Optimization of Well Trajectories and Wellhead Towers' Slots Allocation Through a Collaborative Well-Planning Approach

Marir, Boualem (ADMA-OPCO) | Mandel, Christian (ADMA-OPCO) | Al Jefri, Ghassan (ADMA-OPCO) | Torres, Javier (Halliburton) | Ferdian, Salman (Halliburton)



Traditionally, geoscientists, drilling, reservoir, and facility engineers work separately on projects. The workflows between these disciplines are typically onerous, iterative, and time consuming because there is no common environment between roles. For offshore fields, the limited number of towers from which wells can be drilled make well planning a critical process for a successful development. Usually, planning is done on a well-by-well basis, which could introduce the potential for increased risks.

ADMA-OPCO has begun developing an offshore green field through drilling about 90 wells (duals and singles) from eight wellhead towers. The development scheme for this field is optimized per reservoir, five-spot water injection, natural depletion, and gas injection. For each tower, slots (injector vs. producers) and allocations have to be defined with high confidence and be communicated to surface project teams to start the design and engineering process. This exercise requires working all well trajectories (drillable wells that meet the statements of requirements). Early in the field-development process, the common practice is to do the well-profile work on a well-by-well basis, which takes a minimum of three to five days per well depending on well type and complexity.

This paper addresses a different approach that is used by ADMA-OPCO, which allowed for accelerating the planning process by integrating all stakeholders for the objective of reducing the working hours while optimizing the trajectories and taking into account all criteria and safety guidelines executed within a 3-D static-model environment.

As an outcome, more than 100 horizontal drains were successfully optimized, and slot allocations were defined for all towers within 20 working days (minimum of 380 days would be required if done on a well-by-well basis). A drilling footage of more than 20, 000 ft was saved after optimization. Additionally, the real collaborative value was seen in the integrated working sessions, resulting in an improved deliverable.