The purpose of this section is to describe the requirements with regard to well control standards, procedures and practices. It outlines the standards to be adopted, and describes the general procedures and practices to enable operations and engineering personnel to perform the following tasks :

  • Ensure well control equipment complies with standards.
  • Recognise and react to the signs of well kicks.
  • Ensure that personnel are trained and prepared to shut-in the well in case of a kick.
  • Plan and conduct effective well killing operations.

 

Pressure Testing of Well Control Equipment

This article describes the main requirements for Pressure Testing of Well Control Equipment.

Well Heads and BOP Equipment

Pressure tests on the ram type preventers, other BOP equipment, wellhead…

Barite Plugs

A barite plug is a slurry of barite in fresh water or diesel oil which is spotted in the hole to form a barite bridge that will seal the flow and allow control of the well to be re-established.

The…

Inflow Testing Procedure

Inflow tests are generally carried out to verify if there is communication with the formation through the casing, a liner lap or past a cement plug (bridge plug).

Most of the applications are in…

Well Control - Flowline Shows

A kick is generally recognised by an instantaneous increase in the rate of mud returns and/or an associated gain in mud volume in the active mud tanks. A flowline show (gas cut or fluid contaminated…

Calculation of Maximum Allowable Annular Surface Pressure (MAASP)

Calculation of Maximum Allowable Annular Surface Pressure (MAASP)

The Maximum Allowable Annular Surface Pressure (MAASP) equals the formation breakdown pressure at the point under consideration minus the hydrostatic head of the mud/or influx in the casing. …

Well Control Responsibilities

On both Company and Contractor-owned drilling and workover rigs (regardless of the type of contract) it is the responsibility of the Company representative to ensure that drilling operations are…

Well Control Drills and Exercises

Well Control Drills and Exercises

Three types of drills are to be exercised, one while drilling with the kelly on the string, one normally while tripping without the kelly on the string and one with the bit off bottom ie.:

Kick Drill…

Well Control - Loss of Primary Control

There are four principal causes of loss of primary control: swabbing, insuficient fluid density, losses, failure to fill the hole correctly.

1 Swabbing

Swabbing can also be caused by pulling full…

Casing, wellhead and BOP equipment tests

Casing, wellhead and BOP equipment tests

All pressure tests shall be recorded on pressure recorder charts. A record shall be kept of the volumes required to obtain the test pressure, and of the volumes returned when bleeding off.  …

Well Control - Primary Control Techniques

The following precautions should be observed to ensure that primary control is maintained, whilst tripping, circulating bottoms up after a trip, drilling and circulating on bottom.

Records:

Accurate…

Diverter equipment

Diverter equipment

The diverter is installed on top of the wellhead to enable flow from shallow formations to be diverted away from the work area in case of a shallow gas kick. However, current diverter equipment is not…

Procedure and Calculation example for Change in Circulating Rate

Procedure and calculation example for Change in Circulating Rate while circulating an influx during a well control incident.

1. Calculate the average mud weight (Wav) in the string at the time pumping…

Well Control during Logging Operations

Wireline BOPs are not normally used for open hole logging operations or cased hole operations where the Drilling BOPs are installed.  Exceptions to this rule are:

  • Open Hole logging operations…

General BOP Arrangement

A Blow Out Prevention (BOP) stack is installed on a wellhead to control the removal of an influx from the wellbore.

All pressure contained components of the BOP stack and related equipment shall be…

Well Kill Using Wait and Weight Method (Balanced Method)

The “Wait and Weight” method is the method recommended, in some circumstances, for controlling an influx taken while drilling or circulating on bottom. When drillpipe (string) volume is greater than…

Well Control - Stripping Method

This article describes the keys elements for the stripping method for well control

Discussion on Suitability of Barriers (well control)

this article discuss the suitability of barrier for the following:

  1. Fluids
  2. Mechanical Barriers in completed Wells
  3. Sub-surface Safety Valve
  4. Sustension of a perforated well (with xmas tree)
  5. Sub Sea Well…

Drill String BOP Valves

Components for shutting in the drillpipe internally are a basic part of well control equipment. All drill string BOP valves must have a pressure rating equal to, or greater than, the BOP stack.

The…

Well Control - Driller's Method

With this method, the well is killed in two circulations. During the first circulation: the influx is circulated out of the hole using the existing mud. Additional influx is prevented by adjusting the…

Blowout contingency planning

Main features of a blowout contingency plan shall include:

  • single phone call approach from the wellsite, to activate the plan. This will allow field personnel to concentrate their efforts on…

Subsea blowout prevention (BOP) equipment

The subsea BOP equipment may comprise either a single stack or a two-stack system. The single stack system is preferred. The single stack system consists of one large bore BOP stack (generally 18…

Responsibilities for Well Control

Primary well control shall be maintained at all times. In the event secondary control becomes necessary, the well shall be brought back under control as safely as possible.

For each well control…

Well Control - Combined stripping and volumetric method

When the drillstring is partially or completely out of the hole and a kick is experienced, every effort should be made to safely return the bit to bottom whilst at the same time maintaining well…

Well Control - Kick whilst tripping

If an overbalance existed prior to pulling out of hole, then the only reasons for the well to flow are:·swabbing;·failure to keep the hole full;·losses induced by surge pressures.

Early detection of…

Well Control Standards

This article describes the standards applicable for Well Control.

General Standards

  • All wells drilled shall comply with the guidelines as specified in API RP 53.
  • All pressure containing well control…

Well Control - High Pressure Wells

Kick control when drilling high pressure wells (philosophy, drilling procedure and well control equipment)

1 Well control philosophy

The BOP and surface system, including the drillstring, should be…

Well Control - Bullheading

Bullheading. If normal well killing techniques with conventional circulation are not possible or will result in critical well control conditions, bullheading may be considered. Mud/influx are…

Kicks with Casing in the BOP Stack

Well control precautions to be used when running casing.

  • Change the rams to the casing size (on surface stack) and test the BOP bonnets.
  • Prepare a circulating head.
  • Ensure a cross-over from casing to…

Classification of BOP and well control equipment.

Well control equipment falls into five basic working pressure classifications:·13,800 kPa (2000 psi) WP,·20,700 kPa (3000 psi) WP,·34,500 kPa (5000 psi) WP,·69,000 kPa (10,000 psi) WP,·103,500 kPa…

Well Control - Slim Hole Drilling

Slim Hole Drilling which, for the purpose of well control, means hole sizes of 4 3/4" and smaller, will impose certain restrictions on well killing techniques and will require well planning to take…

Mud Log Gas (background, drilled, swab, connection, trip)

 The gas readings are obtained by the mud loggers from gas analysis equipment and are classified according to the operation that releases the gas into the borehole (background, drilled,…

Installation requirements for wellhead and BOP equipment

The BOP equipment installation shall conform to the following ...

  • Wellhead equipment should withstand anticipated pressures and allow for future remedial operations.
  • Ram type preventers should be…

Well Control - H2S

During drilling and workover operations the consequences of leaks or kicks with sour gas or crude may be very serious. Personnel can be incapacitated by relatively low concentrations of H2S in a very…

Well Control Equipment and Procedures - Standards

  • All BOP equipment and drillstring equipment shall be in a serviceable and fully tested condition. BOP is to be tested as per API every 2 weeks as a minimum.
  • All Stripping drill requirements must be…

Well Control - Shallow Gas

Some areas are notorious for the presence of hydrostatically pressured gas pockets at relatively shallow depths.

1 Prediction of shallow gas

Although the location of gas pockets is difficult to…

Kicks with Drill Collars in the BOP Stack

The detection of a kick when the drill collars are in the BOP stack is a time of concern for the safety of the crew and the drilling unit as the normal methods of secondary control using the BOP’s may…

Shallow Gas - Planning Guidelines

Shallow gas is defined as any hydrocarbon-bearing zone which may be encountered at a depth close to the surface or mudline. Generally it is not possible to close-in and contain a gas influx from a…

Well Control Safety

It is the Company drilling supervisors' responsibility to ensure that all drilling and workover operations are conducted in a manner which provides safe and complete well control. In this capacity he…

Choke and Kill System

The choke and kill system shall provide the valves and piping required to allow controlled circulation of the well under pressure. The choke and kill system shall include:

  • 2 each kill and choke lines…

Hydrogen Sulphide (H2S)

Hydrogen sulphide (H2S) is one of the most toxic of all naturally occurring gases. It occurs world-wide in various concentrations in the scope of the drilling industry. It is explosive and heavier…

Well Control - Preliminary record of information

Pre-recording of information.Proper secondary well control follows a planned course of action. Pre-recording relevant information avoids unnecessary delay. The following aspects concerning the…

Well Control Procedure - While Tripping

To detect a kick while round tripping as early as possible, it shall be standard practice to use the trip tank at all times while tripping both into and out of the hole.

The Driller shall be…

Surface BOP equipment

Surface blowout prevention equipment (BOP) is that equipment used in land operations and operations where the wellhead is above the water level. Given in this article are the MINIMUM requirements for…

Pressure at the top of a Gas Influx in the Annulus using the ‘Wait and Weight’ Method

The pressure at the top of a gas bubble at any point in the annulus while circulating it out using the “wait and weight” method can be calculated as follows:

By calculating the expected…

Relief Well - Homing-In

1 Management summary

This document provides background information on the subjects of relief well planning, homing-in logging method selection, logging optimization and analysis of the obtained…

Wireline Pressure Control Equipment

A wireline pressure control assembly must be capable of shutting in on the size of wire being run, have a working pressure rating which exceeds the anticipated maximum well pressure and also allow the…

Non-conventional well control methods

Non-conventional well control methods

When the standard well control method (drillers' or weight and wait) are not suitable, alternative methods can be considered: Stripping, bullheading, volumetric, off-botton, no circulation, etc

1.…

Setting of retainers, bridge plugs and packers

Retainers, bridge plugs and packers should be set as deep as possible. With a shallow packer or plug, a higher fluid gradient will be necessary to control abnormal pressures which may build up below…

Well Control - Balanced Mud Method

In this method the well is killed in one circulation. The kick is circulated out whilst mud of sufficient density to (over) balance the pore pressure is circulated in.

Mud with a density sufficient to…

Influx Detection

A kick occurs when the hydrostatic pressure of the mud column in the well is less than the formation pore pressure, providing that the well is capable of producing. The article summarise the effects…

Well Control - Deviated and Horizontal wells

All hydrostatic pressure-related calculations should be based on true vertical depth values. This means that the standpipe kill graph of a deviated well has a different curve as compared to the graph…

Loss of primary well control - failure of riser

In floating drilling operations, an accidental disconnect or a failure of the marine riser close to the BOP stack will have a considerable effect on primary control.

The overbalance in the hole will…

Bullheading

If normal well killing techniques are not possible or will result in critical well control conditions bullheading may be considered whereby mud/influx in displaced/squeezed back into the weakest open…

Total Losses and Requirement for Continuous Fill-Up

When drilling through depleted and/or fractured reservoirs, total losses are a common occurrence.  In the worst case, if the well penetrates the top of the formation (fracture) above the gas-oil…

Maintenance and inspection of BOP equipment

General recommendations on maintenance, inspection and testing of BOP and associated equipment are presented below:

  • All BOP equipment will be certified as “fit for use” by a relevant certifying…

Cement Plugs

A cement plug can be used to shut off a downhole flow. However, this generally involves abandonment of the well and loss of most of the drilling tools. It is also likely that the string will become…

Well Control - Well Design

This article descrobes the drilling program and other Well Design considerations for Well Control

1 Drilling programme

The drilling programme is based on the information provided by the subsurface…

Well Control - Volumetric Method

Well control by the volumetric method is a technique whereby bottom hole pressure is maintained slightly in excess of pore pressure whilst the gas influx is allowed to expand as it migrates to…

Complications during well control operations

Complications during well control operations Stopping the control operation, Plugged chokes, Change in circulating kill rate, Plugged bit nozzles, Kick caused by loss of circulation below production…

Pre-Kick Planning

This article describes the planning issues to be addressed to ensure successful well control.

Kick Control Work-Sheet

A kick control worksheet shall be used to pre-record the data required for…

Application and maintenance of secondary well control equipment

The following recommendations refer to the application and maintenance of various types of other well control equipment: chole manifold,  

Inside pipe shut-off tools, Mud-gas separator and…

Well Control - Abnormal pore pressures

For exploratory well, the prediction of abnormally pressured formations can be difficult. Correlation with nearby wells will provide the most reliable information. Before drilling a wildcat, seismic …

Influx Prevention

This article highlights the guidelines which shall be followed during tripping and drilling in order to avoid taking kicks. During any open hole operation the mud level in the well shall always be…

Well Control Procedure - While on Bottom

Should an influx be detected while on bottom, the following procedure shall used:

1. RECOGNISE the kick and ALERT the crew.

2. STOP rotary table.

3. PULL BACK kelly until kelly cock is above rotary…

Problems Encountered During Well Control

Problems Encountered During Well Control

Conventional well killing procedures are based upon the basis that all of the well control equipment operates as designed and the wellbore is able to withstand the imposed pressures.

Mechanical…

Well Control Procedure - While Out of Hole

To detect a kick while the string is out of hole it is essential that drilling fluid is circulated across the well and trip tank at all times.  Automatic alarms should be set to provide early…

Well Control - Recognizing a kick and action to be taken

Recognising a kick and need for immediate action.A kick occurs when the hydrostatic pressure of the mud column in the well is less than the pore pressure of a producing formation.Drilling breaks and…

Well Kill Using The Driller's Method With The Bit On Bottom

In this method the well is killed in two circulations. In the first circulation the influx is circulated out using the original mud. In the second circulation, when weighted up mud is available, the…

Example of BOP Configuration

Example of  BOP Configuration

Examples of  BOP Configuration for the diferent hole sizes.

 

Hole Size

26in

17.1/2in / 16in

12.1/4 / 8.1/2in

6in

Workover

Diverter

fitted

fitted

 

 

 …

Fluid measuring devices

Fluid measuring devices play an important role in the casing design of a well, because the maximum anticipated influx volume is one of the parameters used to calculate maximum safe drilling and casing…