Unconventional Method of Estimating Oilfield Reserve Initially in Place Using Decline Trends Analyses Techniques

Methods to estimate reserves, recovery factor and time are highlighted using uconventional method, to reduce the challenges in an oilfield development. General Information about reserves production estimation using long and short production data is collated. The collated data are plotted against time to build production decline curves. The curves are used to estimate the decline rate trends and constants. The decline constant is then used to predict reserves cumulative recovery. The rate trend is extrapolated to abandonment for estimation of reserves initially in place, recovery factor and the correspondent time. The reserves values are compared with field values for accuracy. It was observed that the result using data from long time production history accuracy was 99.98% while evaluation models built with data from short production history accuracy was 98.64%. The models are then adopted after validation. The validated curves are used to build the governing models which are finally used in estimating cumulative reserves recovery and initially in place. It is concluded that accurate reserves, recovery factor and time estimation challenges can be achieved/matched up using rate decline trend techniques.

Study on the Production Mode of Horizontal Well from Water Huff and Puff to Segmented Injection and Production in Tight Reservoir

Water huff and puff in horizontal wells in tight reservoirs has achieved good results in replenishing formation energy. However, after multiple rounds of treatment, a rapid decrease in formation pressure takes place making it difficult to maintain stable production. To improve the oil recovery rate of tight reservoirs, it is imminent to change the development mode. In this work, the stress distribution characteristics at fracture tips were analyzed based on Irwin theory and elastic theory. A model of propagation and closure length of fractures was established based on the propagation mechanism of water injection-induced natural fracture and the energy balance principle of fracture mechanics. Surfactant imbibition experiments were carried out according to the imbibition principle of surfactant system, and the propagation law of natural fractures was described with numerical simulation to analyze the seepage characteristics of dynamic fracture network. On the basis of the above works, alternating water huff and puff into segmented injection and production was proposed according to the distribution law of dynamic fracture network. The developing process of an actual well case by these two developing modes was simulated to predict 18 years of cumulative recovery, pressure distribution, and recovery rate. Results showed that when stress intensity factor exceeds the fracture toughness, the natural fractures will extend along their original directions and get connected, forming an irregular fracture network. The lengths of fractures after propagation and closure will not bring about water channeling for they are far shorter than well and interval spacing. Surfactant could diminish the resistance of boundary layer by reducing the wetting contact angle, ending up with an improvement in imbibition efficiency. Radial displacement and dynamic imbibition occur simultaneously in a dynamic fracture network during the early stage of water injection, while static imbibition mainly occurs during injection shutdown period and well soaking. According to comparison, the swept area of segmented injection and production was larger, ending up with a continuous increase of simulated recovery rate and cumulative recovery. The findings of this study show alternating water huff and puff after to segmented injection and production in fractured tight reservoir can allow full play of dynamic fracture network’s potential and achieve effective enhancement in oil recovery rate.

Absorption, Distribution, Metabolism, and Excretion of Aprocitentan, a Dual Endothelin Receptor Antagonist, in Humans

Background: Aprocitentan is an orally active, dual endothelin receptor antagonist that may offer a new therapeutic option for the treatment of difficult-to-control hypertension. Objective: To investigate safety, tolerability, mass balance, absorption, distribution, metabolism, and excretion of aprocitentan. Methods: : In this single-center, open-label study a single oral dose of 25 mg containing 3.7 MBq of 14C-radiolabeled aprocitentan was administered to 6 healthy male subjects to investigate safety, tolerability, mass balance, absorption, distribution, metabolism, and excretion of aprocitentan. Metabolites were identified using mass spectrometry and, where possible, confirmed and quantified with reference compounds. Results: Aprocitentan was well tolerated and there were no clinically significant findings for any safety variable. The geometric mean cumulative recovery of radioactivity from urine and feces over 14 days was 77% of the administered radioactive dose, with 52.1% cumulative recovery from urine, and 24.8% from feces. Concentrations of total radioactivity in whole blood were markedly lower compared to plasma. In plasma, 94.3% of total radioactivity was aprocitentan. In urine and feces, 5 and 2, respectively (in feces one being aprocitentan) main products were identified. Metabolism data of aprocitentan identified two main elimination pathways, glucosidation to M3 and hydrolysis to M1, representing approximately 25% and 32% of the radioactive dose, respectively. Conclusions: Based on these metabolism data, aprocitentan can be concomitantly administered without dose adjustment with drugs that are inhibitors or inducers of any metabolizing enzyme, specifically cytochrome P450 enzymes.

Sulfur Uptake from Fertilizer Fortified with Sulfate and Elemental S in Three Contrasting Climatic Zones

Field trials with labeled fertilizers can be used to provide information on fertilizer efficiency, residual value, and nutrient fate. We assessed the uptake from elemental S (ES) and sulfate S (SO4-S) in S-fortified monoammonium phosphate fertilizers by various crops at three sites in Argentina, Brazil, and Canada. The S sources were labeled with 34S, and the 34S abundance in the plant tissue was analyzed at an early stage and at maturity over two consecutive years. At the sites in Argentina and Canada, the recovery of ES in the crop was smaller than that of SO4-S in the first year, while the opposite was true in the second year. At the Brazilian site, the recovery of ES was similar to that of SO4-S in the first year, but higher in the second year. In the Argentina and Canada sites, the cumulative recovery of SO4-S was >65% and that of ES was 20−25%. In the Brazilian site, the cumulative recovery of SO4-S was 9% and that of ES 16%. The higher recovery of ES than of SO4-S in the Brazilian site was attributed to leaching of added SO4-S and relatively fast oxidation of ES due to the warm climate. These results suggest that ES may be more suitable than SO4-S as a fertilizer S source in warm humid climates, while inclusion of SO4-S in the fertilizer is recommended in colder climates as slow oxidation limits the initial availability of ES.

INDONESIAN COVID-19 CASE MODELING USING GAUSSIAN EQUATION

The WHO have been setting Covid-19 as pandemic since it spread over the world including Indonesia. Modeling is needed to see the possibility of this case for raising awareness. This research had been conducted to build a model using the Gaussian equation for modeling the Covid-19 case in Indonesia to fulfill the model gap in previous research. The data acquisition is scraping from Line Siaga official account in Line chatting platform based on KEMENKES RI publication. This Modeling is yielding several models and RMS Error: a daily positive case, a daily recovery, a daily death, the cumulative positive case, the cumulative recovery, the cumulative death, a daily active case, and the cumulative active case. Modeling was started on 2 April 2020 and set parameters that want to be evaluated on 12 April 2020, and evaluating the model on 21 April 2020. The result shows that the infection could exceed 33275 cases and 4342 death. The RMS Error is increasing, the cumulative model generally 56% to 115%, 35% to 52% for daily cases, and 5% to 15% for death and recovery rate. From the RMS Error shows that the equation has not a good precission which affected by the community behaviour and also the goverment policy that could reshaping the curve quite significant. The other possible factor is the reliability of the data, there is dependency between positive case and amount of testing which leads to represents the cummulative positive case to not exactly the same in reality.

Cumulative Active and Recovery Rates Based Criterion for Gradual Lockdown Exit: A Global Observation of SARS Cov-2 Management

On March 11, 2020 the World Health Organization (WHO) had declared SARS-CoV-2 pandemic; and at present there are over 6 million cases across the globe. Based on the interim guidelines of WHO, most of the countries opted for social distancing with lockdown as the only way to control the pandemic. This led to ‘Manufacturing’ shut down, which acted as a spanner in the wheel for international supply chain leading to pressure on governments to review the protocols of the lockdown. We studied epidemiological parameters for 18 countries and obtained crossover time point referring to cumulative case active and case recovery rates and the time point for the peak positive confirmation rate in a time window of 92 days; and linked with the respective governmental decisions. For countries awaiting crossover, time series non-linear models could be used for predicting the crossover point. A sample study was carried out for India. The median time for reaching crossover for 12 countries was 37 days, while peak positive confirmation rate was 30 days after their first intervention. These countries enforced strict lockdown regulations and have shown constant improvement in their recovery rate even after crossover time point. A phase wise relaxation of lockdown is evident after crossover point in most of these countries. The crossover time point with the subsequent increasing recovery rate can be a strategy for lockdown relaxation as evident from the experiences of few countries. Also, we propose a criterion based on 28 cumulative recovery and fatality rate for micro-management of lockdown.

Estimating COVID-19 pandemic severity in Indian context

The case fatality rate (CFR) represents one of the most vital factors in demonstrating the severity of novel infectious disease, COVID-19. Various estimates of COVID-19 fatalities (based on the publicly and published information and data in Indian context of COVID-19): confirmed CFR, asymptomatic CFR, symptomatic CFR, and hospitalized CFR were 2.32% (2.05-2.59), 0.14% (0.12-0.16), 0.32% (0.27-0.36), 1.86% (1.64-2.07) respectively. The relative susceptibility of developing symptoms (RSODS) and relative susceptibility of developing infection (RSODI) of COVID-19 were ~33 times higher among people aged <45 years. The RSODS estimates were 1.97 (0.47-3.47), 0.62 (0.15-1.09), 0.29 (0.07-0.52), 0.06 (0.02-0.10) respectively, for patients <45 years, 45-60, 60-75, >75 years. Similar trend, for RSODI were found, with relatively higher value, compared to RSODS, which decreased with the increase of age. The 14-day lag estimate of CFR were 18.07 (15.67-20.47), and outcome (deaths plus recoveries)-based estimate of CFR were 16.57 (14.65-18.49). The growth rate, serial interval, reproduction number and average time from onset of COVID-19 infection to death were 6.12% (5.30%-6.99%), 11.4 days (9.91-12.85), 1.03 (1.01-1.05), and 11.85 days (10.55-13.15), respectively. Among 1,673,688 samples tested, 62,939 (3.76%) were positive for COVID-19 accounting 1,228 tests per million population of India, as of May 10, 2020. The average daily recovery was 19.45% (14.75- 24.15) and average cumulative recovery was 12.68% (10.70- 14.66) among COVID-19 patients. As per our belief and knowledge, this is the first study of its kind in reporting COVID-19 severity in Indian context during pandemic.

End-to-side versus side-to-side anastomosis after laparoscopic right hemicolectomy for colon cancer: Short-term outcomes of a randomized controlled trial.

27 Background: A standard anastomotic configuration after right hemicolectomy is not well established, although short-term benefits of end-to-side anastomosis have been reported. This study was designed to assess the superiority of end-to-side anastomosis compared to side-to-side anastomosis after laparoscopic right hemicolectomy for colon cancer under an enhanced recovery program. Methods: Between September 2016 and August 2019, 130 patients (18–80 years) scheduled for laparoscopic right hemicolectomy were randomly assigned (1:1) to undergo end-to-side ( n = 65) or side-to-side ( n = 65) anastomosis. All patients underwent an enhanced recovery program with early diet and mobilization. The primary outcome was the cumulative recovery rate 7 days after surgery, defined as the percentage of patients who met all of the following recovery criteria: tolerated diet for 24h, analgesic-free, safe ambulation, and afebrile status without major complications. Results: The cumulative recovery rate did not differ between end-to-side (92.3%, 60/65) and side-to-side anastomosis (92.3%, 60/65) ( P = 1.000). Both approaches had similar cumulative recovery rates at 4, 5, and 6 days (end-to-side vs. side-to-side: 41.5% vs. 35.4%, P = 0.589; 73.8% vs. 63.1%, P = 0.257; 86.2% vs. 81.5%, P = 0.634; respectively) The median recovery time [interquartile range (IQR)] in the end-to-side and side-to-side groups was 105 [90-124] hours and 113 [84-139] hours, respectively ( P = 0.474), showing no significant difference. Length of stay [IQR] was similar in the end-to-side and side-to-side groups (5 [5–7] vs. 6 [5–7] days; P = 0.376). The 30-day complication rate (16.9% vs. 12.3%, P = 0.620), enhanced recovery program failure rate (10.8% vs. 7.7%, P = 0.763), and 30-day readmission rate (4.6% vs. 3.1%; P = 1.000) were not significantly different between the groups. Conclusions: This is the first randomized controlled trial showing that end-to-side anastomosis is not superior to side-to-side anastomosis in terms of short-term outcomes after laparoscopic right hemicolectomy. Clinical trial information: NCT02897531.

Study on Minimum Miscible Pressure and Oil Displacement Law for CO2 Flooding

In laboratory, the minimum miscible pressure (MMP) of oil and CO2 was studied by using a slim tube model. The results showed that the greater the gas injection pressure, the higher the cumulative recovery. The gas breakthrough when the gas was injected with a volume of 0.7~0.8PV, the trend of cumulative recovery increase slowed down and the produced gas-oil ratio increased dramatically. Core flooding experiments were carried to compare the effects of CO2 and water flooding. As a result, the ultimate oil recovery of CO2 flooding increased with the increase of gas injection pressure. If the gas flooding was miscible, the ultimate recovery of CO2 flooding was generally higher than that of water flooding.

Absorption of Colesevelam Hydrochloride in Healthy Volunteers

OBJECTIVE: To assess whether colesevelam hydrochloride is absorbed in healthy volunteers. METHODS: A single-center, open-label, radiolabeled study was performed with 16 healthy volunteers. Subjects were administered non-radiolabeled colesevelam hydrochloride 1.9 g twice daily for 4 weeks, followed by a single dose of [14C]-colesevelam 2.4 g (480 μCi). These subjects continued to receive non-radioactive colesevelam 1.9 g twice daily for 4 days after administration of the radiolabeled dose. Blood, urine, and feces were collected immediately prior to administration of [14C]-colesevelam and at specified intervals after administration. The whole-blood equivalent concentration of colesevelam was calculated using data collected throughout the 96 hours following radiolabeled drug administration. The proportion of [14C]-colesevelam excreted through urine or feces was calculated based on the amount of radioactivity recovered up to 216 hours after the radiolabeled dose. RESULTS: The mean cumulative total recovery of [14C]-colesevelam in urine and feces was 0.05% and 74%, respectively. Excluding 2 subjects for whom cumulative recovery was <25%, the mean cumulative fecal recovery was 82%. The mean maximum whole-blood equivalent concentration of colesevelam was 0.165 ± 0.10 μg equiv/g 72 hours after administration of [14C]-colesevelam, which was estimated to be 0.04% of the administered dose. All blood samples contained <4 × the number of background counts (dpm). CONCLUSIONS: The cumulative recovery data in urine and feces are consistent with the conclusion that colesevelam is not absorbed and is excreted entirely through the gastrointestinal system.