Why choose Minh Phuong Corp?

1. CONTRACTORS SUMMARY 3
2. INTRODUCTION 3
3. CONSTRUCTION RISK ASSESSMENT 4
   1. Risk Ranking of Likelihood 4
   2. Risk Ranking of Consequence 4
   3. Level of Risk 4
   4. Risk Legend 4
   5. Assessment 5
4. PROJECT GEOLOGY 8
5. DOWN HOLE SURVEY SYSTEMS 10
   1. Downhole Survey Techniques 10
   2. Survey Overview 10
   3. Survey Systems – Magnetic Steering Tool – Description 10
   4. Survey Systems – Paratrack 2 Wire Tracking – Description 10
   5. Survey Systems – A.C. Solenoid System – Description 11
6. EXECUTION 11
   1. Pilot Drilling 11
   2. Pilot Tooling 12
   3. Reaming 12
   4. REAMED HOLE SIZE 14
   5. REAMING STEPS 14
   6. REAMING RATE OF PENETRATION 14
7. PULL BACK 15
8. MUD PROGRAM 16
   1. Cuttings Treatment & Displacement Removal 16
9. FRAC-OUT MANAGEMENT 16
   1. Prevention 16
   2. Frac out management 16
   3. Frac-out Contingencies 16
10. DEMOBILISATION 17
11. PRELIMINARY CONSTRUCTION EQUIPMENT LIST 17
    1. Rig - American Augers DD440T 17
12. PRELIMINARY KEY PERSONNEL CHART 18
13. DESIGN AND CONSTRUCT SCHEDULE 18

1. CONTRACTORS SUMMARY

HDD (Thailand) Co. Ltd. is an HDD specialist with expertise in delivering technically challenging multi rig HDD projects worldwide. We strive to exceed industry standards and bring exceptional quality and value to our clients. HDDT has over 150 professionals working on projects worldwide including Asia, Australasia, and Africa. HDDT have ensured success on crossings of 42” over 1,465 metres and smaller diameters over 3,014 metres Our carefully selected specialist staff provide the highest standards of quality, safety, and environmentally considerate production possible.

HDDT’s objective is to exceed industry standards and bring exceptional quality and value to our clients. HDDT has continued involvement in every major pipeline project in Thailand since 2012 and continues to deliver the best Horizontal Directional Drilling experience.

2. INTRODUCTION

This document has been prepared to describe the methodology by which MCD/HDDT propose undertaking the site preparation, mobilization, drilling operations, pipe installation, pre-commissioning and reinstatement operations for the installation of the 6 HDD crossings on the Block B Omon Project - Onshore Pipeline. The 30” pipelines are to be installed with an additional 6” FOC duct as per the supplied alignment sheets.

Prior to construction a detailed engineering design will need to be prepared to further evaluate and determine the final design and methodology. The following method statement presents our proposal based on our understanding of the crossing requirements and may alter following the detailed design works.

3. CONSTRUCTION RISK ASSESSMENT

To provide suitable mitigation measures risks need to be properly identified, a Construction Risk Assessment has been developed to help identify constructability risk and consequences without control. The risk is measured by likelihood, consequence, and severity. Risk is then reassessed with control measures in place to determine if the risk is acceptable. Ideally our risk score after control measures should be 6 or below to be considered tolerable.

1. 1. Risk Ranking of Likelihood

1. 2. Risk Ranking of Consequence

1. 3. Level of Risk

1. 4. Risk Legend

1. 5. Assessment

PROJECT GEOLOGY

An overview of the geotechnical information is shown above, the green shaded cells indicating jetting pilot hole methodology and barrels for reaming. All suitable tooling options will be available with a suitable number of spares on- site. The final tooling plan will be prepared before mobilizing and is site specific to design, services, and final geotechnical information.

Local borehole information is indicated by a Standard Penetration Test (SPT), this is a field test that involves driving a 2” split spoon sampler into the soil by dropping a hammer of a specific weight to determine the number of blows necessary to drive the sample 12 inches. The number obtained is the standard penetration resistance value (N) and is used to estimate the relative density of cohesion less soils. The geotechnical borehole information supplied suggest predominantly soft silty sands with clay and should present a relatively straightforward approach for HDD methodology with a good mud program, jetting pilot tooling, and LTBR neutral buoyancy barrel reamers.

5. DOWN HOLE SURVEY SYSTEMS
   1. Downhole Survey Techniques

It is proposed to use three separate downhole surveying techniques to achieve the accuracy required for these crossings. The three methods/techniques have been selected after considering all the available surveying methods, and are as follows: -

• • • Magnetic steering tool utilizing the Vector Magnetics P2 Magnetic Steering Tool
    • Surface Coil Tracking utilizing the Vector Magnetics P2 system.
    • Solenoid Tracking utilizing the Vector Magnetics AC Solenoid system.
  • Survey Overview

The methods proposed will allow for optimum tracking of the drill bit during the drilling process, so that the position of the drill will be known always in relation to the proposed profile.

The primary steering tool will be the Vector Magnetics Steering Tool, the secondary system will be surface tracking utilizing the Vector Magnetics Paratrack 2 wire tracking system, and the third system will be surface tracking utilizing the Vector Magnetics AC Solenoid system.

A wire will be laid along or offset to the center line at the entry point and a closed loop will be formed by running a return line back to the start of the wire. The main problems associated with directional control through this section are expected to be magnetic interference from the drilling equipment near the entry point. This is typically only experienced over the initial 20 or 30 meters, and the use of the tracking from the wire will eliminate any error from this source. An accurate determination of the line azimuth (entry to exit reference line) is expected from this entry wire. It is proposed to have available a AC Beacon to be used once over the water or areas where the surface wire is not possible. By utilizing these tracking systems, the position of the drill will be known confidently by a minimum of 2 independent systems at any one time to a position of +/- 200 mm.

1. 3. Survey Systems – Magnetic Steering Tool – Description

The Magnetic Steering Tool is manufactured by Vector Magnetics LLC. The tool consists of a sensor package located in the bottom half of the tool, and a data processing section located in the upper half. The sensor package consists of three triaxial fluxgate AC and DC magnetometers, and three triaxial accelerometers. The triaxial configuration allows the tool to be all angle capable.

The fluxgate magnetometers measure the parameters Bx, By, and Bz where B is the magnetic vector component along the axis of each magnetometer. The x axis is defined as the high side of the tool. The accelerometers measure Gx, Gy, and Gz where G is the measured acceleration component of the earth’s gravitational field.

From these raw sensor readings, the direction of the tool is computed in degrees of Azimuth relative to magnetic north, as well as the inclination in degrees from vertical and tool face in degrees from high side (x axis of the tool).

The tool is linked to the surface via a single core cable of size 4-6mm square, which enables real time data to be viewed whilst drilling, and for surveys to be taken directly on to a surface computer. The tool is placed in the drill string inside one or two non-magnetic drill collars. This will allow the tool to be placed in a relatively magnetically clean environment away from interference from the drill string and the jetting assembly. As well as recording the inclination and azimuth, the instrument also measures the total magnetic field, B total, and the angle of magnetic flux, the Dip. These two parameters are used for Q.A purposes as they indicate the presence of any external magnetic interference.

The B total and Dip are known for any area and can be derived either from published magnetic charts, commercially available modelling software, or simply by measuring the earth’s background field in the local area. Additionally, the measured parameter, G total, is used as a Q.A indicator as it indicates that the tool was stationary while the survey was being taken.

1. 4. Survey Systems – Paratrack 2 Wire Tracking – Description

Paratrack 2 is a wire based locating system. An AC current is passed through a single core wire that either forms a closed coil of known geometry, or a single wire grounded at both ends. As the current passes along the wire, an alternating magnetic field of known strength and geometry is produced. The magnetic vector component of this field is measured by the steering tool downhole, and the software is then able to model the position of the steering tool in relation to the

coil. As the generated field is of a known frequency, it is possible to filter out most the background noise, enabling a much higher signal to noise ratio, and hence more accurate tracking at greater depths.

The Paratrack 2 system requires a local based co-ordinate system based on a reference azimuth. This is usually the line azimuth and is the line between entry point and exit point. Positions measured by the Paratrack 2 system are defined by the distance along this line, (Away), the distance to the right of the line, (Right), and the elevation. Each corner of each coil needs to be pegged. These pegs will be placed to provide the maximum accuracy achievable. Corners will be set so that the wire can be placed between the corners in a straight line both in the horizontal and vertical planes. If this is not possible then an extra corner will be added.

Generally, the wire will be placed so that it will be positioned above the steering tool downhole, i.e. on center line. As the accuracy of the system relies on the accurate positioning of the coil itself then it is important that the coil corners are defined as accurately as possible. The corners will be pegged out, and then picked up by a land surveyor. The grid co- ordinates as supplied by the land surveyor can then be translated into the Away, Right, and Elevation co-ordinate system for entry into the Vector software.

1. 5. Survey Systems – A.C. Solenoid System – Description

The AC Beacon consists of two wire wound coil solenoids mounted bi-axially on a non-magnetic table. Power to the AC Beacon is supplied via a 12 V DC deep discharge battery. Typically, the Beacon is oriented with a Total Station to a known azimuth, either the line or actual drill azimuth, and is placed either on or offset to the drill path. The Beacon can then be remotely actuated via the Paratrack software. Once the Beacon has been energized, it generates a known AC magnetic field. As the Beacon is in effect a point source, the generated field can be modeled accurately, allowing for an accurate determination of the steering tool position. Depending on the signal to noise ratio, it is possible to track up to 125m away from the Beacon, allowing in effect for a 250m tracking window.

The AC solenoid will work on the same local based co-ordinate system (away, right, elevation) that is used both for the Steering Tool and the Paratrack 2 system. The solenoid can be placed anywhere that is convenient along the drill path.

6. EXECUTION
   1. Pilot Drilling

Successful drilling projects require the use of quality down hole tooling, drill pipe, connections, and tooling management. The following overview of tooling proposed for this project is as follows, however can change with ground conditions. A 9 7/8” tri-cone bit and jetting assembly is planned for soft crossings and a down-hole mud motor will be used if conditions require for firmer ground conditions.

9 7/8” Soft hole jetting assembly

9 7/8” and 6 ¾” Mud motor assembly

The pilot drill string will be advanced along the engineered and approved path from the entry surface location to the exit location, as the string is advanced the action of the bentonite being pumped down the string and through the bit erodes the soil formation in the soft formations. For harder formations, as the drill fluid is pumped through the drill string it flows through the mud motor and rock bit and uses mechanical action to cut or chip away the hard and rock formations before it exits through nozzles in the bit and flows back to surface through the annulus between the drill pipes and the borehole walls. The drill fluid then carries these cuttings out of the hole.

The bit is steered by means of an offset behind the bit, the string is rotated to drill straight and the offset positioned to achieve build or steer depending on the design profile and the ongoing survey data. Pilot-hole data will be recorded for as-built drawings and at the completion of the pilot-hole drilling as-built information will be prepared including,

tabulation sheets of co-ordinates, length, depth, inclination, azimuth and drawing, which accurately describe the location of the pilot hole, will be submitted.

The anticipated rate of penetration (ROP) suggests that the pilot drilling bit will not need to be changed during the drilling of each pilot hole.

1. 2. Pilot Tooling

Premium drill pipe will be used for this project built to API RP7G and API 5D specifications. Based on the information available the BHA will entail a 6 ½” non-magnetic drill collar, orienting sub, offset or bent sub, 9 7/8” tri-cone bit, and 6 5/8” drill pipe employed on the longer crossings and more flexible 5” drillpipe for the shorter crossings.

Based on the the geotechnical information supplied, we expect soft ground jet tool pilot however, if hard ground is encountered the jetting assembly will not be suitable therefore a 6 ¾” BICO mud motor will be available. This will be coupled with a 9 7/8” tri-cone bit and 6 ½” NMDC.

Motor Specifications 6-3/4" P100 XL Flex Drill