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Once the design well depth is reached, the formation is tested and evaluated. To complete the production well, casing is installed and cemented, and the drilling rig is dismantled. A service rig is brought in to perforate the production casing and run production tubing along with downhole equipments. Production begins after surface safety equipment installation inished.
WELL COMPLETION and STIMULATION Bài giảng soạn Bộ mơn Khoan – Khai thác Dầu khí Khoa Kỹ thuật Địa chất Dầu khí Đại học Bách Khoa TP HCM Tel: (08) 8647256 ext 5767 GEOPET CONTENTS Basic Completion Methods Completion Procedure Perforating Stimulation GEOPET Well Completion and Stimulation BASIC COMPLETION METHODS GEOPET Well Completion and Stimulation INTRODUCTION Once the design well depth is reached, the formation is tested and evaluated PLATFORM To complete the production well, casing is installed and cemented, and the drilling rig is dismantled SEA BED A service rig is brought in to 30’’ CASING 20’’ CASING perforate the production casing 13 3/8’’ CASING and run production tubing along Production casing (9 5/8) with downhole equipments 7’’ LINER Production begins after surface safety equipment installation RESERVOIR inished GEOPET Well Completion and Stimulation WHAT IS COMPLETION? Well completion creates a dependable pathway to the surface for the hydrocarbons The term ‘completion’ describes the assembly of downhole tubulars and other safety equipments that is required to enable the safe and efficient production of oil or gas from the well after it has been drilled GEOPET Well Completion and Stimulation BASIC WELL COMPLETION TECHNOLOGY Each drilled wellbore awaiting completion is unique Even nearby wells drilled to the same reservoir can have differencies in: depths, formation characteristics, and hole sizes A wide variety of equipment designs and procedures have been developed to provide safe, efficient conduits from subsurface reservoirs to the surface in different situations The ideal completion design minimizes initial completion and operating costs, providing for the most profitable operation of an oil or gas well over its entire life GEOPET Well Completion and Stimulation TYPE OF COMPLETION Natural Completions Natural completions are those in which little or no stimulation is required for production Sandstone and carbonate systems with good permeability and mechanical stability are ideal for natural completions Stimulated Completions These completions are generally applied to improve the natural drainage patterns of hard, low-permeability formations It is used to remove barriers that prevent easy passage of fluids into the wellbore Sand-Control Completions Sand-control completions support the formation while allowing the flow of fluids They are performed in young, unconsolidated or less mechanically competent sandstones GEOPET Well Completion and Stimulation TYPE OF COMPLETION The design of a particular completion depends on: The number and type of productive zones, The expected pressures and flow rates, The need to control sand production, The need for artificial lift or stimulation the regulations governing operations in the area GEOPET Well Completion and Stimulation WELL COMPLETION ACTIVITIES Well completion activities include: Conducting well test Setting production casing Running production tubing along with downhole equipments GEOPET Installing surface safety equipments Starting production flow Well Completion and Stimulation BASIC COMPLETION METHODS Once we drill to the target and evaluate our well by Mud analysis: density & viscosity Well logging (electrical, ascoustic, nuclear, etc…) Coring: at bottomhole or sidewall Welltest: bottomhole pressure vs time -> reservoir properties Next decision is whether to complete or abandon it???? In the latter case: set a cement plug or plugs in the hole, possibly recover whatever casing can be removed, and return the drill-site to its original condition The more fortunate is one in which our well not only is productive, but economically justifies a completion GEOPET Well Completion and Stimulation 10 SAND CONTROL Gravel packs require There is a good bond between casing and formation, The perforations be large and free of debris, and that the gravel pack sand is GEOPET Evenly placed around the screen And not mixed with formation sand or dirty completion fluid Well Completion and Stimulation 79 SAND CONTROL Sand consolidation techniques are best applied to shorter completion intervals Careful mixing and injecting of the plastic resins is important to prevent the mixture from hardening either too far into the formation from the wellbore or inside the casing Although some permeability is lost in this technique, no restrictions to flow are placed inside the casing as is the case in gravel packing This is attractive if future downhole work is anticipated and the wellbore may need to be cleaned out GEOPET Well Completion and Stimulation 80 SAND CONTROL “Frac and Pack” completion methods combine hydraulic fracturing and gravel packing into a single well treatment They are designed to create relatively short, highly conductive fractures in reservoirs of moderate to high permeability Frac and pack techniques have come into wide use, and in some areas have largely supplanted the more conventional sand control methods described above GEOPET Well Completion and Stimulation 81 SAND CONTROL Areas of application include - bypassing near-wellbore formation damage that can’t be removed with acid treatments - increasing formation support of casing in reservoirs that have formation compacting tendencies - vertically connecting productive intervals in thin, laminated sand-shale sequences - Improving productivity in some low-permeability reservoirs - alleviating problems caused by high wellbore differential pressure GEOPET Well Completion and Stimulation 82 SAND CONTROL The decision to complete a well with sand control is not always easy For example, in a formation where sand production may occur, the completion designer may risk the cost of a future workover in order to save the immediate expense of a gravel pack This may be particularly true if multiple producing zones in the well will require future work down hole Of course, the cost of remedial work to clean out and gravel-pack a sanded-up well may be much higher than if the work had been done during the original completion This is particularly true at some offshore locations where the cost of simply moving a work over rig on to a producing structure can be enormous With sand control, as with other facets of the completion procedure, decision making is dependent on a number of factors GEOPET Well Completion and Stimulation 83 Completion Components GEOPET Well Completion and Stimulation 84 COMPLETION COMPONENTS Oil Well After Completion Tubing hanger Well Head X-mas Tree Hydraulic Control Line Safety Valve Production Tubing Reservoir Gas Lift Valve Perforation Packer Pump Out Plug GEOPET Well Completion and Stimulation Sump 85 COMPLETION COMPONENTS PLATFORM WELL HEAD EQUIPMENT Only this casing is visible from outside SEA BED 30’’ CASING PRODUCTION TUBING 20’’ CASING 13 3/8’’ CASING Production casing (9 5/8) 5/8’’ CASING 7’’ LINER GAS O WATIL ER GEOPET Well Completion and Stimulation RESEVOIR 86 DOWNHOLE EQUIPMENT The parts of a downhole equipment are: Hydraulic Control Line Safety Valve Gas Lift Valve Packer Pump Out Plug GEOPET Well Completion and Stimulation 87 DOWNHOLE EQUIPMENT Packer Packer is a device consisting of a sealing device, a holding or setting device and an inside passage for fluids It expands externally to seal the well bore It helps in blocking the fluids through the annular space between the pipe and the well bore wall Packers use flexible, electrometric elements that expand It is set hydraulically from the surface GEOPET Well Completion and Stimulation 88 DOWNHOLE EQUIPMENT Gas Lift Valve The gas lift valve is a device installed on a gas lift cylinder or mandrel This device is used to control the flow of gas between the exterior and interior of well tubing It consists of an inlet, outlet, a main valve, a main chamber and so on The design of the side pocket is such that the components that are installed not obstruct the flow of production This enables access to the well bore and the other components of completion GEOPET Well Completion and Stimulation 89 DOWNHOLE EQUIPMENT Safety Valve A safety valve is a device that is installed in the upper well bore to provide emergency closure of the channels that produce oil The valve has a housing and a movable valve element that controls the flow of fluid in the well GEOPET Well Completion and Stimulation 90 DOWNHOLE EQUIPMENT Hydraulic Control Line Hydraulic control line is a device filled with hydraulic fluid and connected to a hydraulic fluid source Hydraulic control line is used to operate the safety valve When the control line is pressurized up to a certain pressure limit, the safety valve opens Its one end connects at the top of the safety valve and the other end to a pressurizing panel at the surface It is lowered along with the safety valve while lowering the tubing string during completion GEOPET Well Completion and Stimulation 91 SURFACE CONTROL EQUIPMENTS Well Head The surface termination of a wellbore that incorporates facilities for installing casing hangers during the well construction phase is the well head The well head is installed on top of the casing before starting to drill It has two or three sections Each section has two flanges to facilitate the connections at both the ends GEOPET Well Completion and Stimulation 92 KẾT THÚC