Data-Driven Well Pad Development Performance Review: Focus on the Role of Liner Design on Well Performance

Steam Assisted Gravity Drainage (SAGD) is the dominant in-situ method for oil production in Western Canada. The current study analyzed the relative performance of various well-completion practices using data from 4,000 well pairs that were drilled over a decade. The data analysis provided a unique opportunity to find best operating practices. The scope of this paper is to review the performance of major thermal projects in Canada and investigating the effect of liner design and Flow Control Devices (FCDs) on well pair performance and development. Cumulative oil production and cumulative steam oil ratio (cSOR) were used as the key metrics in comparing the well performance in a SAGD operation. However, to compare different pads and different projects, it was critical to normalize the data with geological variation, well length, well spacing, and with consideration to the well failure rate, remedial completion and re-drills. In this paper we review seven thermal projects of four key operators with almost 3,500 wells and 1,200 well pairs in operation as early as 1996. All geoscience, and production/injection data have been extracted from public databases and utilized to develop a data-driven model. The reservoir thickness variation for each well was determined using available geoscience data, and through the development of a geological model based on the available core data and well logs. The model was used to define the drainage volume for each well pair, which in turn was used to assign a geological ranking to the well. The cumulative oil production and cSOR were then normalized with the geological ranking and the size of the net drainage volume. The number of well pairs in each pad and the cumulative pad production were normalized against the number of days in production and their relative decline, which allowed for comparison between pads within the same project, as well as pads from other projects. The cumulative production of the active pads in each project was used to compare the relative performance of different projects. Also, we separated the projects and wells based on their use of FCDs in the producer and injector to compare the relative performance of each technology in the field. This paper is the initial phase of the study on the role of completion design on relative well and well pad performance. The results will help completion and production engineers to better understand the well pair and pad relative performance and how to normalize the oil production data against geological variation to compare performance.

A comparative study of new-type-retractor-assisted wiltse approach TLIF, MIS-TLIF and traditional PLIF in the treatment of single- level lumbar degenerative diseases

Background To compare the clinical efficacy of new-type-retractor assisted wiltse approach Transforaminal lumbar Interbody Fusion (TLIF), Minimally Invasive Transforaminal Lumbar Interbody Fusion (MIS-TLIF) and traditional Posterior Lumbar Interbody Fusion (PLIF)in single-level lumbar degenerative diseases. Methods A retrospective study was conducted by analyzing clinical and imaging information of consecutive patients with single-level lumbar degenerative diseases who underwent either the new-type-retractor assisted wiltse approach TLIF or the MIS-TLIF or the traditional PLIF. 87 concurrent patients with similar age ,weight and severity of the imaging and symptom between June 2016 and December 2019 were included(wiltse approach 29 cases; MIS-TLIF 28 cases; PLIF 30 cases).The three groups were compared for perioperative indicators(including intraoperative blood loss, postoperative drainage volume, operation time, intraoperative fluoroscopy time, bed time), creatine kinase (CK), Visual Analogue Scale(VAS), Oswestry disability index (ODI), Japanese Orthopaedic Association (JOA) score, intervertebral fusion rate, muscle atrophy and fatty infiltration(including ratio of multifidus atrophy and ratio of lean-to-total cross sectional area(CSA)). Results Intraoperative blood loss, postoperative drainage volume and bed time in MIS-TILF group and wiltse group was significantly lower than PLIF group. The operative time and intraoperative radiation time of MIS-TILF group was significantly longer than wiltse group and PLIF group. CK level in wiltse and MIS-TILF group were significantly lower than PLIF group 1 and 3 days after surgery. PLIF group back pain VAS score was higher than wiltse and MIS-TLIF group. PLIF group displayed a higher ODI and a lower JOA score than the wiltse and MIS-TLIF group 6 months and 12 months after surgery. There was no significant statistical difference in lower limb pain VAS score and intervertebral fusion rate. Ratio of multifidus atrophy in the PLIF group was significantly higher than the wiltse group and the MIS-TILF group. Ratio of lean-to-total CSA (cross-sectional area) in PLIF group was lower than wiltse group and MIS-TLIF group after surgery. There was no significant difference between wiltse group and MIS-TLIF group except that MIS-TLIF group showed longer operation time and intraoperative fluoroscopy time while lower blood loss and drainage volume. 2 cases of durotomy and 2 cases of incision fat liquefaction occurred in PLIF group, 1 case of skin edge necrosis was found in MIS-TILF group. Patients were followed up at 3 months,6moyhs,12months after surgery, The mean follow-up time of the patients was 12.14±2.78 months in wiltse group, 13.57±2.60 months in MIS-TLIF group, and 12.73±2.80 months in PLIF group, with no significant diffirence among 3 groups. (P༞0.05) Conclusion Wiltse approach TLIF assisted with the new-type retractor is a more convenient and simple minimally invasive surgical method than traditional PLIF and MIS-TLIF, which requires a long learning curve, long operation and fluoroscopy time.

The effect of early arm exercise on drainage volume after total mastectomy and tissue expander insertion in breast cancer patients: a prospective study

Background In prosthesis-based breast reconstruction patients, the drain tends to be kept in place longer than in patients who undergo only mastectomy. Postoperative arm exercise also increases the drainage volume. However, to preserve shoulder function, early exercise is recommended. In this study, we investigated the effect of early exercise on the total drainage volume and drain duration in these patients.Methods We designed a prospective randomized trial involving 56 patients who underwent immediate breast reconstruction following mastectomy using tissue expanders. In each group, the patients were randomized either to perform early arm exercises using specific shoulder movement guidelines 2 days after surgery or to restrict arm movement above the shoulder height until drain removal. The drain duration and the total amount of drainage were the primary endpoints.Results There were no significant differences in age, height, weight, body mass index, or mastectomy specimen weight between the two groups. The total amount of drainage was 1,497 mL in the early exercise group and 1,336 mL in the exercise restriction group. The duration until complete removal of the drains was 19.71 days in the early exercise group and 17.11 days in the exercise restriction group.Conclusions Exercise restriction after breast reconstruction did not lead to a significant difference in the drainage volume or the average time until drain removal. Thus, early exercise is recommended for improved shoulder mobility postoperatively. More long-term studies are needed to determine the effect of early exercise on shoulder mobility in prosthesis-based breast reconstruction patients.

Risk factors for 30-day mortality in patients who received DeBakey type I aortic dissection repair surgery

Objective This study aimed to identify risk factors for 30-day mortality in patients who received DeBakey type I aortic dissection (AD) repair surgery. Methods A total of 830 consecutive patients who received acute DeBakey type I AD surgery between 2014 and 2019 were included in the study. The associations between 30-day mortality and perioperative parameters were examined in order to identify risk factors. Results Our data suggested that the overall 30-day mortality rate of all enrolled patients was 11.7%. Unsurprisingly, non-survivors were older and more frequently accompanied with histories of cardiovascular diseases. For intraoperative parameters, the prevalence of coronary artery bypass grafting and cardiopulmonary bypass times were increased in non-survivors. In addition, acute kidney injury (AKI), dialysis, stroke, and deep sternal wound infection were more commonly seen among non-survivors. The multivariate logistic regression analysis suggested that cardiovascular disease history, preoperative D-dimer level, drainage volume 24 h after surgery, and postoperative AKI were independent risk factors for 30-day mortality after DeBakey type I aortic dissection repair surgery. Conclusions Our study demonstrated that cardiovascular disease history, preoperative D-dimer level, drainage volume 24 h after surgery as well as postoperative AKI were risk factors for 30-day mortality after DeBakey type I aortic dissection repair surgery.

Impact of the Tranexamic Acid on Bleeding Amount of Surgical Patient With Degenerative Spinal Disease: A Randomized Blinded Study

Objective: This study aims to explore the effectiveness and safety of tranexamic acid (TXA) in reducing the bleeding amount of surgical patients with degenerative spinal disease in the perioperative period.Methods: A total of 80 cases of patients, who underwent elective posterior lumbar interbody fusion surgeries under general anesthesia, were enrolled in this study. The age of these patients ranged within 41–69 years old, and the surgical vertebral body segments were ≥2. The ASA classification was Level I or Level II. These patients were divided into two groups using the random number table (n = 40): TXA group and control group (S group). In the TXA group, the skin was incised after the anesthesia induction, and 20 mg/kg of TXA was immediately injected into the vein. The injection continued at a rate of 10 mg·kg−1·h−1 during the surgery, until the surgery was finished. In the S group, IV and pump injection with an equal amount of normal saline (NS) were performed. Then, the RBC, Hb, HCT, AST, ALT, BUN, Cr, PT, TT, APTT, FIB, and D-dimer were measured before the surgery and at 1 day after the surgery, and the SSFQ, intraoperative bleeding amount, homologous transfusion volume, urine volume, infusion quantity, surgical duration, drainage volume at 24 h after the surgery, total bleeding amount and adverse event occurrence at 1 week after the surgery were recorded.Results: The RBC, Hb and HCT at 1 day after the surgery were higher in TXA group than in the S group (average P < 0.05). Intraoperative bleeding, drainage volume at 24 h after surgery, and total blood loss were lower in the TXA group than in the S group (average P < 0.05). The SSFQ score and length of stay were lesser in the TXA group than in the S group (average P < 0.05). The differences in AST, ALT, BUN, Cr, PT, TT, APTT, FIB, and D-dimer at 1 day after the surgery for these two groups of patients had no statistical significance (average P > 0.05).Conclusion: TXA can reduce the bleeding amount of surgical patients with degenerative spinal disease in the perioperative period and decrease the length of stay, but does not increase the occurrence rate of adverse events, thereby promoting postoperative rehabilitation.Clinical Trial Registration:www.chictr.org.cn/index.aspx, identifier: ChiCTR2000033597.

Safety and Effectiveness of the Topical Application of Tranexamic Acid to Reduce Drainage of Elderly Femoral Neck Fractures After Total Hip Arthroplasty: An observational pilot study

Background: There is a common disease of femoral neck fractures in elderly patients. And the incidence of postoperative wound bleeding and hyperfibrinolysis is very high. Tranexamic acid (TXA) has a certain effect in decreasing blood loss in orthopaedic surgery. A randomized controlled trial will assess the safety and effectiveness of TXA in decreasing drainage of elderly femoral neck fractures after total hip arthroplasty. Methods: 144 elderly femoral neck fractures are randomly and evenly divided into experimental group and control group, the experimental group receives 3g of infused retrogradely into the drainage tube tranexamic acid mixed in 100ml of saline after the operation and the control group receives an equivalent volume bolus of saline-infused retrogradely into the drainage after the operation. Observation indicators include drainage volume, total drainage volume, and the postoperative hemoglobin loss on the 1st, 2nd, and 3rd day after operation, postoperative wound healing, cardiovascular and cerebrovascular events, and pulmonary embolism, etc. Data analysis was performed using SPSS 25.0 software and GraphPad InStat. Results: The estimated drainage volume was significantly lower in the experimental group than control group on the first day after operation and the second day after operation (p <0.05). And the hemoglobin and hematocrit levels on the first day after operation, the second day after operation, and the third day after operation in the experimental group were higher than those in the control group (P < 0.05). Moreover, there was no significant difference in coagulation function between the two groups, and a lack of significant intergroup differences in the postoperative complications, such as the incidences of deep vein thrombosis, pulmonary embolism, myocardial infarction, reoperation, and readmission or in terms of mortality rates. Conclusion: This clinical study demonstrated that topical application of TXA administration safely reduced drainage and blood loss without affecting the coagulation function for elderly femoral neck fractures after total hip arthroplasty. Abbreviations: TXA=Tranexamic acid; PE=Pulmonary embolism; DVT=Deep vein thrombosis; BMI=Body mass index; MI=Miocardial infarction.

An Efficient Deep Learning-Based Workflow Incorporating a Reduced Physics Model for Subsurface Imaging in Unconventional Reservoirs

We present a novel deep learning-based workflow incorporating a reduced physics model that can efficiently visualize well drainage volume and pressure front propagation in unconventional reservoirs in near real-time. The visualizations can be readily used for qualitative and quantitative characterization and forecasting of unconventional reservoirs. Our aim is to develop an efficient workflow that allows us to ‘see’ within the subsurface given measured data, such as production data. The most simplistic way to achieve the goal will be to merely train a deep learning-based regression model where the input consists of some measured data, and the output is a subsurface image, such as pressure field. However, the high output dimension that corresponds to spatio-temporal steps makes the training inefficient. To address this challenge, an autoencoder network is applied to discover lower dimensional latent variables that represent high dimensional output images. In our approach, the regression model is trained to predict latent variables, instead of directly constructing an image. In the prediction step, the trained regression model first predicts latent variables given measured data, then the latent variables will be used as inputs of the trained decoder to generate a subsurface image. In addition, fast marching-method (FMM)-based rapid simulation workflow which transforms original 2D or 3D problems into 1D problems is used in place of full-physics simulation to efficiently generate datasets for training. The capability of the FMM-based rapid simulation allows us to generate sufficient datasets within realistic simulation times, even for field scale applications. We first demonstrate the proposed approach using a simple illustrative example. Next, the approach is applied to a field scale reservoir model built after the publicly available data on the Hydraulic Fracturing Test Site-I (HFTS-I), which is sufficiently complex to demonstrate the power and efficacy of the approach. We will further demonstrate the utility of the approach to account for subsurface uncertainty. Our approach, for the first time, allows data-driven visualization of unconventional well drainage volume in 3D. The novelty of our approach is the framework which combines the strengths of deep learning-based models and the FMM-based rapid simulation. The workflow has flexibility to incorporate various spatial and temporal data types.

The association between bone mineral density and postoperative drainage volume following cruciate-substituting primary total knee arthroplasty: a cross-sectional study

Background The prevalence of osteoporosis in patients who undergo a primary total knee arthroplasty (TKA) is increasing. Low bone mineral density (BMD) is related to unfavorable outcomes following TKA such as migration of uncemented tibial components. Postoperative blood loss in TKA is an important complication. Non-modifying predicting factors for postoperative blood loss in patients undergoing primary TKA need further elucidation. Studies on the association between BMD and blood loss after TKA are limited. We aimed to demonstrate the relationship between BMD and postoperative drainage volume following primary TKA. Methods A cross-sectional study was conducted between January 2014 and August 2020. A total of 119 primary varus osteoarthritis knees with BMD results were included in the study. Patients with secondary causes of osteoporosis were excluded. Results The median postoperative drainage volume of participants in the normal total hip BMD group and the normal trochanter BMD group was higher than that of patients in the low total hip BMD group and the low trochanter BMD group (285.0 ml vs 230.0 ml, P = 0.003; 282.5 ml vs 240.0 ml, P = 0.013, respectively). Multivariate regression analyses showed that operative time, spinal anesthesia, and normal total hip BMD status were significant predictive factors associated with increased postoperative drainage volume (P = 0.014, 0.022, and 0.013, respectively). No association was identified between the lumbar spine BMD status and postoperative drainage volume. Conclusions The relationship between BMD and postoperative blood loss in primary TKA was identified in this study. Normal total hip BMD was found to be associated with an increased postoperative drainage volume after primary TKA compared with low BMD.

Study on the optimal position of the roof low roadway based on the response surface methodology

For determine the optimum position of the roof low roadway, the optimal solution is derived according to the response surface methodology. The UDEC numerical simulation of the overburden gives the porosity distribution of the strike fractured zone, the upper limit heights of the caving zone and the fractured zone are obtained as 18 m and 65 m, respectively. Based on the porosity distribution, the FLUENT numerical models of the goaf zone, air inlet roadway, air return roadway, working face and roof low roadway were established to simulate the gas concentration in the upper corner and gas drainage volume in roof low roadway during mining. Using the vertical and horizontal distance of the roof low roadway as the influencing factors, the experimental scheme of the position of the roof low roadway was designed according to the response surface method, and the response values were obtained from the FLUENT simulation experiments, predicting that the vertical and horizontal distances of the roof low roadway were 7.7 m and 5.9 m respectively when the interaction between the gas concentration in the upper corner and gas drainage volume in roof low roadway was optimal. Field tests showed that the average gas concentration in the upper corner and the average gas drainage volume in roof low roadway were 0.432% and 40.861 m3/min respectively, both of which were less than 10% of the error from the simulations. The design of the roof low roadway has effectively managed the gas accumulation problem in the upper corner.

The efficacy and safety of topical tranexamic acid for spinal surgery: a meta-analysis

Background: Spinal surgeries are often accompanied by significant blood loss both intraoperatively and postoperatively. Excessive blood loss caused by surgery may lead to several harmful medical consequences. Tranexamic acid (TXA) is a kind of antifibrinolytic agent that has been widely used in spinal surgery. Currently, it is commonly accepted that intravenous TXA (ivTXA) can reduce blood loss in spinal fusion surgeries. Compared with ivTXA, topical TXA (tTXA) seems to be much easier to administer. This advantage provides a maximum concentration of TXA at the hemorrhagic site with little to no TXA entering the circulation. Objective: To evaluate the effect of tTXA on blood loss during and after spinal surgery via a comprehensive meta-analysis of the published data in randomized controlled trials (RCTs) and other comparative cohort studies. Methods: A comprehensive search of PubMed, EMBASE, the Web of Science, and the Cochrane Central Register of Controlled Trials were performed for RCTs and other comparative cohort studies on the effect of tTXA on blood loss during and after spinal surgery. The outcomes were total blood loss, hidden blood loss, intraoperative blood loss, total postoperative drainage volume, drainage tube duration postoperatively, drainage volume and drainage of blood content at postoperative day (POD) 1 and POD2, length of hospital stay, number of patients who received a blood transfusion, serum HB level at POD1, operative timespan, side effects, and complications. The final search was performed in October 2020. We followed the PRISMA guideline, and the registration number is INPLASY202160028. Results: In total, six studies with 481 patients were included. tTXA treatment, compared with the control conditions, can significantly reduce the total blood loss, hidden blood loss, total postoperative drainage volume, and several patients receiving blood transfusions; reduce the drainage volume and drainage of blood content at POD1; shorten the drainage tube duration postoperatively and length of hospital stay, and enhance the serum HB level at POD1 for spinal surgery. tTXA treatment did not significantly influence the intraoperative blood loss, drainage volume, or drainage of blood content at POD2 or the operative duration. Conclusion: Compared with control conditions, tTXA has high efficacy in reducing blood loss, and drainage volume enable quick rehabilitation and has a relatively high level of safety in spinal surgery.