Development and Use of a Cost-Effective, Low-Density Cementing System forReducing Equivalent Circulating Densities (ECDs) and Obtaining ImprovedPipe/Cement/Formation Bonding

摘要

Cementing wells drilled through weak formations can result inrnlost-circulation problems. The industry typically uses high-cost,rnlow-density cementing solutions that include the use ofrnhollow beads or nitrogen. In other cases, stage cementing mayrnbe employed, which could also raise the overall well cost. Arnnew, non-nitrified cement system using cost-effective, non-traditionalrncementing materials has been developed that canrnprovide adequate placement and set properties. Emphasisrnduring development of this system was to provide low-density,rnlow-viscosity slurries that would result in the lowestrnequivalent circulating densities (ECD) possible whilernmaintaining sufficient set properties.rnThis paper provides information on performancerncharacteristics of the new cementing systems critical tornproviding effective cementing solutions, includingrncompressive- strength development, flow properties,rnthickening times, and expansion properties.rnCase histories presented show how use of the systemrnresulted in significant savings in cementing cost in wells thatrnrequired reduced ECD.