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Barite scale is the most common oilfield scale in oil and gas wells. Barite scale removal still represents a challenge to the oil and gas industry because of its low solubility in mineral acids such as HCl. Chelating agents such as diethylene triamine pent acetic acid (DTPA), ethylene diamine tetra acetic acid (EDTA), and hydroxy ethyl ethylene tri acetic acid were introduced as barite scale removers, but the solubility of barite in these chelates was very low. Huge amount of chelating agents are required to remove the barite scale, but we are constrained by the hole volume of the well. In this study, a novel formulation was developed to dissolve the barite scale by using chelating agents and a catalyst to enhance the solubility of barite in chelating agent (DTPA) with small volume of chelating agents. Using the catalyst in this formulation is the main feature of the treatment. Solubility experiments were conducted to determine the dissolution rate of barite in DTPA chelating agent at different temperatures. The effect of pH on the dissolution rate of barite was studied using two bases (potassium base KOH and sodium base NaOH). The optimum chelating agent (DTPA) concentration and time were identified that will achieve the maximum barite scale solubility. Also, the catalyst type and concentration were determined using high-temperature high-pressure solubility experiments. Kinetics experiments using rotating disk apparatus were performed to investigate the mechanism of catalyst during the reaction of DTPA with barite. Based on the results from this study, DTPA (0.5M concentration) potassium base chelating agent was able to dissolve 60% of barite scale at high pH (11–12) in 24 h. The solubility of barite in the DTPA increased with time up to 24 h and after that it remained constant which means the optimum time for the barite scale removal is 24 h. The removal of barite scale increased up to 80–90% after adding (5–7 wt %) of one of the following catalyst: potassium carbonate (K2CO3), potassium chloride (KCl), and potassium formate (CHKO2). The developed formulation (DTPA/catalyst) can be used to remove the barite scale from oil and gas wells effectively. Rotating disk experiments showed that the catalyst enhanced the DTPA diffusion to the rock surface and in turn enhanced the mass transfer reaction rate. [ABSTRACT FROM AUTHOR]

The article presents a case study of power-water injectors which provides pressure support for the Unayzah-A reservoir in Field N. It states that scientists carried out experiments on the field and injectors and also determined the process of calcium sulfate precipitation. It further states that scientists also carried out solubility experiments in order to remove the drill-in-fluid (DIF) filter cake.

In order to determine the effect of some factors, as different levels of energy and protein, milking interval, lactation stage, and lactation rank on she-camel performance after weaning of camel-calves, 20 lactating shecamels were divided into four groups, 5 animals each, according to age and weight at last parturition. Groups had randomly allocated to one of four treatments diets. Group A received diet with 13% Crude Protein (CP) and 2.4 MCal Metabolisable Energy (ME). Group B received diet with 13% CP and 3.0 MCal ME. Group C and D received diet with 15% CP and 2.4, 3.0 MCal ME respectively. Diets contain 35/65 (roughage/concentrate, respectively). After 14 days of adaptation period, individual feed offered and orts had been recorded, daily and continued up to entire experimental period of 10 months. Milk yield was recorded two milking time from three consecutive days. The results show that diet (B) gave higher milk yield (MY), Fat Corrected Milk (FCM), Energy Corrected Milk (ECM) and Feed Conversion Ratio (FCR) 8.32, 11.77, 7.47, and 1.38 respectively. Diet (A) has higher fat % content when comparing with the other diets. Treatment did not affect milk composition except on fat and ash percentage. Milk secretion rate for 10 hours milking interval "evening milking" was higher comparing with 14 hours milking interval "morning milking" 397, 353 g/h respectively. Maximum MY, FCM and ECM were at mid lactation. In late lactation MY, FCM, ECM decreased. Higher milk productivity was at 3rd and 6th season of lactation. [ABSTRACT FROM AUTHOR]

In this retrospective study we compared obstetric brachial plexus palsy (OBPP) in two non-operated groups of newborn babies delivered vaginally by breech or cephalic presentation. There were 35 cases of OBPP in the breech group and 663 cases in the cephalic group. The former group was more likely to develop upper Erb's palsy while the latter group was more likely to develop total palsy. The breech group also had a significantly lower mean birth weight, a significantly higher percentage of bilateral OBPP palsies and concurrent phrenic nerve palsy. Spontaneous recovery of shoulder abduction and elbow flexion in newborn babies with upper Erb's palsy was significantly worse in the breech compared with the cephalic group. It was concluded that OBPP following vaginal breech delivery has several unique demographic features and breech babies with upper Erb's palsy have a worse prognosis for spontaneous recovery than those in the cephalic group. [ABSTRACT FROM AUTHOR]

Compared to non-diabetic mothers, diabetic mothers are known to deliver larger babies who are at higher risk for shoulder dystocia and obstetric brachial plexus palsy. The intrapartum forces applied during delivery of larger babies are expected to be higher. Hence, the chances of these babies for good spontaneous recovery are expected to be lower; and this is a generally believed hypothesis. The objective of this retrospective study was to compare obstetric brachial plexus palsy in newborn babies of diabetic and non-diabetic mothers. There were a total of 655 cases of obstetric palsy: 253 cases with diabetic mothers and 402 with non-diabetic mothers. The former were more likely to develop total palsy while the latter were more likely to develop extended Erb's palsy. Newborn babies of diabetic mothers had significantly larger birth weights than those of non-diabetic mothers regardless of the type of palsy. The rate of good spontaneous recovery of the motor power of the limb in the two groups was not significantly different except in total palsy cases for shoulder external rotation and elbow flexion where the recovery was significantly better in the diabetic group. It was concluded that the generally believed hypothesis is not correct if one compares the outcome in the diabetic and non-diabetic groups for each type of palsy. [ABSTRACT FROM AUTHOR]

Coiled tubing is usually used to conduct acid pickle treatments. The purpose of the treatment is to prevent pumping damaging materials into the formation before the main acid job. In this case, the acid is pumped down the coiled tubing, and then flowed up through the tubing-coiled tubing annulus. Pickling is a process of flow with heterogeneous reactions occurring with mill scale (Fe304) and other contaminants at both the inner wall of the production tubing and the outer surface of the coiled tubing. Pickling is an essential part of well stimulation treatments if the main treatment fluids (e.g., acidizing, fracturing, and gravel packing) if the main treatment fluids are to be bullheaded. However, it appears that traditional pickle practices are overestimating the required acid volume and/or concentration. Field data indicate that excessive acid volumes are used for tubing pickle because large returns of unreacted acid are usually recovered on the surface. In this paper, mechanisms to explain the behavior of acid contact with the tubing are presented, and a model for predicting acid consumption and dissolution of tubular contaminants is developed. The model includes reactions of acid with mill scale. A system of nonlinear, partial differential equations is developed, and the equations are solved numerically to predict the concentrations of major species as a function of axial position along the tubing and in the effluent from the well during flowback. Field application included pickling of low-carbon steel tubing (11,900 ft of 5.5-in. C-95) using coiled tubing. A slug of 5,000 gals of 20 wt% HCl with additives was used. Samples were collected from the treated well during the flowback of the pickling treatment. The model was used to predict the concentrations of various species in the well flowback samples. Model predictions for acid, chloride iron and total iron concentrations were in agreement with field results. In addition, the model proved to be a valuable tool in optimizing future pickling treatments. [ABSTRACT FROM AUTHOR]