class10-11upg2014

WS UPG 2013 -2014

Ingineria exploatarii optimale a utilajului petrolier

By Dr. C. Teodoriu

UPG 2014, Dr. Dr. –Ing. habil. Catalin Teodoriu

Ingineria exploatarii optimale a utilajului petrolier

Drilling Concepts, Drilling Optimization

By Dr. C. Teodoriu


Outcomes

At the end of this lecture, you will be able to;

- Understand the costs involved in drilling operation

- Understand the meaning of RISK in drilling and fishing

- Calculate when to quit fishing operations, calculate the cost per foot


Well Integrity Concept

Well Planning

Virtual

Well

Simulations

Well

Construction

Quality

assurance

Re-

evaluation

Well Exploitation

Well

monitoring Repair


Well Components

Casing-cement system

Well head complex

Production tubing

and completion


Barrier Terminology, D-010 Well Integrity in Drilling and Well Operations, Presentation from 07.09.2004

Working Well Barrier Stage:

This is the stage which shows the well barrier elements that

are used to confine the pressure in a normal working mode.

Example: Closed CT strippers + CT body + surface test tree w. closed wing valve, +++

Intermediate Well Barrier Stage:

This is the stage(s) of a well barrier element activation

sequence before the ultimate well barrier stage is reached.

Examples: Leak in CT strippers – close CT pipe rams.

Ultimate Well Barrier Stage:

This is the final stage of a well barrier element activation sequence which normally

includes closing a shearing

device. Example: Closed CT shear ram (primary

barrier) or closed master valve (secondary barrier),+++

Primary Well Barrier:

This is first object that prevents flow from a source.

Example - blue items: Strippers + CT BOP+ surface test tree,+++

Common Well Barrier Element:

This is a barrier element that is shared between primary and

secondary barrier. Examples: Body of LRP, X.mas tree and

production wing valve

Well Barrier Element: An object that alone can not prevent flow from one side to

the other side of itself. Example: CT BOP

Secondary Well Barrier: This is the second object that prevents flow from a source.

Example - red items: Lower riser package + production tree + wellhead,+++


4) NOTE:

Legend:

1. This describes the name of the well barrier elements.

2. A complete description of general acceptance criteria for this barrier element is found in

Clause 15, which contains a library of Well Barrier Element Acceptance Criteria tables.

3. This table column is used to describe comments.

4. The place can be used for describing additional requirements and guidelines. For example a

description of compensative measures if there exist common barrier elements.

5. The illustration shows the primary barrier in its normal working stage, while the secondary

barrier is shown in its ultimate stage. This stage often described with a closed shearing device.

5.

Well

Barr

ier

Sch

em

ati

cs

1) Well barrier elements

See Table

2)

3) Comments

Primary well barrier

1. Fluid column 1

Secondary wellbarrier

1. Casing cement 22

2. Casing 2 Last casing set

3. Wellhead 5

4. High pressure riser 26 If installed

5. Drilling BOP 4


Risk Assessment of Drilling Projects

1. Introduction

2. Definition

- Kind of Risks

- Development of Risk Assessment

- Methods of Risk Assessment

3. General Conditions of Risk Assessment

External Conditions

Internal Conditions

4. Example

Risk Assessment to compare different Projects

Risk Assessment for a certain Drilling Project


What is a Risk?


Risk Workshop Frequency Assessment Guidelines


Chances and Dangers


Kind of Risks

Geological Risks

Technical Risks

HSE Risks

(Health, Safety & Environment)

Financial Risks

Human lives!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!


Development of Risk Assessment

Deterministic Analysis Stochastic Analysis

Risk Assessment


Decision –Tree


Spider Diagram for a Diesel Powered Vehicle


General Conditions of Risk Assessments

External

Conditions:

Governmental Regulation

Non – Governmental

Relations

Internal

Conditions:

Economical Forces


Trend lost in Time incident Frequency (LTIF) per region


How to Tackle Corporate Problems?


The Two Questions:

Is the project viable?

Which options of the chosen

project is the favourable?


Price Sensitivity of three Example Projects


Scenario Analysis of three Example Projects


Example Well Design Options


Casing Option 1


Casing Option 2


Comparison of three Casing Options


Decison Tree – Definition

A decision tree maps out the result of different decisions which can be

made.

It helps to select the best way to proceed in a situation when the

outcomes are uncertain.

It uses values and probabilities to calculate

Effective Monetary Value


Decision Tree 1


Decision Tree: Exercise New Game

Now instead of either winning or not losing money you have a different

game: win $ 100 or lose $ 110

Would you play this game?


Decision Tree: Answer

EMV = (0.56 x 100) + (0.44 x (- )) =

I Would!


Decision Tree 2


Fishing Decision Tree

A decision tree is used to evaluate the Effective Monetary Value (EMV) of

different courses of action.


Decision Tree if Fail on the First Day


Some Rules of Thumb

Fishing economics become secondary when radiactive sources are in the

fish.


Project Time Breakdown – Texas


Project Time Breakdown – Senegal


Project Cost Breakdown – Texas


Drilling Concept – think different!!!


Drilling Optimization Using Different Drilling Concepts


Drilling Optimization


ROP

Optimization


How to Improve Bit Life – Optimized BHA Design


Central Jet System

Standard Diverting Mini Extended

Jet Nozzles Optimization


Drill Bit Optimization

Recommended rotary speed for core bits (Courtesy Hughes Christensen)


Drill Bit Optimization

Bit weight for core bits (Courtesy Hughes Christensen)


Drill Bit Specifications

Critical rotary speed for core bits

(Courtesy Hughes Christensen)


Feet per Day vs. Effective ROP, SPE 50557


Interval length vs. Bits per Interval, SPE 50557


Drill Path Optimization

Plan view of application B shows the comparison between

optimized GA design and conventional design


Source: Bit Optimization for the Shetland in Hydro’s

Oseberg south Field, SPE Bergen, April 2004


Increase exponentially with depth.

Thus, when curve-fitting drilling cost data, it is often to assume a

relationship between total well cost, C, and depth, D, given by:

Drilling Costs


When major variations are not present in the subsurface lithology, the

penetration rate usually decreases exponentially with depth. Under these

conditions, the penetration rate can be related to depth, D, by:

Where K and a2 are constants.

Penetration Rate


The Drilling time td, required to drill a given depth can be obtained by

separating variables and integrating.

Seperating variables gives;

Integrating and solving for td yields

Drilling Time

Cf = drilling cost, $/ft

Cb= cost of bit, $/bit

Cr= fixed operating cost of rig, $/hr

tb= total rotating time, hrs

tc= total non-rotating time, hrs

tt= trip time (round trip), hrs

= footage drilled with bit, ft D

ft

$

D

)ttt(CCC

tcbrbf

The Drilling Cost Equation


Cost per ft for one entire bit run


Can pull bit after about 25 hr. ($42.50/ft)

- The precise pulling time is not critical

- Note that the cost in dollars per foot was $43.00 after 30 hr

Primarily applicable to tooth – type bits where wear rate is predictable

Economic Procedure


Also used with tungsten carbide insert bits when inserts are brolken or

pulled out of the matrix

Unfortunately, wear rate with insert bits is unpredictable

Economically, the insert bit should be pulled when the

cost in $/ft begins to increase

Economic Procedure


Bits pulled for economic reasons make it hard to obtain

wear information

Operator might pull bit after 120 hr of use but part of bit

might get left in hole.

Recovery is difficult. AVOID!

75% of rock bits are pulled green or before the bit is worn

out

Economic Procedure


Variables:

-Type of Drill Bit

-Bit weight

-Rotary speed

-Bottom-hole cleaning

-Mud properties

Fixed factors:

-Rock hardness

-Formation pore pressure

Factors Affecting Penetration Rate


Evaluate whether to fish or sidetrack?

- Assume one fishing attempt cost $60,000

- Assume sidetrack cost is $500,000

- Assume probability for success first attempt is 60%

- Assume probability for success second attempt is 40%

- Assume probability for success third attempt is 30%

Exercise


EMV = probability of success time cost of fishing plugs probability of

failure times cost of failure of even event plus side track cost

EMV first attempt = .6 x $60k +.4 x $560k = $260k

- Since EMV < ST decide to fish

EMV second attempt = .4 x $120k +.6 x $620k = $420k

- Since EMV < ST decide to fish

EMV third attempt = .3 x $180k +.7 x $680k = $524k

- Since EMV > ST don´t fish third time

Fishing Exercise Results


OFT = Time at which the fishing problem occured until

fishing should stop

Based on complex statistical studies of historical data, the

OFT can be calculated

Suprisingly, OFT is independent of location and

independent of the nature of the problem

Optimum Fishing Time (OFT)


Calculate the OFT

SPE 22380


All time depent fishing costs = $48,000/day = $2,000/hour

Cost of sidetracking to the same depth = $750,000

Example

class10-11upg2014

Documents

barrier stage

barrier schematics

common barrier elements

teodoriu upg

ultimate stage

catalin teodoriu outcomes

final stage

ct bop secondary