Abstract
Today’s North American land drilling and cementing are facing new challenges due to increased hydrocarbon extraction, especially in the Permian basin. For instance, operators in the region frequently face severe losses during drilling or cementing, which are not prevalent in the other US basins. Lost circulation is a major problem that increases well construction costs and time as well as delays well completion and production in a market where efficiency and costs are the main drivers.
Solutions to this perennial problem include two-stage cementing, contingency liners, and use of lightweight cement systems. Lightweight cement reduces hydrostatic pressure to prevent losses particularly in weak formations. Typically, lightweight cements are designed by incorporating expensive micro spheres and/or foam. These designs are relatively costly compared to conventional technologies, and they involve operational complexity in the field. There are other cost-effective materials that allow for designing lower density cements, which have pozzolanic reactivity to increase strength of the set cement. But these traditional materials cannot provide enough compressive strength in the 10.3 ppg to 11.5 ppg density range.
In this paper, several case histories will be presented from more than 100 jobs pumped to date. The selected job(s) will be explained with real-time acquisition data, and these data will be compared to pre/post-job computer simulations to explain the dynamics of the placement. Numerous field applications of the novel and cost-effective non-beaded lightweight cementing technology will be described. The new lightweight has a lower hydrostatic pressure during pumping, hence preventing the occurrence of lost circulation. It also delivers superior strength after cement setting, thereby providing better zonal isolation and mechanical support to the casing. Because of its efficient delivery utilizing the same equipment, processes and personnel, this new cementing technology is easily integrated into the current field operations.
The novel contribution to the industry is the successful field application of a non-beaded lightweight low permeability cement to more than 100 jobs. This lightweight cement is uniquely formulated with a new unconventional micromaterial that provides superior strength performance, improved operational efficiency, and safety combined with better economics over beaded or foamed cement system. Based on multiple jobs that were completed, this innovative lightweight cement has successfully mitigated losses, thus maintaining lower equivalent circulating densities to achieve the required top of cement. It also eliminated the need for multiple cementing stages, thereby enabling faster well completion and dramatically reducing well construction costs.
