Casing Drilling in the San Juan Basin to Eliminate Lost Returns in a Depleted Coal Formation

Abstract

A casing drilling pilot program was conducted in the San Juan basin to determine if lost returns could be eliminated in a depleted coal formation. The pilot program proved that casing drilling can mitigate lost returns drilling through the coal and can be made economic in a low cost environment. The reduction in the amount of fluid lost should result in less damage to offset producing coal wells, resulting in higher ultimate recoveries. Development costs may also be reduced, by replacing directional wells drilled to avoid lost return zones, with lower cost vertical wells. A total of six wells were drilled with non-retrievable casing drilling bits. Two wells were drilled using a casing drilling bit on drillpipe (DP). Based on the bit performance four other wells were drilled with casing. Three wells drilled through the coal and had losses that were eliminated with casing drilling. One well experienced a bit failure and did not drill into the coal. The pilot program was completed with significant learnings. Losses were healed in the coal. A non-retrievable casing drilling system successfully drilled to the intermediate casing point without a trip. The bit design was changed significantly and resulted in 54% improvement in drill rate with instantaneous rates of penetration (ROP) similar to traditional polycrystalline diamond compact (PDC) bits. The initial casing design was modified to decrease vibration, and eliminate fatigue after a failure was experienced. The casing drilling bit was successfully drilled out with an air hammer and hammer bit. Other tools and techniques applied during the pilot program included cement stage tools, foam cement, and aerated fluids to reduce the equivalent circulating density (ECD) and to improve ROP. Introduction Background The San Juan basin is located in northwestern New Mexico and southwestern Colorado in the USA. The majority of the basin is in northwestern New Mexico (Fig. 1).

Computational Modeling of Drilling Fluids Dynamics in Casing Drilling

“…Smaller cutting size coming out of the hole during casing drilling operations is one supporting evidence to smearing effect (Fontenot et al, 2006). Second, eccentric wear on casing drilling couplings has been noticed (Robinson et al 2008). Third, there is a disagreement between the pressure loss obtained in the field and calculated theoretically by Diaz et al (2004) which could be attributed to neglecting the eccentricity effect.…”

“…Several examples from applications around the world include Canadian arctic permafrost by Vrielink et al (2008), Lobo field in south Texas by Fontenot (2003), in Brazil by Placido et al (2005 and, Mississippi Canyon by Rosenberg and Gala (2012), in Peruvian Jungle by Beaumont et al (2010), in Saudi Arabia by Chima et al (2012), in Gabon by Askew et al (2011), in San Juan basin by Robinson et al (2008), and finally in Oman by Sanchez et al (2012). The theory behind the field observations has not been fully understood yet.…”

All in One for Casing while Drilling Technology: Numerical, Analytical, and Experimental Results and Field Observations

“…How does this affect the ECD control? As previously noted in literature (Salehi et al, 2013, Robinson et al, 2008, the casing's eccentricity can play a significant role and experience with ECD control in a CwD application indicates no serious concern for fracturing. Although, loss prevention and well integrity increase is rarely quantified in CwD cases, one of the operators managed to quantify the integrity increase by performing open-hole leak-off tests recording significant improvements (Watts et al, 2010).…”

“…Additionally, due to the larger pipe-to-annulus size ratio of CwD compared to conventional drilling, the casing rotation forms a better mud cake (Figure 1). Previous applications of CwD have reported wellbore stability control improvements , formation damage reductions (Robinson et al, 2008), ROP increases (Placido et al 2005), drilling surface sections, significant NPT reductions (Sanchez et al, 2010;De Luca and Aliko, 2009) and better shallow gas kick management (Costeno et al, 2012).…”

Archives of Mining Sciences

“…Special dedicated drilling bits are permanently attached to casing ending. After reached total depth, BHA is left on casing ending, cemented and drilled up (similar to float should in conventional technology) with next casing column (if required) (Robinson et al, 2008). CwD technology has lots of advantages e.g.…”