• UBD is defined as drilling operations where the drilling fluid pressure in the borehole is less than the pore pressure in the formation rocks.

1. Hawler Petroleum Institute
Drilling Department
Drilling Services
Underbalanced Drilling Equipment
Prepared by :
Shivan A.Sabir
Second Stage
Group : D

2. Underbalanced Drilling Services
Definition :-
• UBD is defined as drilling operations where the drilling fluid
pressure in the borehole is less than the pore pressure in the
formation rocks.
• During underbalanced operations,specific techniques and
equipmentare used for handling and controlling the formation
fluids influx to the wellbore and lifting up to the surface.
AIM OF UBD :-
 To minimize drilling problems.
 To optimize hydrocarbons recovery

3. Advantages of UBD :-
1. Reduce formation damage / increase productivity.
2. Minimize loss of circulation.
3. Increase ROP.
4. Eliminate pipe differential sticking.
5. Improve formation evaluation.
6. Reduce stimulation requirements.
7. Prolong bit life.
Disadvantages of UBD :-
1. Expense.
2. Safety Concern.
3. Wellbore Instability.
4. Sever Formation Damage.

4. Underbalanced Drilling Equipment:
Have Two Typeof UBD Equipment:-
1. Key Tools .
2. Other Tools.
1. Key Tools :-
1.Rotating Control Head .
2.Chokes .
3.Non Return Valve.
2.Other Tools:-
1. Downhole Deployment Valve.
2. ECD Reduction Tool.
3. Coriolis Flow Meter .
4. Downhole Air Diverter.
5. Nitrogen Generation Unit .
6. Multiphase Separation System.
7. Real-time Pressure and Flowrate Monitoring .
8. Continuous Circulation Valve.

5. Rotating Control Head :-
Rotating control head technology has become an important tool for lowering
drilling costs and increasing well productivity, especially in many hard-rock
areas and mature oil and gas fields.
Lower drilling costs are achieved primarily by the faster penetration rates,
reduced nondrilling time, and reduced mud volume requirements associated
with underbalanced drilling.
Greater well productivity can sometimes be obtained because of reduced
formation damage from mud. Recent advances in rotating head technology
have increased the range of well conditions to which this technology can be
applied. In addition, rotating control heads are being used for enhanced
safety and environmental protection in areas where underbalanced drilling is
not currently feasible.
Approximately one-fourth of the rigs working in the U.S. and Canada today
use a rotating control head at some point during the drilling program.
Chokes :-
A device incorporating an orifice that is used to control fluid flow rate
or downstream system pressure. Chokes are available in several
configurations for both fixed and adjustable modes of operation. Adjustable
chokes enable the fluid flow and pressure parameters to be changed to suit
process or production requirements. Fixed chokes do not provide this
flexibility, although they are more resistant to erosion under prolonged
operation or production of abrasive fluids

6. Non Return Valve:-
A non-return valve allows a medium to flow in only one direction. A non-return
valve is fitted to ensure that a medium flows through a pipe in the right
direction, where pressure conditions may otherwise cause reversed flow.
A non-return valve can be fitted to ensure that a medium flows through a pipe
in the right direction, where pressure conditions may otherwise cause
reversed flow. A non-return valve allows a medium to flow in only one
direction. The flow through the non-return valve causes a relatively large
pressure drop, which has to be taken into account when designing the
system.
There are different types of non-return valves, such as spring-loaded, swing
type, and clapper type valves. Non-return valves are e.g. used with mixing
loops in heating and cooling systems to ensure proper operation, and with
domestic water systems to prevent backflow.
Downhole Deployment Valve:-
Underbalanced drilling is a specialized drilling technique in which the bottom
hole pressure exerted by the hydrostatic head of the wellbore fluid column is
less than the pressure of the formation being drilled.
The downhole deployment valve (DDV) allowed rig personnel to trip the
drillstring out of the well twice, during and following underbalanced drilling
operations for the horizontal laterals, without pumping kill fluids to control
3,400-psi reservoir pressure.

7. ECD Reduction Tool:-
High equivalent circulation density (ECD) is responsible for many wellbore
pressure-related problems during drilling. Proper wellbore pressure
management is a critical part of normal drilling practices, where static and
dynamic fluid pressures are used to contain formation pressures and assure
wellbore stability. Excessive fluid pressure while circulating can create
problems including reduced operating margins between fracture and pore
pressures and, in the extreme, lost circulation. To address these problems, an
ECD Reduction Tool (ECD RT) is being developed.
The ECD RT is designed to counter downhole pressure increase due to
friction in the annulus by reducing the hydrostatic head. The tool is expected
to have a broad range of drilling applications including the narrow
pore/fracture pressure margin in the deepwater environment, wellbores prone
to instability, pressure depleted reservoirs and extended reach wells. The
ECD RT will also potentially reduce the impact of uncertainty when selecting
casing setting depth by widening the usable margin between pore pressure
and fracture gradient.
Downhole Air Diverter:-
A down hole air diverter having a first opening in communication with the
central passageway of a drillstring; a second opening in communication with
the well bore annulus; and a means to control the flow of pneumatic fluid
between the first opening and the second opening. The means to control the
flow further includes a first sealing means and a first biasing means to control
the first sealing means. The first sealing means allows communication with
the well bore annulus when the well bore annulus pressure exceeds the first
biasing means pressure and prevents communication when the bias pressure
exceeds the bore annulus pressure. A second sealing means prevents
communication with the drillstring when the pressure from the second sealing
means chamber exceeds the first opening pressure and allowing
communication when the first opening pressure exceeds the chamber
pressure.

8. Nitrogen Generation Units:-
Maximize protection and production of mature reservoirs
M-I SWACO nitrogen generation units offer nitrogen gas generation and
injection at selectable flow rates to assure purity for multiphase managed
pressure and underbalanced drilling applications.
Mobile nitrogen generation unit
Mobile nitrogen generation units (MNGUs) are mounted on a single trailer,
with full interconnection and calibration, complete with inlet and outlet
metering. They are specifically designed for rapid deployment to remote
locations. MNGUs minimize transport, rig-up and removal time, and
environmental footprint, while maximizing efficiency and maintenance. The
MNGU is the optimal, cost-effective choice for remote locations because it
facilitates nitrogen logistics, provides continuous mobility, and produces
nitrogen at high purities.
Skid nitrogen generation unit
Skid nitrogen generation units (SNGUs) are mounted in protective ISO
containers for easy, reliable handling and stacking. The SNGU includes diesel
or electrically powered motors, a membrane nitrogen generation system,
three compressors, and a booster. The electrically driven SNGU is efficiently
quiet, using a generator driven by one engine that requires less maintenance
and has a smaller carbon footprint in terms of exhaust, engine oil, and
coolant. It can be modified for use on offshore applications.
Multiphase separation system
The current disclosure relates to multiphase fluid separation via a multiphase
separation system. The multiphase separation system is configured to feed a
multiphase fluid into feed lines within the multiphase separation system,
wherein the feed lines consist of an upper line, a middle line, and a lower line.
The upper line is configured to flow a first stream substantially including oil
into an oil section of a control volume. The middle line is configured to flow a
second stream substantially including an oil/water emulsion into an oil/water
emulsion section of the control volume. The lower line is configured to flow a
third stream substantially including water into a water section of the control
volume. The control volume is configured to adjust fluid flow rate at an outlet,
wherein the oil section, the water section, and the oil/water emulsion section
each commingle at different heights of the control volume.