Abstract
Drilling the structurally complex overthrusted fault blocks associated with the Andes foothills of Colombia has always presented a number of distinctive challenges. Borehole instability, hard and abrasive formations, undesirable hole deviation associated with multiple fault planes and steeply dipping formations, low progress rates and frequent drill string failures are the most common problems encountered while drilling wells in the area.
In order to efficiently drill a deep exploration well in Colombia, the operator elected to implement its internal Beyond the Best (BtB) initiative to increase the chances of achieving or exceeding performance goals. A strategy was developed to anticipate challenges and address critical elements of the detailed design, the identification of the optimum well trajectory to manage subsurface hazards as well as continuous updates of the subsurface model while drilling. As a part of the Front End Loading requirements of the BtB initiative, the operator elected to engage a drilling optimization service to conduct a detailed analysis of the overburden including a critical review of drilling performance, mud logging and wireline data from reference wells. This detailed and in-depth analysis helped identify potential problems that led the operator to set optimization objectives for the upper hole sections of achieving the highest penetration rate possible while maintaining a near-vertical wellbore. An action plan with recommended solutions to overcome anticipated problems was developed and specific fit-for-purpose technologies were identified as appropriate solutions.
To introduce and build support for this new drilling philosophy and tool implementation, the operator implemented the Technical Limits Process that challenged operator and service company personnel to work as an integrated team to achieve best-in-class drilling performance using the appropriate technology. The process also encourages trust and camaraderie between team members and challenges them to feel personally responsible for delivering significant performance improvement. The authors will discuss how proper planning and understanding key issues that previously restricted drilling performance led to the identification of improved drilling practices and the application of the proper technology that resulted in breakthrough drilling performance including new world records for impregnated and PDC bits.
To measure the effectiveness of the initiatives, the authors will document savings relative to offset wells. The typical well drilled in the Colombian foothills averages 188 days per 10,000 feet to complete. However, by applying application specific technology the team has cut the average time required to drill this well to 140 days per 10,000 feet with the resultant savings in time and money to the company.
