A Quantitative Study of Sr2+ Impact on Barite Crystallization and Inhibition Kinetics

Scale inhibitors have been widely used for barite scale control. Our group has developed several barite crystallization and inhibition models to predict the crystallization and inhibition kinetics of pure barite with different inhibitors and calculate the minimum inhibitor concentration (MIC) required. However, instead of pure barite scale formation, the incorporation of Sr2+ can be frequently found in the oilfield, because of the coexistence of Ba2+ and Sr2+ in the produced water, which can influence the kinetics of crystallization and inhibition significantly. As a result, the MIC predicted could be off significantly. Therefore, in this study, the effect of Sr2+ on barite crystallization and inhibition kinetics is quantitatively investigated to evaluate the accuracy of MIC values under various conditions. The induction time of barite with different concentrations of Sr2+ was measured by laser apparatus without or with different concentrations of scale inhibitor diethylenetriamine penta(methylene phosphonic acid) (DTPMP) at the conditions: barite saturation index (SI) from 1.5 to 1.8; temperature (T) from 40 to 70 ℃; and [Sr2+]/[Ba2+] molar ratios from 0 to 15, all with celestite SI < 0. The results show that the induction time of the barite increases with [Sr2+]/[Ba2+] ratio at a fixed barite SI, T and DTPMP dosage. That means the MIC will be overestimated if it is calculated by previous semiempirical pure barite crystallization and inhibition models, without considering the presence of Sr2+. Based on the experimental results, the novel quantitative barite crystallization and inhibition models that include the influence of Sr2+ were developed for the first time as follows: Barite crystallization model with the influence of Sr2+: l o g 10 t 0 B a S O 4 , S r = ( 1.523 − 10.88 S I − 895.67 T ( K ) + 5477 S I × T ( K ) + 0.829 × [ C a 2 + ] ) + ( 0.823 S I + 85.44 T ( K ) − 0.667 ) × ( [ Sr 2 + ] [ B a 2 + ] ) Barite inhibition model including the influence of Sr2+ l o g 10 ( t i n h B a s o 4 , S r t 0 B a S O 4 , S r ) = b B a S O 4 , S r × C i n h l o g 10 b B a S O 4 , S r = ( − 2.187 − 1.411 × S I + 1329.29 T ( K ) + 0.153 × p H ) + ( 0.0983 × S I − 74.66 T ( K ) + 0.099 ) × ( [ Sr 2 + ] [ B a 2 + ] ) These novel models are in good agreement with the experimental data. They are used to predict the induction time and MIC more accurately at these common Ba2+ and Sr2+ coexisting scenarios. The observations and new models proposed in this study will significantly improve the barite scale management when Ba2+ and Sr2+ coexist in the oilfield.

A Semiempirical Model for Predicting Celestite Scale Formation and Inhibition in Oilfield Operating Conditions

Mineral scale formation has always been a serious problem during production. Most scales can be treated by adding threshold scale inhibitors. Several crystallization and inhibition models have previously been reported to predict the minimum inhibitor concentration (MIC) needed to control the barite and calcite scale. Recently, more attentions have been paid to the formation of celestite scale in the oilfield. However, no related models have been developed to help determine the MIC needed for the celestite scale control. Therefore, in this study, the crystallization and inhibition kinetics data of celestite under a wide range of celestite saturation index (SI = 0.7 – 2.6), temperature (T = 25 – 90 °C), ionic strength (IS = 1.075 – 3.075 M) and pH (4 – 6.7) with one phosphonate inhibitor (diethylenetriamine penta(methylene phosphonic acid, DTPMP) and two polymeric inhibitors (phophinopolycarboxylate, PPCA and polyvinyl sulfonate, PVS) were measured by laser apparatus or collected from previous studies. Then, based on the results, the celestite crystallization and inhibition models were established accordingly. Good agreements between the experimental results and calculated results from the models can be found. By using these newly developed models, the MIC needed for three commonly seen inhibitors, DTPMP, PPCA and PVS on celestite scale control can be predicted under extensive production conditions. The developed models can fill in the blank in scaling management strategies for high Sr2+ and SO42- concentrations in the produced waters.

A Semiempirical Model for Barium-Strontium-Sulfate Solid Solution Scale Crystallization and Inhibition Kinetics at Oilfield Conditions

Summary Scale inhibitors have been widely used as one of the most efficient methods for sulfate-scale control. To accurately predict the required minimum inhibitor concentration (MIC), we have previously developed several crystallization and inhibition models for pure sulfate scales, including barite, celestite, and gypsum. However, disregarding the wide existence of barium-strontium-sulfate (Ba-Sr-SO4) solid solution in the oil field, no related models have been developed that would lead to large errors in MIC determination. In this study, the induction time of Ba-Sr-SO4 solid solution was measured by laser apparatus with or without different concentrations of scale inhibitor diethylenetriamine penta(methylene phosphonic acid) (DTPMP) at the conditions of barite saturation index (SI) from 1.5 to 1.8, temperature (T) from 40 to 70°C, and [Sr2+]/[Ba2+] ratios from 0 to 15 with celestite SI < 0. The results showed that the Ba-Sr-SO4 solid solution’s induction time increases with the [Sr2+]/[Ba2+] ratio at a fixed barite SI, T, and DTPMP dosage. That means the MIC will be overestimated if it is calculated by the previous semiempirical pure barite crystallization and inhibition models without considering the presence of Sr2+. To resolve such deviations, the novel quantitative Ba-Sr-SO4 solid solution crystallization and inhibition models were developed for the first time. The novel models are in good agreement with the experimental data. They can be used to predict the induction time and MIC more accurately at these common Ba2+ and Sr2+ coexisting scenarios. The observations and new models proposed in this study will significantly improve the barite scale management while Ba2+ and Sr2+ coexist in the oil field. NOTE: Supplementary materials are available in support of this paper and have been published online under Supplementary Data at https://doi.org/10.2118/205367-PA.

Efficacy of Acupoints Dual-Frequency Low-Level Laser Therapy on Knee Osteoarthritis

Background. Knee osteoarthritis (OA) presented with knee pain and limitation of mobility is common, and it may become a chronic problem resulting in major loss of function, with related impaired activity of daily living. Current traditional therapy for knee OA includes pharmacological treatment and physiotherapy, but the efficacies are limited. An alternative noninvasive treatment low-level laser therapy (LLLT) applied to acupoints is still contradictory and the efficacy needs to be assessed. Methods and Materials. We conduct the randomized double-blind control study to investigate the efficacy of a dual-frequency LLLT (combines red light (780 nm) and near-infrared light (830 nm)) in patients suffering knee OA. Participates were randomly assigned into active laser therapy (ALT) and placebo laser therapy (PLT) groups. Subjects in the ALT group were separately treated by laser apparatus at the three acupoints (SP9, SP10, and EX-LE2) on their knee joints under continuous radiation for 15 min at the maximum intensity, three times per week for four weeks. The PLT group used laser apparatus of the same model according to similar procedures without laser light emission. Outcome Measurements including visual analog scale (VAS), pain pressure threshold (PPT), and Lequesne index were used. Results. A total of 30 subjects with two-sided knee OA in both groups completed the experiment. Statistically significant decreases were observed in the Lequesne index (5.27 ± 3.26 vs. 10.83 ± 3.83), conscious VAS 4 weeks after treatment (moving: 2.87 ± 1.13 vs. 5.67 ± 1.72; resting: 0.33 ± 0.62 vs. 2.67 ± 1.29), and the increase was noted in PPT (21.23 ± 1.82 kg vs. 13.02 ± 1.46 kg) in the ALT group compared with the PLT group. Conclusion. It appears that the knee OA pain and disability can be decreased after a dual-frequency LLLT applied to acupoints (SP9, SP10, and EX-LE2). The clinical efficacy of LLLT is highly related to the therapeutic settings of the laser apparatus; hence, more clinical trials with diffident parameter settings are needed to be further clarified.

Clinical course and surgical treatment of paraurethral cysts in women

The results of surgical treatment of 59 women (average age 31.9 1.3 years) who underwent laser ablation of paraurethral cysts using the Lakhta-Milon laser apparatus (Russia) (diode laser with a wavelength of 0.97 m) are presented. The postoperative period in all patients proceeded without serious complications. The average hospital stay was 1.7 1.5 days. 4 weeks after surgery, all 59 patients noted improvement such as lack of dysuria, only 10 (16.9%) had minor discharge from the genital tract. 6 weeks after surgery all 59 operated patients had wound epithelization. Conclusion: The treatment of paraurethral cysts should be surgical and as radical as possible. The operation of choice is laser ablation of paraurethral formations.

The results of two-stage optico-functional rehabilitation of patients with refractive disorders and the risk of postoperative asthenopic syndrome after FemtoLASIK

Purpose. A comparative analysis of the results of two-stage optico-functional rehabilitation of patients with a high risk of postoperative asthenopic syndrome (AS).Materials and methods. 36 patients (72 eyes) who had no binocular vision at a distance of 5 m and had a symmetrical position of the eyes, or a position close to symmetry, were randomly divided into 2 equal groups of comparison. Patients in both groups underwent functional treatment followed by the correction of refractive errors with FemtoLASIK technology. To eliminate accommodation dysfunctions, a medical device OXYS was used. Diploptic treatment was carried out using a Speckle-M laser apparatus and Bagolini raster glasses. To expand fusional reserves, a prism compensator (OKP-20, Russia) and a Speckle-M laser apparatus were used. The patients of the first group underwent a fast course of medical and functional rehabilitation for 5 working days (2 times a day with a break of 2–3 hours). As an additional pharmacological support, daily instillations of phenylephrine hydrochloride 2.5 % without preservatives were prescribed. The other group received the same functional treatment for 10 working days.Results. After the fast and the standard rehabilitation courses, the patients revealed an increase in absolute accommodation and a decrease in the coefficient of micro fluctuations, an expansion of fusional reserves, an increase in stereovision acuity, and an increased number of cases of binocular vision. No statistically significant difference of clinical and functional parameters obtained as a result of the fast and the standard rehabilitation courses was revealed.Conclusions. Functional and medicament treatment of patients with refractive disorders and the absence of binocular vision prior to FemtoLASIK is shown to be effective. This treatment reduces the risk of postoperative AS and increases the patient’s satisfaction with the results of the surgery.

Flexible cystoscope retrieval of detached resectoscope sheath beak

Surveillance cystoscopy for bladder cancer following transurethral resection of the prostate (TURP) can have unexpected consequences, such as the detachment of the resectoscope beak. This is an infrequent event, with few published or standard techniques for its retrieval. These techniques range from the use of forceps, as Grainger et al described in the first published case report on resectoscope sheath extraction, to the use a holmium YAG laser with a 200 μm fiber to fragment the 26 French (Fr) resectoscope sheath in the patient’s bladder and other laser-based techniques. We hypothesize that resectoscope beak extraction can be achieved efficiently and safely using a flexible cystoscope in the absence of a laser apparatus and with better postoperative results than rigid resectoscope or forceps for extraction.

Study of CIGS Thin Films Solar Cell P2 Layer Scribing Using UV Laser

This study will be UV (355nm) laser processing system as a carrier. Using laser direct forming for CIGS solar cell technology P2 layer of stainless steel studied electrode insulated characteristic. To explore the impact of this process on the way to a stainless steel substrate P2 film sizes using its laser different frequency parameters. The experimental results indicated that the electrode pattern of the experiment was similar to that of the simulation result, and the laser process has good results in scribing processing. The analysis results confirm the effectiveness of the laser apparatus when applied to a CIGS solar cell P2 layer of stainless steel.