Abstract
Drilling with Casing (DWC) has been used in over 2200 strings in the last 10 years in Argentina and Bolivia. More than 1400 of the total strings were for surface casing applications.
In Argentina and Bolivia, drilling with casing has been used extensively in mature fields and shale applications. In all the cases, the objective was to reduce cost and improve efficiency during drilling. However the drivers where not always identical, in some cases the technology aimed to overcome drilling difficulties as wellbore stability and circulation losses; in others reduce drilling time and increase efficiency.
The objective of this paper is to present the approach taken for the optimization of drilling parameters and reliability of the Drilling with Casing operation in the 13 3/8" sections of Vaca Muerta. A detailed and engineered path followed since the beginning of this initiative shows steps taken in the casing string design to minimize the possibility of failures and at the same time allow for an increased Rate of Penetration, contributing to well optimization by reducing drilling times and risks.
YPF has standardized DwC for surface section (9 5/8") of their slim wells in Vaca Muerta, and has begun to extend this application to robust design wells with 13 3/8" surface casing sections.
DwC operations with 13 3/8" started successfully in two wells in La Amarga Chica field. However, two consecutive failures occurred later in Las Cavernas field, creating uncertainty on the method. This led to a reevaluation of the technology and the need of looking for alternative solutions, such as the strengthening of the BHA with thicker pipes to prevent casing buckling and fatigue. This includes the possibility of considering hardfacing centralization to increase the stiffness of the string.
These actions were implemented for the following DwC operations in 13 3/8" in La Amarga Chica. In addition the Shoe Track was eliminated, resulting a successful initiative, but with opportunities of improvement in terms of optimization of drilling parameters.
In the subsequent 13 3/8" DwC jobs of Loma La Lata and Las Cavernas fields, the dynamics of the drilling procees where monitored by means of the measuring device coupled with a visualization tool developed for this purpose.
