ABSTRACT
An oil rim reservoir is a reservoir with a relative thickness of 10ft – 50ft. Such reservoirs, though despite their small thickness contains oil that can be of economic quantity if properly produced. It is a known knowledge that horizontal wells perform better than vertical wells in the production of such reservoirs because of the large surface contact it will have with the reservoir if the optimum wellbore placement is accurately located.

With the use of horizontal wells, one is faced with the option of producing below or above the critical rate. The critical rate is the highest production rate with no water or gas mixing with the oil.

The maximum efficient rate (MER) was used as an evaluation analysis to compare the net incomes of using both production options in producing a sample oil rim reservoir. It was however shown that producing above the critical rate gave a higher income value and therefore should be a preferred option in this case.

This forms the basis of this research work as detailed explanations are carefully presented and itemized as necessary.

TABLE OF CONTENT
Title page                                                                 i

Certification                                                             ii

Dedication                                                               iii

Acknowledgment                                                     iv

Table of content                                                       v

List of tables                                                            vii

List of figures                                                           viii

Abstract                                                                   ix

CHAPTER ONE

1.0 Introduction                                                       1

1.1 Statement of the problem                                  3

1.2 Objectives of the study                                       3

1.3 Significance of the study                                    4

1.4 Scope of the study                                             4

CHAPTER TWO

2.0 Literature Review                                               6

2.1 Coning                                                               9

2.2 Horizontal well in oil rim reservoirs                   10

2.3 Geological modeling                                           12

2.4 Critical production rate                                      14

2.5 Breakthrough time                                             16

2.6 Practical difficulties of placing the well              19

2.7 Further recovery optimization                            22

CHAPTER THREE

3.0 Materials and methodology                                        29

3.1 Case history: Niger Delta’s Anan field                        36   

3.2 Anan-003 Reservoir parameters                                36

3.3 Critical oil flow rate for a horizontal well            36

3.4.2 Breakthrough time for a horizontal well          38

3.5 Post-breakthrough performance                                38

3.6 Using MER to compare options                         40

 

CHAPTER FOUR

4.0 Results and Discussion                                     43

4.1 Parameter sensitivity analysis                            44

4.2 Discussion                                                                 49

CHAPTER FIVE

5.1 Conclusion                                                                52

5.2 Recommendations                                             53

References                                                               55