Experimental Research of Compound Monitoring on Multiple Temporary Blocking Refracturing for Long-Section Horizontal Wells

As an important energy replacement block in China, the tight conglomerate oilfields in the Mahu area are difficult to develop and are characterized by strong heterogeneity, large horizontal stress differences, and undeveloped natural fractures. However, new development processes including temporary blocking diversion and large section-multiple clusters have been implemented on the oilfields in the past few years. In 2020, two adjacent horizontal wells in the MD well area experienced a poor fracturing development effect compared with the earlier wells in this area. Analysis suggests that the main reasons are water sensitivity of the reservoir, insufficient fracturing scale, and/or interference from the adjacent old wells. To ameliorate the problem, this study presents an experimental study of multiple temporary plugging and refracturing technology in long horizontal well sections, in combination with electromagnetic and microseismic monitoring. Results from the study show a great difference between the two monitoring techniques, which is attributed to their different detection principles. Interestingly, the combination of the two approaches provides a greater performance than either approach alone. As the fracturing fluid flow diversion is based on temporary plugging diversion and electromagnetic monitoring of fracturing fluid is advantageous in temporary plugging diversion monitoring, both approaches require further research and development to address complex situations such as multiple temporary plugging and refracturing in long intervals of adjacent older wells.

The Identification of Fouling in Reverse Osmosis in Reverse Osmosis in the Treatment of Water with Petroleum Substances

Water containing petroleum substances is very difficult to clean, and the treatment process usually consists of several stages. Despite the increasing use of integrated membrane processes to purify natural waters, including the removal of organic substances, work is underway on the search for new processes and their optimization. This paper deals with the study of the removal of petroleum hydrocarbons from the benzene, toluene, ethylbenzene, and xylene (BTEX) group by reverse osmosis and optimization. The research was conducted on surface water enriched with a fuel mixture. Then, the reverse osmosis efficiency was modeled using the constant pressure filtration model (Hermia model), which determined the most likely membrane blocking mechanism. When the membrane was operated on surface water enriched with BTEX, the blocking of the membrane was based on the n = 0 cake mechanism. In surface water alone, the highest correlation coefficient was 0.9994 and corresponded to a temporary blocking mechanism (n = 1).

Probabilistic Strategic Conflict-Management for 4D Trajectories in Free-Route Airspace

The expected growth of air traffic in the following decades demands the implementation of new operational concepts to avoid current limitations of the air traffic management system. This paper focuses on the strategic conflict management for four-dimensional trajectories (4DT) in free-route airspace. 4DT has been proposed as the future operational concept to manage air traffic. Thus, aircraft must fulfil temporary restrictions at specific waypoints in the airspace based on time windows. Based on the temporary restrictions, a strategic conflict management method is proposed to calculate the conflict probability of an aircraft pair (that intersects in the air) and to calculate temporary-blocking windows that quantify the time span at which an aircraft cannot depart because one conflict could occur. This methodology was applied in a case-study for an aircraft pair, including the uncertainty associated with 4DT. Moreover, a sensitivity analysis was performed to characterise the impact of wind conditions and speed control on the temporary-blocking windows. The results concluded that it is feasible to propose 4DT strategic de-confliction based on temporary-blocking windows. Although, uncertainty variables such as wind and speed control impact on the conflict probability and the size of the temporary-blocking windows.

RPAS integration in non-segregated airspace: Safety metrics for tactical planning

The integration of remotely piloted aircraft system in non-segregated airspace requires a significant effort and new methodologies to underway this challenge. This paper develops a methodology to assess the impact of remotely piloted aircraft system integration by applying safety metrics in tactical planning. This methodology builds five modules to simulate remotely piloted aircraft system introduction in a conventional-aircraft schedule: Base scenario, path modelling, conflict detection, temporary-blocking window and safety metrics. The safety metrics quantify the safety state of the operation by the number of conflicts, the conflict severity and the airway availability. This last safety metric represents a step forward in the decision-making process because it provides the airway risk-suitability to integrate remotely piloted aircraft system. Moreover, the temporary-blocking window underlies the airway availability metric. This concept provides temporary restrictions to the integration of remotely piloted aircraft system depending on the entry times of the conventional aircraft. Finally, this methodology is applied in an air traffic volume of the Spanish upper airspace. Different simulations were performed by introducing remotely piloted aircraft system covering every airway of the airspace. Results provided the temporary-blocking windows that specified the temporary restrictions to remotely piloted aircraft system introduction as a function of the airway flown by the conventional aircraft. Furthermore, the methodology appraised the airway availability characterising the airways depending on the risk impact by the remotely piloted aircraft system.