reduce the wear of the drilling tool, and improve the service life of the drilling tool.

3. Balance the rock side pressure of the well wall, form a filter cake on the well wall, and close and stabilize the well wall. Prevent pollution of oil and gas reservoirs and borehole collapse.

4. Balance (control) formation pressure. Prevent blowouts, well leaks, and prevent pollution of drilling fluids by formation fluids.

5. Suspended cuttings and weighting agents. Reduce the sedimentation rate of cuttings and avoid sand jamming.

6. Sand and cuttings can be sunk on the ground.

7. Effectively transmit hydraulic power. Transmit the power required by the downhole power drilling tool and the hydraulic power of the drill bit.

8. Bear part of the gravity of the drill pipe and casing. The buoyancy of the drilling fluid on the drilling tool and casing can reduce the load on the hoisting system when starting and unloading.

9. Provide a large amount of information about the drilled strata. The drilling fluid can be used to carry out electrical logging, cuttings logging, etc. to obtain trapped downhole data.

10. Hydraulic crushing of rocks. The high-velocity jet formed by the drilling fluid passing through the nozzle can directly or assist in crushing the rock.

11. Suspended cuttings and density adjustment materials: When the circulation is stopped, the drilling fluid is in a static state, and the bentonite particles in it can be connected with each other to form a structure and suspend the cuttings. If a density-adjusting material (e.g. barite) is added to the drilling fluid, it can also be suspended when the circulation is stopped.

The ability of the drilling fluid to suspend cuttings and density-adjusted material allows for easy re-start-up after the drilling fluid has stopped circulating.

Drilling fluid is a general term for various circulating fluids that meet the needs of drilling work with their various functions in the drilling process. Drilling fluid is the blood of drilling, also known as borehole flushing fluid. Drilling fluids can be divided into clear water, mud, non-clay phase flushing fluid, emulsion, foam and compressed air according to their composition.

Clean water is the earliest drilling fluid, which does not need to be treated, is easy to use, and is suitable for intact rock formations and areas with sufficient water sources. Mud is a widely used drilling fluid, which is mainly suitable for slipping and is used for loose, fracture development, easy to collapse and fall blocks, expansion and spalling in contact with water and other unstable rock formations with hole walls. Initial formative period:

1888 In 1928, rotary drilling began, initially with clear water. Rapid development period: 1928-1948, it was found that mud with sand had a better carrying capacity than clear water.

As a result, finely dispersed drilling fluids are developed and simple treatment agents are used. Rapid development period: 1948-1965, the insufficiency of finely dispersed mud was discovered:

The anti-invasion ability is poor, so it develops into a coarsely dispersed drilling fluid with calcium treatment and moderate flocculation. Scientific optimization period: In 1965, in high-pressure jet drilling, low solid phase was required, so polymer non-dispersed low solid phase drilling fluid appeared.

Since the late 80s and early 90s of the last century, drilling fluid systems such as positive glue, silicate, formate, polyol, and biodegradable have appeared successively, and have been widely used. However, none of them have formed the mainstream and cannot completely replace the polymer drilling fluid system.

At the same time, the oil-based drilling fluid used in the 40s of the last century is also developing, from the beginning of the development of diesel to mineral oil; from all-oil-based to water-in-oil emulsion drilling fluid; From toxic and polluted oil-based drilling fluids to low-toxicity and non-toxic oil-based drilling fluids.

Hello dear<>

According to the questions you provide, the drilling fluid system and characteristics? For your query as follows: drilling fluid is a liquid used in drilling operations to cool, lubricate the drill bit, control the stability of the borehole, carry cuttings to the surface, maintain the pressure at the bottom of the well, etc.

There are many types of drilling fluids, including water-based drilling fluids, oil-based drilling fluids, emulsion drilling fluids, gas drilling fluids, etc. Different drilling fluid systems have different characteristics, and the following are several common drilling fluid systems and their characteristics:1

Water-based drilling fluid: mainly composed of water, clay, saturated brine and chemical additives, etc., it has the advantages of low cost, environmental friendliness, easy handling and high quality. However, its stability is poor under the conditions of high temperature, high pressure and high salinity, which is easy to cause wellbore collapse and drilling accidents.

2.Oil-based drilling fluid: mainly composed of mineral oil, solvents, lubricants, antioxidants, etc., it has the advantages of maintaining stability under harsh conditions such as high temperature, high pressure and high salinity.

However, its cost is high, the processing and processing are difficult, and the environmental pollution is greater. 3.Emulsion Drilling Fluid:

It is composed of oil, water, emulsifier, clay and chemical additives, etc., and has the advantages of both water-based drilling fluid and high temperature and high pressure stability of oil-based drilling fluid. However, it is difficult to prepare and costly. 4.

Gas drilling fluid: It is mainly composed of gas (such as nitrogen, carbon dioxide, natural gas, etc.) and lubricants, clays, chemical additives, etc., which has the advantages of little impact on the stability of the wellbore, high drilling efficiency, and can reduce drilling costs. However, it requires a high-pressure air source, and it is easy to cause environmental pollution and other dangers.

To sum up, there are differences in different drilling fluid systems at the special lease point, and the appropriate drilling fluid system should be selected according to the specific drilling operation requirements.