Oil and Gas Presentation
Transcript: Thank You! Well Life Cycle Well Life Cycle Planning Planning Formulate a program for drilling a well that has the following characteristics: 1. Safe 2. Minimum cost 3. Usable Unfortunately, it is not always possible to accomplish these objectives on each well because of constraints based on geology, drilling equipment, temperature, casing limitations, hole sizing, or budget. Objective Objective - Highest priority in well planning - Personnel considerations must be placed above all other aspects of the plan - Safety of the well - Designed to minimize the risk of blowouts and other future problem factors Safety Safety - Minimize cost of the well without jeopardizing the safety aspects - Costs can be reduced to a certain level as additional effort is given to the planning Minimum Cost Minimum Cost - Drilling a hole to the target depth is unsatisfactory if the final well configuration is not usable. - Term "usable" implies the following: 1. The hole diameter is sufficiently large so an adequate completion can be made. 2. The hole or producing formation is not irreparably damaged. Usable Holes Usable Holes The drilling engineer is required to plan a variety of well types, including: 1. Wildcats 2. Exploratory holes 3. Step-outs 4. In-fills 5. Re-entries. Generally, wildcats require more planning than the other types. Infill wells and re-entries require minimum planning inmost cases. Well-Type Classification Well-Type Classification - Unproven area - No concrete historic production records - Unexplored as a site for potential oil and gas output Wildcat Well Wildcat Site selection based on seismic data or satellite survey Exploratory Well Exploratory - Delineates the reservoir boundaries - Drilled after the exploratory discoveries - Site selection usually based on seismic data Step-out (Development) Well Step-out (Development) - Adding new wells in an existing field within the original well patterns - Accelerate recovery or to test recovery methods - Used to confirm the presence of hydrocarbon between the step-out drill holes In-Fill Well In-Fill - Existing well re-entered to deepen, side track, rework, or re-complete - Various amount of planning is required - Depending on the purpose of the re-entry Re-entry Well Re-entry The formation, or pore, pressure encountered by the well significantly affects the well plan. The pressures may be normal, abnormal (high), or subnormal (low). Formation Pressure Formation Pressure - Generally do not create planning problems - The mud weights are in the range of 8.5 to 9.5 lb./gal - Kicks-and blowout-prevention problems should be minimized - Casing requirements can be stringent even in normal-pressure wells deeper than 20,000 ft. because of tension/collapse design constraints Normal-pressure Wells Normal-pressure - May require setting additional casing strings to cover weak or low-pressure zones - The lower-than-normal pressures may result from geological or tectonic factors or from pressure depletion in producing intervals Subnormal-pressure Wells Subnormal-pressure - Affect the well plan in many areas, including: 1. Casing and tubing design 2. Mud-weight and type-selection 3. Casing-setting-depth selection 4. Cement planning - Following problems must be considered as a result of high formation pressures 1.Kicks and blowouts 2. Differential-pressure pipe sticking 3. Lost circulation resulting from high mud weights Abnormal pressures Wells Abnormal pressures Drilling Drilling The well is created by drilling a hole into the earth using a drilling rig that rotates a string with a bit attached To Drill you Need : 1. A way to descend; drill pipe 2. A way to rotate the pipe; "Kelly" or top drive - Kelly or Rotary: rotation is achieved by turning a square or hexagonal pipe (the "Kelly") at drill floor level. - Top Drive: rotation and circulation is done at the top of the drill string, on a motor that moves in a track along the derrick. 3. A place to hold the pipes; derrick 4. A way to raise & lower the pipe; draw works 5. A cutting tool; bit 6. A media to remove cuttings; mud Objectives Objectives - Variety of configurations and designs - For different surface environments that range from; 1. Arctic 2. Desert 3. Ocean 4. Mid-continent 5. Everything in between Types of Rigs Types of Rigs Land or Onshore Rigs Offshore Rigs Offshore Rigs - Or a self-elevating unit is a type of mobile platform - Consists of a buoyant hull fitted with a number of movable legs. - Depth Range from few feet to over 400 feet Jack-up Rigs Jack-up Rigs - Supported on large pontoon-like structures - Provide buoyancy allowing the unit to be towed from location to location. - Once on the location, the pontoon structure is slowly flooded until it rests securely on its anchors, of which there are usually two per corner. - Operating deck is elevated 100 feet above the pontoons on large steel columns to provide clearance above the waves. - After the well is drilled, the water is pumped out of the buoyancy tanks and the - -