Quantitative Identification Cracks of Heritage Rock Based on Digital Image Technology

Digital image processing technologies are used to extract and evaluate the cracks of heritage rock in this paper. Firstly, the image needs to go through a series of image preprocessing operations such as graying, enhancement, filtering and binaryzation to filter out a large part of the noise. Then, in order to achieve the requirements of accurately extracting the crack area, the image is again divided into the crack area and morphological filtering. After evaluation, the obtained fracture area can provide data support for the restoration and protection of heritage rock. In this paper, the cracks of heritage rock are extracted in three different locations.The results show that the three groups of rock fractures have different effects on the rocks, but they all need to be repaired to maintain the appearance of the heritage rock.

Semi-Rigid Fixation Using a Sliding Plate for Treating Fractures of the Mandibular Condylar Process

Occlusal displacement often occurs after surgery for condylar process fractures because it is difficult to reduce these fractures precisely. However, performing semi-rigid fixation using a sliding plate may overcome this limitation. A retrospective clinical comparison between semi-rigid and rigid fixations was performed. Among 34 patients who had unilateral condylar process fractures, 17 were treated with rigid fixation and the remaining with semi-rigid fixation using a sliding plate. For all patients, panoramic radiographs were collected 1 day and 6 months after surgery. In these radiographs, ramus height and condylar process inclination were measured, and the differences between the fractured and normal sides were assessed. Additionally, the radiographic density of the fracture area was measured. Differences in surgical outcomes and operative times between the two groups and changes in postoperative deviations within each group were analyzed. There was no statistically significant difference in ramus height and condylar process inclination between the two groups at postoperative day 1 and 6 months. Radio-density was observed to be higher in the rigid fixation group, and it increased with time in both groups. The semi-rigid fixation group had a significantly shorter operative time than the other group did. Semi-rigid and rigid fixations showed no differences in terms of effectiveness and outcomes of surgery. In terms of operative time, semi-rigid fixation was superior to rigid fixation.

Research on Technology of Supporting in Super-Large Section Cut in Working Face with Large Mining Height

For the support problem of the super-large section cut in working face with large mining height, the 1105 cut pilot chamber of Zhaogu No. 2 Mine, the roof strata structure detection and the strata movement rule research were conducted. The results prove that concentrate fracture area, gradually sparse fracture area, and rare fracture area regularly distributed from the surface to the deep area of the roof of 1105 cut, and less fracture exists in the rock stratum of roof above 3.5 m, and the stratum of roof within the range of 4–6 m is stable. Authors propose the long bolt and cable combined supporting technology and optimized the design plan applying theoretical calculation and computer numerical simulation. The scheme has been applied in the field of the 1105 super-large section cut in Zhaogu No. 2 Mine. The monitoring results show that the scheme can effectively control surrounding rock of roadway, and the support with long bolt has good effectiveness.

Incorporation of Neutrally Buoyant Proppants in Horizontal Unconventional Wells to Increase Propped Fracture Area Results for Substantially Improved Well Productivity and Economics

Hydraulic fracturing stimulation of unconventional wells employing large volumes of sand in low viscosity fluids provides propped fracture conductivity in less than 25% of the created fracture area, primarily because of poor sand transport mechanics. The remaining unpropped area is at best only marginally productive using the conventional sand/slickwater hydraulic fracturing process alone. Near-neutrally buoyant proppants (NBPs, ASG 1.055) have proven to be highly effective in accessing production from fracture area that is otherwise left unpropped. Fracture models illustrate the propped fracture area of designs incorporating NBPs is improved to over 85% of the created fracture area. Production simulations of typical slickwater and sand frac designs supplemented with NBPs at 3% by weight of sand distributed evenly throughout the slurry stages show cumulative production increases of 20% to greater than 50% compared to the large volume slickwater/sand treatments without NBPs. Efforts have been directed to justification of the incremental expense involved with the NBP applications and assessment of the associated value-added economic metrics, including the value of the realized incremental production vs. time, the payback time for recovery of the incremental costs, and Return on Investment (ROI). For example, in a 2018 trial of NBP wells in the Middle Bakken formation of North Dakota, the production uplift observed for NBP wells achieved payback of the incremental costs in an average of 26 days; the 1-year cumulative oil production of the NBP wells averaged 69,632 barrels greater than control wells, resulting in a 25% uplift compared to the offset control wells. The Year 1 Return on Investment (ROI) for the drilling and completion costs of the first Middle Bakken well with NBP was 97% versus 64% for the sand-only control wells. Controlled multi-stage horizontal completions of wells with sand-only have been evaluated against wells utilizing NBPs in the application have been executed within several unconventional plays, including the Permian and Williston basins. The performance of the NBP wells have consistently validated the production uplift predictions of the production simulation models. The case studies analyzed herein expand the economic assessment of the NBP stimulation designs by including production analyses quantitative comparison of Net Present Value, production decline rates, and projected EURs of the NBP wells and non-NBP offset wells.

​​The Effect of Platelet Rich Plasma on Wound Healing in the Repair of Experimental Penile Fractures

Background: Penile fractures are caused by the rupture of the tunica albuginea and the underlying layers of corpus cavernosum as a result of the exposure of the erect penis to blunt trauma. Although conservative treatment methods have been recommended in former studies, recent studies favor early surgical options. Platelet-rich plasma (PRP) is a blood product rich in cytokines and several growth factors, obtained from the patient’s own blood commonly used to stimulate healing in acute and chronic wound treatments. The efficiency of homologous PRP treatment in rats with penile fractures have been assessed in terms of clinical manifestation and histopathological findings in the present study. Methods: Thirty-five rats were randomly divided into five groups, each containing seven rats as follows: 1. Conservative group: Following the formation of penile fracture, medical interventions were not initiated on fracture area and the wound was left for secondary healing. 2. Bandage group: Following the formation of penile fracture, self-adherent elastic bandage (3M Coban) was applied to the fracture area for three days. 3. Primary repair group: Following the formation of a penile fracture, the lacerated area was repaired with 7/0 vicryl primary sutures. 4. Primary repair + Homologous Platelet Rich Plasma group: Before the operation, 10 cc of blood was taken from one rat under general anesthesia by intracardiac puncture and PRP material was prepared from this blood. Homologous PRP was topically administered on the wound in the fracture area and then the penile fracture was repaired with 7/0 vicryl as simple separate stitches. 5. Non-operative control group: Surgical procedures were not applied to this group; it was used as the control group. Result: The effect of the PRP treatments on the surgical repair options in the rats with penile fractures was investigated. The present findings revealed that following the repair with conservative treatments, the fracture format persisted and various complications like infection, oedema, excessive fibrosis and hyperemia were encountered. On the other hand, the best healing was achieved in primary repair + PRP group in terms of clinical manifestation and histopathological findings.

Biomechanical Effects of a Cross Connector in Sacral Fractures – A Finite Element Analysis

Background: Spinopelvic fractures and approaches of operative stabilization have been a source of controversial discussion. Biomechanical data support the benefit of a spinopelvic stabilization and minimally invasive procedures help to reduce the dissatisfying complication rate. The role of a cross connector within spinopelvic devices remains inconclusive. We aimed to analyze the effect of a cross connector in a finite element model (FE model).Study Design: A FE model of the L1-L5 spine segment with pelvis and a spinopelvic stabilization was reconstructed from patient-specific CT images. The biomechanical relevance of a cross connector in a Denis zone I (AO: 61-B2) sacrum fracture was assessed in the FE model by applying bending and twisting forces with and without a cross connector. Biomechanical outcomes from the numerical model were investigated also considering uncertainties in material properties and levels of osseointegration.Results: The designed FE model showed comparable values in range-of-motion (ROM) and stresses with reference to the literature. The superiority of the spinopelvic stabilization (L5/Os ilium) ± cross connector compared to a non-operative procedure was confirmed in all analyzed loading conditions by reduced ROM and principal stresses in the disk L5/S1, vertebral body L5 and the fracture area. By considering the combination of all loading cases, the presence of a cross connector reduced the maximum stresses in the fracture area of around 10%. This difference has been statistically validated (p < 0.0001).Conclusion: The implementation of a spinopelvic stabilization (L5/Os ilium) in sacrum fractures sustained the fracture and led to enhanced biomechanical properties compared to a non-reductive procedure. While the additional cross connector did not alter the resulting ROM in L4/L5 or L5/sacrum, the reduction of the maximum stresses in the fracture area was significant.

Novel Learnings of Proppant Transport Behavior in Unconventional Hydraulic Fractures

Effective and economic proppant placement has been one of the key objectives of hydraulic fracturing. Different proppant & fracture fluid characteristics, and placement methodologies have been historically applied based on learnings from standard proppant transport studies with parallel plate slots. The standard test setup represents a simplified planar fracture with constant width and confined height, incorporating only basic flow characteristics, and thus, is incapable of capturing unique phenomena of proppant transport in unconventional reservoirs. In this study, proppant transport laboratory tests were conducted on a large-scale (10 ft × 20 ft) tortuous slot flow system. This novel setup incorporates many significant unconventional fracture features, including lateral and vertical tortuosity, variable width, leak-off, fluid dynamics replicating upward fracture growth, etc. Proppant transport behavior was investigated for multiple parameters such as proppant size, density and concentration; fracture fluid type and viscosity; pumping sequence; pump rate; and fracture properties (width, leak-off location and rate, fracture tortuosity profile, flow directions). The detailed parametric and integrated study of test results includes analysis of proppant dune evolution, dune shape, particle size distribution across dune, propped area, fluid, and proppant collected from leak-off and exit ports. Multiple unique phenomena occurring at tortuous interfaces were observed, including the generation of isolated pockets of proppant pack, restriction of upward movement due to proppant bridging, and creation of discontinuous and sparsely distributed proppant pillars above the dune. The test results demonstrated a larger proppant dune angle in front of the dune peak during injection and a subsequent fall-off of proppant pack with a higher percentage of smaller mesh proppant back filling the area at and near the inlet (analogous to the wellbore). Self-segregation of proppant in slickwater as per mesh size resulted in higher percentage of smaller mesh proppant settled near the injection point, and a higher percentage of larger mesh proppant placed farther in the system. These observations and novel learnings highlight that it is critical to account for tortuous fracture pathway, leakoff effects and flow directions (both lateral and upward) to better understand proppant transport behaviors in unconventional fractures. A partially proppant-filled fracture area is recognized in unconventional fracture in addition to general classification of propped and unpropped fracture area. Utilizing proppant with large mesh size distribution range or pumping smaller mesh proppant first in slickwater helps achieve dual benefits of higher near wellbore conductivity and improved far-field transport. This study demonstrates and physically verifies unique proppant transport behaviors in unconventional hydraulic fractures. It also provides novel learnings that will help the industry to optimize hydraulic fracture design through the selection of optimum proppant and fluid properties with enhanced pumping strategies for overall well productivity improvement in an unconventional reservoir.

A New Fracture Analysis Technique for Charpy Impact Test Using Image Processing

The Charpy impact test is used to identify the transition between ductility and brittleness. The percentages of ductile and brittle fractures in steel can be evaluated based on each fracture area, which is presently determined by an analyzer with the naked eye. This method may lead to subjective judgement, and difficulty accurately quantifying the percentage. To resolve this problem, a new analysis method based on image processing is proposed in this study. A program that can automatically calculate the percentage of the ductile and brittle fractures has been developed. The analysis is performed after converting an RGB fracture image into a binary image using image processing techniques. The final binary image consists of 0 and 1 pixels. The parts with the pixel values of 1 correspond to the brittle fracture areas, and the pixel values of 0 represent the ductile fracture areas. As a result, by counting the number of 0 pixels in the entire area, it is possible to automatically calculate the percentage of ductile fracture. Using the proposed automatic fracture analysis program, it is possible to selectively distinguish only the brittle fracture from the entire fracture area, and to accurately and quantitatively calculate the percentages of ductile and brittle fractures.

Against the Grain: Three Proppant Delivery Approaches That Buck the Status Quo

Pumping proppant down a wellbore is the easy part. Ensuring that the precious material does its job is another matter. A trio of field studies recently presented at the 2020 SPE Annual Technical Conference and Exhibition (ATCE) highlight in different ways how emerging technology and old-fashioned problem solving are moving the industry needle on proppant and conductivity control. These examples include the adoption of unconventional completion techniques in a conventional oil field in Russia and work to validate the use of small amounts of ceramic proppant in North Dakota’s tight-oil formations. Both studies seek to counter widely held assumptions about proppant conductivity. A third study details a recently developed chemical coating that Permian Basin producers are applying “on the fly” to sand before it is pumped downhole. The new adhesive material has found a niche in helping operators mitigate the amount of sand that returns to surface during flowback, a sectorwide issue that drives up completion costs and later may spell trouble for artificial lift systems. Disproving “The Overflush Paradigm” After conventional reservoirs are hydraulically fractured, both from vertical and horizontal wells, it has been standard practice for decades to treat the newly propped perforations with a gentle touch. The approach to this end is known as underflushing. When underflushing, the goal is to leave behind just a few barrels’ worth of proppant-laden slurry over the perforations before attempting to complete further stages. The motivation for this boils down to the need for an insurance policy against displacing the near-wellbore proppant pack and causing the open fracture face to pinch off before it ever has a chance to transmit hydrocarbons. Such carefulness comes at a price. Underflushing raises the risk of needing a cleanout before oil can flow optimally to surface. This not only delays the arrival of first oil, it means extra equipment and personnel are required. However, a more glaring downside to underflushing is that it appears to be an unnecessary precaution. The near-wellbore fracture area is, in fact, more robust than what conventional wisdom allows credit for.