Mud Report

Dr. Catalin Teodoriu

Institut fr Erdl- und Erdgastechnik 1TBT I 2014

Vorlesung Tiefbohrtechnik 1

Introduction to Rotary-Drilling Technology (inc. Rig Count)

Drilling a Well, Drilling methods

Rock Mechanics I

Drilling Mud: Functions, Properties, Rheology

Rock Mechanics II, Well stability

Borehole hydraulics, Overbalance vs. Underbalance

Drilling bits, Selection criteria

Drilling optimisation concepts

Drill-string basics

Downhole motors I (Theory, Moineu Motoren)

Downhole motors II (Turbinen, Selection Criteria)

Special drilling systems (Drilling Hammer, Coring)

Formation pressure, Frac-gradienten

Measuring drilling parameters



INTRODUCTION:

Accurate Pore Pressure Prediction (PPP) is the basis for:

Drilling fluid density. Well Safety. Rapid Drilling Rate. Prevention of Kicks. Selecting Casing Setting Depths. Cement Slurry Density. Avoid Lost Circulation



PORE PRESSURE PREDICTION TECHNIQUES

Before Drilling.

During Drilling.

After Drilling.



BEFORE DRILLING

Seismic Method of Pore Pressure Prediction

A pre-drill estimate of pore pressure can be obtained from seismicvelocities given a suitable velocity to pore pressure transform.



Eaton Method:

Eaton method which direct transform from velocity to pore pressure

Pp = Pobs (Pobs Phyd) x (Vi/Vn)

Pp = Predicted pore pressure

Pobs = Overburden pressure (rocks and

fluids)

Phyd = Hydrostatic pressure

Vi = Interval Velocity (seismic data)

Vn = Normally compacted shale velocity

The Bowers Method:

Bowers method assess the effectivestress from the velocities and calculate

pore pressure.



Uncertainties in pore pressure from seismic data is reduced by information

while drilling : sonic log, mud weight, and pore pressure data.

Source: www.cggveritas.com



DURING DRILLING

Using Logging while drilling method.

Using d-Exponent method.



Equation used for measuring d- Constant

d-Exponent Equation

Well Engineering & Construction by Hussain Rabia

d



D-Exponent Method

d = d exponent

dc = corrected d exponent

ROP= Rate of penetration.

RPM= Rate per minute.

WOB= Weight on bit.

B= Diameter of the bit



Procedure to determine dc

Plot dc value on a semi-log paper against depth.

Establish the normal pressure trend line through dc value corresponding to known clean normally pressured shale.

Plot the actual dc value alongside the trend line.

Calculate the pore pressure using Eaton Method and Ratio Method



Plot of depth and dc exponent




Equations

Eaton Method:

Ratio Method



AFTER DRILLING:

It based on Well Logging like Resistivity, Density which depend upon:

Porosity measurements

Salinity of pore water.

Temperature.



CONCLUSIONS

In order to determine which type analysis is adequate, it is necessary toconsider structure of area, the faults, salt bodies, lithology and evaluate

quality of seismic data.

During drilling we can used D exponent, which will help in knowing thepore pressure.

Understanding Pore and Frac Pressure helps reducing well controlproblems and optimizing drilling operations



Measuring drilling parameters

It is necessary at all time to know the bit position and well trajectory (path)

WHY?



Terminology

4

Inclination Angle

q, a, I

Direction Angle

f, e, A



Types of directional wells

12

Type I Type II Type III

Build

and Hold

Build-Hold

and Drop

Continuous

Build

KOP

EOC



Kickoff Methods

35



Survey Methods

Single-Shot



Survey Methods

Multishot



Survey Methods

Steering Tools



Survey Methods

MWD



Drilling Parameter describing well path: I, A, DMD



Building Hole Angle



Holding Hole Angle



Pendulum Effect

Mud Report

Documents

Transcript of Mud Report