DEVELOPMENT OF DRILLING FLUID FROM BIOMATERIALS

ABSTRACT

 

New Biodegradable drilling fluids were developed using Brachystegia eurycoma (achi), Detarium microcarpum (ofo) and Pleurotus (osu). The drilling properties such as yield point, apparent viscosity, low shear rate yield point and fluid loss were determined.The field polymer muds that are currently in use namely; PAC-R and PAC-L were formulated and used as control samples to the new proposed product. Herschel –Buckley model was used to obtain the yield stress. Cutting transport ratio, cutting transport efficiency and cuttings concentration volume% of  both the proposed mud and the existing PAC Polymer mud were calculated for low flow rates, high flow rates, large hole diameters and small hole diameters. Economic evaluation was carried out using Incremental Discounted Cash Flow Rate of  Return to determine the viability of the proposed materials. The proposed mud was compared with the existing mud and results show that yield stress for un-weighted, low solids, and weighted muds are 18lbs/100ft², 36lbs/100ft², 30lb/100ft² for proposed muds respectively. The results of unweighted, low solids and weighted muds of existing also show the yield stress of 14lbs/100ft², 34lbs/100ft², 26lbs/100ft² and  8lbs/100ft², 10lbs/100ft², 10lbs/100ft² for regression line. Both the proposed mud and the existing mud gave good hole cleaning results of cuttings concentration 1.64 volume% and cutting transport ratio 0.997 at high flow rates and small diameter holes. In terms of economic analysis, Detarium microcapum, Brachystegia eurycoma, Pleurotus muds additives gave the better result in cost reduction than the alternative. The proposed materials are not commercially available to be used in preparing drilling fluids but they are environmentally friendly.

 

Key words:

Materials,  Hole cleaning, Economic Evaluation, Biodegradable Drilling Fluids, Brachystegia eurycoma, Detarium microcarpum, Pleurotus.

 

 

 

 

TABLE OF CONTENTS

Certification                                                                                            i

Declaration                                                                                              ii

Dedication             iii Acknowledgment           iv

Abstract                                                                                                    v

Table of contents            vi List of Tables           vii

List of Figures                                                                                       viii

CHAPTER I

1.0  INTRODUCTION                                                                        1

1.1 Background                                                                                     1

1.2 Statement of the Problem                                                                4

1.3 Objectives                                                                                        4

1.4  Scope of the Work                                                                          5

1.5 Research/work Approach                                                                6

 

CHAPTER II

2.0 LITERATURE  REVIEW                                                              7

2.1 Rheological  Properties                                                                 7

2.2     Classification of viscous  Fluids                                                8

2.3     Rheological Models                                                                   10

2.3.1  Newtonian model                                                                       10

2.3.2 Bingham Plastic Fluid model                                                       12

2.3.3 Power Law model                                                                        12

2.3.3  Herschel Buckley model                                                             13

2.3.3.1  Pipe flow                                                                                14

2.3.3.2 Annular flow                                                                            15

2.4 Carrying Capacity of a Drilling Fluid                                             15

2.4.1 Cutting Transport Ratio                                                               18

2.4.1.1  Some Previous Investigation on Cutting Transport Ratio         19

2.5: Fluid Loss                                                                                      22

2.5.1 Theory:                                                                                        22

2.5.2: API Model                                                                                  23

• 3: Henri Darcy Model                                                             23
  • Classifications of Drilling fluids                                                 24

6.1.1 Non- Inhibitive Fluids                                                                  26

2.6.1.1: Clear Water                                                                             26

 

2.6.1.2 Native Muds                                                                           27

2.6.1.3: Bentonite-Water Muds                                                            27

2.6.1.4: Lignite-Lignosulfonate (Deflocculated) Muds                          28

 

• Inhibitive Fluids                                                                          29
  • Calcium- Based Muds                                                   30
  • Saturated Salt Muds                                                                31
  • KCL-Polymer (KCL-PHPA) Muds                                       33
• Polymer fluids                                                                             34
  • Non- Dispersed Polymer Muds                                        35
  • High- Temperature Deflocculated Polymer muds                   36
• Glycol Muds                                                                               38

• Characterization of The Biomaterials                                        40
  • DetariumMicrocarpum (Ofo)                                         40
  • BrachystegiaEurycoma (Achi)                                       44
  • Characterization of Pleurotus                                                  45
• Economics Evaluation Tools                                                   48
  • The Discount rate                                                             49
  • NPV in Decision Making

51

 

CHAPTER III

• METHODOLOGY                                                                       52
• Sample Procurement

52

• Experimental Procedure

53

• Mud Formulations                                                                       53
• Processing/Measurements

57

• Data Applications                                                                57

3.5.1 Application of Modified Power Law Model

58

3.5.2:  Application of Hole cleaning data	58
3.6  Economic Evaluation   CHAPTER  IV	61
4.0   RESULTS AND DISCUSSION	63
4.1 Experimental Results	63
4.1.2 Viscometer and filtrate loss readings for low solids muds 4.1.3 Viscometer and filtrate loss readings barite as the weighting	65
material   4.2  Results of the Calculated Yield Stress using Herschel-Buckley	66
Model	70
4.2.1   Model Application	70
4.2.2  Sample Calculations for Proposed and Existing Muds.	70
4.3  Effect of Temperature on Mud Properties	74
4.4:  Economic Evaluation Data Generation	74
4.5 Discussion	78
4.5.1: Calculations of Yield Stress Using Herschel Buckley Model	78
4.5.2: Effect of Temperature on Mud Properties	84

 

4.5.3: Cutting Transport Ratio, Cutting Transport Efficiency,

                Cuttings Concentration                                                              97

4.5.4: Economic Analysis of the Proposed Mud and the Existing Mud 123

4.6.0  Commercial Availability                                                             129

4.6.1 Detarium microcarpum                                                                129

4.6.2 Brachystegia eurycoma                                                                130

4.6.3 Pleurotus                                                                                      131

4.7.0 Environmental Impart Assessment (EIA)                                     132

4.7.1: Beneficial Impacts                                                                      132

4.7.2: Adverse Impacts                                                                         133

 

4.7.3: Feasibility Study, Distributive and Marketing Possibilities         134

4.7.4: Licensing and Consultancy                                                         135

CHAPTER V

5.0  CONCLUSION AND RECOMMENDATION                             137

5.1 Conclusions                                                                                   137

5.2 Contribution to Knowledge                                                            137

5.3 Recommendations        138 References          139

Appendix : Sample Calculations                                                           146

 

CHAPTER I

1.0                                      INTRODUCTION

1.1     Background

A drilling fluid is a mixture consisting of solids, liquids and gases distributed throughout the liquid or gaseous phase. A major component in the success of drilling operation is the performance of the drilling fluid. The search for hydrocarbon reserves has become significantly more expensive that offshore operations have moved into the deeper waters, and more hostile environments. These environments require the drilling fluid to excel in many performance categories. This is especially important now that oil producing nations emphasize the development of a drilling fluid that is effective, economically viable and environmentally friendly. This indeed has become a challenge to petroleum industry.

 

Drilling fluid’s effectiveness is measured based on its rheological properties among other yardsticks, which include;  mud weight, yield point, low shear rate yield point, plastic viscosity, fluid loss, gel strength and lubricity. The functions of drilling fluids that are dependent on these properties include:

• Cuttings transportation along the wellbore annulus.

 

• Cooling and lubricating the bit and drill string.
• Maintaining sufficient hydrostatic pressure to withstand the borehole pressure.
• Being capable of suspending drilled cuttings and high gravity solids when the circulation is stopped.
• Depositing of impermeable filter cake on the wall of the wellbore.
• Transmitting hydraulic horsepower to the bit.
• Ability to remove cuttings under the bit to avoid smaller particles from adversely affecting the penetration rate, bit life and mud properties.

Hole cleaning which is one of important functions of the drilling fluid is the focal point in the development of drilling fluids from biomaterials, that is, locally sourced materials that are biodegradable. Failure to achieve effective hole cleaning can result to serious problems including stuck pipe, excessive torque and drag, annulus pack-off, lost circulation, high mud costs and slow drilling rates. Cuttings transport is affected by several interrelated mud and drilling parameters. Removing cuttings from below the drill bit is still a crucial function of a drilling fluid.

 

The thicker the fluid, the more dense the fluid and therefore the lower the slip velocity. For effective cuttings removal, the fluid velocity must be high enough to overcome the slip velocity of the cuttings. The viscosity desired will depend upon the desired hydraulics and the size of the cuttings contained in the fluid. The velocity will depend on several factors which include; the pump capacity, pump speed and efficiency, as well as the drill pipe size and that of the  borehole.

In drilling fluid hydraulics, the flow profile can be categorized as:

• No flow
• Plug flow
• Laminar flow
• Transition flow
• Turbulent flow.

The “ideal” velocity is one that will achieve laminar (or streamline) flow because it provides the maximum cuttings removal without eroding the well bore. On the other hand, turbulent flow (resulting from a high velocity) requires more horsepower but can cause excessive hole erosion. The proper combination of velocity and viscosity is a must for the right hydraulics and efficient hole cleaning. Cuttings will have a tendency to collect at points of low fluid velocity in the well bore annulus. These areas are located in washouts and where the drill pipe rest against the wall of the well bore. It is therefore, a good practice to rotate and work (raise and lower) the drill string while circulating the drilling fluid. This helps to keep the cuttings in the main flow of the fluid and not allow them to gather next to the wall or pipe.

 

• Statement of the Problem

 

Generally, not much attention has been paid to the development of drilling fluids from locally sourced materials which has rheological properties like yield point, low shear rate yield point  that are effective. Drilling fluids ought to be effective in hole cleaning as well as economically attractive, available and environmentally friendly.

• Objectives

This work is aimed at the development of drilling mud from locally sourced  biomaterials, that are naturally biodegradable namely; Detarium microcarpum(ofo), Brachstychia eurycoma(achi) and Pleurotus(osu). The rheological and filtration properties of new drilling mud will be  compared to those of  conventional PAC polymer muds, which are  non-Newtonian and has yield  stress and temporary gel similar to the proposed muds.

• Scope of the work

The scope of the current study are presented as follows:

• Knowledge of the degree of non-Newtonian of the proposed muds.
• Measure of the degree of the effectiveness of the muds at low shear

rates.

• Application of proposed mud to high temperature environments through the measured mud properties.
• Evaluation of the proposed mud properties for hole cleaning.
• Economic evaluation of the proposed mud additives Detarium microcarpum, Brachystegia eurycoma, Pleurotus muds in comparison to existing PAC polymer muds.
• Evaluation of the commercial availability of the proposed local mud additives.
• Assess the Environmental impact of the proposed local mud additives

1.5    Research/Work Approach

The research approach of the development of the drilling fluids from local materials are stated as follows:

• The study was both experimental and analytical.
• Rheological data and fluids loss data were obtained at different temperatures ranging from 100^OF to 180^O
• Herschel-Buckley model was used to verify the fluids’ behaviors at low shear rate ranges.
• Experimental data were used to evaluate the proposed mud for cutting transport efficiency at high flow rates, low flow rates, large and small diameter holes using the existing models.
• Economic evaluation of the performance of the proposed and existing muds were carried out using Incremental DCF-ROR.

 

DEVELOPMENT OF DRILLING FLUID FROM BIOMATERIALS

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