Optimizing The Planning, Design And Drilling Of Extended Reach And Complex Wells

Abstract

Extended Reach Drilling (ERD) is an integrated methodology for drilling high-angle wellbores with long horizontal displacements. Several problems are associated with extended reach wells. Thus for high levels of performance improvement to be achieved, it is essential to analyze the interrelationship among the elements involved in the entire drilling process. This is because a system that considers the individual elements of the drilling system in isolation is inadequate to deliver desired performance improvement.In this study, an algorithm that sets forth a design for a drilling program that is suitable to drill an extended reach well was developed using Visual Basic. Although the algorithm touches on several factors affecting extended reach drilling, the major focus is on the six elements, which are considered the critical factors. These are: Well Trajectory Design, Bottom Hole Assembly (BHA) Design, Bit Hydraulics, Drill String Design, Torque and Drag, Hole Cleaning and ECD Management. The proposed algorithm evaluates the interrelationship among these critical factors and provides direction on the processes and tasks required at all stages in the design and drilling of an ERD well to achieve maximum drilling performance. The development of the model is based upon information gathered from several sources, many new ideas from technical publications, along with information and feedback from field-based personnel. The output generated from the model compare well with results from actual field data.

Drillstring Buckling Prediction and Its Impact on Tool-Joint Effects in Extended Reach Wells

“…With the increasing complexity of petroleum geological formations, and the decreasing oil price, it becomes paramount to optimize AWA gas operations. One area of this optimisation is in drilling and completions [1]. Drilling in oil and gas asset development requires high investment cost [2,3].…”

“…The development of longer reach or ERWs enables maximum contact with reservoirs allowing more drainage area and requiring less number of platforms on new development assets. ERWs are wells in which the horizontal departure is at least two times the true vertical depth [1,4]. These high angle wells prove very challenging to drill and complete especially during tripping and sliding operations.…”

“…In ERWs, Excessive torque and drag, buckling of drillstring and tubulars are commonly encountered due to complex wellpath, and also due to doglegs and tortuosities which are usually connected with extended reach drilling (ERD) architectures. Engineers are faced with the challenge of designing safe operational practices and windows to ensure that acceptable design factors are met at least operating costs [1,5]. In ERWs, due to high angle, there is tendency for high compression generated in the drillstring during tripping and sliding operations.…”