Well control equipment and well control technology

A, well control equipment

Well control equipment refers to the implementation of a complete set of equipment, oil and gas pressure control required instrumentation and special tool.

(a) safety standards for supporting the oil and gas drilling well control equipment

In order to meet the requirements of the oil and gas pressure control, well control equipment must be able to accurately monitor and prediction of formation pressure, formation fluid, main parameters, the drilling fluid parameters in the process of drilling; when overflow, blowout, it can quickly control the wellhead, fluid control wellbore emissions, and promptly pumped pressure drilling fluid to reconstruction of pressure balance between the bottom and formation in the bottom hole pressure condition to maintain the stability of the. Even if the occurrence of blowout out of control and fire accident, also have to deal with effective. Therefore, the standard matching well control equipment shall be determined by the following main parts.

1 in order to hydraulic blowout preventer as the main body of the drilling well head, also called a blowout preventer combination. It mainly includes:

(1) hydraulic blowout preventer;

(2) the casing head;

(3) four;

(4) the transition flange.

2 hydraulic BOP control system. It mainly includes:

(1) the driller's console;

(2) the remote control console;

(3) auxiliary remote control console.

3 in order to choke manifold based well control department. It mainly includes:

(1) the choke manifold and hydraulic throttle valve control box;

(2) the discharge pipeline;

(3) kill manifold;

(4) the water injection pipeline;

(5) fire extinguishing pipeline;

(6) the reverse circulation pipeline.

(two) the combination of hydraulic blowout preventer

Hydraulic blowout preventer portfolio selection includes pressure level, nominal size (diameter), the number of control points combination form and control system selection. Factor in the selection of hydraulic blowout preventer combination should be considered mainly has: Well, casing size categories, formation pressure, formation fluid type, personnel of technology of condition, technological requirements, the influence of climate, traffic conditions, material supply and environmental protection requirements etc.. In a word, should be able to achieve balanced drilling, drilling safety guarantee and save drilling cost.

1 pressure level selection

The pressure of work on hydraulic blowout preventer combination in used internal pressure strength of casing, casing shoe at the naked eye formation fracture pressure and the expected maximum wellhead pressure. But is based mainly on the blowout preventer wellhead pressure under combined maximum expected to decide.

Blowout preventer pressure level has a total of five: 14MPa, 21 MPa, 35MPa, 70MPa, 105MPa, 140MPa.

2 path selection

BOP combined path depends on the well structure design of casing size, which must be slightly larger than the outer diameter of the connected casing.

BOP path consists of nine types: 180mm, 230mm, 280mm, 346mm, 426mm, 476mm, 528mm, 540mm, 680mm. The field commonly used with 230mm, 280mm, 346mm, 540mm.

The 3 form of combination selection

Select the combination form mainly according to the formation pressure, drilling technology, drilling tool structure requirements and equipment matching.

14MPa BOP combination has four kinds of forms for choice (see Figure 2 - 6).

21MPa and 35MPa BOP combination has two kinds of forms for choice (see Figure 2 - 7).

70MPa and 105MPa BOP combination has two kinds of forms for choice (see Figure 2 - 8).

For the sake of safety, various combinations should be equipped with 1 ~ 2 drilling four. Two main functions of drilling four generic, is easy to connect well control department; two is to protect the blowout preventer, director of its service life. If fluid contains a large amount of debris, sand and chemicals, and even metal chips, will accelerate wear, erosion of the blowout preventer, and shorten its service life.

4 point control control system selection

The number of control points in addition to meet the control of selecting the number of BOP combinations need, the need to increase the two control points, used to control the two hydraulic valve, or used to control a hydraulic valve, the other as a backup.

(three) the annular BOP

1 Structure and principle

Overflow occurs close the annular BOP control system, from the high pressure oil to enter into the closed chamber, push the piston upward, in the top of the constraints, forcing the rubber core centripetal movement, supporting ribs move closer together, in between rubber extruded to the well center, to achieve sealing drill, or full well sealing mouth. When opened, into the open cavity from the high-pressure oil control system, pushes the piston down, the rubber core in itself rubber elastic force reduction, head open.

2 types and specifications

(1) type

Types of field common annular preventer on its sealing rubber core shape can be divided into spherical annular BOP, conical annular BOP and combination type annular preventer.

(2) technical specification

Annular blowout preventer used technical specification see Table 2 - 10 and 2 - 11 (table in an annular Hua Shi Erji plant BOP as an example).

The 3 function

The main function is to:

(1) the overflow or blowout occurred in drilling, coring, well logging and other operations, can close the Kelly, drill pipe, coring tools, cable, wire rope formed tools and wellbore annular space.

(2) when the well tube with no can fully closed wellhead.

(3) in the use of vacuum pressure regulating valve or the buffer storage device control, can pass butt welded drill pipe 180 shoulder forcibly from under the drill, but under the slower, more slowly through the joints (not more than 0.2m / s), forced pressure shut in well drilling tool under the appropriate to reduce, allowing a small amount of leakage between the rubber core and drill pipe. Can play under the drill force operations must also consider the situation underground safety and construction conditions.

4 the use of safety technical requirements

(1) in the BOP scene after installation, should be in accordance with the new standards for field pressure testing of pressure test.

(2) into the objective layer after tripping, each two times, try to chop preventer again to check the well sealing effect. Such as the discovery of the rubber core failure or other problems, should be replaced immediately with.

(3) in the well a drilling tool blowout, can first use the annular blowout preventer wellhead control, but try not to make long time to seal the well.

Because of a rubber core is easy to damage, and no locking device. The special circumstances, not closed empty well. Letter of empty well when the maximum pressure rated working pressure half.

(4) the blowout preventer is well sealing state, allowed to work the string up and down, but does not allow for rotary drill. Similarly, in the drill rotates, not allowed to close the blowout preventer, to prevent the rubber core wear.

(5) it is prohibited to open the ring opening blowout preventer to leak wellhead pressure, to stab the ring rubber core.

(6) every time after opening, must check whether the open rubber core, in order to prevent the hanging bad rubber core.

(7) the blowout preventer to open, should use the hydraulic oil standard, and pay attention to keep them clean.

(8) recommended the blowout preventer control of maximum pressure of 10.5MPa.

(9) for storing rubber core: according to the old and new program according to the time sequence number, to the old new ordinal use; kept in the light is dark and dry room. Temperature is not too high, should avoid the heating equipment and direct sunlight; away from corrosive goods; away from the high voltage electrified equipment, in order to prevent ozone corrosion; let the rubber core stored in a relaxed state, no bending, extruding and suspension; regularly check, if found to have become brittle, cracking, bending, cracks are no longer the use of.

Judgement and elimination methods of 5 fault

(1) BOP not tightly closed. If the rubber core is not closed tightly, can solve the multiple activities; support ribs have been closer still closed lax, replace the rubber core; if long time to open the process for closed using the rubber core, the debris deposited on the rubber core grooves and other parts should be cleaned, the rubber core, and according to the regulation of activity of rubber core.

(2) BOP closed not open, this is because a long time after the closure, the rubber core to generate permanent deformation aging or is used in the solidification of cement slurry after fixing the rubber core and causes. In this case, only the cleaning or replacement.

(3) the blowout preventer switch is not flexible. Tubing leakage, BOP long time no activity, dirt clogging, symptomatic treatment.

(four) ram blowout preventer

The 1 Principle

When the high-pressure oil into the ram BOP control system about hydraulic closed chamber, push the piston to drive the gate shaft and a ram assembly along the interior rib guide rail defined by the wellhead center respectively to realize mobile, shut in action. When the high-pressure oil control system into the gate open cavity blowout preventer about hydraulic, push the piston to drive the gate shaft and a ram components don't move away from the wellhead center direction, realize the well opening action. Gate switch consists of three position four way reversing valve control system, the general in 3 ~ 8 seconds to complete the well open or shut in action.

Flow path of hydraulic oil for:

Closed: hydraulic oil through the shell closed oil inlet, shell oil circuit, oil circuit hinge seat, side door, liquid cylinder oil, cylinder head oil + liquid cylinder closed cavity.

Open: hydraulic oil through the shell opening oil export, shell oil circuit, oil circuit hinge seat, side door, the liquid cylinder open cavity.

The sealing principle:

Ram blowout preventer to have four sealing effect, can effectively close the wellhead, i.e.:

The front seal: seal between the gate leading and drill core;

The top seal: seal between the gate and the top of the shell core steps;

Side seal: seal between the casing and the side door;

Shaft seal: seal between the gate shaft and a side door.

2 types and specifications

(1) type

According to the purposes to ram: ram blowout preventer can be divided into full letter, half seal, reducing, shear and the cable gate;

By gate chamber to divide: ram blowout preventer can be divided into a single gate, double plate, three gate.

(2) technical specification

Ram blowout preventer used technical specification see Table 2 - 12 (to ram Hua Shi Erji plant BOP as an example).

Note: 1in=0.0254m.

3 function

Its main function is to:

(1) when the well a drill pipe, tubing and casing and the occurrence of an overflow or blowout, can seal the annular space corresponding pipe and wellbore formation.

(2) in the well tube with no, can fully closed wellhead.

(3) special cases can be liquid circulation and throttle drilling well pressure operation through the shell side outlet flange.

(4) can be cut off in the hole shear ram under special circumstances, to achieve the purpose of sealing the well.

(5) when necessary can also hanging drill pipe gate.

The 4 gate locking device

(1) the manual locking device

Manual locking device is on human rotating the handwheel to close and lock the gate. Its role is: a long-term seal well, in the hydraulic flashboard is closed after the gate locked in the closed position, at this time can be discharged hydraulic; two is the control system without pressure, can be used to manually closed wellhead.

Manual locking device operation formula:

Locking formula: smooth rotation in place, swing half circle

Unlock the formula: reverse rotation in place, swing half circle

(2) automatic locking device of hydraulic

Hydraulic automatic locking device is arranged on the main piston through locking piston and piston arranged in radial four fan-shaped groove of the four locking blocks to realize the. When the hydraulic oil in the role of closed cavity, while promoting the master piston and piston lock gate is closed due to the direction of movement, inclined locking block inner and outer circumference is provided with a certain angle, inner bevel contact and locking piston inclined surface, so that the locking block push in the locking piston always directed radially outer movement trend. Once the main piston to the closed position, the locking block in the radial locking piston bearing out under the action of 7mm on hydraulic cylinder motion and base on the steps, the locking block outer slope and the liquid cylinder inclined surface contact with steps, lock the piston to move forward through the locking block diameter into circumferential contact, and realizes the lock. If the gate, as long as the functions of the hydraulic oil in the open cavity first makes the locking outward movement of the piston, a locking block outer bevel and the bevel makes the component of the liquid cylinder step locking block inward contraction makes the locking block is unlocked, the main piston to drive the gate shaft and gate realized opening movements.

5 ram blowout preventer switch well operation

Normal hydraulic shut: valve control system quickly moved off position

Normal hydraulic open wells: the reversing valve control system quickly moved to the open position

Long shut in (or manually shut in): the first reversing valve control system quickly moved off position, then the manual locking

The lock opening after well: first, manual unlocking, hydraulic open well

6 pressure test

The blowout preventer pipe combination station in the whole assembly, with water pressure test. The annular BOP sealing drill pipe pressure test to the rated working pressure of 70%; ram BOP and the throttle, killing manifold pressure test to the rated working pressure, pressure holding time of not less than 10min, no leakage of sealing parts.

The first pressure test method (pressure method to improve the leather bowl tester test): the leather bowl tester connected to the lower drill string, human casing with water filled; wellhead; close half sealed flashboard blowout preventer or annular BOP (Note: never close the complete sealed flashboard); put the leather bowl tester for drilling rig hoisting system slowly, and observe the set pressure gauge, raised to the required test pressure, then check the connecting parts and sealing parts for leaks. Note: during the pressure test, the drill string weight function on the tester of the tongue part force plus lower suspension, not safe load capacity than the upper pipe, otherwise it will make the fracture.

Second pressure test method (pressure test pump pressure test method): plug type tester connected to the lower drill string, the people sitting casing head; with water filled the wellhead; close half sealed flashboard blowout preventer or annular BOP (when the drill exit, can close the complete sealed flashboard pressure test) for test; pressure pump slow pressure down into the well, and to observe the set pressure gauge, pump to the required test pressure, then check the connecting parts and sealing parts for leaks.

7, field installation and use of safety technical requirements 

(1) the site installation safety technical requirements of the gate: the best in the sealing gate half above the disc, when half sealing gate in the process of controlling overflow, blowout, due to the damage and cannot play its normal functions, safe and easily to replace the whole sealing gate with half sealing gate; Ram preventer on well before installation should be sealed pressure to pressure of work, qualified rear can be shipped to the well site; According to well control requirement to the bop combination form for installation; Should be careful not to put wrong, make shell indicating arrow direction and disc cavity top seal face in; Bop installation method should be generally make the manual door lock the lever of the resettlement and the handwheel is located in the derrick two side, on the shell side flange export to the derrick door direction; To be on the safe side, want to install all the manual locking device, fixed, and show that the switch turns on the handwheel; Shall ensure that steel and steel tank clean without damage, the steel ring groove coated light oil; Blowout preventer in according to the size of ram, must be used in well and pipe size is consistent, and that on the rig and remote control on the ram size, in case of fault clearance; To protect the well's mouth, whether ram preventer on the wellhead flange, two side are not allowed to open at the same time. 

(2) to install and remove clamp connection safety technical requirements: the bop form of connecting clamp can be used. Install the clamp, the first should be installed card assembly tooling, then clamp on tooling, cant within the clamp and the clamp head coated with lubricating oil on the inclined plane. Push forward band card on the clamp head inclined plane, put on the joint bolt, attention on spherical gasket. Start to tighten the nut in the ratchet wrench, when hand tight with ratchet plate is difficult in using special wrench, with hammer shock clamp, to facilitate assembly. Clamp connection by face to face seal, the two theory under the space between the clamp head is zero, considering the machining errors, when the distance between the two close to zero and the bolt tightening torque is activated when a recommended value is reached. If the gap is bigger, appropriate to increase the tightening torque. Remove the clamp nut off first, use special wedge iron clamp wedge open. Clamp assembly fixtures on the blowout preventer, can also be removed. 

(3) ram preventer the preparing work before use: ram preventer installed on the wellhead, should pay attention to check before use, and test run, think it is no problem before use; Check whether oil connection line in accordance with the bop marked by the switch. Can be controlled by the console to 2 ~ 3 mpa pressure for each ram try to switch the two, to eliminate oil in the air, such as gate switch action do not agree with the console handle instructions, should be rearrangement of pipe connection; Manual locking mechanism is good connection, manual lever control gate closing is flexible to use, and make a note of the handwheel when shut-in rotating circle number, listed on the handwheel. After the test will return the handwheel sinistral unlock, open the gate with hydraulic; The comprehensive test on the wellhead pressure testing standard should be in accordance with relevant regulations well control procedures. Of each connecting bolt fastening again after pressure testing, to overcome the uneven slack phenomenon; Check on the gate size core size and downhole drilling tools are consistent; Check whether the choke and kill, throttling tube connection is good. 

(4) ram preventer safety technical requirements of use: the use of the blowout preventer shall have the specialist is responsible, clear responsibility, do SanDong sihui (understand operating principle, understand equipment performance and understand the process flow, operation, maintenance, maintenance, will determine treatment failure); When well without tube test closed half sealing gate, largest hydraulic controlled hydraulic cannot exceed 3 mpa, so as not to damage the rubber core. It is forbidden to close when well inside the tube with whole sealing ram blowout preventer; Well site for at least a damper used in the borehole, once need to change in time; Enter the objective layer, switch gate once a day, check whether the switch is flexible, locking device is easy to use. Every time a 7 after also should be tested for all sealing gate switch; Not allowed to use the method of open the blowout preventer to drain off the wellhead pressure, so as not to damage the rubber core; Locking and unlocking must reach the designated position, so as to avoid the lock is not tight ram or tripping touch bad ram; Switch before the side door should drain off the liquid control oil pressure, so as not to damage the hinge sealing ring; Long-term application of locking device lock gate, and listed on the display, in order to avoid wrong operation.