Although several workflows have been developed over the years for the design of the optimal sand control solutions in thermal applications, numerous sand control failures still occur every year. This paper aims at assessing the failure mechanism of different sand control techniques and the factors contributing to the failure by analyzing different failed sand control screen samples recovered from thermal and non-thermal wells. Several failed standalone screens have been studied, which were collected from various fields and operational conditions. The screens were first inspected visually, and then certain sections of screens/pipes were selected for more detailed study on the failure mechanism. The liners/screens were cut into sections to be studied through SEM-EDX, reflective light microscopy, X-ray micro CT scan and petrographic thin sections to better understand the localized plugging mechanism. Through the studies of several polished sections, a statistical variation of the plugging zone was found. Moreover, we further focused on the critical zones such as the inlet and outlet of the aperture and the zone adjacent to the formation to better investigate the plugging mechanism. The study on wire wrap screen samples revealed significant plugging of the annular space between the base pipe and the screen. Extensive clay/fines buildup in the annular space led to full to partial clogging in some sections. The base pipe corrosion study reveals that the corrosion mechanism is highly flow dependent since the perforation on the base pipe was enlarged to an oval shape from the original circular shape with its larger axis pointing toward the flow direction. The size of the plugged zone was significantly higher in the outer diameter section where a mixture of the clay and corrosion byproducts plugged the near screen pore space and the screen aperture. Examined premium mesh screen samples showed that the plugging mechanism is highly sensitive to the mesh size and assembly process. The highest pore impairments were associated with mesh screens in which the mesh was directly wrapped around the base pipe causing a reduced annular gap for the flow toward the perforations. The investigation of slotted liner samples showed widest plugging zone in the slot entrance and the lowest on the slot wall. A distinct interplay of the clay and corrosion byproduct led to the adsorption of clay, forming a compacted layer over the slot wall. This paper reviews the plugging mechanism of the standalone sand control screen obtained from the field to provide first-hand evidence of the plugging mechanism and provides explanations for some of the poor field performances. The results could help engineers to better understand the micro-scale mechanisms leading to sand control plugging.

Oil sands applications are well known to be one of the most demanding drilling environments in the industry with regard to durability. The bodies of the cutters and the body of the bit experience severe wear in these applications, leading to inconsistent drilling performance. Extensive efforts in the past decade to solve this issue have been met with limited success. In oil sands applications, the sands are highly abrasive and unconsolidated. The result is that the sand particles quickly become suspended in the drilling fluid and mimic the effect of sandblasting the bit for the duration of the run. In many cases, the bit body wear around the cutters is extensive enough to cause premature bit failure due to cutter loss. The bodies of the PDC cutters themselves also suffer extreme material loss, which leads to cutter breakage and an associated reduction in drilling performance. Finally, in the lateral interval, the sands in cutting beds lying on the low side of the hole cause serious wear to both the gage and backreaming portions of the bit. This paper will discuss new technologies that have proven to eliminate bit wear in the horizontal reservoir interval. Comparisons will be made detailing the severe wear experienced with conventional bits and the absence of wear experienced with identical bit designs using a new body construction technology. A novel PDC cutter will also be presented that has been developed to eliminate cutter body wear. The requirements for improving drilling performance in oil sands applications are as unconventional as the wear experienced in these applications. Unlike traditional applications where improving performance includes an effort to drill faster or further, oil sands applications are typically control drilled and the entire interval is almost always completed in one run. The focus in these applications to augment performance is to improve directional control, enhance backreaming efficiency and hole quality, and increase bit durability. The new technologies detailed in this paper have proven to dramatically enhance each of these key performance indicators, resulting in the ability to drill further and faster, while improving the possibility of success of the well completion.