bluuebunny/crossref_metadata_2025_split huggingface dataset:
High Performance Water-Based Fluid Replaces Oil-Based Mud on the Execution of a Complex 3D Well Trajectory in Aguarague National Park, Bolivia
Authors: Rojas Danny , Soruco Andrea , Jimenez Carlos , Soriano Victor , Ahmed Ramadan 
Published: June 2023

Abstract
The South Sub-Andean Bolivian Basin hosts Aguarague National Park, which prohibits the use of oil-based mud due to its high environmental sensitivity. In response, the drilling team selected a high-performance water-based fluid as the mud system for the 16-inch hole section. The objective was to manage engineering and operational issues related to reactive shales and hole inclination. Lessons learned from an appraisal well drilled in a complex 3D trajectory are presented in this article.
The drilling team designed an appraisal well with two main objectives: to drain hydrocarbons from the main structure and limit reservoir extension. To accomplish these goals, they designed a high-angle S-shaped 3D well, including a 16-inch hole section with an inclination of up to 50 degrees and a slight turn to align geological targets. The section consisted mainly of 1000 m of challenging shale formation at an unfavorable target angle. Moreover, the team used high-performance water-based mud due to environmental constraints in the area.
The drilling team drilled 1250 m of the 16-inch section through high reactive shales without any wellbore stability issues, thanks to accurate density control and suitable mud additive concentrations, such as biopolymers or synthetic polymers. The mud met lubricity requirements and reduced drilling torques. The synergy of the key drilling fluid components produced stable rheology and low fluid loss, proving to be a cost-effective alternative to oil-based mud in environmentally sensitive areas. The team achieved the planned trajectory without major problems, meeting the estimated schedule. The well was completed on time and within budget, and wireline logs were able to survey the open hole without issues. Finally, the 13,375-inch surface casing reached the bottom and was cemented in place successfully.
The drilling team successfully used a high-performance water-based mud system to drill complex 3D well trajectories in the South Sub-Andean Bolivian Basin, despite environmental constraints. The operation's success in achieving well objectives depended on appropriate mud formulation and maintaining the right concentration of shale inhibitors.
Improving Acid Coverage in a Naturally Fractured HPHT Carbonate Reservoir by Combining Chelating Fluids and Chemical Diversion Optimization
Authors: Velázquez Diana L. , Tellez Fernanda , Ramírez Carmen J. , Fragachán Francisco E. , Omer Mohammed , Figueroa Frank , Mejias Gustavo , Brito Bonifacio 
Published: June 2023

Abstract
Uniform distribution of stimulation fluids in a naturally fractured reservoir with high permeability contrasts and a long open hole configuration (more than 800 m) requires an efficient temporary blocking of the preferential zones to allow the fluid to be diverted towards zones with less admission. While having bottomhole temperatures above 175°C means that controlling reaction rates and achieving effective etching to allow appropriate penetration into the invaded zone will be required and thus eliminate skin damage caused during drilling and completion. Therefore, accomplishing the optimal stimulation involves improving not only acid etching efficiency, natural fractures connectivity and adequate fluid penetration, but also achieving homogeneous fluid distribution throughout the interest zone to assure production enhancement.
A chelating base fluid system was formulated based on reservoir evaluation through an engineering process that involved numerous laboratory tests, such as rock dissolution capability, acid etching patter analysis, acid spending time evaluation, corrosion control, and compatibility with reservoir fluids, while optimal diverting agent was carefully selected using advance CFD modeling to confirm diversion effectiveness to uniformly distribute fluids under bottomhole conditions and complex well configuration. Finally, stimulation treatment was defined considering fluid invasion, skin removal and productivity analysis. This paper discusses laboratory tests and modeling results as a coupled engineering process to improve acid coverage during an actual implementation in a HPHT well.
Laboratory results confirmed that the smart fluid system can create long conductive channels increasing conductivity by dissolving rock formation and prevent by-products precipitation. On the other hand, CFD results demonstrated that the application of multi-stage chemical diversion pills at specific conditions (flow rate, volume, rheology) optimizes fluid distribution.
Oil production increased from 3,973 to 4,375 BPD and gas production from 10.0 to 13.4 MMSCFD (½"choke) after executing the stimulation job. Wellhead pressure registered before was 3,845 psi, and after the job increased up to 5,276 psi. Successful stimulation was confirmed with bottomhole conditions which showed an increase of 2,045 psi and 5°C, logged through a bottomhole sensor while the productivity analysis allowed to support skin damage reduction from S=76 to S=0.
A Comprehensive Approach to Organic Precipitation Damage by CPA EoS from Monte Carlo, and Machine Learning Methods
Authors: Cundar C. , Guerrero-Benavides C. , Aristizabal J. D. , Moncayo-Riascos I. , Rojas-Ruiz F. A. , Orrego-Ruiz J. A. , Cañas-Marín W. , Osorio R. 
Published: June 2023

Summary
In this study, an integrated machine learning (ML) model was proposed that allows to identify the risk of organic precipitation damage and estimate the asphaltene onset pressure (AOP). In addition, an estimation of the association parameters to estimate the AOP using a Cubic-Plus-Association (CPA) equation of state (EoS) using stochastics (Monte Carlo) and ML approach was carried out. To predict the asphaltene damage risk the asphaltene stability class index (ASCI) data and the in-situ live crude oil densities were used along with the support vector machines (SVM) method. To propose the AOP-ML model a dataset of 53 samples was considered, evaluating different ML methods. In both cases, 80 % of the dataset was used to train the model, whereas 20% was to validate it. In the Monte Carlo (MC) simulations, 6 fluids taken from literature were used. The ML classification model had a perfect accuracy (100 %), which was compared to conventional compositional asphaltene screening models, with a classification accuracy of 33% for the resin/asphaltene ratio, 29% for ASI, 67% for CII, and 88% for de Boer plot. The AOP-ML model described properly the 77% of the variation of the experimental AOP of the 6 fluids evaluated using a stepwise bidirectional linear regression with 9 input features. Finally, the MC results indicated that several combinations of association energies and volumes reproduce the experimental AOP, obtaining a linear model for estimating the cross-interaction energy with a coefficient of determination of 0.934. This study provides disruptive findings since it opens the possibility of formulating predictive EoS, obtaining the association parameters from a fluid's compositional and structural characteristics. This approach is an opportunity for a comprehensive understanding of asphaltene precipitation damage that allows to understand the mechanisms of formation damage and therefore look for promising solutions to restore the productivity of fields affected by asphaltene precipitation formation damage.
Practical Aspects and Implications of Long-Term CO2 Sequestration in Saline Aquifers Using Vertical Wells
Authors: Moridis G. J. , Reagan M. T. , Huang T. , Blasingame T. A. 
Published: June 2023

Abstract
The primary objective of this work are (a) to analyze the impact of salinity on the attempt to sequester CO2 in saline aquifers by means of vertical wells over long times—covering both the early short injection period and the subsequent long ‘rest’ period of inactivity—by determining its effect on key well and aquifer properties, conditions and rates of mass and heat transport, and (b) to investigate possible methods to mitigate the problems caused by salt precipitation (halite). We use a widely used numerical simulator that accounts for all the multiphase flow and transport processes associated with CO2 sequestration, including halite precipitation. The non-isothermal simulations use a high-definition cylindrical grid with radial subdivisions as small as 0.01 m in the vicinity of the well to accurately capture the critically importance effect of halite precipitation (the evolution and impact of which may be eluded when using coarser grids). Using two different well configurations of vertical wells, we inject CO2 as realistic rates into aquifers with varying salinity levels until a geomechanically safe maximum pressure is attained, and allow the system to rest for 100 yrs. During the entire simulation period, we monitor the evolutions of (a) pressures and temperatures in the near-well region and in the entire aquifer and (b) of mass and heat losses through the overburden. Additionally, we investigate possible methods to alleviate injectability problems caused by halite precipitation. The study shows that (a) wells completed in the entire aquifer depth are more effective in low-salinity aquifers, but shorter wells completed at the base of the aquifer are superior in high-salinity cases, (b) the storage potential of CO2 dissolved in the aqueous phase is limited (both in terms of the magnitude of the dissolved concentration and its spatial extent), and its benefit decreases rapidly with an increasing salinity, (c) salinity can have pronounced adverse effects on the well injectivity, as halite precipitation can cause severe blockage in the vicinity of the well and a rapid rise of the near well pressure to geomechanically unsafe levels, thus potentially reducing the usefulness of an aquifer as a CO2 storage facility and (d) the mitigation of the effects of precipitated halite in the well vicinity is a challenging endeavor, with concurrent H2O-CO2 injection being ineffective.
Tailored Cement Spacer System Improves Barrier Dependability in High Permeability Reservoir Sections in Colombia
Authors: Arroyave Juan Manuel , Paredes Jose Luis , Castro Fabian , Agapiou Kyris , Barreto Diogenes , Vela Jose David , Lopez Alexander , Guzman Leonardo , Fiaga Maria Anayibe , Garcia Nelson 
Published: June 2023

Abstract
Lost circulation (LC), commonly encountered during oilwell drilling and cementing, can be a costly problem that increases non-productive time. LC is especially concerning in high permeability reservoir sections. When LC occurs during cementing, poor annular coverage and cement fall back may occur which results in an undesired top of cement and the need for remediation.
Described herein is the use of a new tailored spacer fluid system engineered to effectively mitigate LC or seepage losses while preparing the wellbore to receive cement.
Ecopetrol S.A, the National Oil Company in Colombia was concerned about cementing production liners in highly permeable, depleted sandstone sections of a formation. The challenges included permeabilities from 7-8 Darcy, lost circulation events, and unacceptable hydraulic seals according to cement evaluation logs resulting in remedial operations. Managed Pressure Drilling (MPD) was an initial solution.
As part of the best cementing practices to meet this objective, designing and tailoring of the spacer needs to be taken into consideration. Optimum tuning allows the cement to cover zones of interest and reduce contamination such that the cement properties can develop and bond with the formation in an efficient way.
A new spacer system was designed to optimize cementing jobs, the tailored spacer system utilizes additive synergies to help prevent LC in porous or fractured formations and enable control of rheological hierarchy and wellbore fluid displacement efficiency.
Use of the new cement spacer system with the tailored approach enabled flawless execution per the job design. The spacer exhibited excellent rheological behavior to meet and maintain hierarchy requirements. Cement was circulated to the top of the liner.
After performing the cementing operation, LC was not observed. Cement bond log (CBL) and variable density log (VDL) results confirmed zonal isolation objectives were achieved. Operations with previous wells in the same field required remedial squeeze jobs to complete. In this case, the Tailored Cement Spacer System helped eliminate the need for remediation, allowing a significant cost saving opportunity on these wells.
The new spacer system successfully employed in high permeability formations in cementing operations in Colombia allowed savings for the operator and helped improve barrier dependability.
A Novel Workflow to Design Cementing Fluids for Loss Mitigation
Authors: Jandhyala Siva Rama Krishna , Yerubandi Krishna , Jimenez Walmy Cuello 
Published: June 2023

Abstract
Lost circulation remedial techniques will be effective when they are tailored for the specific challenge. Examples of factors that govern the remedial technique are the type of losses (induced vs. natural fractures, permeable formations, etc.), characteristic size of loss zone, difference between equivalent circulation density and pore pressure gradient, etc. Typically, localized workflows are designed based on experience from wells where these factors are within certain limits. These workflows are limited to the new wells where these factors are within the same limits. Additionally, these workflows usually involve the selection of certain type/size of lost circulation materials (LCMs) with less emphasis on tuning fluid density, rheology, and pump rates. A comprehensive approach, one that caters to a wide range of loss scenarios and allows tuning all engineering parameters available for tailoring the unique solution is needed.
The work method discussed herein is built using the principles of mass and momentum conservation. These hydraulic calculations also account for rheology changes due to temperature. The domain of analysis is both the wellbore and the loss zone. Thus, any changes in the wellbore will impact the loss rate and vice-versa. To such a two-way coupled system, a cake buildup model is added in the loss zone to describe the role of filter cake resistance on loss rate. Thus, the proposed method is the most comprehensive approach available to model losses based on wellbore pressures, temperatures and plugging of the loss zone. Such a method allows for greater design flexibility to the engineer in tailoring wellbore fluids during drilling or cement operations.
The proposed method is used to understand the sensitivity of the loss zone size to the loss type, loss rate and the depth at which losses occur. This helps engineers highlight the critical information needed from job location to tailor the remedial treatment. The effect of loss zone size on the efficacy of an LCM is demonstrated by evaluating the performance of LCMs of different size and shape. This analysis is useful in tailoring blends made up of different LCMs. Moreover, this work method is used to also compare the impact of rheology and density modification vs. LCMs addition on loss control. This provides greater flexibility in tailoring different aspects of wellbore fluids and placement characteristics.
The understanding gained from the above analysis is used in predicting the loss control performance across multiple jobs. These jobs varied in loss rate and loss type. The proposed methodology presented herein revealed an optimum match with actual field observation for all the evaluated jobs. For an example job, the model was able to predict the observed surface pressure. All this analysis further demonstrates the capability of the work method in combating losses by tailoring different aspects of a cement job.
Numerical Simulation of Cyclic Steam Stimulation and Solvents Enhanced With Nanocatalysts: A Methodologic Approach
Authors: Ruiz-Cañas M. C. , Garcia-Duarte H. A. , Perez-Romero R. A. , Manrique E. 
Published: June 2023

Abstract
One of the alternatives to optimize conventional Thermal EOR is using hybrid technologies such as the combination of steam and solvent enhanced with nanomaterials. Due to the necessity to evaluate nanocatalysts' impact in this hybrid technology, it is necessary to forecast different injection scheme scenarios. This work shows a numerical simulation methodology approach for evaluating the impact of including nanocatalysts in Cyclic Steam Stimulation (CSS) supported by experimental data obtained from previous steam-based hybrid evaluations.
Based on viscosity curves, phase behavior of reservoir fluids and solvent enhanced with nanomaterials, thermogravimetric tests at high pressure, fluid-fluid and fluid-rock tests, and properties of produced oil samples, among others, it was possible to determine kinetic properties required for the construction of the numerical simulation model of the steam-based hybrid technology. The methodology includes the evaluation of injection scheme scenarios to compare the hybrid Cyclic Steam Stimulation (CSS) - solvent with nanoparticles and conventional CSS.
Supported by the experimental results of the hybrid technology and the study of the phenomena involved in this thermal EOR process, a procedure was established that considers the main characteristics of the hybrid cyclic steam technology with solvents enhanced with nanomaterials (HYB-SEN), the reservoir, and some operational variables. The main objective of this procedure is to evaluate the oil production response of the catalysis of aquathermolysis reactions of asphaltenes. Also, this methodology includes the development of the kinetic model based on the thermogravimetric analysis performed on nanoparticles adsorbed by asphaltenes and Friedman's isoconversional kinetic method. The latter allowed for determining the activation energy, pre-exponential factor, and reaction order, which are inputs to numerical simulation. On the other hand, fluid property modeling was useful for integrating experimental tests such as simulated distillation, compositional analysis, properties of crude oil resulting from the aquathermolysis reaction, and the solvent used in the process (Naphtha).
The lack of information on how to represent catalytic phenomena by numerical simulation due to the presence of nanomaterials represents a great challenge to evaluating new hybrid technologies. This innovative methodological approach allows integrating the experimental results into the numerical simulation. It represents physical and chemical phenomena that occur during the process to improve the understanding of the impact of using HYB-SEN for CCS.
How Fluids Performance Ratio Analysis of ICD/AICV can be used to Analyze Oil Production, Unwanted Water and Gas Breakthrough in Carbonate or Sandstone Reservoirs
Authors: Ismail I. Mohd , Bjerke A. , Mathiesen V. 
Published: June 2023

Abstract
Enhanced oil recovery technique for carbonate or sandstone reservoirs using inflow control technology are often affected by undesired production of water and gas. Limited density and viscosity differences between oil, water and gas is often a challenge for most autonomous and passive inflow control technology due to limited fluids performance ratio between oil, water and gas when breakthrough happen. The fluid performance ratio describes how the ICD (Inflow Control Device) and AICD (Autonomous Inflow Control Device) preferably choke the unwanted fluid (water/gas) compared with oil.
Different ICD/AICD are utilizing both density and viscosity that effect the flow behavior difference in the valve to differentiate the pressure drop for oil, water, and gas. Different designs have been tested in single phase and multiphase full-scale flow loop testing that replicates downhole operating conditions. In order to understand the ICD/AICD behavior in reservoir environments for the duration life of the well, a wellbore model where the effect of fluids performance ratio is included. The model also includes the effect of mobility ratio and how this affects the importance of the fluid performance ratio.
Well completion has a critical role to optimize the well performance and enhanced oil recovery. In today’s engineer toolbox, a wide variety of inflow control technology completion options are available including various ICD and AICD. A new methodology and workflow have been developed to compared different type of inflow control technology completion to understand the capability to reduce unwanted water and gas production without needing detailed information about rock property variation along the wellbore in the reservoir. These methods are based on laboratory flow performance data from each device and will compare various downhole inflow control tools based on their fluid phase performance ratio to produce oil, choke water and/or gas and express the fluid preference by ratio in percentage.
Experimental flow loop results illustrate a significant different in fluids performance ratio of conventional ICD and AICV. AICD with dynamic flow area are choking water breakthrough more effectively, resulting in better sweep along the wellbore section that were not previously being produced. By limiting the water and gas production operators are therefore able to apply higher drawdown to increase oil recovery significantly. This improves the economics of thin-oil rim development and benefits of reduced environmental impact per oil produced due to less un-needed water and gas being produced to surface.