Experimental Study on the Initiation and Propagation of Multi-Cluster Hydraulic Fractures within One Stage in Horizontal Wells

Competitive propagation of fractures initiated from multiple perforation clusters is universal in hydraulic fracturing of unconventional reservoirs, which largely influences stimulation. However, the propagation mechanism of multi-fractures has not been fully revealed for the lack of a targeted laboratory observation. In this study, a physical simulation experiment system was developed for investigating the initiation and propagation of multi-cluster hydraulic fractures. Different from the traditional hydro-fracking test system, the new one was equipped with a multi-channel shunting module and a strain monitoring system, which could guarantee the full fracture extension at each perforation clusters and measure the internal deformation of specimens, respectively. Several groups of true tri-axial fracturing tests were performed, considering the factors of in situ stress, cluster spacing, pumping rate, and bedding structures. The results showed that initiation of multi-cluster hydraulic fractures within one stage could be simultaneous or successive according to the difference of the breakdown pressure and fracturing fluid injection. For simultaneous initiation, the breakdown pressure of the subsequent fracture was lower than or equal to the value of the previous fracture. Multiple fractures tended to attract and merge. For successive initiation, the breakdown pressures of fractures were gradually increasing. The subsequent fracture tended to intersect with or deviated from the previous fracture. Multiple fractures interaction was aggravated by the decrease of horizontal stress difference, bedding number and cluster spacing, and weakened by the increase of pump rate. The propagation area of multiple fractures increased with the pump rate, decreased with the cluster spacing. The strain response characteristics corresponded with the initiation and propagation of fracture, which was conducive to understanding the process of the fracturing. The test results provide a basis for optimum design of hydraulic fracturing.

Topical Nitroglycerin for Osteoporosis: Old Drug New Application

ABSTRACT Osteoporosis is a progressive bone disease characterized by a decrease in the bone mass and density, which can lead to an increased risk of fracture. Multiple treatments have been formulated for it like calcium, vitamin D supplements, bisphosphonates, raloxifene, hormone replacement therapies, teriparatide and calcitonin. However, all of these have their own shortcomings. Topical nitroglycerin is a cost-effective, novel medication that not only increases bone formation but also decreases its resorption, and also has the potential to decrease vertebral fractures more than that provided by the existing treatments. Therefore, it could be the answer to the need of an efficacious, cost-effective, affordable, safe and a convenient form of therapy for the prevention of post-menopausal bone loss and osteoporosis as a whole. Therefore, we recommend that individuals with osteoporosis be treated with topical nitroglycerin ointment (15 mg/day). How to cite this article Malhotra J, Garg R, Agrawal P, Agarwal A, Singh O. Topical Nitroglycerin for Osteoporosis: Old Drug New Application. J South Asian Feder Obst Gynae 2016;8(1):1-3.

Design of Y422 Retrievable Fracture Bridge Plug and Analysis of Slip Characteristics

According to the demand of exploiting the poor-thin oil layer in Daqing oilfield, Y422 retrievable fracture bridge plug is designed. Match usage of this bridge plug and other instruments can fracture multiple oil reservoirs with one-trip string, which is characterized by simple technology and safety operation. This bridge plug has realistic significance and practical value for improving oilfield economic benefits and provides an extensive application prospect. After setting process, the slips brace the bridge plug whose performance have a directly influence on the oil well productivity and production safety. In order to make sure that the bridge plug slips can meet the anchoring requirement, the actual working state of the slips system was analyzed by using finite element software, and the stress distribution rules were obtained. The results provide theoretical basis for optimizing slip structure and improving working reliability.

Metastatic Pulmonary Adenocarcinoma in a Llama (Lama Glama)

An adult female llama with a comminuted fracture of the left femoral head was necropsied. A firm multinodular mass infiltrated skeletal muscle adjacent to the fracture. Multiple, firm, white nodules were in the pulmonary parenchyma and pleura. A single nodule was in the liver. Microscopically, transition from nonneoplastic bronchiolar epithelium to neoplastic epithelium that formed acinar structures was evident at bronchioloalveolar junctions. A diagnosis of pulmonary adenocarcinoma was made. Similar neoplastic tissue was in the liver and in the perifemoral mass. Immunohistochemically, neoplastic cells were positive for pan-cytokeratin, cytokeratin 7, and cytokeratin 5/6 antibodies and negative for vimentin and cytokeratins 8/18 and 20.

Revascularization of the Scalp by Microsurgical Techniques after Complete Avulsion

A total scalp replantation was performed after a complete traumatic avulsion of the scalp with skull fracture. Multiple arterial and venous anastomoses were required. Satisfactory healing occurred, and the patient has had a subsequent uneventful cranioplasty to fill a bony defect, with normal scalp healing.