Well Planning Objective
The objective of well planning is to formulate a program from many variables for drilling a well that has the following characteristics: • safe
• minimum cost • usable
Minimum Cost. Minimize the cost of the well without jeopardizing the safety aspects. Monies should be spent as necessary to develop a safe system.
Usable Holes • The hole diameter is sufficiently large
so an adequate completion can be made. • The hole or producing formation is not irreparably damaged.
Classification of Well Types • wildcats • exploratory holes • step-outs • infills • reentries
Formation Pressures Abnormal pressures affect the well plan in many areas, including the following: • casing and tubing design • mud weight and type selection • casing setting depth selection • cement planning
Formation Pressures Cont. The following problems must be considered as a result of high formation pressures: • kicks and blowouts • differential pressure pipe sticking • lost circulation resulting from high mud weights • heaving shale
Well Planning
Prospect development Data collection Pore pressure analysis Fracture gradient prediction Pipe setting depth selection Hole geometry selection Completion planning Mud plan Cement plan
Cont. Well Planning Bit program Casing design Tubing design Drillstring design Rig sizing and selection
Well Project Management These have covered the following areas: Offset drilling and completion reviews Well design and planning Well interventions and enhancement Scoping studies Completion design Well abandonment Conceptual field development studies AFE preparation Equipment upgrade, selection and installation Drilling rig selection Peer reviews Development of operational programs and writing of well
Under-Balanced Drilling (UBD) PLanning Implementation of UBD projects which includes: • Reservoir and production modeling • Technical and commercial presentations • Feasibility studies and candidate selection • Equipment selection and optimization • Flow modeling • Personnel training • Planning and Programme preparation • Operations implementation and management • Operations close-out and follow up Drilling engineers should have an extensive data base from past successful UBD projects which is used to ensure planning and execution of Client UBD
Well Programme Planning
Prior to commencement of Well Operations. A typical example of such "deliverables" being: Project Plan Client specific Drilling Management System Budget and AFE Documentation Contracting Strategy Document Rig and Service Contracting Documentation: Drilling Rig(s) Invitation to Bid Scope of Work & Compensation Schedule Format Drilling and/or Well Completion Services Invitation (s) to Bid Scope of Work & Compensation Schedule Format Logistics Services Invitation (s) to Bid Scope of Work & Compensation Schedule Format Technical and Commercial Bid Evaluations Rig Contract Finalized Scope of Work & Compensation Schedule Drilling and/or Well Service Contracts Finalized Scope of Work & Compensation Schedule Logistics Service Contracts Finalized Scope of Work & Compensation Schedule Completion Design Review and Optimization Procurement Requirements for Development Programme Offset Data Review and Casing Design
Drilling Management System
Integrated system of documentation, which covers: Drilling Rig Contracting Drilling Rig Inspection Drilling Policy and Procedures Risk Assessment Procedures Well Project Planning Health, Safety and Environmental Guidelines Safety Management Systems Well Cost Monitoring and Cost Control Procedures Drilling Rig and Service Company Contracting Procedures Well Design and Engineering Change Management Procedures Emergency Response Procedures H2S Safety Procedures Well Control Procedures Casing Design Directional Surveying Policy and Procedures Drilling Supervisors Guide Well Testing Procedures Well Services Procedures Materials Ordering and Tracking Wellsite Reporting Lessons Learnt Data Base End of Well Reporting
Rig Sizing & Selection
Top Criteria For Rig Selection..
1-Quality Of Supervision And Personnel 2-Hydraulic Horsepower Requirements. 3-Drill String Requirements (Preferred With Emphasis On Hydraulics). 4-Requirements For Adequate Mud Handling 5-Rotary Speed Requirements. 6-Derrick And Load Requirements ( Casing And Drill String). 7-Well Control Equipment Requirements
Considerations In Rig Selection.
1- Overall Mechanical Suitability . 2- Capital Cost Or Contractual Rate. 3- Mobility. 4- Dependability 5- Ease Of Operation. 6. Past performance of rig under consideration 7. Actual appraisal after rig inspection (preferably during a drilling operation) 8. Type of formations to be drilled 9. Expected formation pressure to be encountered 10. Hole and casing program, straight or deviated 11. Auxiliary equipment as required
What makes a rig effective?
1. Can be rigged up and torn down rapidly 2. Can be handled with minimum and convenient loads 3. Can be rigged up or torn down without special cranes or other unusual mobile equipment 4. Can implement the optimized drilling program as planned.
a)
Optimized programs usually fail if:
Solids control is not maintained. Inadequate equipment and/or supervision can cause this. Hydraulics is inadequate. Lack of pump horsepower and/or too small a drill string causes this problem. Improper weight on bit is run. Lack of drill collars and/or not running drill off tests to evaluate proper weight on bit causes this problem. Rotary horsepower is limited. Sometimes a tradeoff between pump(s) and rotary table horsepower causes failure of optimized program
Effective rig
Round trip the pipe with a well-trained crew with a minimum of time wasted. A good crew won't disturb hole stability on the trip because they keep accurate trip trends and use good tripping practices Personnel's attitude with respect to operator's (and contractors) goals is good. Training in drilling technology and good communications between contractor and operator personnel is the key to this. A competitive spirit of staying below the drilling performance curve is very beneficial to overall effectiveness.
Rig requirements influence on drilling program implementation
1. Mud handling and solids control equipment 2. Hydraulic horsepower requirements 3. Rotary horsepower requirements 4. Drill string requirements to provide good hydraulics and weight on bit 5. Derrick loading capacity for casing and drilling operations 6. Blowout preventer equipment requirements
The principal items in the hoisting system are drawworks crown and traveling blocks wireline ancillary equipment such as elevator?, hooks, and bails
Mud handling and solids control equipment
A- Shaker-Rig up properly.
Have enough shakers. As a rule of thumb use two shakers when drilling 9-7/8" hole or larger.
B- Sand trap.
Use a small (20 bbl) V-bottom sand trap below shakers to facilitate dumping and to prevent loading-up of downstream tanks.
C- Hydrocyclones. Velocity should be 5-10 ft/sec in suction lines to prevent settling and cavitations. Size centrifugal pump to give 75 ft of head. ∆p = 75 ft x 0.052 x MW. The volume should be circulating rate plus 25 to 50% excess.
Power Systems Raw power is transmitted via one the following systems: mechanical drive direct current )DC) generator and motor alternating currant (AC), silicon controlled rectifier (SCR), direct current (DC) motor. Load Mechanical horsepower = ——— efficiency
Energy output - Energy input
E = ——————————————— Energy output
Cont. Power Systems
The system efficiency is computed as (0.98)n, where n is the number of shafts and chains. If more than one engine is used, an average value is calculated. The mechanical horsepower requirements must be modified for harsh temperature environments or altitudes. According to API Standard 7B-IIC * deduct 3 % of the standard brake horsepower for each 1,000-ft rise in altitude above sea level * deduct 1 % of the standard brake horsepower for each 10 rise in temperature above 85 F-or add 1 % for each 10 fall 85 F . The engine manufacturer should be consulted for specific variances.
Cont. Power Systems Example A drilling rig is working in an arid climate at an elevation of 3,600 ft. During the day, the peak temperature is l05°F. The minimum temperature (prior to dawn) is 45°F. The rig has three 1,000-hp prime movers. Determine the minimum and maximum horsepower available during any 24-hr period.
Cont. Power Systems Solution: 1. The total available horsepower from the prime movers is 3,000 hp. 2. The loss in horsepower due to altitude is: {3% loss / 1,000 ft} x 3,600 ft x 3,000 hp = 324 hp 3,000 hp - 324 hp = 2,676 hp 3. The minimum horsepower will occur at the maximum temperature: (1% loss / 10°F) x (105°F - 85°F) x 2,676 hp = 53.5 hp 2,676 - 53.5 = 2,622 hp 4. Conversely, the maximum horsepower will occur at the minimum temperature: (1% gain / 10°F) x (85°F - 45°F) x 2.676 hp = 107 hp 2,676 + 107 == 2,783 hp
Typical hoisting system
Typical hoisting system
Solids Control Equipment Shale Shakers Hydrocyclones
Desanders and Desilters Mud Cleaner Centrifuge
Shale Shaker Running Considerations:
1. Keep shaker screens tight and well supported. 2. Do not bypass shaker during drilling as this will overload all the solids equipment downstream. 3. Remember that shakers remove mud solids finer than the shaker screens. Do not destroy this action by adding water onto the shaker screen. 4. Shaker capacity depends critically on mud PV. Mud PV is the single most important factor that determines shaker cleaning.
Blowout Preventer Equipment
5M- 13-5/8 - SRRA
