Common drilling accidents and prevention
Common drilling accidents
The most likely underground engineering accidents during drilling are:Drilling accidents(Scratches, wheels and drills.Drilling rig accidentBroken drilling equipment, broken drilling equipment, etc., and tube accidents(Carcasses, breakers, etc.Accidents in wells(Small tools, etc. fell into the well.The drill.(The rig cannot move up or down,Well-detection accidents(well cable survey encounter cards, obstruction or well instrumentation landing well, etc.)Note Cement Accident(Cement slurry is not replaced in the rigs, the cement slurry is not high enough, or the cement slurry is fully replaced in circular space etc.) andWell blowout out of control.(Unmanageable drilling well blow-outs, etc.
Causes of drilling accidents
1) Geological factors
The wells were drilled to the ground floor, and the structure of the ground floor.Hard and soft.Unforeseen problems can arise if there is insufficient understanding of the stress systems and the porosity of the pressure systems.
First, we should know about the design well.Hole pressure on the ground floor, break-down pressure on the ground floor, collapse pressure on the ground floorAnd some special layers (saline, moist mud) have the creeping resilience that is the main basis for the design of well-body structure and drilling fluids. In general, in the same naked borehole.Spraying, leaking, and worming cannot be allowed to exist simultaneously with the leak.If the above-mentioned requirements are not met on the well body structure and the high pressure layer and the worm layer are at the lower end of the trough, then the trough should be pretreated and cannot go blindly into the deep. If there’s a low pressure layer or a leak layer at the lower of the pressure layer or the worm layer, then the pressure layer orThe worm layer is sealed with a condom.。
And second, for some special layers, it’s certain.Temperature, pressureThe subtidal salines, salines, water-rich soft salines, salines, cracks that can easily collapse and fall.Mud, coal, and some fire-forming rock.The intrusive layers should be known in more detail, as they are the main cause of the sub-well complexity. And for some geological phenomena,Faults, cracks, holes, super-high permeation layersInformation should also be provided on the location and presence and content of hydrogen sulphide and carbon dioxide.
This information is essential for a well. But the more detailed information from the geology department is,Oil and gas data,Not much, if not much, of the critical information required for the project.Some of the data are far from the actual situation.Even the oil fields that have been developed, as a result of the development of the water,Underground pressure systems have changed a lot.It is also difficult to rely on information from the adjacent wells. This has often led to the drilling of wells having to be fought, and thus complex and recurrent.
2. Engineering factors
Drilling operations are covert and complex, and because of the lack of complete geological information or the strict scientific design of the well structure, although reliable geological information exists, they cause the same naked eye to spray, the leak to be inserted, the leak to be treated and the leak to be treated. It’s a tube, but it’s not loaded and controlled.When drilled into high-pressure layers and emergency use, leaks were made everywhere and even caused the well blow-out to run out of control.Drilling fluid systems and performances are not compatible with the characteristics of the Earth,Even one-sided emphasis on the conservation of well-drilling fluid treatment agents has worsened well-drilling fluid performance, resulting in the indents or collapses of certain layers of the naked borehole.
Drilling.Well, it’s not a good well.It also causes well blow-outs, well leaks or well collapse. It’s not working properly. It’s too fast to drill.Excited stress.It’s easy to suffocate. Too fast to drill can generate a lot of suction, which can spray oil and gas or collapse loosely structured layers, especially in the case of oil and gas.Drilling or strung-up mud bagThe situation is even more serious.
The drilling equipment is not working.Forced to stop drilling or the flow of drilling fluidIt was an accident in the well.Most commonFactors. In addition, management is weak, disciplined, watchless (heavy, pumped, tweaked) and blindly determined, but saves effort, and without consequence,Drill up, drill down, bump up, bump down, bump down.，This is a common cause of underground accidents.
Common approach
1) Causes and Treatment of Carcasses
The reason for this is the fact that the drilling of the rigs is due to geological factors, poor water performance and inadequate technical measures.It’s a long-term lack of freedom of movement in the well.That’s called a drill. The main ones are sticky, sandy, sandy, sandy, welly, condensed, muddy, fally, and cut-down-down-to-cage.
Methods of dealing with the accident of a card drill: (1) Boiled card; (2) Use of a shocker shock decal; (3) Rewinding the button; (4) Detonation of the blast; (5) The blast drills are sided with new eyes etc.
2) Causes of well crashes and their disposal
The well collapses during drilling.The well wall is falling apart.The phenomenon. The reasons for the well collapse include:The pressure of the liquid column in the well does not balance the pressure of the layer; (a) The subsurface is immersed in well fluids, with water-sensitive expansion, fragmentation and stripping;The floor itself is broken and loose, caused by the lifting of the rig.Suction(b) Reduced pressure on the lower wells; In the drilling process,We didn’t get back to the well.(a) A decrease in the pressure of the liquid column in the well; (a) The length of the drilling stop and the fluid performance of the drilling has changed; It’s been a long time in the naked well.Large Flow CycleWait. When the wells collapse seriously, they cause complications in the boreholes and cause accidents inside them.
►The following measures should be taken in the event of a well collapse:
(1) The down-drilling process, if the wellhead is found not to be re-drilling or the back-drilling of the rig is a symbol of the well collapse, shall cease immediately. The pump is recycled or pierced and the drilling is resumed when conditions are normal below the well.
(2) The drilling process shall cease immediately if the liquid surface of the wellhead is found to be undefeated, or if the anti-drilling fluid inside the rig is a symbol of the well’s collapse. Pump-cycled drilling fluids • Re-entry of drilling operations after normal pump pressure, unimpeded access to the well and internal and external pressure balance of the tube.
(3) At all times, when a well collapse is detected, the pump must be pumped with a small charge. Then the charge is gradually increased and the pump cannot be stopped. If the small charge ceiling is not working, the pump pressure rises, and the wellhead is not re-drilled, it proves that the layer is missing and cannot continue to be squeezed into the well fluid.
3) Drilling accidents and preventive measuresDrilling incidents during drilling, includingThe wheel’s head is falling out of its claws.– Tooth wheels, broken teeth, teeth, wheels;Scratch drill.– The PDC drill is off; Or man-made crystals, or natural diamonds.It’s called a drill accident.
The following measures should be taken to prevent drilling accidents:
(1) Selection of well-qualified drills, out of the plant use instructions requiring proper use of drills
(2) Deliberately operating, evenly delivering drills, and insulated against the occurrence of drills and drills.
(iii) The correct operation, the construction as designed, and the required pressure as a combination of rigs and the depth of the wells.
4) Well spills and disposal
The well leak is during the drilling.Leaking of well-drilled fluids or other media (condensed well cement, etc.) into the pore, cracksThe phenomenon of space. A well leak is a common in-well complication in drilling work, with most well drilling processes being subject to varying degrees of leakage. A serious leak leads to a decrease in the pressure in the well.Impacts normal drilling, causing damage to well wallsSteady.、Inducing the formation of a stratospheric fluid into a wellhole andWell blow.。
Measures to address well leaks:
(1) Underground pressure systems and more complex subsurface wells can only be addressed by a leaking approach;
(2) For wells with a single sub-well pressure system, with a more tectonic strength, the treatment can be done by reducing the fluid density of drilling wells.
(3) Leakage materials such as sawdust, horse dung, shell powder, clay, etc. may be added to the drilling fluid.
(4) Leakage requires the use of dense drilling fluids with leaks such as sawdust, cotton hulls, etc., and the handling of well leaks in combination with process measures, the slowness of the drilling down and the appropriate pump charge.
5) Well blow-outs and disposal
Well blow-outs, a phenomenon of the hydrosphere, ejection of the ground or flow into other layers of the wellMost of them occurred at the site of oil and gas extraction. The reason for the blow-out is many:(a) Unpredictable pressure management, low mud density and lower levels of mud in wells; Get up and suck.And other inappropriate measures.
The method of control of the well after the blowout is called the pressure well, which is mainly the case.Driving wells and engineers.
1) The method of drilling wells is first to remove gas or oil from the wells.And then we replace it with heavy mud.This method takes a long time and is often used when the equipment is inadequate.
2) Engineer’s pressure well method is after calculating the amount of mud required.The method of one-time access to the wells.The well blow-out incident has already been described in the front, and is not repeated here.