The Well Efficiency Criteria Revisited—Development of a General Well Efficiency Criteria (GWEC) Based on Rorabaugh’s Model

The Strategic Water Storage & Recovery (SWSR) Project in Liwa, Abu Dhabi is a leading and unique hydrogeology project in the world because of both its financial and scientific dimensions. The objective of the project is to store desalinized water in the local Liwa aquifer, to be able to supply water to Abu Dhabi in case of emergency. A total of 315 recovery wells have been drilled in pursuance of the scope of the SWSR project. Out of the total 315 wells, 25 wells met construction problems and were removed from the study. The remaining 290 wells have been analyzed using step drawdown tests (SDTs) and the model of Rorabaugh. This provided a large and unique database regarding the parameters of this model: linear aquifer-loss coefficient (B), non-linear well-loss coefficient (C) and the exponent p. Analysis of this exceptional data set revealed noteworthy and novel findings: (1) the range of the exponent p values is found to be very extensive, varying from 0.35 to 6.01. For comparison, the highest values of p given in the literature very seldom exceed 4; (2) p behaves like a lognormal variable; (3) parameters C and p are closely correlated. A semi-logarithmic diagram displays a linear relation of p vs. log C, with a determination coefficient R² = 0.83; (4) A graphical and tabulated procedure, termed General Well Efficiency Criteria, is proposed to assess well efficiency. Given the very wide range of p values implied in this procedure, it becomes possible thus to assess the efficiency of any well analyzed with an SDT. This study finally raises questions about Jacob’s model validity, which assumes that p is constant and equal to 2.

IDENTIFICATION AQUIFER PARAMETERS THROUGH SINGLE WELL PUMPING TEST SERIES AT PT. KALTIM KARIANGAU TERMINAL, BALIKPAPAN, EAST KALIMANTAN

Aquifer Parameters are very important in groundwater and well management. The objective of this research is to determine aquifer parameter in order to be used in determining suitable production rate of well. Research was carried out in PT. Kaltim Kariangau Terminal, which is administratively, located in Balikpapan City, East Kalimantan, Indonesia. PT. Kaltim Kariangau Terminal has developed four wells with distance of each of well is between 50 and 300 meters, but it is a pity because just one well was completed by pumping test without observation well. Result of constant pumping test analyzing through Cooper – Jacob method has shown that value of Transmissivity (T) of aquifer is 319.0718283 m2/day, and it is known from geophysical logging and well construction design that the thickness of aquifer is 48 m, so hydraulic conductivity (K) of aquifer is 6.6473 m/day. Coefficient of aquifer loss is 0.0013 and coefficient of well loss is 0.0000008. Factors development of well could be classified as very effective with the well condition is properly designed and developed.

We all fail in interviews

This chapter considers failure in an interview, how it impacts on us as candidates, and how it can be utilized to improve our future performance. Learning from past mistakes is essential in the process of preparing and performing in an interview, and the best lessons are when things don’t go well. Loss and failure are an opportunity for growth if harnessed correctly. This chapter looks at techniques to employ during an interview, to help bounce back after mistakes have been made. The chapter also includes a practical exercise that can help us as candidates constructively analyse a failed interview after the event.

Session 13: Identifying Early Warning Signs for Depression Recurrence

Chapter 16 of Family-based Interpersonal Psychotherapy (FB-IPT) for Depressed Preadolescents presents the thirteenth session of family-based interpersonal therapy (FB-IPT) in which the therapist helps the preadolescent identify potential stressors that may trigger another depressive episode, emphasizing the need to be aware of early warning signs (e.g., not sleeping well, loss of appetite) that may signal a relapse or recurrence. The preadolescent is also supported in talking about these stressors and early warning signs with her parent. With the therapist’s continued assistance, the preteen enlists the parent’s help to monitor her stress and changes in functioning to catch any future episodes of depression as early as possible.

Lost Circulation

Lost circulation is defined as the uncontrolled flow of mud into a thief zone and presents one of the major risks associated with drilling. The complete prevention of lost circulation is impossible, but limiting circulation loss is possible if certain precautions are taken. Failure to minimize lost circulation can greatly increase the cost of drilling, as well as the risk of well loss. The risk of drilling a well in areas known to contain potential zones of lost circulation such as fractured, cavernous, or high permeability formations is a key factor in making a decision to approve or cancel a drilling project. The successful management of lost circulation should include identification of potential loss zones, optimization of drilling hydraulics, and remedial measures when lost circulation occures.