Multiplex Electrohydraulic System

As greater water depths were encountered the problems of umbilical handling and reaction times became significant. In order to overcome them the hydraulic lines controlling the pilot valves were replaced by separate electrical cables which operate solenoid valves. These valves then send a hydraulic signal to the relevant pilot valve which in turn is actuated and directs power fluid to its associated BOP function. The time division multiplexing system provides simultaneous execution of commands...

Pressure Readback

In order to ensure that the subsea regulator has set the desired operating pressure the manifold incorporates a readback system. The output of each subsea regulator is connected through a 1 8 hose in the umbilical back to a pressure gauge in the control manifold. Pressure transducers transmit the readback pressures to remote panels. A shuttle valve also in the manifold unit connects the lines from both umbilicals and isolates the active and inactive pods. All the electrical components are...

Bop Closure Sequence

All Hydril Annular Blowout Preventers employ the same time-tested design for sealing off virtually anything in the BOP bore or the open hole. During normal wellbore operations, the BOP is kept fully open by leaving the piston down. This position permits passage of tools, casing, and other items up to the full bore size of the BOP as well as providing maximum annulus flow of drilling fluids. The BOP is maintained in the open position by application of hydraulic pressure to the opening chamber,...

Section methods of well control

1 Kill Methods General 1 5. 2 Constant Bottom Hole Pressure Kill Methods 4 5. 3 The Driller's Method 5 5. 4 The Wait and Weight Method 13 5. 5 Volumetric Well Control 17 5. 6 Volumetric Stripping 23 5. 7 Edited Extract From API RP53 28 5. 8 Removal of Gas Trapped in BOP's 30 5. 9 Kick Detection and Well Control Problems on Deviated and Horizontal Wells 34

The Functions Of Drilling Muds

(a) To help maintain the stability of the wellbore, by outward hydrostatic pressure and mud filter cake. (b) To carry the drill cuttings up the annulus and back to the surface by its upward motion and viscosity. (c) To maintain pressure balance in the well during drilling, tripping and other operations. The mud hydrostatic pressure must be at least equal to or greater than the reservoir pore pressure. (d) To cool the bit and drillstring and to lubricate the cutting surfaces at the bit. (e) To...

Hangoff Drill Subsea Blowout Preventers Only

Following prescribed procedures, the crew should place the drill string in position for hang-off. One hang-off should be made before drilling out of surface pipe to ensure that all necessary equipment is on hand and in working condition. Actual hang-off will not normally be performed on subsequent drills. This drill can be conveniently performed in conjunction with the pit drill.

Classification Of Drilling Muds

Drilling muds can be divided into the following classes (1) Water-based muds ie fresh water or sea water. (2) Oil-bascd muds (a) Invert emulsions, with oil water ratios from 50 50 to 90 10. (b) Low toxic invert emulsions, as in (a) but with low to base oils. (3) Synthetic or pseudo oil-based muds. In addition to muds, gas and stable foams may be used as drilling fluids. INGREDIENTS of DRILLING MUDS All muds have 4 categories of ingredients (a) A liquid base to support other components (b) A...

Umbilical Hose

The umbilical transmits all power fluid and all pilot signals from the surface to the subsea control pods. Hydraulic pressure from the regulated side of the subsea regulators is also transmitted through the umbilical to pressure readback gauges at surface. The power fluid is supplied only to the umbilical of the selected active pod, whereas pilot pressure is normally supplied to both the active and inactive pods. The most common umbilicals contain a 1 ID supply hose for the power fluid which is...

To Closing Unit Manifold And Accumulators

EXAMPLE REDUNDANT AIR NITROGEN SYSTEMS FOR OPERATING CLOSING UNIT PUMPS EXAMPLE REDUNDANT ELECTRIC NITROGEN SYSTEMS FOR OPERATING CLOSING UNIT PUMPS is l TO CLOSING UNIT MANIFOLD AND ACCUMULATORS EXAMPLE REDUNDANT ELECTRIC NITROGEN SYSTEMS FOR OPERATING CLOSING UNIT PUMPS SECTION 8 SURFACE BOP CONTROL SYSTEMS

Stripping Drill

The performance of a stripping drill by at least one crew on each well should be considered. This drill can be conveniently performed after casing is set and before drilling out cement. With drill pipe in the hole a blowout preventer should be closed and the desired pressure trapped. Each crew member should be assigned a specific position. Following an acceptable procedure, the crew should strip sufficient pipe into the hole to establish the workability of the equipment and to allow each crew...

Causes Of Kicks And Influxes

The most common causes of kicks are Improper monitoring of pipe movement (drilling assembly and casing). - Trip out - making sure hole takes the proper amount of mud. - Trip in - making sure it gives up proper amount of mud and preventing lost circulation due to surges. Swabbing during pipe movement. - Abnormal pressured formations - Drilling into an adjacent well - Excessive drilling rate through a gas sand Surveys in the past have shown that the major portion of well control problems have...

Diverter Procedure While Drilling On A Fixed

Where shallow casing strings or conductor pipe are set, fracture gradients will be low. It may be impossible to close the BOP on a shallow gas kick without breaking down the formation at the shoe. If a shallow gas kick is taken while drilling top hole then the kick should be diverted. Drilling shallow sand too fast can result in large volumes of gas cut mud in the annulus and cause the well to flow, also fast drilling can load up the annulus increasing the mud density leading to lost...

Subsea Control Pods

Bully Bop Control Pod

8.B.14 There should be two completely redundant control pods on the blowout preventer stack after drilling out from under the surface casing. Each control pod should contain all necessary valves and regulators to operate the blowout preventer stack functions. The control pods may be retrievable or non-retrievable. The hoses from each control pod should be connected to a shuttle valve that is connected to the function to be operated. A shuttle valve is a slide valve with two inlets and one...

Remotely Actuated Valves

Questions 1-4 refer to the stack and manifold diagram. The valves shown in the diagram are on the choke and kill line at the stack numbered F1 to F8. The valves on the manifold are numbered 1 to 31. 1. If all of the above valves were closed, indicate below those valves that should be in the open position if the Manifold is lined up to suit a Soft Shut-in while drilling. 2 . Referring to the above question indicate the position of the chokes, when lined up for a Soft Shut-in . a. Left hand...

Constant Bottom Hole Pressure Kill Methods

There are three 'constant bottom-hole pressure' kill methods in common use today which are Wait & Weight Method (also known as the 'Engineer's Method') These three techniques are very similar in principle, and differ only in respect of when kill mud is pumped down. In the Driller's Method, the kill is split into two circulations. During the first, the kick fluid is circulated without changing the mud weight once the kick is out, the mud is weighted up and pumped around the well on the second...

Section kick indicators

2 Increase in Drilling Rate of Penetration - 3. 3 Increase Torque and Drag 2 3. 4 Decrease in Shale Density 2 3. 5 Increase in Cutting Size and Shape 3 3. 7 Increase in Trip, Connection and a 3. 8 Change in the Temperature of the Return 3.10 Positive Kick Signs 8 3.11 Hydrocarbon Kick Behaviour 10

Increased Torque And Drag

Increased drag and rotary torque are often noted when drilling into overpressured shale formations due to the inability of the underbalanced mud density to hold back physical encroachment of the formation into the wellbore. Drag and rotating torque are both indirect and qualitative indicators of overpressure. They are also indicators of hole instability and other mechanical problems. Torque and drag trend increases often indicate to the driller that a transition zone is being drilled. Up drag...

Choke Drill

Choke drills should be performed before drilling out surface casing and each subsequent casing string. With pressure trapped below a closed preventer, the choke should be used to control casing pressure while pumping down the drill pipe at a prescribed rate. This drill will establish equipment performance and allow the crew to gain proficiency in choke operation. It is desirable to discharge into a trip tank to accurately monitor flow rates for correlation with choke opening, pump rates, and...

Accumulators

Accumulators are ASME coded pressure vessels for storage of high pressure fluid. These accumulators are available in a variety of sizes, types, capacities and pressure ratings. The two (2) basic types are bladder and float which are available in cylindrical or ball styles. The accumulators can either be bottom or top loading. Top loading means the bladder or float can be removed from the top while it is still mounted on the accumulator unit. Bottom loading accumulators must be removed from the...

Fast Shutin Procedure While Drilling On A Fixed

When any indication is observed while drilling that the well maybe flowing, stop rotating the drill string, raise the drill string with pumps on until tool joint is above the drill floor. 2. Stop pumps and check for flow, if positive 5. Call supervisors and commence plotting a graph of shut in drill pipe pressure. Check pit volume gain. Note There are no A.P.I recommendations for the fast shut-in

Hard Shutin Procedure While Drilling On A Fixed

When any indication is observed while drilling that the well maybe flowing, stop rotating the drill string, raise the drill string with pumps on until tool joint is above the drill floor. 2. Stop pumps and check for flow, if positive 5. Call supervisor and commence plotting a graph of shut in drill pipe pressure. Check pit volume gain. 6. Refer to A.P.I. R.P. 59 sections 3 7 for advantages and disadvantages of the hard shut-in. In any shut-in procedure it is prudent to line up the annulus to...

Pump Power Requirements

8.A.12 Power for closing unit pumps must be available to the accumulator unit at all times, such that the pump will automatically start when the closing unit manifold pressure has decreased to less than 90 percent of the accumulator operating pressure. 8.A.13 Two or three independent sources of power should be available on each closing unit. Each independent source should be capable of operating the pumps at a rate that will satisfy the requirement described in Para. 8.A.10. The dual source...

Extracts From Api Rp

Loss of primary well control most frequently results from 1) failure to keep the hole full 2) swabbing 3) insufficient drilling fluid density and or 4) lost circulation. These problems can occur during any operation conducted on a well. The goal of well control is to prevent a well kick (influx of formation fluid into the wellbore) from becoming a blowout (uncontrolled flow of formation fluid). 6.2 Conditions Necessary for a Kick. The two conditions that must be present in the...

Formation Integrity Tests

A leak-off test is made to determine the pressure at which a formation will begin to fracture. Leak-off tests are usually run after drilling a short distance below the surface casing shoe. These tests may also be made on other casing strings. A leak-off test is performed by pumping drilling fluid into the wellbore at a slow rate (typically one-half barrel per minute), with blowout preventers closed and carefully plotting the resulting pressure versus the total volume pumped....

Remotely Operated Connector

9.2.5 A remotely operated connector (hydraulically actuated) connects the riser pipe to the blowout preventer stack and can also be used as an emergency disconnect from the preventer stack, should conditions warrant. Connector internal diameter should be at least equal to the internal bore of the blowout preventer stack. Its pressure rating can be equal to either the other components of the riser system (connectors, flexible joint, etc.) or to the rated working pressure of the blowout preventer...

Abnormal Pressure

Every pressure which does not conform with the definition given for normal pressure is abnormal. The principal causes of abnormal pressures are - When first deposited, shale has a high porosity. More than 50 of the total volume of uncompacted clay-mud may consist of water in which it is laid. During normal compaction, a gradual reduction in porosity accompanied by a loss of formation water occur as the thickness and weight of the overlaying sediments increase. Compaction reduces the pore space...

Control Panels

These panels permit the operation of the manifold unit from remote locations. Usually two remote panels are used - a master one on the drill floor, and a minipanel in a relatively safe location such as a rig office. Other mini-panels can be integrated into the system if desired. The drillers master panel is normally explosion proofed or air-purged since it is located in a hazardous area. It contains a set of graphically arranged push-button indicating lights for operation and status indication...

Ram Type Preventers and Drilling Spools

7.A.2 Following are recommended inspections and tests for this equipment a. Visually inspect the body and ring grooves (vertical, horizontal, or ram bore) for damage, wear, and pitting. b. Check bolting, both studs and nuts, for proper type, size, and condition. Refer to Section 8-A for bolting recommendations. c. Check ring joint gaskets for proper type and condition. Refer to Section 8-A for ring joint gasket recommendations. d. Visually inspect ram type preventers for 1) Wear, pitting, and...

Physical Response From the Well

Increase in drilling fluid return rate. 3. Changes in flowline temperature. 5. Variations in pump speed and or standpipe pressure. 7. Drilling fluid density reduction. 8. Effects of connections, short trip, and trip on shows and gains. 9. Hole problems indicating underbalance (i.e., tight hole, packing-off, sloughing). 10. Excessive pressure or pressure changes between casing strings. C. Chemical and Other Technical Responses From the Well. 1. Chloride changes in the drilling fluid. 7. Drilling...

Mpl Automatic Ram Locking Refer to

Hydril Ram Blowout Preventers are available with automatic Multiple-Position Ram Locking. Multiple-Position Locking (MPL) allows the ram to seal off with optimum seal squeeze at every closure. MPL automatically locks and maintains the ram closed with the optimum rubber pressure required for seal off in the front packer and upper seal. Front packer seal wear (on any ram BOP) requires a different ram locking position with each closure to ensure an effective seal off. Multiple-Position Locking is...

Surface Inspection And Testing

7.B.1 Prior to delivery to an offshore drilling unit, visually inspect the preventers, spools, high pressure connector, and kill and choke valves for condition of bodies, machined surfaces, grooves, actuating rods, rams, seals, and gaskets. Inspect in accordance with procedures in Para. 7.A.2.e. 7.B.2 Test each individual component of the blowout prevention system to be utilised in test facilities under shop conditions to rated working pressure utilising procedures outlined in Para.7.A.2.e....

Installation

A blowout preventer operating and control system is required to actuate the Spherical BOP. Several systems are available and those commonly used on drilling rigs work well. The recommended installation requires 1. A control line to the closing (lower) port. 2. For stripping, an accumulator bottle in the closing line adjacent to the BOP. This bottle should be precharged to 500 psi for surface installations and to 500 psi plus 45 psi per 100' of water depth for subsea installations. 3. control...

Answer

The maximum allowable annular surface pressure should be re-calculated b. As soon as possible after a drilling break c. When approaching a suspected transition zone d. When the mud weight has been increased in the system e. If a kick has occurred and the well is shut-in The calculated M.A.A.S.P. value is relevant a. When the influx is in the open-hole section b. As the influx approaches the surface Depth Bit size Shoe depth Mud weight 10000ft TVD 8 1 2 8500ft TVD 12.6 ppg Metal...

Second Circulation

Once the kill mud is ready, open the choke about one quarter, start the pump and break circulation. Then bring the pump up to the kill rate. 9. While the Driller is bringing the pump up to the kill rate, the choke operator should operate the choke so as to keep the casing pressure steady at the same pressure as when closed in. 10. While the drill pipe is being filled with heavy mud there are two options for keeping B.H.P. constant, either keep the casing pressure constant or make out a graph...

Positive Kick Signs

A kick occurs when the hydrostatic pressure of the mud column in the well is less than the formation pressure provided that the formation has the ability to produce. A kick is a positive indicator that formation fluid is entering the wellbore and Secondary Well Control must be initiated. Flow into the wellbore causes two changes to occur in the mud circulating system Increase of active mud system volume. The mud return flow rate exceeds the mud flow rate into the well. Since a rig's fluid...

Table A

Minimum Recommended Pr charg Pressure Usable Fluid Volume fraction of bottle size Notes Based on minimum discharge pressure of 1200 psi. SECTION 8 SURFACE BOP CONTROL SYSTEMS 8.A.5 The closing system should be capable of closing each ram preventer within 30 seconds. Closing time should not exceed 30 seconds for annular preventers smaller than 18 3 4 inches and 45 seconds for annular preventers 18 3 4 inches and larger. Operating Pressure and Precharge Requirements for Accumulators 8.A.6 No...

CTrip Tank

Trip tanks are used to fill the hole on trips, measure mud or water into the annulus when circulation has been lost, monitor the hole when tripping, logging or other similar type operations. There are two basic types of trip tanks - gravity feed and pump. The pump type system is better because it provides for safer and more expedient trip operation. The trip tank would be isolated from the surface mud system to prevent inadvertent loss or gain of mud from the trip tank due to valves being left...

Section Marine Riser Systems General

9.2.1 A marine riser system is used to provide a return fluid flow path from the wellbore to either a floating drilling vessel semi submersible or hull type or a bottom supported unit, and to guide the drill string and tools to the wellhead on the ocean floor. Components of this system include remotely operated connectors, flexible joints balljoints , riser sections, telescopic joints, and tensioners. Data on these components, together with information on care and handling of the riser, are...

Surface Subsea Bops While Wireline Logging

- Direct the wireline loggers to cease operations and close the well on the upper annular. - Open kill line valves and begin to record shut in pressure and pit gain. - Pass word to the OIL COMPANY REPRESENTATIVE and SENIOR DRILLING CONTRACTOR REPRESENTATIVE of the well condition. Note If at all possible the wireline should be pulled or stripped out of the hole. If the line needs to be cut and dropped, a surface hydraulic cable cutter should be used. The shear rams should be considered as a last...

Typical Surface Bop Control System

Accumulators - Precharge per label. Warning USE NITROGEN ONLY-DO NOT USE OXYGEN Check every 30 days. 2. Accumulator Bank Isolation Valve -Manually operated, normally open. 3. Accumulator Bank Bleed Valve - Normally closed. 5. Air Filter - Automatic Drain. 6. Air Lubricator -Fill with SAE 10 lubricating oil, set for 6 drops per minute. Check oil level weekly. 7. Air Pressure - Gauge - 0 to 300PSI. Switch -Automatically stops air operated pumps when pressure reaches 2900 PSI and starts pumps...

Rotating Heads

When used, rotating heads are installed above the BOP stack. They provide a seal on the kelly or drillpipe. A drive unit, attached to the kelly, locates in a bearing assembly above the stripper rubber. Some applications for rotating heads are Drilling with air or gas, to divert the returns through a Blooey line. To permit drilling with underbalanced mud, by maintaining a back pressure on the wellbore. As a diverter for surface hole. To keep gas away from the rotary table. This is especially...

Decrease In Dexponent

The D-Exponent will be plotted by the well loggers and maintained current at all times. This value was introduced in the mid sixties to calculate a normalised penetration rate in relation to certain drilling parameters. The D-exponent may be corrected and normalised for mud weight changes and or ECD equivalent circulating density by the following A plot of Dc-Exponent versus depth in shale sections, has been used with moderate success in predicting abnormal pressure. Trends of Dc-exponent...

Section shutin procedures

4. 1 Introduction to Shut-in Procedures 4. 2 Soft Shut-in Procedure While Drilling 4. 3 Soft Shut-In Procedure While Tripping 4. 4 Hard Shut-In Procedure While Drilling 4. 5 Fast Shut-In Procedure While Drilling on 4. 6 Diverter Procedure While Drilling on 4. 7 General Introduction for Shut-In Procedure 4. 8 Soft Shut-In Procedure While Drilling on a 4. 9 The Hard Shut-In Procedure on a Floating Rig 7 4.10 The Fast Shut-In Procedure on a Floating Rig 8 4.11 Shallow Gas and Diverting Procedure...

Closing Unit Pump Requirements

8.A.10 Each closing unit should be equipped with sufficient number and sizes of pumps to satisfactorily perform the operation described in this paragraph. With the accumulator system removed from service. The pumps should be capable of closing the annular preventer on the size drill pipe being used, plus opening the hydraulically operated choke line valve and obtain a minimum of 200 psi pressure above accumulator precharge pressure on the closing unit manifold within two 2 minutes or less.

Stripping Operations

Drill pipe can be rotated and tool joints stripped through a closed packing unit, while maintaining a full seal on the pipe. Longest packing unit life is obtained by adjusting the closing chamber pressure just low enough to maintain a seal on the drill pipe with a slight amount of drilling fluid leakage as the tool joint passes through the packing unit. This leakage indicates the lowest usable closing pressure for minimum packing unit wear and provides lubrication for the drill pipe motion...

Block Function

The block function is used to vent a pilot control valve. By doing this individually on each valve a leak in the control system or the preventers can be located and isolated. By centring and venting all the valves when the accumulator unit is first being pressurised unintentional and inadvertent operation of the various other positions and functions can be eliminated. Referring to Fig 9.3b, when the 'block' button is pressed, both the solenoid valves are actuated in such a way as to apply...

System Description General

Oil Pipeline Blowout Rings

A Blowout Preventer BOP Control System is a high pressure hydraulic power unit fitted with directional control valves to safely control kicks and prevent blowouts during drilling operations. A typical system offers a wide variety of equipment to meet the customer's specific operational and economic criteria. The following text gives a brief description of the equipment and some of its major components. Figure 8.0.3 ACCUMULATOR UNIT MODULE Figure 8.0.3 ACCUMULATOR UNIT MODULE The primary...

Workshop b Answers

The valves which should be in the open position numbers 8, 9, 10, 11, 12, 25, 26, 27 and 30 2. Left hand remote choke- closed Manual Adjustable choke- closed Right hand remote choke- opened 3. Left hand remote choke- closed Manual Adjustable choke- closed Right hand remote choke- closed 5. 2, 1, 13, 4, 8, 12, 6, 15, 14, 10 and 16 6. 2, 1, 13, 4, 8, 6, 15, 14, 10 and 16 7. 2, 1, 13, 8, 4, 6, 15, 14, 10 and 16

Accumulator Precharge Pressure Test

8.A.22 This test should be conducted on each well prior to connecting the closing unit to the blowout preventer stack. Test should be conducted as follows- a. Open the bottom valve on each accumulator bottle and drain the hydraulic fluid into the closing unit fluid reservoir. b. Measure the nitrogen precharge pressure on each accumulator bottle, using an accurate pressure gauge attached to the precharge measuring port, and adjust if necessary. 8.A.23 This test should be conducted on each well...

Hose Reels

Marine Riser

The hose bundles are mounted on heavy duty reels for storage and handling and are connected to the hydraulic control manifold by jumper hoses. The reels are driven by reversible air motors and include a disc brake system to stop the reel in forward or reverse rotation. When the subsea control pod is run or retrieved, the junction box for the jumper hose is disconnected from the hose reel. However in order to keep selected functions 'live' during running or retrieval operations, five or six...

Subsea Testing

7.B.5 The blowout prevention system should be operated on each trip but not more than once every 24 hours during normal operations. The annular preventers need not be operated on each trip. They must, however, be operated in conjunction with the required pressure tests and at an interval not to exceed seven days. The periodic actuation test is not required for the blind or blind shear rams. These rams need only be tested when installed and prior to drilling out after each casing string has been...

Blowout Preventer Operating Test

7.A.4 A preventer operating test should be performed on each round trip but not more than once per day. The test should be conducted as follows while tripping the drill pipe with the bit just inside casing a. Install drill pipe safety valve. b. Operate the choke line valves. c. Operate adjustable chokes. Caution Certain chokes can be damaged if full closure is effected. d. Position blowout preventer equipment to check choke manifold. Open adjustable chokes and pump through each choke manifold...

Causes Of Kicks

The objectives of this section are to Highlight the Causes of Kicks and Influxes. Primary control is defined as using the drilling fluid to control formation fluid pressure. The drilling fluid has to have a density that will provide sufficient pressure to overbalance pore pressure. If this overbalance is lost, even temporarily then formation fluids can enter the wellbore. Preventing the loss of primary control is of the utmost importance. A kick is an intrusion of unwanted fluids into the...

How MPL works

Hydril Mpl

This figure shows the ram maintained closed and sealed off by the MPL. Hydraulic closing pressure has been released. The Hydril Ram Blowout Preventer with MPL automatically maintains ram closure and seal off. MPL will maintain the required rubber pressure in the front packer and upper seal to ensure a seal off of rating working pressure. MPL will maintain the seal off without closing pressure and with the opening forces created by hanging the drill string on the ram. Locking and unlocking of...

Model Sl Poslock System

SL preventers equipped with Poslock pistons are automatically locked in the closed position each time they are closed. The preventers will remain locked in the closed position even if closing pressure is removed. Opening hydraulic pressure is required to reopen the pistons. The hydraulics required to operate the Poslock are provided through opening and closing operating ports. Operation of the Poslock requires no additional hydraulic functions, such as are required in some competitive ram...

Valves Fittings and other Components Required

8.A.16 Each installation should be equipped with the following a. Each closing unit manifold should be equipped with a full-opening valve into which a separate operating fluid pump can be easily connected refer to Fig. 8.A.1 . b. Each closing unit should be equipped with sufficient check valves or shut-off valves to separate both the closing unit pumps and the accumulators from the closing unit manifold and to isolate the annular preventer regulator from the closing unit manifold. c. Each...

Jzl

Yellow Junction

1 4 Manipulator Valve Or Selector Valve With 2 Position Air cylinder Failsafe Valve Operator Showing Spring Housing And Gate Figure 9.5 PILOT FLUID CIRCUIT 2-POSITION FUNCTION SECTION 9 SUBSEA BOP CONTROL SYSTEMS amp MARINE RISER SYSTEMS Can Be Used For Critical Functions, Such As Shear Rams Figure 9.6 PILOT FLUID CIRCUIT 3-POSITION FUNCTION Figure 9.6 PILOT FLUID CIRCUIT 3-POSITION FUNCTION SECTION 9 SUBSEA BOP CONTROL SYSTEMS amp MARINE RISER SYSTEMS

Idealised Leakoff Test Curves

SECTION 1 FUNDAMENTAL PRINCIPLES OF WELL CONTROL Working example of leak-off test procedure floating rigs Operational Drilling Procedures for Floating Rigs is designed to determine the equivalent mud weight at which the formation will accept fluid. This test is not designed to break down or fracture the formation. This test is normally performed at each casing shoe. Prior to the formation leak-off, have handy a piece of graph paper see graph 1 , pencil and straight edge ruler . Utilising the...

Connection

Connection gases are measured at surface as a distinct increase above background gas as bottoms up occurs after a connection. Connection gases are caused by the temporary reduction in effective total pressure of the mud column during a connection. This is due to pump shut down and the swabbing action of the pipe. In all cases, connection gases indicate a condition of near balance. When an increase trend of connection gases are identified, consideration should be given to weighting up the mud...

Mfc Control Console

Offshore Drilling Mud Gas Separator

To prevent loss of hydrostatic pressure it is necessary to fill the hole on a regular schedule, or continuously, using a trip tank to keep the track of the fluid volume required. The metal volume of the pipe being pulled can be calculated, but mud additions necessary to replace hole seepage losses due to filtration effects can only be predicted by comparison with the mud volumes required to keep the hole properly filled on previous trips. For this reason, it is import that a record of mud...

Example Closing Forces In Relation To Area

Bop Ram Closing Ratios

A When closing the well in on a floating rig the hard shut in method is usually applied. The string is picked up say 20' off bottom, the rotary table or top drive is shut off and both pumps are shut down. The annular preventer is then closed and the fail-safe's opened against a closed choke. b The tool joint is then spaced out for the correct pipe rams. c The string is stripped down until the tool joint is hung off' on the rams. The correct operating pressure to set on the manifold regulator is...

Use The Pod Selector Valve To Operate The System On The Other

If the leak does not stop then it must be located either in the hydraulic control manifold or downstream of the subsea control pods if the leak does stop then it will be known which side of the system it is in Further checks would then be as follows -If the Leak Stops - assuming conditions permit, switch back to the original pod and block each function in turn allow plenty of time for the function to operate and check the flowmeter on each operation if the leak stops when a particular function...

Soft Shutin Procedure While Drilling On A Fixed

When any indications are observed, while drilling, that the well may be flowing, stop rotating the drill string, raise the drill string with pumps on until tool joint is above the drill floor. 2. Stop pumps and check for flow, if positive 5. Close choke. If the choke is not a positive closing choke then close a valve downstream of choke. 6. Call supervisors and commence plotting a graph of shut in drill pipe pressure. Check pit volume gain. 7. Refer to A.P.I. R.P. 59 section 3.8 for the...

Failure To Keep The Hole Full During A Trip

Trip Tank Drilling

If the fluid level in the hole falls as pipe is removed a reduction in bottom hole pressure will occur. If the magnitude of the reduction exceeds the trip margin or safety overbalance factor a kick may occur. The hole must be kept full with a lined up trip tank that can be monitored to ensure that the hole is taking the correct amount of mud. If the hole fails to take the correct mud volume, it can be detected. A trip tank line up is shown in Fig 2.5. Figure 2.5 CONTINUOUS CIRCULATING TRIP TANK...

Maximum Head Available Developed By This Height Of Fluid

Well Control Equipment Degasser

Eg 10 foot HEAD AT 1.5 SG GIVES 6.5 psi MAXIMUM CAPACITY 8 NOMINAL 'U' TUBE 2 DRAIN OR FLUSH LINE The height and diameter of an atmospheric separator are critical dimensions which affect the volume of gas and fluid the separator can efficiently handle. As the mud and gas mixture enters the separator, the operating pressure is atmospheric plus pressure due to friction in the gas vent line. The vertical distance from the inlet to the static fluid level allows time for additional gas break-out and...

Kick Behaviour

A Comparison Between Oil and Water Base Muds Due to high temperatures and pressure a small gas kick can turn into a serious well control problem with oil base muds. Solution gas can become dissolved and miscible. The reason for this is that the gas remains in solution until it reaches its bubble point. In the same way that gas in a disposable lighter remains in its liquid phase until the pressure is relieved. In fig 3.4a three barrels of mud have entered the wellbore at 10,000 ft, but we would...

Hydril Ram Blowout Preventers Features Refer to Fig and

The Ram Body Casting has controlled and predictable structural hardness and strength throughout the pressure vessel. Hydril pressure vessel material has equal strength along all axes to provide reliable strength and resistance to sulphide stress cracking in hydrogen sulphide service. 2. The Ram Assembly provides reliable seal off of the wellbore for security and safety. The Ram accommodates a large volume of feedable rubber in the front packer and upper seal for long service life. 3. The...

Spherical Blowout Preventers

Shaffer Spherical Blowout Preventer

Shaffer Spherical blowout preventers are compact, annular type BOP's which reliably seal on almost any shape or size kellys, drill pipe, tool joints, drill collars, casing or wireline. Sphericals also provide positive pressure control for stripping drill pipe into and out of the hole. They are available in bolted cover, wedge cover and dual wedge cover models. There are also special lightweight models for airlifting and Arctic models for low temperature service.

Overview

Fig 9 .1 shows the general arrangement. Fluid used to operate the functions on the BOP stack is delivered from the hydraulic power unit on command from the central hydraulic control manifold. This contains the valves which direct pilot pressure to the pilot valves in the subsea control pods and which are operated either manually or by solenoid actuated air operators. In this way the manifold can be controlled remotely via the actuators from the master electric panel usually located on the rig...

Gas Migration When Gas In Solution

Well Control problems can result in blowouts because of the solubility of certain gases in specific types of mud e.g. Methane dissolves in oil base mud, and S dissolves in water base mud. This fact makes it more difficult to detect a kick. A large gas influx entering the wellbore may change the pit level very little if the gas dissolves in the mud. The influx is then circulated up the wellbore in the mud column, until the hydrostatic pressure on top of the gas decreases to a certain point then...

Choke Manifold Pressure

Ph 5200 psi in annulus PUMP AT KILL RATE HOLDING CONSTANT KILL LINE PRESSURE READING CHANGE IN BHP 0 psi increase SECTION 1 FUNDAMENTAL PRINCIPLES OF WELL CONTROL It is extremely important to note that regardless of which method is used, they both accomplish the goal of maintaining constant bottom hole pressure equal to formation pressure, just as would be the case were CLFL absent. This is done without the need to alter any calculations on the kick sheet. Thus initial and final circulating...

Choke Bean Wrench

Flared Orifice entrance reduces erosion on the entrance surface. Accuracy levels are maintained over extended periods of use. Choke beans save time and money because replacement intervals are extended. Cameron K choke beans come in two styles, positive and combination. The positive bean has a fixed orifice diameter. The combination bean has a fixed diameter and a throttling taper at the entry. The combination bean is used with an adjustable choke needle to make incremental changes to orifice...

Swabbing And Surging

Swabbing is when bottom hole pressure is reduced below formation pressure due to the effects of pulling the drill string, which allows an influx of formation fluids into the wellbore. When pulling the string there will always be some variation to bottom hole pressure. A pressure loss is caused by friction, the friction between the mud and the drill string being pulled. Swabbing can also be caused by the full gauge down hole tools bits, stabilisers, reamers, core barrels, etc. being balled up....

Extracts From Api Rp Closing In Kicks

For a soft close-in, a choke is left open at all times other than during a well control operation. The choke line valves are aligned such that a flow path is open through the choking system, with the exception of one choke line valve located near the blowout preventer. When the soft close-in procedure is selected for closing in a well the 1 choke line valve is opened, 2 blowout preventer is closed, and 3 choke is closed. This procedure allows the choke to be closed...

Type Gl Psi Annular Blowout Preventers Patented

Lifting Eye Bolt For The Hydril Element

Hydril GL Annular Blowout Preventers are designed and developed both for subsea and surface operations. The GL family of BOPs represents the cumulation of evolutionary design and operator requirements. The proven packing unit provides full closure at maximum working pressure on open hole or on virtually anything in the bore - casing, drill pipe, tool joints, kelly, or tubing. Features of the GL make it particularly desirable for subsea and deep well drilling. These drilling conditions demand...

Annular Preventers

Anular Hydril

In the unique design of the Cameron DL annular BOP, closing pressure forces the operating piston and pusher plate upward to displace the solid elastomer donut and force the packer to close inward. As the packer closes, steel reinforcing inserts rotate inward to form a continuous support ring of steel at the top and bottom of the packer. The inserts remain in contact with each other whether the packer is open, closed on pipe or closed on open hole. Other features of the DL BOP include The...

Figure Accumulator Sizings

The volume of the accumulator system as calculated by using Boyle's law P1 Maximum pressure of the accumulator when completely charged P2 Minimum pressure left in accumulator after use. Recommended minimum is1200 psi V Total volume of accumulator fluid and nitrogen VI Nitrogen gas volume in accumulator at maximum pressure P1. V2 Nitrogen gas volume in accumulator at minimum pressure P2. V2 V, plus usable fluid maximum to minimum pressure. V2-V1 Total usable fluid with safety factor usually 50...

Type Shear Rams

Shear Rams Type Hydril

Type 72 shear rams shear pipe and seal the well bore in one operation. They also function as blind or CSO complete shut-off rams for normal operations. The hydraulic closing pressure required to shear commonly used drill pipe is below 1,500 psi for BOP's with 14'' pistons. These pistons are standard in all BOP's rated at 10,000 psi working pressure and higher. On lower pressure preventers, optional 14 pistons can be supplied for shearing instead of the standard 10 pistons. When shearing, the...

Marine Riser Flexible Joint Ball Joint

9.2.8 A flexible joint is used in the marine riser system to minimise bending moments, stress concentrations, and problems of misalignment engagement. The angular freedom of a flexible joint is normally 10 degrees from vertical. A flexible joint is always installed at the bottom of the riser system either immediately above the remotely operated connector normally used for connecting disconnecting the riser from the blowout preventer stack, or above the annular preventer when the annular...

Control Fluid Circuit

Bop Control System Schematic

In addition to the control fluid circuits used to operate stack functions such as ram or annular preventers, the control system must also perform other functions such as control of subsea regulators, provide readback pressures, latch unlatch the subsea control pods and charge the subsea accumulators. Fig 9.4 shows a typical control fluid circuit. The hydraulic fluid is mixed, pressurised and stored in accumulator bottles by the hydraulic power unit. A pilot operated accumulator isolator valve...

Automatic Opening To Diverter Lines As Bag Closes

Riser Annulus Vent

Figure 6.3.3 Example diverter with annular packing element Figure 6.3.3 Example diverter with annular packing element Figure 6.3.4 Example diverter with insert - type packer Figure 6.3.4 Example diverter with insert - type packer Figure 6.3.5 Example diverter with rotating stripper Figure 6.3.5 Example diverter with rotating stripper Figure 6.3.6 Example diverter systems - Integral sequencing Figure 6.3.6 Example diverter systems - Integral sequencing

Balance Of Pressures

Well Control Pressures

Once the well is shut-in providing nothing has broken down, the pressures in the well will be in balance. What is lacking in hydrostatic head of fluid in the well is now being made up by surface applied pressure on the annulus and on the drill pipe. Providing the bit is on bottom and the string is full with a known mud density this allows us to determine what the formation pressure is and hence what kill mud weight is required to achieve balance. On the drill pipe side of the U-tube. Figure 5.1...

The Drillers Method

Driller Method Well Control

In the Driller's Method, the kick is circulated out of the hole using the existing mud weight. The mud weight is then raised to the required level and circulated around the well. Two complete circulations are thus required, as a minimum, for this method. Since it deals separately with the removal of the kick and the addition of kill weight mud, it is generally considered to be the simplest of well control methods, and it requires least arithmetic. However, this results, in the well being...

Secondary ram shaft seal

1 Manual-lock piston in open position Locking shaft 2 Manual-lock piston in closed and locked position Locking shaft 2 Manual-lock piston in closed and locked position 2 Poslock piston in closed position 3 Manual-lock piston in closed position 3 Manual-lock piston in closed position

Workshop

Convert the following mud densities into pressure gradients. 2. Convert the following gradients into mud densities. 3. Calculate the hydrostatic pressure for the following. a. 9.5 ppg mud at 9000ft MD 8000 ft TVD _ b. 15.5 ppg mud at 18000ft TVD 21000ft MD _ c. 0.889 psi ft mud at 11000ft MD 9000ft TVD _ 4. Convert the following pressures into equivalent mud weights in PPG. c. 12000ft MD 10500ft TVD with 9000 psi High bottom hole temperatures could affect the hydrostatic pressure gradients...

Special Features

Blind Ram Bop

To change the rams, apply opening hydraulic pressure to move the rams to the full open position. Remove the door cap screws and swing the door open. Remove the ram from the ram shaft and replace it. It is not necessary to apply closing hydraulic pressure to move the rams inward to clear the door. Door seals on most sizes have a hard backing moulded into the rubber. This fabric and phenolic backing prevents extrusion and pinching at all pressures to assure long...

Inside Bops

Gray Valve Well Control

The drill pipe float valve and the flapper type of back pressure valve, serve essentially the same purpose, but differ in design. These valves provide instantaneous shut-off against high or low back pressure and allow full fluid flow through the drill string. Another advantage is that it prevents cuttings from entering the drill string, thus reducing the likelihood of pulling a wet string. Abnormal pressures and anticipated subnormal pressure zones should be the deciding factor regarding what...

Close Function

Function The Well Control

In Fig 9.3a one of the BOP rams is being closed using the drillers master control panel. Pushing the 'close' button on this panel actuates the solenoid valves on the hydraulic manifold thus allowing air pressure to move the pilot control valve to the 'close' position. The solenoid valve on the right in the diagram vents the other side of the air cylinder. With the pilot control valve in the 'close' position, pilot fluid at 3000 psi is sent down the umbilical to the RAMS CLOSE SPM valve in the...

Figure

Annular Preventer

Figure 6.3.9 HYDRIL ANNULAR PREVENTER - TYPE MSP - 2000 PSI Figure 6.3.9 HYDRIL ANNULAR PREVENTER - TYPE MSP - 2000 PSI 1. Will close on open hole and hold 2000 psi but not recommended . 2. Primary usage is in diverter systems. 3. Automatically returns to the open position when closing is released. 4. Sealing assistance is gained from the well pressure. 5. Greater stripping capability of the packing unit since fatigue wear occurs on the outside of the packing unit.

Kick Tolerance Exercise

A well has a TVD of 14500 ft with the casing shoe at 13200 ft TVD. The fracture gradient is 0.87 psi ft and the current mud is 15.3 ppg. There is 700 ft of 6 1 2 OD drill collar and the open hole diameter is 8 1 2, with 5 drill pipe. 1 Calculate the kick tolerance if the well is shut-in with the current mud and a SIDPP of 570 psi. 2 Calculate the kick tolerance for a swabbed kick when the mud weight is equivalent to the formation pore pressure. 1 MAASP Gfrac - GM x DShoe GM 15.3x 0.052...

Pod Select Valve

Spm Valve Pod Subsea

ACCUMULATOR psi REGULATOR psi VENT psi Figure 9.2 SUBSEA CONTROL SYSTEM - BLOCK DIAGRAM ACCUMULATOR psi REGULATOR psi VENT psi Figure 9.2 SUBSEA CONTROL SYSTEM - BLOCK DIAGRAM SECTION 9 SUBSEA BOP CONTROL SYSTEMS amp MARINE RISER SYSTEMS The power fluid is routed to the subsea control pod selected by the pod selector valve which is located in the central hydraulic control manifold. The line to the non-selected pod is vented. When power fluid reaches the pod, it is combined with fluid stored at...

Test Plugs And Test Joints

Several makes of test plugs are available for testing preventer stacks. The testing tool arrangement should provide for testing the bottom blowout preventer flange. Test plugs generally fall into two types, hanger type and cup type. a. The hanger type test plug has a steel body with outer dimensions to fit the hanger recess of corresponding types of casinghead. An O-ring pressure seal is provided between the tester and the hanger recess refer to Figs 7.A.1 and 7.A.2 . The...

Increase In Cutting Size And Shape

In transition zones or in abnormally pressured shales sandy shales and bedding sand streaks the shales break off and fall into hole because of under balanced condition pore pressure greater than mud hydrostatic pressure . Water wetting may further aggravate this problem. Changes in the Shape of Shale Cuttings can occur as an underbalanced situation is developing. The particles are often larger and may be sharp and angular in the transition zone. Extra fill on bottom may coincide with the trend...

Profile of Circulating and Annular Pressure While Killing by Drillers Method

Determination of Initial Circulating Pressure If no slow circulating rate pressure has been taken, then the initial circulating pressure can be determined using the start-up procedures described in the circulations of the Driller's Method. Where the casing pressure has been held constant while the pumps are brought up to a kill rate, the drill pipe pressure reading will be the initial circulating pressure. WARNING the existence of a predetermined kill rate gives rig personnel a wrong impression...

Accumulative Volumes

After 15' stripped pressure at 460 psi After 15' stripped pressure at 510 psi After 15' stripped pressure at 560 psi After 15' stripped pressure at 460 psi After 15' stripped pressure at 510 psi After 15' stripped pressure at 560 psi Allow casing pressure to increase to calculated Pchoke pressure while stripping first stand, then hold casing pressure constant by bleed off at choke. Note The casing pressure may not rise straight away because the gas has to be compressed. It may take 2 - 3 stands...

The Hard Shutin Procedure On A Floating

When any indication is observed while drilling that the well maybe flowing, stop rotating the drill string, raise drill string with pumps running and space out for hang off rams. 2. Stop pumps and check for flow, if positive 3. With compensator at mid-stroke close annular or pipe rams. 4. Open fail-safe valves on the choke line. 5. Call supervisors and commence plotting a graph of shut in drill pipe pressure. Check pit volume gain. 6. If rams have been closed then reduce manifold pressure,...

Workshop Netwas

The following questions 1-5 refer to the first stage of the Drillers Method. 1. A well was shut-in on a kick that occurred whilst drilling. During the first circulation of the Drillers Method, the choke operator maintains a constant drill pipe pressure at a constant pump speed. 2 . Referring to the question above, the choke operator has not taken into account the large volume of the surface lines, i.e. from the pump to the rig floor. This will result in a. An increase in bottom hole pressure b....

Subsea Bop Control Systems Introduction

Every component in a blowout preventer assembly is operated hydraulically by moving a piston up and down or back and forth. Thus the function of a BOP control system is to direct hydraulic fluid to the appropriate side of the operating piston and to provide the means for fluid on the other side of the piston to be expelled. On land, jack-up or platform drilling operations the control of the BOP is easily achieved in a conventional manner by coupling each BOP function directly to a source of...

Early Warning Signs

The alertness in determining early warning signs in well control is of the upmost importance to wellbore safety. Careful observance and positive reaction to these signs will keep the well under control and prevent the occurrence of a well flow situation. The various signs that have been recorded as early warning indicators are not consistent in all situations. The signs however may have to be used collectively as one indicator may not accurately provide the warning of getting into an unbalanced...

The Fast Shutin Procedure On A Floating

When any indication is observed while drilling that the well maybe flowing, stop rotating, raise drill string with pumps running and space out for hang off rams. 2. Stop pump and check for flow, if positive 3. Open fail-safe valves on the choke line. 4. With compensator at mid-stroke, close annular. 5. Call supervisors and commence plotting a graph of shut in drill pipe pressure, check pit volume gain. 6. Close hang off rams with reduced pressure, reduce annular pressure, slack off and land...