Fracturing Technique Research Articles

Biomechanical analysis of plating techniques for unstable lateral clavicle fractures with coracoclavicular ligament disruption (Neer typeIIB).

Neer type IIB lateral clavicle fractures are inherently unstable fractures with associated disruption of the coracoclavicular (CC) ligaments. Because of the high rate of nonunion and malunion, surgical fixation is recommended; however, no consensus has been reached regarding the optimal fixation method. A newplating technique using a superior lateral locking plate with anteroposterior (AP) locking screws, resulting in orthogonal fixation in the lateral fragment, has been designed to enhance stability and reduce implant failure. The purpose of this study was to biomechanically compare 3 different clavicle plating constructs within a fresh frozen human cadaveric shoulder model. Twenty-four fresh frozen cadaveric shoulders were randomized into 3 groups (n=8 specimens): group 1, lateral locking plate only (Medartis Aptus Superior Lateral Plate); group 2, lateral locking plate with CC stabilization (No. 2 FiberWire); and group 3, lateral locking plate with 2 AP locking screws stabilizing the lateral fragment. All specimens were subject to cyclic loading of 70 N for 500 cycles. Data were analyzed for gap formation after cyclic loading, construct stiffness, and ultimate load to failure, defined by a marked decrease in the load displacement curve. After 500 cycles, there was no statistically significant difference between the 3 groups in gap formation (P=.179). No specimen (0/24) failed during cyclic loading. Ultimate load to failure was significantly higher in group 3 compared to group 1 (286 N vs. 167 N; P=.022), but not to group 2 (286 N vs. 246 N; P=.604). There were no statistically significant differences in stiffness (group 1: 504 N/mm; group 2: 564 N/mm; group 3: 512 N/mm; P=.712). Peri-implant fracture was the primary mode of failure for all 3 groups, with group 3 demonstrating the lowest rate of peri-implant fractures (group 1: 6/8; group 2: 7/8; group 3: 4/8; P=.243). Biomechanical evaluation of the clavicle plating techniques showed effective fixation across all specimens at 500 cycles. The lateral locking plate with orthogonal AP locking screw fixation in the lateral fragment demonstrated the greatest ultimate failure load, followed by the lateral locking plate with CC stabilization. This new plating technique showed compatible stiffness and gap formation when compared to conventional lateral locking plates as well as plates with CC fixation. The use of orthogonal screw fixation in the distal fragment may negate against the need for CC stabilization in these types of fractures, thus minimizing surgical dissection around the coracoid and potential complications.

Three‐dimensional visualization experimental study on proppant transportation and placement in the Hi‐way channel hydraulic fracturing technique

AbstractThe pattern of placement of the proppant in the fracture determines the stimulation and success of the surgery. Using a three‐dimensional visual parallel plate fracture model capable of simulating fracture height, length, and variable fracture width, we experimentally investigate the impact of fiber loading, fracture fluid viscosity, sand concentration, pulse time, perforation pattern, and injection rate on proppant transport, placement pattern, and access rate. Experimentally and visually, the migration process and the morphology of the proppant placement in the fracture were assessed. The formation laws of stable support columns and well‐shaped high conductivity fracture channels in fractures have been elucidated. Experimental results show that increasing the fiber concentration improves the channel rate and the proppant mass is large and stable. The channel rate increases with the viscosity of the fracturing fluid, and it is difficult to form a perfect channel when the viscosity is small. If the constructive displacement is too slight or too large, it will not favor the formation of a Hi‐way channel in the fracture. The optimal design displacement is 4.5 m3/min. When the proppant concentration is low, the passage rate is large, but the stability of proppant mass is poor under the scour of large displacement, the conductivity is low under the high closure pressure, the proppant concentration is too high, the suspension is difficult, the settlement rate is large, and it is difficult to form a large passage. The current column and the passage rate are larger for pulse times of 15–20 s. Cluster perforations are better than large continuous perforations. The higher the number of clusters in the same number of holes, the higher the channel rate. The formation laws of stable support pillars and well‐shaped high conductivity fracture channels in fractures have been elucidated, which can be useful for efficient stimulation of oil and gas reservoirs.

Minimally Invasive 360° Fusion Using a Combination of INFIX and Minimally Invasive Spinopelvic Fixation by Intraoperative Computed Tomography Navigation for Unstable Pelvic Ring Fracture: A Technical Note

Fluoroscopy is often used in the surgery of unstable pelvic ring fractures, and improved safety in implant placement is an issue. An anterior subcutaneous pelvic fixator (INFIX) combined with a percutaneous screw has been reported to be a minimally invasive and effective surgical technique for unstable pelvic ring injuries. However, although percutaneous screw fixation is minimally invasive, its indications for fracture fixation and fractures with large fragment displacements in the vertical plane remain controversial. Therefore, this technical note aims to describe a new technique for unstable pelvic ring fractures. We describe a 360° fusion of the pelvic ring to treat unstable pelvic ring fractures, including vertical shear pelvic ring fractures, using an intraoperative CT navigation system. Seven patients were treated with 360° fusion for type C pelvic ring fractures. In surgery, after reducing the fracture with external fixation, intraoperative CT navigation is used to perform a 360° fusion with INFIX and minimally invasive surgical spinopelvic fixation (MIS-SPF). We will introduce a typical case and explain the procedure. A 360° fixation was performed, and no perioperative complications were noted. The mean blood loss was 253.2 ± 141.0 mL, and the mean operative time was 224.3 ± 67.4min. In a typical case, bone union was obtained 1 year after surgery, and we removed all implants. MIS-SPF has a strong fixation force and helps reduce fractures' horizontal and vertical planes. In addition, 360° fusion with intraoperative CT navigation may help treat unstable pelvic ring fractures.

Clinical and radiological results of early pin removal in pediatric radial neck fractures treated with stepwise percutaneous leverage technique.

The aim of this study was to compare radiological and clinical results between early (≤3 weeks) and late (>3 weeks) removal of pins in patients treated with the stepwise percutaneous leverage technique for radial neck fractures. 37 patients (aged 3-15) who underwent fixation with stepwise percutaneous leverage technique for Judet class III and class IV radial neck fractures between 2003 and 2019 were included in this retrospective study. Patients were divided into two groups according to the time of pin removal; 19 had early pin removal (≤3 weeks) and 18 had late pin removal (>3 weeks). The patients' radiological results were graded using the Metaizeau classification and their clinical results were evaluated by measuring their range of motion (ROM) and Mayo elbow performance scores (MEPS) at postoperative follow-ups. Statistical tests, including the Mann-Whitney U and Chi-square tests, were performed to compare the demographic factors and outcomes. The mean time of removal of pins for all patients was 21 (10-43) days. The mean time for early and late removal was 15.1 (10-21) and 27.6 (22-43) days, respectively. There was no statistically significant difference between groups radiologically according to the Metaizeau classification (P = .723). Furthermore, no statistically significant difference was found in the ROM (extension/flexion: P = .620, pronation/supination: P = .578) or MEPS (P = .695) between groups. This study has shown us that early removal of pins in patients with pediatric radial neck fractures treated with stepwise percutaneous leverage technique demonstrated good radiological and clinical results comparable to late pin removal. Level of Evidince: Level IV, Therapeutic Study.

Technique of tension band wiring in patella fracture management-our experience

: Fractures of the patella account for about 1% of all skeletal injuries. Displaced patella fractures often result in disruption of the extensor mechanism of the knee. Open reduction and internal fixation is the recommended treatment to restore the extensor mechanism Tension band wiring (TBW) technique using K-wires and stainless steel wires is the most commonly used. The purpose of this study is to study surgical outcome of patella fractures treated with, tension band wiring (TBW) technique and functional outcome of patella fractures treated with TBW technique. It is a Retrospective study of 21 patients carried out from July 2019 to February 2021 admitted to orthopedic ward at our institution. All patients underwent same surgical technique and similar postoperative and physiotherapy protocol. Bostman scoring system was used to perform functional assessment.: In our study there were 14 males and 7 females. Fracture union was achieved in all patients. The mean bostman score was 26.54 at the final follow up.we had 4 complications 1 superficial infection of the surgical wound, 1 knee stiffness and 2 cases of symptomatic implant. We had 8 excellent, 9 good and 4 satisfactory result.: Tension band wiring technique for transverse patella fractures can be a very good option with effective fixation method and relatively easy surgical procedure.

The use of a 30-degree radiolucent triangle during surgery in distal avulsion fractures of the patella

BackgroundAvoiding patella baja or alta after the Krackow suture technique for distal avulsion fractures of the patella can be challenging. We aim to introduce a simple and reproducible technique using a 30-degree radiolucent triangle involving the contralateral knee to ensure the correct positioning of the patella intraoperatively.MethodThe radiolucent triangle is positioned under the contralateral knee before operating the injured knee. A strict lateral view is obtained using fluoroscopy as a reference before a Krackow technique is performed on the avulsion fracture of the patella.ResultsThe triangle technique is straightforward and easily reproducible by surgeons of all levels. It allows the surgeon to correctly position the patella intraoperatively in avulsion fracture repair and modify tension on the patellar tendon.ConclusionThis method avoids millimetric mispositioning of the operated patella, thus improving the management intraoperatively and could decrease postoperative complications.

Efficacy of Fascia Iliaca Compartment Blocks in Proximal Femoral Fractures in the Prehospital Setting: A Systematic Review and Meta-Analysis.

Proximal femoral fractures are characterized as one of the most common and most painful injuries sustained by patients of all ages and are associated with high rates of oligoanalgesia in the prehospital setting. Current treatments include oral and parenteral opiates and sedative agents, however regional anesthesia techniques for pain relief may provide superior analgesia with lower risk of side effects during patient transportation. The fascia iliaca compartment block (FICB) is an inexpensive treatment which is performed with minimal additional equipment, ultimately making it suitable in prehospital settings. In adult patients sustaining proximal femoral fractures in the prehospital setting, what is the effect of the FICB on non-verbal pain scores (NVPS), patient satisfaction, success rate, and adverse events compared to traditional analgesic techniques? A librarian-assisted literature search was conducted of the Cochrane Database, Ovid MEDLINE, PubMed, Ovid EMBASE, Scopus, and Web of Science indexes. Additionally, reference lists for potential review articles from the British Journal of Anesthesia, the College of Anesthetists of Ireland, the Journal of Prehospital Emergency Care, Annales Francaises d'Anesthesie et Réanimation, and the Scandinavian Journal of Trauma, Resuscitation, and Emergency Medicine were reviewed. Databases and journals were searched during the period from January 1, 1980 through July 1, 2022. Each study was scrutinized for quality and validity and was assigned a level of evidence as per Oxford Center for Evidence-Based Medicine guidelines. Five studies involving 340 patients were included (ie, two randomized control trials [RCTs], two observational studies, and one prospective observational study). Pain scores decreased after prehospital FICB across all included studies by a mean of 6.65 points (5.25 - 7.5) on the NVPS. Out of the total 257 FICBs conducted, there was a success rate of 230 (89.3%). Of these, only two serious adverse events were recorded, both of which related to local analgesia toxicity. Neither resulted in long-term sequelae and only one required treatment. Use of FICBs results in a significant decrease in NVPS in the prehospital setting, and they are ultimately suitable as regional analgesic techniques for proximal femur fractures. It carries a low risk of adverse events and may be performed by health care practitioners of various backgrounds with suitable training. The results suggest that FICBs are more effective for pain management than parenteral or oral opiates and sedative agents alone and can be used as an appropriate adjunct to pain management.

Laboratory evaluation on oil-soluble resin as selective water shut-off agent in water control fracturing for low-permeability hydrocarbon reservoirs with bottom aquifer

During the development of low-permeability hydrocarbon reservoirs with bottom aquifer, hydraulic fracturing is essentially employed for commercial oil flow while increasing the potential risk of serious water production, thus water control hydraulic fracturing technology plays important role on addressing this challenge. In this work, a water control fracturing technique is developed to integrate fracture height containment with selective water shut-off. Specifically, oil-soluble resin is used as selective water shut-off agent and is injected with sinking agent simultaneously, carried by fracturing fluid at the fracture generation stage, to establish an improved artificial barrier. Afterwards, a modified fracture conductivity test equipment is designed and manufactured to measure the selective conductivity of the artificial barrier, its sensitivity to temperature, ratio of oil-soluble resin to sinking agent, two-phase flow are studied to evaluate the capability of selective water shut-off.The results demonstrated that 1) the occupation in porous space of sinking agent (0.212–0.425 mm) and the status change from glassy state to high elastic state of oil-soluble resin are mainly responsible for water shut-off; 2) The ratio of oil-soluble resin to sinking agent in 10 g: 70 g and temperature at 75 °C are two critical value to significantly reduce water conductivity in our experiments; 3) Fast dissolution of resin in oil results in oil conductivity over 5 to 100 times higher than water conductivity to achieve selective water shut-off. The results presented herein will provide important guidance on water control in low permeability reservoirs with active bottom aquifer and will promote the unconventional hydrocarbon recovery.

Arthroscopic percutaneous pullout suture transverse tunnel technique repair for tibial spine fractures in skeletally immature patients.

We introduce an arthroscopic percutaneous pullout suture transverse tunnel (PP-STT) technique for repair tibial spine fractures (TSF) in skeletally immature patients (SIPs) to avoid damage to the tibial epiphyseal and evaluate the clinical and radiological outcomes of the PP-STT technique for repair TSF in SIPs. Between February 2013 and November 2019, 41 skeletally immature patients were diagnosed with TSF; 21 patients were treated using the conventional transtibial pullout suture (TS-PLS) technique (group 1), and 20 patients were treated using the PP-STT technique (group 2). We compared clinical outcomes using the International Knee Documentation Committee (IKDC), Lysholm, Tegner, and visual analog scale (VAS) scores and participant sport levels, after a minimum of twoyear follow-up. Residual knee laxity was evaluated using Lachman and anterior drawer tests. Fracture healing and displacement were compared using X-ray. Significant improvements in clinical and radiological outcomes between preoperative and final follow-up (Lysholm, Tegner, IKDC, and VAS scores; Lachman and anterior drawer tests; and fracture displacement; p = 0.001) were achieved in both groups, with no significant between-group differences. Groups 1 and 2 exhibited no significant difference in time to radiographic healing (12.2 ± 1.3weeks vs 13.1 ± 1.5weeks, respectively; p = 0.513) or in the rate of return to sports level (19 (90.4%) vs 18 (90.0%), respectively; p = 0.826). Both surgical techniques provided satisfactory clinical and radiological outcomes. PP-STT may be a suitable alternative to protect the tibial epiphyseal for repair TSP in SIPs.

Phase Field Modeling of Multiple Fracture Growth in Natural Fractured Reservoirs

In recent years, hydraulic fracturing techniques have been widely used in extracting unconventional reservoir resources. During multicluster fracturing process, the stress shadowing effect can lead to a nonuniform distribution of fracturing fluid. In this paper, a two-dimensional multiple fracture propagation model is developed based on phase field method considering the distribution of fracturing fluid within each fracture during fracturing process. The distribution of fracturing fluid injected into each fracture is calculated through solving governing equations of perforation friction as well as wellbore friction. Numerical results demonstrate that the natural fractures in the reservoir have a significant influence on the distribution of injected fluid and the morphology of fracture network. In addition, higher injection rates and higher fluid viscosity stimulations are in favor of inducing uniform distribution of injected fluid into each cluster. The presented numerical model provides an effective tool to extend our understandings in generating fracture networks.

Elbow Arthroscopy for the Treatment of Radial Head Fractures: Surgical Technique and 10 Years of Follow Up Results Compared to Open Surgery

This study aimed to describe the ARIF (Arthroscopic Reduction Internal Fixation) technique for radial head fractures and to compare the results with ORIF (Open Reduction Internal Fixation) at mean 10 years. A total of 32 patients affected by Mason II or III fractures of the radial head who underwent ARIF or ORIF by screws fixation were retrospectively selected and evaluated. A total of 13 patients were treated (40.6%) by ARIF and 19 patients (59.4%) by ORIF. Mean follow-up was 10 years (7-15 years). All patients underwent MEPI and BMRS scores at follow-up, and statistical analysis was performed. No statistical significance was reported in Surgical Time (p = 0.805) or BMRS (p = 0.181) values. Significative improvement was recorded in MEPI score (p = 0.036), and between ARIF (98.07, SD ± 4.34) and ORIF (91.57, SD ± 11.67). The ARIF group showed lower incidence of postoperative complications, especially regarding stiffness (15.4% with ORIF at 21.1%). The radial head ARIF surgical technique represents a reproducible and safe procedure. A long learning curve is required, but with proper experience, it represents a tool that might be beneficial for patients, as it allows a radial head fracture to be treated with minimal tissue damage, evaluation and treatment of the concomitant lesions, and with no limitation of the positioning of screws.

Effectiveness comparison of two minimally invasive plate osteosynthesis techniques for proximal humeral shaft fractures

To compare the effectiveness of lateral approach minimally invasive plate osteosynthesis (MIPO) and helical plate MIPO in the treatment of proximal humeral shaft fractures. The clinical data of patients with proximal humeral shaft fractures who underwent MIPO via lateral approach (group A, 25 cases) and MIPO with helical plate (group B, 30 cases) between December 2009 and April 2021 were retrospectively analyzed. There was no significant difference in gender, age, injured side, cause of injury, American Orthopaedic Trauma Association (OTA) fracture classification, and time from fracture to operation between the two groups ( P>0.05). The operation time, intraoperative blood loss, fluoroscopy times, and complications were compared between two groups. The angular deformity and the fracture healing were evaluated according to anteroposterior and lateral X-ray films postoperatively. The modified University of California Los Angeles (UCLA) score for shoulder and the Mayo Elbow Performance (MEP) score for elbow were analyzed at last follow-up. The operation time in group A was significantly shorter than that in group B ( P<0.05). However, the intraoperative blood loss and fluoroscopy times presented no significant difference between the two groups ( P>0.05). All patients were followed up 12-90 months, with an average of 19.4 months. There was no significant difference in follow-up time between the two groups ( P>0.05). In terms of the quality of postoperative fracture reduction, there were 4 (16.0%) and 11 (36.7%) patients with angulation deformity in group A and group B, respectively, and there was no significant difference in the incidence of angulation deformity ( χ 2=2.936， P=0.087). All fractures achieved bony union, there was no significant difference in fracture healing time between group A and group B ( P>0.05); delayed union occurred in 2 cases and 1 case in group A and group B, respectively (healing time was 30, 42, and 36 weeks after operation, respectively). In group A and group B, 1 patient had superficial infection of incision, respectively; 2 patients and 1 patient had subacromial impact after operation, respectively; and 3 patients in group A had symptoms of radial nerve paralysis of different degrees; all of them were cured after symptomatic treatment. The overall complication incidence of group A (32%) was significantly higher than that of group B (10%) ( χ 2=4.125, P=0.042). At last follow-up, there was no significant difference in the modified UCLA score and MEPs score between the two groups ( P>0.05). Both lateral approach MIPO and helical plate MIPO can achieve satisfied effectiveness in the treatment of proximal humeral shaft fractures. Lateral approach MIPO may be beneficial to shorten the operation time, while the overall complication incidence of helical plate MIPO is lower.

Optimization of Carbon Dioxide Foam Fracturing Technology for Shale Gas Reservoir

Major shale gas exploration and development fields are located in the Sichuan basin. It requires huge water sources for shale gas fracking, but the well sites are mostly in the hills, which limits the industrialization of shale gas development. CO2 foam fluids can meet the requirements of fracking fluids and relieve water stress. It analyzed the feasibility of CO2 foaming fracturing for shale gas formation fracturing, proposed a design philosophy for CO2 foaming fracturing, and optimized fracturing parameters such as foam mass, proppant concentration, friction, and discharge rate. The flowchart of CO2 foam fracturing was established in, where the fracture morphology and propagation behavior of CO2 foam fracturing were obtained from numerical simulations comparable to the hydraulic fracture generated by conventional hydraulic fracturing. The CO2 foaming fracturing technique can provide a discharge rate of 6.0 m3/min and fluid volume and captures the volume effect of the current stimulated reservoir, which needs to be improved. It can be considered an initial survey of CO2 foam fracturing available in the Sichuan Basin shale formation, which may provide new methods and clues for stimulation.

Mechanism and Practice of Multifracturing Using Dynamic Loads in a Low-Permeability Coal Reservoir.

The geological conditions of coal reservoirs in China are complex, and the reservoir permeability is generally lower. Multifracturing is an effective method of improving reservoir permeability and coalbed methane (CBM) production. In this study, two types of dynamic loads, CO2 blasting and a pulse fracturing gun (PF-GUN), were used to conduct multifracturing engineering tests in nine surface CBM wells in the Lu'an mining area in the central and eastern parts of the Qinshui Basin. The curves of pressure versus time of the two dynamic loads were obtained in the laboratory. The prepeak pressurization time of the PF-GUN was 200 ms, and that of the CO2 blasting was 2.05 ms, which just falls in the optimum pressurization time of multifracturing. The microseismic monitoring results revealed that, in terms of the fracture morphology, both the CO2 blasting and PF-GUN loads produced multiple sets of fractures in the near-well zone. In the six wells used for the CO2 blasting tests, an average of three branch fractures were produced outside of the main fracture, and the average angle between the main fracture and the branch fractures exceeded 60°. In the three wells stimulated by PF-GUN, an average of two branch fractures were produced outside of the main fracture, and the average angle between the main fracture and the branch fractures was 25-35°. The multifracture characteristics of the fractures formed via CO2 blasting were more obvious. However, a coal seam is a multifracture reservoir with a large filtration coefficient; the fracture will not extend after reaching the maximum scale under a certain gas displacement condition. Compared with the traditional hydraulic fracturing technique, the nine wells used in the multifracturing tests exhibited an obvious stimulation effect with an average increase of 51.4% in daily production. The results of this study provide an important technical reference for the efficient development of CBM in low- and ultralow-permeability reservoirs.

Self-supporting conductivity in shallow and ultra shallow shale reservoirs: Under hydraulic, CO2 and Sc-CO2 fracturing

To study the differences in self-supporting conductivity among fractures obtained by hydraulic fracturing, CO2 fracturing, and Sc-CO2 (Supercritical carbon dioxide) fracturing, laboratory large-scale fracturing experiments and conductivity tests were carried out. To simulate the reservoir conditions as realistically as possible, the rock slabs used in the conductivity tests were all cut from the samples after fracturing experiments. Before a conductivity test, the fracture surfaces of each rock slab were digitized by laser scanning and 3D reconstruction technology. The JRC of each rock slab is calculated by using the point cloud data. Then, the self-supporting conductivity of each rock slab was tested under different conditions, and a relationship between the JRC, closure stress and sliding displacement and the self-supporting conductivity of fractures obtained by different fracturing techniques was analyzed. The experimental results show that: The JRC of the fractures obtained by Sc-CO2 fracturing is higher than that of CO2 fracturing. Moreover, the JRC of fractures in hydraulic fracturing is the lowest among the three fracturing technologies. The self-supporting conductivity of the fractures has a positive correlation with their JRC value. Compared to hydraulic fracturing and CO2 fracturing, the fractures obtained by Sc-CO2 fracturing have significant advantages in self-supporting conductivity regardless of slip displacement and closure stress.

Improved Methodology of Cross-Sectional SEM Analysis of Thin-Film Multilayers Prepared by Magnetron Sputtering

In this work, an improved methodology of cross-sectional scanning electron microscopy (SEM) analysis of thin-film Ti/V/Ti multilayers was described. Multilayers with various thicknesses of the vanadium middle layer were prepared by magnetron sputtering. The differences in cross sections made by standard fracture, focused ion beam (FIB)/Ga, and plasma focused ion beam (PFIB)/Xe have been compared. For microscopic characterization, the Helios NanoLab 600i microscope and the Helios G4 CXe with the Quanta XFlash 630 energy dispersive spectroscopy detector from Bruker were used. The innovative multi-threaded approach to the SEM preparation itself, which allows us to retain information about the actual microstructure and ensure high material contrast even for elements with similar atomic numbers was proposed. The fracture technique was the most noninvasive for microstructure, whereas FIB/PFIB results in better material contrast (even than EDS). There were only subtle differences in cross sections made by FIB-Ga and PFIB-Xe, but the decrease in local amorphization or slightly better contrast was in favor of Xe plasma. It was found that reliable information about the properties of modern nanomaterials, especially multilayers, can be obtained by analyzing a two-part SEM image, where the first one is a fracture, while the second is a PFIB cross section.

Plating versus Ilizarov Technique for Complex Tibial Plateau Fractures: A Comparative Study on Functional Outcome and Patient Satisfaction

Objective To compare clinical and functional outcomes and complications of open reduction internal fixation (ORIF) by plating and Ilizarov technique in complex tibial plateau fractures. Methods This study is a randomized clinical trial accompanying 56 patients having Schatzker type V and VI tibial plateau fractures. We divided patients into two groups for management. Group I; open reduction internal fixation and Group II; ilizarov technique. We conducted study at the orthopedics department, Jinnah Post-Graduate Medical Center, Karachi, from April-2018 to Oct-2020. The endpoint was to assess patients’ satisfaction and clinical and functional outcomes up to an 18-month follow-up. Results The etiology of tibial fracture was mainly road traffic accident (RTA); 17 (70.9%) in ORIF versus 23 (71.8%) in the Ilizarov group. According to clinical outcomes, excellent extension lag was achieved in 100% of patients in both groups. Most patients had excellent knee flexion, thigh atrophy and instability outcomes (54.1% vs 59.37%, 87.5% vs 81.2% and 83.3% vs. 87.5%). The functional outcome assessment was done and recorded for 18 months of follow-up. There was no significant difference in normal walking, stair climbing, squatting, jumping and duck walking between the groups. The overall rate of complications was similar; 11 (45.8%) in ORIF versus 17 (53.12%) in the illizarov group (p=0.78). Conclusion Our study concludes that there is an excellent clinical and functional outcome found in both procedures as both are safe and effective procedures with fewer complications Keywords Complex Tibial Plateau Fractures, ORIF, Ilizarov Technique

Experimental Study on the Effect of Supercritical CO2 on Mechanical Properties and Fracture Characteristics of Longmaxi Shale

Conventional hydraulic fracturing techniques typically consume large amounts of water when producing shale gas. Fracking fluids may cause environmental pollution. In contrast, supercritical carbon dioxide (scCO2) (above 31.8°C, 7.29 MPa) can displace CH4 in shale reservoirs. Achieve CO2 sequestration while increasing the shale gas production. We studied the mechanical properties and fracture characteristics of a shale under the action of scCO2, nitrogen, helium, and water by comparing the triaxial compression tests of shale samples with seven coring angles. The results show that: (1) scCO2 effectively reduced compressive strength of the shale and weakened the anisotropy of shale; (2) scCO2 caused the content of dolomite, calcite, and illite to decrease by 4.7%∼13.5%, respectively; (3) scCO2 produced micropores and microfractures 10 times larger than the original size in the microstructure. These microstructures can help improve the seepage and gathering of shale gas, leading to enhanced shale gas recovery and CO2 storage.

Experimental Investigation of Asphaltene Deposition and Its Impact on Oil Recovery in Eagle Ford Shale during Miscible and Immiscible CO2 Huff-n-Puff Gas Injection

One of the challenges in extracting oil from unconventional resources using hydraulic fracturing and horizontal drilling techniques is the low primary recovery rate, which is caused by the ultra-small permeability of these resources. Consequently, it is essential to investigate gas injection methods to produce the trapped oil in shale formations. However, the injection process can cause asphaltene depositions inside the reservoir, leading to plugging of pores and oil recovery (OR) reduction. There has been limited research on using gas injection techniques to improve oil production in tight/unconventional resources, although carbon dioxide (CO2) and gas-enhanced oil recovery methods have been used in conventional resources. In order to determine whether or not the cyclic (huff-n-puff) CO2 process improves OR and aggravates asphaltene precipitation, a rigorous experimental investigation was undertaken utilizing filter membranes and Eagle Ford shale cores. After the minimum miscibility pressure was calculated for CO2, various injection pressures were selected to perform CO2 huff-n-puff experiments. Investigations were carried out at 70 °C on injection pressure, cycle number, production time, and huff-and-puff mode injection. The results demonstrated that when the pore size structure of the membranes used was smaller and gas injection cycles increased, a higher asphaltene weight percent (wt %) was determined during the static experiments (i.e., employing filter paper membranes). Miscibility improved OR in dynamic testing (i.e., using shale cores), but a more oil-wet system was detected in wettability measurements taken following CO2 huff-and-puff tests. The plugging impact of asphaltene particles on the pore structure was studied using optical microscopy and scanning electron microscopy imaging. Following the huff-and-puff tests, a mercury porosimeter revealed how severely the pores were plugged, and after the CO2 tests, the pore size distribution reduced as a consequence of asphaltene deposition. This study examines the significance of CO2 injection in OR under miscible/immiscible conditions to identify the critical parameters that could impact the effectiveness of CO2 huff-n-puff operation in unconventional formations.

Investigation of thermal induced damage of deep shale considering in-situ thermal shock effects

Thermal shock caused by injecting cold fluids into hot underground formations, like deep shale hydraulic fracturing and geothermal extraction, is believed to cause deterioration of rock mechanical properties. Consequently, investigating thermally induced damage in deep shale under in-situ conditions is necessary to understand its mechanical behaviors. In this study, the structure and permeability characteristics of shale rock before and after different cooling modes are measured with the gas permeability measurement and CT-Scanning, the compression mechanical response of thermal shock specimens under in-situ conditions and its application prospects are discussed, and a statistical damage model is established eventually to predict deep shale mechanical constitutive. Results show that cooling rate was critical in the deterioration of rock properties, since micro-cracks were induced in water-cooling specimens, the physical properties of these samples were significantly enhanced. Moreover, rock mechanical properties were also deteriorated by thermal shock immensely and the deterioration was aggravated as the contact temperature difference increased. The understanding suggested that thermal shock was beneficial to increase fracture complexity and enhance shale seepage capacity, cryogenic fracturing techniques were applicable in enhancing stimulation response. Finally, the overall experimental and modeling methods introduced in this paper could well reflect the mechanical behaviors of deep shale considering thermal shock effects.