Carbon dioxide has gradually found widespread usage in the field of science and engineering while various efforts have focused on ways to combat the menace resulting from the release of this compound in the atmosphere. A major approach to combating this release is by storage in various geological formations ranging from depleted reservoir types such as saline aquifers to other carbon sinks. In this research study, we reviewed the experimental, modeling, and field studies related to the underground storage of CO2. A considerable amount of research has been conducted in simulating and modeling CO2 sequestration in the subsurface. This review highlights some of the latest contributions. Additionally, the impact of CO2 sequestration on its surroundings due to chemical reactions, adsorption, capillarity, hysteresis, and wettability were reviewed. Some major challenges associated with CO2 injection have also been highlighted. Finally, this work presents a brief history of selected field scale projects such as Sleipner, Weyburn, In Salah, Otway Basin, Snøhvit, Alberta, Boundary Dam, Cranfield, and Ketzin. Thus, this study provides a guide of the CO2 storage process from the perspectives of experimental, modelling, and existing field studies.

Hole cleaning for the majority of vertical and directional drilling wells continues to be a substantial difficulty despite improvements in drilling fluids, equipment, field techniques, and academic and industrial research. Poor hole cleaning might cause issues such as stuck pipe incidents, drilling cuttings accumulation, torque and drag, the erratic equivalent circulating density in the annulus, wellbore instability, tight spots, and hole condition issues. In order to enable the real-time and automated evaluation of hole cleaning efficiency for vertical and directional drilling, the article’s objective is to develop a novel model for the cutting transport ratio (CTRm) that can be incorporated into drilling operations on a real-time basis. The novel CTRm model provides a robust indicator for hole cleaning, which can assess complications and enhance drilling efficiency. Moreover, the novel CTRm model was successfully tested and validated in the field for four wells. The results of the real-time evaluation showed that the novel model was capable of identifying the hole cleaning efficiency in a normal drilling performance for Well-C and a stuck pipe issue in Well-D. In addition, the novel CTRm improved the rate of penetration by 52% in Well-A in comparison to Well-B.

The drilling industry has evolved significantly over the years, with new technologies making the process more efficient and effective. One of the most crucial issues of drilling is borehole cleaning, which entails removing drill cuttings and keeping the borehole clean. Inadequate borehole cleaning can lead to drilling problems such as stuck pipes, poor cementing, and formation damage. Real-time drilling evaluation has seen significant improvements, allowing drilling engineers to monitor the drilling process and make adjustments accordingly. This paper introduces a novel real-time borehole cleaning performance evaluation model based on the transport index (TIm). The novel TIm model offers a real-time indication of borehole cleaning efficiency. The novel model was field-tested and validated for three wells, demonstrating its ability to determine borehole cleaning efficiency in typical drilling operations. Using TIm in Well-A led to a 56% increase in the rate of penetration (ROP) and a 44% reduction in torque. Moreover, the efficient borehole cleaning obtained through the use of TIm played a significant role in improving drilling efficiency and preventing stuck pipes incidents. The TIm model was also able to identify borehole cleaning efficiency during a stuck pipe issue, highlighting its potential use as a tool for optimizing drilling performance.

The main challenge in deviated and horizontal well drilling is hole cleaning, which involves the removal of drill cuttings and maintaining a clean borehole. Insufficient hole cleaning can lead to issues such as stuck pipe incidents, lost circulation, slow rate of penetration (ROP), difficult tripping operations, poor cementing, and formation damage. Insufficient advancements in real-time drilling evaluation for complex wells can also lead to drilling troubles and an increase in drilling costs. Therefore, this study aimed to develop a model for the hole-cleaning index (HCI) that could be integrated into drilling operations to provide an automated and real-time evaluation of deviated- and horizontal-drilling hole cleaning based on hydraulic and mechanical drilling parameters and drilling fluid rheological properties. This HCI model was validated and tested in the field in 3 wells, as it was applied when drilling 12.25″ intermediate directional sections and an 8.5″ liner directional section. The integration of the HCI in Well-A and Well-B helped achieve much better well drilling performance (50% ROP enhancement) and mitigate potential problems such as pipe sticking due to hole cleaning and the slower rate of penetration. Moreover, the HCI model was also able to identify hole-cleaning efficiency during a stuck pipe issue in Well-C, which highlights its potential usage as a real-time model for optimizing drilling performance and demonstrates its versatility.

Hole cleaning of drilled hole section of planned oil or gas well is considered as a major part of optimization of rate of penetration (ROP). ROP significantly depends on hole cleaning of drilled hole section. Hole cleaning can minimize hole problems such as stuck pipe incidents, drilling cuttings accumulation, torque and drag, erratic equivalent circulating density (ECD) in annulus, wellbore instability, tight spot and hole conditions and improves well drilling performance to maximum limit of rate of penetration which depends on rig equipment as well, however, hole cleaning will help to utilize maximum output of those equipment to achieve satisfactory performance. In addition, hole cleaning contributes effectively to optimize rig performance as well. It can optimize running time of casings, cementing and well displacement. Hole cleaning is practical more than theoretical and it requires immediate intervention for ensuring efficient hole cleaning to have optimized performance of rate of penetration. In order to achieve proper hole cleaning efficiency, it must be planned and engineered in well design. A new hole cleaning automated models or indexes were developed to monitor, optimize and alert drilling team to realize and recognize and perform an immediate intervention to optimize or control well drilling and operations performance. Drilling parameters and fluid rheology were collected and studied to come up with efficient hole cleaning models. Collected parameters were compared with other hole cleaning models parameters and rate of penetration to assign strong, qualitative and quantitative relationships that support developed models. The hole cleaning model (or hole cleaning efficiency index) can be automated and provide general idea about hole cleaning efficiency applied in drilled hole section and optimized drilling rate. The developed models were applied in challenging hole sections and showed improvement in well drilling and operations performance. Similarly, it has shown improvement of drilling rate more than 50%.