Universal Fluid: A Drilling Fluid to Reduce Lost Circulation and Improve Cementing

Abstract

A universal fluid (UF) is typically a water-base fluid that has been treated with finely ground blast furnace slag and that still maintains the appropriate characteristics of a good drilling fluid. The slag becomes concentrated in the filter cake formed while drilling permeable formations and slowly sets to form a hard layer intimately bonded to the formation. True zonal isolation can be obtained by using a UF and subsequently cementing with slag-based mud solidification technology. Complete mud displacement and efforts to remove filter cake are not necessary prior to cementing since the solidified UF filter cake bonds strongly both to the formation and to the cement and since undisplaced portions of the UF set up as well. The universal fluid (UF) has been developed primarily out of the need to improve cementing in horizontal and extended-reach wells. To date UFs have been used to improve zonal isolation and to reduce or prevent lost circulation or cement fallback during drilling and cementing. Two Diatomite wells in the Belridge Field, California and the vertical portion of one horizontal well in the Midway Sunset Field, California were successfully drilled with a UF and cemented with slag mix cement slurries. Also, a well in the Midway Sunset Field, where losses are routinely experienced, was drilled with a UF specifically to control lost circulation, and no losses were experienced. Five wells in the Peace River area in Canada were successfully drilled with aUF to prevent cement fallback upon cementing.

A Review of Past, Present, and Future Technologies for Permanent Plugging and Abandonment of Wellbores and Restoration of Subsurface Geologic Barriers

“…The formation of many holes in a hydrated cement matrix and the lubrication effect of the oil phase lead to a reduction in strength and an increase in the porosity. Nahm et al (1994), and Hale and Cowan (1991) reported the conversion of designed drilling fluid to cement adding blast furnace slag. This special drilling fluid called universal fluids (UF) was a water-based fluid that would be activated by alkaline materials such as caustic soda and soda ash.…”

Onshore monitoring with virtual‐source seismic in horizontal wells: Challenges and solutions

“…Therefore proper yard/field tests are required to assess this option. For permanent deployment we advocate "cementing" of the coiled tubing in place by means of Shell's Universal Fluid (Nahm et al, 1994) that is used as a drilling fluid but later turns into solid material (Figure 7).…”

Cementos petroleros con adición de escoria de horno alto. Características y propiedades

“…Innovaciones en los procesos de cementación de pozos petroleros ha llevado a la utilización de escoria de alto horno para contrarrestar los problemas surgidos durante la cementación de pozos horizontales, minimizando los problemas de recirculación y facilitando la operación tradicional (6)(7)(8)(9). Algunos trabajos indican que la utilización de un fluido de perforación universal que contenga escoria granulada de alto horno como adición (entre un 25 y un 35%); además del empleo de lechadas de cemento con un porcentaje de reemplazo variable de escoria granulada (entre un 20 y un 40%) (6-9) han sido casos exitosos.…”

“…This has minimised recirculation problems and facilitated traditional well operation (6)(7)(8)(9). A number of authors have proposed the use of a universal drilling fluid containing granulated blast furnace slag as an addition (at rates of from 25 to 35%).…”

“…A number of authors have proposed the use of a universal drilling fluid containing granulated blast furnace slag as an addition (at rates of from 25 to 35%). Cement slurries with a variable replacement ratio of granulated slag (from 20 to 40%) have also been successfully applied (6)(7)(8)(9). To date efforts have focused on optimising this technology, but little has been done to understand hydration processes or strength development in slag-containing cement slurries.…”