A Scaled Model Study of Waterjet Drilling

Abstract

Laboratory experimental results of waterjet drilling have rarely been scaled up to the field scale. This article presents the scaling criteria for designing waterjet drilling laboratory experiments for simulating a given oilfield operation. Dimensional analysis is used to derive scaling groups for the waterjet drilling technique. The proposed scaling approach meets all important requirements of this drilling process. Experiments were conducted to determine the strength and the relation between the rate of penetration (ROP) and depth of penetration (DOP) with drilling time. Experimental results are scaled up for field application. Laboratory measurements with such models accurately duplicate the behavior of the drilling performance of a reservoir. Such modeling is the most effective tool for the study of drilling behavior, performance, and management in the reservoir field.     

Numerical Investigation of the Prospects of High Energy Laser in Drilling Oil and Gas Wells

Abstract

Lasers are expected to provide a less expensive alternative to conventional machining and have found wide spread use in many industries. However, the physical phenomena involved in many laser applications are not fully understood. A better and more quantitative understanding of the physical mechanisms governing these phenomena will diminish the need for extensive trial and error experiments. Most of the theoretical models available in the literature have dealt with quasi-steady material removal using a continuous wave laser. This article presents a numerical model to predict the transient thermal behavior process of rocks under the influence of a pulsed laser. A wide range of parameters were considered in this study, the laser powers were varied from 0.1 to 100 kW and the lasing time was varied between 1 and 100 s. One of the results presented in this article shows that limestones consume less energy per unit volume of material removed as compared to sandstones. A comparison between the findings of this numerical study and published experimental data is also presented and shows a qualitative agreement. Finally, it is shown that numerical modeling can be useful in scaling up laboratory results to field applications.     

An Analytical Model for Brine-Induced Oil Recovery

Abstract

An analytical model for field application of improved waterflooding through brine concentration is presented. Based on several laboratory studies, many researchers suggested that changing the brine concentration during waterflooding offered viable options for improved oil recovery. In this regard, particularly in cyclic waterflooding, these studies have confirmed the effectiveness of such an approach. Generally, however, they are limited to laboratory studies without much field application. Most laboratory results do not present a clearly defined approach for practical application. This article analyses laboratory results and proffers a concise approach for field application. To this end, based on the reinterpretation of the Civan and Knapp model, an oil recovery model is developed for cyclic waterflooding. This model monitors waterflood performance based on the impact of brine injection for increased oil recovery.     

油田污水电化学诱导防垢新技术

针对油田注水开发中加阻垢剂进行污水防垢处理时存在药剂作用距离有限、效果受环境因素变化影响的问题,提出了电化学诱导防垢的技术思路,并开展了试验研究。设计了室内评价装置并进行了试验,重点考察了诱导防垢处理前后污水中Ca2+、Mg2+质量浓度的变化情况;加工了现场小试装置,并在FM污水处理站进行了评价试验,考察了处理前后污水中阴离子、阳离子含量的变化情况。通过室内试验,优化了电极材料、极板间距、阴极面积、水流形式等电化学诱导防垢参数。现场试验结果显示,FM站污水经诱导防垢处理后,水中Ca2+质量浓度下降了18.2%、HCO3-质量浓度下降了23.6%;Scalechem 3.1垢化学分析软件预测显示,污水理论结垢量下降了43.4%。研究结果表明,电化学诱导防垢技术可以有效去除污水中的成垢离子,从而起到较好的防垢效果。      

Well-data-based prediction of productivity decline due to sulphate scaling

Sulphate scaling can have a disastrous impact on oil production in waterflood projects with incompatible injected and formation waters. This is due to precipitation of barium/strontium sulphate from the mixture of both waters and the consequent permeability reduction resulting in loss of well productivity.The system where sulphate scaling damage occurs is determined by two governing parameters: the kinetics coefficient characterising the velocity of chemical reaction and the formation damage coefficient reflecting permeability decrease due to salt precipitation.Previous work has derived an analytical model-based method for determination of two coefficients from laboratory corefloods during quasi-steady state commingled flow of injected and formation waters. The current study extends the method for determination of kinetics and formation damage coefficients from production well data consisting of barium concentrations in the produced water and of well productivity decline.We analyse production data for five wells from giant offshore field A, submitted to seawater flooding (Campos Basin, Brazil), and obtain values of the two sulphate scaling damage parameters. The two coefficient values were used for prediction of productivity decline for these wells. The values of kinetics and formation damage coefficients as obtained from either laboratory or field data vary in the same range intervals. These results validate the proposed mathematical model for sulphate scaling damage and the analytical model-based method “from lab and wells to wells”.     

The Prediction of Calcium Carbonate and Calcium Sulfate Scale Formation in Iranian Oilfields at Different Mixing Ratios of Injection Water with Formation Water

Abstract

This article presents the prediction of calcium carbonate and calcium sulfate scale formation by water injection in oilfields at different mixing injection water-to-formation water ratios. The experimentally measured chemical analyses of formation water and injection water were input to the OLI ScaleChem model to determine the tendency of scale formation. The scaling tendency of CaCO₃ and CaSO₄ at reservoir temperatures and pressures is presented. This model has been applied to investigate the potential of calcium carbonate and calcium sulfate scale precipitation in Iranian oilfields in onshore and offshore fields as a method of secondary recovery or reservoir pressure maintenance.     

LIGNITE RETORTING USING SOLID HEAT CARRIER

ABSTRACT

A retorting pilot plant with capacity of 10 kg/h using hot char as solid heat carrier was constructed. This paper describes experimental results using four different lignites. The product char was used as solid heat carrier and the retorting temperature range was 450^°C-670^°C. The maximum yield of tar was up to 92% of the value of Fischer Assay. Produced gas and tar can be used as chemical feedstock and they are clean energy.     

相态变化对气藏流体结垢的影响

采用高温、高压地层流体无机盐结垢综合测试装置,结合建立的多相平衡结垢预测模型,对实际气藏流体的无机盐结垢规律进行了研究,重点分析了气藏及井筒中不同位置处相态变化对无机盐结垢的影响。研究结果表明,地层水的蒸发及酸性气体的溶解、析出是无机盐结垢程度的主要相态影响因素。实际气藏流体的无机盐结垢情况是流体各组分相态变化和化学反应的综合结果。地层流体的相态变化及无机盐结垢规律在地层中主要受地层压力的影响,在井筒中主要受温度的影响。不考虑相态变化将导致无机盐结垢量的预测值明显偏低,且随压力降低和温度增加,预测偏差不断增大。     

The Research of Ultra-deep Desulfurization in Diesel via Ultrasonic Irradiation Under the Catalytic System of H2O2-CH3COOH-FeSO4

Abstract

In recent years, many countries have drawn up strict laws regarding the sulfur-containing compounds of fossil fuels, especially the gasoline and diese. Ultra-deep desulfurization of fuel is a main component of fossil fuel development. The experiment imposes the photochemistry field on the catalytic oxidation system in order to broaden the newly desulfurization technology. The sulfur-containing compounds, such as dibenzothiophene (DBT) and its derivatives, in diesel fuel are oxidized to corresponding sulfones using H₂O₂-CH₃COOH-FeSO₄ oxidation systems via ultrasonic irradiation. Later, the oxidized sulfur compounds (sulfones) are extracted by a suitable polar solvent. The influences of the catalytic system, reaction time, and ultrasonic source (frequency, intensity) are tested on desulfurization efficiency. Experimental results show that the removal efficiency of the sulfur compound could amount to 97.5%, and the recovery of oil is above 92% under the catalytic system of H₂O₂-CH₃COOH-FeSO₄ by the assistance of ultrasound.     

煤层气井分散防固结-定期洗井工艺

针对蜀南煤层气田井筒存在铁盐-煤泥复合垢的问题,开展了室内实验和现场工程相结合的防垢技术研究。通过建立室内实验评价方法,完成了3种有机膦酸和2种聚合物类药剂对煤粉颗粒物的分散性实验和防煤泥固结实验。通过动态光散射及表面Zeta电位测试,分析了药剂对颗粒物粒径分布、Zeta电位的影响,以及影响药剂对煤粉颗粒物分散和防煤泥固结效果的原因。研究结果表明,有机膦酸类药剂中乙二胺四亚甲基膦酸(EDTMPS)分散性较好,但受高铁盐的影响,防煤泥固结能力较差,不适合本区的结垢防治,而聚合物类药剂更适用于此类复杂水质下的结垢防治。根据药剂特性,在现场施工中实施了分散防固结-定期洗井组合工艺,该方案开展3年以来区块煤层气井结垢速率显著下降,检泵周期延长至1.3~3倍,取得了良好的应用效果。     

Applying Pebax-1657/ZnO mixed matrix membranes for CO2/CH4 separation

Abstract

Membrane technologies as conservative approaches have absorbed much attention in chemical and petroleum engineering, recently. The current research presents the preparation of effectively mixed matrix membranes (MMMs) using polyether-block-amide (Pebax-1657) as a polymeric matrix and zinc oxide (ZnO) nanoparticles with various contents (0.0, 2.5, 5.0, 7.5, and 10.0?wt%) as a filler. X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and field emission scanning microscopy (FESEM) were conducted to characterize the prepared membranes. The membrane performance was evaluated by caring out permeation experiments of the CO₂ and CH₄ at a pressure of 3?bar and temperature of 30?°C. Based on the obtained results, the CO₂ permeability and ideal CO₂/CH₄ selectivity increased about 13 and 21%, respectively at 10.0?wt% loading of ZnO in the polymer matrix.     

OILFIELD CARBONATE SCALE CONTROL BY ANHYDRIDE-BASED CHEMICAL ADDITIVE

ABSTRACT

A field study of anhydride-based chemical additive for carbonate scale control in oilfield produced waters has been carried out at Nigerian Obama and Tebidaba flow stations.

Results of the study revealed that the additive brought down considerably the precipitation indices and hence the scaling tendencies of Obama and Tebidaba waters. It also caused a remarkable reduction in the total suspended solids, TSS and total dissolved solids, TDS concentration of these waters at ultra low injection concentration (< < 0.5 ppm), thus re-affirming its unique dual role capability for inhibiting the process of scale formation and promoting dissolution of existing scales' suspension in the produced water. Similar dual-role capability has not been reported for any carbonate scale control system.     

Integrating Neural Network and Numerical Simulation for Production Performance Prediction of Low Permeability Reservoir

Abstract

It is difficult to predict the production performance of low permeability fractured oil reservoirs. This is because complicated factors such as geological and engineering factors affect well production performance. This paper presents a methodology to predict well production performance in the Hanq oil field, which is a low permeability fractured reservoir. Integration of neural network with numerical simulation is employed. First we study the regularity of fluid flow and oil displacement mechanism by injection well group numerical simulation and analysis of production performance. Then we form the “expert knowledge” affecting production performance. The neural networks based on expert knowledge are trained using production data. This method will play an important role in future waterflood management and the design of recovery strategy for the Hanq oil field.     

TEXAS LIGNITE DESULFURIZATION

ABSTRACT

Texas lignites are a low-Btu, high-ash and moderately high-sulfur fuel that can be readily upgraded before combustion using physical and microbial desulfurization technology. Although physical and chemical processes and some microbial processes are effective in removing pyritic sulfur, they are ineffective for removing organic sulfur. Microbial processing of Texas lignite with sulfur content of up to 15 wt.% was investigated using laboratory shake-flask experiments. Organisms of the genus Thiobucillus ferrooxiduns, Leptospirillum Jerrooxidans and Pseudomonas putidawere investigated. It was found that up to 77% of the sulfur compounds present in the Texas lignite with more than 90% of the pyritic sulfur could be removed by the use of these microbes. Texas lignite samples were pulverized to pass through 149-μim sieve. Thiobucillus ferrooxiduns reduced up to 54% of the total sulfur and 78% of the pyritic sulfur in 14 days and Leptospirillum ferrooxidans removed up to 41% and 60%, respectively. A mixed culture of these two bacteria was also studied for sulfur removal The lignite was retreated with P. putidu which further removed 50% of the total sulfur in 7 days. P. puiidu could successfully remove up to 37% of the organic sulfur in 7 days.     

SOAKER VISBREAK1NG OF SOME IRAQI RESIDUES

ABSTRACT

An attempt has been made to increase the fuel oil yield of two Iraqi residues using a soaker visbreaking process. This was carried out in a continuous laboratory scale unit at a range of mild conditions, namely, A20–A8O^°C and A3-109 sec. in the coil and 151–379 sec. in the soaker.

Physical properties of the products have been characterized and reported. The fuel oils obtained under the studied conditions remained stable compared with the original feedstocks. Furthermore, data on yield and characteristics of the different distillates from the visbroken products have been obtained. There was an increase in the distillates up to 350^°C (11%) for type A residue and (15%) for type B residue.     

含硫气田净化厂原料气过滤分离设备腐蚀主控因素研究

含硫气田天然气净化厂原料气过滤分离设备为关键设备,其腐蚀失效情况也备受关注。现场调研发现,使用一段时间后,分离设备底部积液位置出现腐蚀层,且分离设备存在较多鼓泡。通过开展金相分析、理化性能分析及腐蚀微观分析,确定了设备失效原因,室内模拟现场条件找出腐蚀失效主控因素。结果表明,在材料力学性能、化学成分满足标准要求的前提下,材料本身存在较多夹杂是导致设备鼓泡失效的主要原因,随着H_2S与CO_2分压比的增加,腐蚀速率增大,氢鼓泡现象更加严重。     

Recovery of Value Added Products Can Help Survival of Solvent Extraction Unites in a Lube Processing Refinery: A Case Study

Abstract

This article investigates the disadvantages of polymer sulfonate and oil-based drilling fluids after use, such as pollutants seriously exceeding current standards and poor degradation. After the later stage treatments, like landfill and solidification, waste drilling fluids also have secondary pollution. Based on laboratory experiments, we established the green performance evaluation standards and specifications of drilling additives and drilling fluid systems, including chemical toxicity, biological toxicity, and biodegradability. We developed a green drilling fluid additive and drilling fluid system that are nontoxic, biodegradable, and reservoir protective. The green drilling fluid additive and drilling fluid system can effectively control the production of environmental pollutants from the source. The green drilling fluid system was successfully applied in Tarim oilfield and Karamay oilfield for the first time, fulfilling the pollution-free disposal of throwing waste drilling fluid onto the soil. This technique could be used in improving and enriching soil. The laboratory experiments and field applications indicated that the drilling fluid system had low chemical toxicity. The contents of heavy metals Cd, Hg, Pb, Cr, and As are respectively below 0.3, 0.02, 3.7, 4.9, and 3.1 mg/kg; the acute biotoxicity EC₅₀ was greater than 30,000 mg/l; and the biodegradation index BC (Biological oxygen demand [BOD₅]/Chemical oxygen demand [COD]) was greater than 0.35. Soil organic matter and the major fertility indexes, such as nitrogen, phosphorus, potassium, were increased by 40% after throwing waste drilling fluid onto the soil. The core permeability recovery value was greater than 80%. This drilling fluid system realizes the organic unity of low toxicity, biodegradability, improving soil conditions after throwing, and reservoir protection. This is an important advancement for the coordinated development of Chinese oil industry and environmental protection.     

Laboratory and analytical methods for explosives residues in soil

Abstract

Standard analytical methods have been developed to characterize explosives residues in soil at U.S. Department of Defense installations. The laboratory analysis is conducted using RP-HPLC, and the most commonly found analytes are TNT and RDX. Other analytes commonly detected are the environmental transformation products of TNT including TNB, dinitroaniline, and the isomers of amino-DNT, and the manufacturing by-products DNB and the isomers of amino-DNT. Field methods designed to detect TNT and RDX have enhanced site characterization by providing rapid on-site results for a greater number of samples than would be economically feasible by depending solely on off-site laboratory analyses for all samples. Attempts may be made to use both laboratory and field methods to analyze treatment matrices such as incinerator ash and compost, but further analytical method development is needed to enhance extraction and minimize interferences.