Filter Cake Buildup in Horizontal Wells: Characterization and Impact on Removal Operation

Abstract

The drilling fluid in a vertical well may only be in the pay zone for few hours while in a horizontal well the time can be measured in weeks. This can cause a significant formation damage problem that has the potential for reducing productivity in horizontal wells during drilling operations. A common practice following drilling operations involove filter cake removal operation followed by displacement of wellbore fluids by completion fluid in order to prepare the well for production operations. Presence of drilling fluids in horizontal wells for several weeks is not considered in the design for cleaning fluid recipies targeting drill-in fluid damage. The filter cake buildup time affect its physical characteristics and thus, on the removal process. This study focused on the characterization and the cleanout of the filter cake during the different buildup stages that may occur in the horizontal section. The focus of this study is to highlight the effects of not promptly removing the filter cake. Filter press instrument was used to simulate filter cake formation on the wellbore wall at 500 psi and 300°F. The filter cake formation process was performed using oil-based drilling fluid at different buildup times (i.e., 3 hours, 3 days and 3 weeks), under 500 psi and 300°F. The comparison of the different scenarios showed that a thicker filter cake was formed with buildup time (up to 2.5 inch after 21 days). The CT scan results showed that the heterogeneity increased up to 4 layers and the solubility of in the cleanout fluid decreased to 4% by weight.

One-Stage Calcium Carbonate Oil-Based Filter Cake Removal Using a New Biodegradable Acid System

“…Figure 1 shows a schematic of the filter cake through the wellbore. This filter cake saves the integrity of the wellbore during the drilling operation and reduces the fluid filtrate invasion [3][4][5][6]. To avoid any production restraint, the filter cake must be removed after completing drilling operations and before commencing production [7].…”

Optimizing hematite filter cake treatment using reducing agents

“…The optimal method for hematite dissolution involves the utilization of hydrochloric acid (HCl), given hematite's insolubility in weak acids 31 . The interaction between hematite and HCl yields Ferric chloride (FeCl 3 ), a water-soluble product.…”

“…Siddig et al 31 , probed the dissolution of hematite filter cake using hydrochloric acid (HCl). In alignment with this trajectory, the present endeavor aims to furnish valuable insights into hematite filter cake treatment when reducing agent is incorporated within the treatment solution.…”