Eliminating Non-Productive Time Associated With Drilling Trouble Zones

Abstract

Cost overruns can easily manifest during well construction due to unexpected issues including lost returns, differential sticking, and narrow pore pressure/fracture gradients. To better plan for potential overruns, operators sometimes earmark 10 to 25% of the Authorization for Expenditures (AFE) to cover the unexpected, which can significantly impact drilling budgets. Technical and operational risks versus the potential return on investment (ROI) are critical factors in determining whether a project proceeds. Too often the best drilling practices used to address trouble zones are limited to a few conventional methods with a narrow range of effectiveness. Also, a lack of rock mechanics knowledge can prevent the most efficient solution being applied. Some operators are implementing planning programs that assess and integrate the latest processes and technologies to address drilling risks up-front. Cutting-edge technologies such as managed pressure drilling methods, drilling with casing / drilling with liners, and solid expandable casing have been highly effective. Implementing proactive evaluation processes and applying the latest tools and techniques can efficiently address operational risks and trouble zones to ultimately reduce NPT and associated costs. Employing common practices and technologies that are typically ineffective and that drive up NPT cost should be considered unacceptable. Common sense well construction evaluation processes used in conjunction with validated conventional and new technologies have proven their worth by reducing expenditures and risks, preventing the loss of wells, and increasing the operator's ROI. This paper will review real drilling challenges that have been encountered and the common practices that were employed to address these drilling hazards. This paper will compare and contrast how these same circumstances have and can be addressed much more efficiently with engineering evaluation processes that help determine the best drilling tool and/or technique to mitigate risks and reduce NPT.

Model‐uncertainty quantification in seismic tomography: method and applications

“…In extreme cases this could manifest itself in situations such as wellbore instability, losses, stuck pipe and even blowouts. This in turn can lead to severely extended drilling programs, significant cost overruns, abandonment of wells and in the worst cases, loss of capital equipment, sizable legal costs, significant fines and payments for third-party damages and potentially loss of life (York et al 2009;Pritchard and Lacy 2011). Pre-drill assessment of geohazards has therefore become an essential component of well planning.…”

Impacto del Tiempo no Productivo en Operaciones de Perforación y Análisis de los Datos Mediante la Prueba de Chicuadrado

“…Esta es la causa principal de los retrasos en los proyectos. York et al (2009) encontraron que alrededor del 40% del NPT fueron causado por inestabilidad del pozo y por la presión de poro (amagos, influjo de aguas poco profundas, pérdida de circulación, la inestabilidad del pozo, derrumbes, y el atascamiento de la tubería).…”

Application of Modern Technology to a Multi-position Down Hole Drilling Electronic Circulating Valve and Integral Disconnect Mechanism

“…In the Gulf of Mexico, statistics gathered estimated a total $7.6 billion USD would be spent on stuck pipe issues (Tollefson et al, 2008). In addition, data collected by the James K Dodson Company for Gulf of Mexico deepwater operations between 2004-2009(York, 2009, calculated that 5.6% of total well time of Pre Salt wells would be spent on wellbore stability issues and 12.6% on Sub Salt wells. Extrapolating this to today's potential $100M deepwater well cost, this could be anything between $6M and $12M spent on wellbore stability issues including stuck pipe related issues per well.…”