Oilfield Water Injection Research Articles

Numerical Simulation Research on Reasonable Production Time Limit Optimization of Advanced Water Injection in Low Permeability Oilfield

Based on the characteristics of low permeability, low pressure, poor effect of conventional waterflood development and low recovery efficiency in Chao Yanggou oilfield, advanced water injection is applied. Taking the Chang 10th block of Chao Yanggou oilfield as an example, the research on reasonable production time and pressure limit of advanced water injection in low permeability oilfield are carried out using methods of numerical simulation and reservoir engineering. The result shows that the average permeability of the Chang 10th block is 7.0×10-3μm2, the reasonable time of advanced water injection is about 6 months, and the recovery efficiency increases 2.26% compared with synchronized water injection. The successful application of advanced water injection development technology has some guidance on low-permeability oilfield development.

Friction Factors of Oilfield Water Injection Network - Calculating Cases Analysis

Firstly, possible pipe combination, that needs to give friction factor value, is found by orthogonal experimental method. Then friction factor sensitivity of pipe section is analyzed in the possible pipe combination by sensitivity analysis, supplementary boundary conditions is gotten, friction factor value of every pipe is given according to solving analogical node equation method. At last, Case study showed that the method is true and better in result matching and convergence rate aspect. The approach is a theoretical guarantee to network design and optimal analysis of oilfield water injection network, and has a specified engineering significance.

Friction Factors of Oilfield Water Injection Network - Research on Solving Approach

Oilfield water injection network is a special network, where all pressure and flow rate of node is known. Using empirical friction factor value formerly leads to great deviation between optimal result of network and fact operating condition, because of small pipe diameter, severe scale and lots of valves, which is difficult to guide Oilfield production. Firstly, possible pipe combination, that needs to give friction factor value, is found by orthogonal experimental method. Then friction factor sensitivity of pipe section is analyzed in the possible pipe combination by sensitivity analysis, supplementary boundary conditions is gotten, friction factor value of every pipe is given according to solving analogical node equation method.

Water Injection Station Design Based on One-For-Several Rotor VVVF Technique

In the process of oilfield water injection volume of injection allocation often appears with the pump displacement situation does not match; the widespread adoption of stator frequency technology allows the pump displacement and volume of injection allocation phase matching. But the technology in pump class load application speed range is limited, there is still a reflux valve control blind area," turn off undead" problem. One-for-several" rotor frequency Technique in water injection station application solved the control blind area problem, the full realization of the variable frequency close return voltage injection, at the same time, the successful implementation of the slip power efficient feedback. Stable water injection pressure of the system and the electric energy is saved, satisfy the oilfield high efficiency, fine water needs, has a high application value.

Experimental Study of Pumping and Shunting Pump under Pressure in Water Injection Station

At present in the process of water injection station operation, starting and stopping the pump caused system pressure fluctuations, and the fluctuations caused many problems about downstream injection wells. In order to eliminate the fluctuations and reduce problems, taking start pump, connect pump test under pressure in the water injection station installed the rotor frequency control system Changqing oil field developed. During the experiment, by progressively increasing the pressure pump to verify start pump with pressure feasibility test , the result shows when the pressure in the 0-25MPa pressure start and connect pump can be realized, and forecast the maximum pressure of the current start of the station with pressure pump. Start pump with pressure achieve the elimination of pressure fluctuations, provide the prerequisites about realizeing stable water injection pressure, and ultimately realize oil field water injection station to be automatic water injection laid a foundation.

The Study of Calcium Sulfate Scale Formation during Water Injection in Iranian Oil Fields at Different Pressures

Scale formation in surface and subsurface oil and gas production equipment has been recognized to be one of the major operational problems. It has also been recognized as one of the major causes of formation damage either in injection or producing wells. Scale contributes to equipment wear and corrosion and flow restriction, thus resulting in a decrease in oil and gas production. This article presents the predicting of calcium sulfate scale tendency of formation water, injection water, and mixing of injection water with formation water at different pressures. The experimentally measured chemical analyses of formation water and injection water were used by OLI ScaleChem software to determine the tendency of scale formation. This software has been applied to investigate the potential of calcium sulfate scale tendency in Iranian oil fields, either in onshore or offshore fields where water injection is being performed for desalting units' water disposal purpose or as a method of secondary recovery or reservoir pressure maintenance.

Study on seawater nanofiltration softening technology for offshore oilfield polymer solution preparation

Nanofiltration (NF) is suitable for softening seawater and providing permeates with excellent quality for oilfield water injection. However, the industrial application of aqueous polymer solution prepared by NF softened seawater for oilfield polymer flooding has not been reported yet. In this work, a pilot-scale ultrafiltration (UF)–NF integrated membrane system (IMS) has been investigated as a method of removing divalent ions from seawater and providing softened water for oilfield polymer flooding. The performance of the selected NF 4040 spiral membrane module was investigated under different operating conditions. In addition, the performance of the NF membrane module at high system recovery was also investigated to simulate the practical situation. Finally, NF permeation waters were used to prepare HPAM polymer solutions to evaluate the possibility of preparing polymer solution with NF permeation water for polymer flooding in offshore oilfield. The results showed that, with the properly selected NF membrane, the operation factors and the order of membrane modules had little effect on its permeate quality, which could keep more than 90% removal rate for Ca2+ and Mg2+. And NF2 membrane modules could provide good quality permeate for preparing polymer solution for polymer flooding in offshore oilfield.

Fault Sealing Property Analyzing by Water Injection in Oilfields

The quantity and availability of water injection are affected by geological environments in complex small fault-block oilfields, especially nearby faults. It is a general method to qualitatively determine fault sealing ability by water injection availability. The availability analysis of several injection wells can judge sealing ability of five faults of block M28-1 in JD oilfield. The water injection data show that fault F1, F4, F5 are main areas of pressure releasing for unsealing. Fault F2 and F3 are distributed on each side of the water injection well, which have a little influence on loss of water injection for sealing.

The Feasibility Experimental Study of Pumping and Shunting Pump under Pressure in Oilfield Water Injection Station

In order to simplify the operation process of water injection station and improve the utilization rate of water injection. We carried out the experiment of pumping under pressure and shunting pump when installed the rotor frequency control devices. The results shows that when the start pressure ranges from 0MPa to 15MPa, the surge current of power system keeps below the maximum allowed surge current so that the water injection pump runs smoothly and the instruments and devices are in good condition. And so does the system when the pressure changes from 0MPa to 16MPa in the shunting pump under pressure experiment. By making use of the rotor frequency control devices, the station reduces the labor intensity and simplifies the operation. Besides, the utilization rate of water injection is improved.

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

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.

已开发油田水驱评价体系及波及系数计算方法综述

近年来低渗透油藏在我国油田开发中所占的比重越来越大。而注水是低渗透油藏有效开发的最重要手段，如何改善水驱效果，提高水驱效率是低渗透油藏注水开发过程中的关键问题，而水驱评价方法是评判低渗油田注水开发效果的重要手段。本文主要针对低渗油田水驱评价体系相关文献展开调研分析，主要内容包括以下二个方面：低渗油藏水驱评价方法；水驱波及系数影响因素及相关计算方法和应用。文献调研分析结果表明，现有的一些水驱评价体系和水驱波及系数计算方法都不能全面考虑油层的非均质性产生的影响，从而导致非均值低渗油藏的水驱评价结果和水驱波及系数的符合率不高。 In recent years, low permeability reservoir has played an important role in oil field development and water injection is the most important method for reservoir development. How to improve the water drive efficiency and wa-terflooding effect is the main problem and water flooding assessment has played an important role in judging the level of oil field development. In this paper, we mainly discussed the method of waterflooding evaluation and calculation and application of sweep efficiency. Research found that some of the existing methods could not fully take into account the effect of the heterogeneity of the reservoir, making the coincidence rate of waterflooding evaluation and sweep effi-ciency low.

Calibration of Pipe Friction Factor Based on Improved Genetic Algorithm

This paper presents a method to calibrate pipe friction factor in oilfield water injection pipeline based on genetic algorithm. For the shortcoming, of basic genetic algorithms, genetic algorithm is made the corresponding improvements, this algorithm is improved global searching capability. Finally, a practical example verified the feasibility of the presented method.

Evaluation and prevention of formation damage in offshore sandstone reservoirs in China

Reduction in water injectivity would be harmful to the waterflood development of offshore sandstone oil reservoirs. In this paper the magnitude of formation damage during water injection was evaluated by analyzing the performance of water injection in the Bohai offshore oilfield, China. Two parameters, permeability reduction and rate of wellhead pressure rise, were proposed to evaluate the formation damage around injection wells. The pressure performance curve could be divided into three stages with different characteristics. Analysis of field data shows that formation damage caused by water injection was severe in some wells in the Bohai offshore oilfield, China. In the laboratory, the content of clay minerals in reservoir rock was analyzed and sensitivity tests (including sensitivity to water, flow rate, alkali, salt and acid) were also conducted. Experimental results show that the reservoir had a strong to medium sensitivity to water (i.e. clay swelling) and a strong to medium sensitivity to flow rate, which may cause formation damage. For formation damage prevention, three injection schemes of clay stabilizer (CS) were studied, i.e. continuous injection of low concentration CS (CI), slug injection of high concentration CS (SI), and slug injection of high concentration CS followed by continuous injection of low concentration CS (SI-CI). Core flooding experiments show that SI-CI is an effective scheme to prevent formation damage and is recommended for the sandstone oil reservoirs in the Bohai offshore oilfield during water injection.

Modicisalibacter tunisiensis gen. nov., sp. nov., an aerobic, moderately halophilic bacterium isolated from an oilfield-water injection sample, and emended description of the family Halomonadaceae Franzmann et al. 1989 emend Dobson and Franzmann 1996 emend. Ntougias et al. 2007

An aerobic, moderately halophilic, Gram-negative, motile, non-sporulating bacterium, strain LIT2(T), was isolated from an oilfield-water injection after enrichment on crude oil. Strain LIT2(T) grew between 15 and 45 degrees C and optimally at 37 degrees C. It grew in the presence of 1-25 % (w/v) NaCl, with an optimum at 10 % (w/v) NaCl. Predominant fatty acids were C(16 : 0) (26.9 %), C(18 : 1)omega7c (22.6 %), C(16 : 1)omega7c (20.4 %) C(19 : 0) cyclo omega8c (10.9 %) and C(17 : 0) (8 %). Interestingly, the relative percentages of these last two fatty acids were intermediate compared with most species among the family Halomonadaceae for which fatty acid composition has been determined. The DNA G+C content was 53.7 mol%, which is very low among the family Halomonadaceae. Strain LIT2(T) exhibited 16S rRNA gene sequence similarity values of 94.06-95.15 % to members of the genus Chromohalobacter, 94.21-94.65 % to members of the genus Halomonas and 93.57 % with the single species representative of the genus Cobetia. Based on the phylogenetic and phenotypic evidence presented in this paper, we propose the name Modicisalibacter tunisiensis gen. nov., sp. nov. to accommodate strain LIT2(T). The type strain of Modicisalibacter tunisiensis is LIT2(T) (=CCUG 52917(T) =CIP 109206(T)). A reassignment of the descriptive 16S rRNA signature characteristics of the family Halomonadaceae permitted placement of the new genus Modicisalibacter into the family.

中東地域下部白亜系炭酸塩岩油層における５点水攻法下の水付き現象とその地質学的要因

Premature water breakthrough was observed in a Lower Cretaceous carbonate reservoir under five spot pattern water injection in a Middle East oil field. Openhole log resistivity anomalies in recently drilled wells and time lapse pulsed neutron logs suggested preferential water movement in certain horizons. Reservoir heterogeneity depending on lithological variation is identified as a cause of the water breakthrough.Two high permeable lithofacies were defined by core and thin section observation. One is altered bioclast dominant coarse grainstone/packstone in the middle part of the reservoir. The other is very fine altered bioclastic peloidal grainstone/packstone in the upper part of the reservoir. These lithofacies are composed mainly of rarely micritized bioclastic grains with rigid framework preserving intergranuler porosity. Large molds and vugs associated with rudists in the upper part of the reservoir are locally connected and contribute to the fluid flow.Relative sea level change and paleo-topography are recognized as important factors to control lithofacies distribution. Areal distribution of the lithofacies shows aggradational stacking pattern and abrupt lateral lithofacies change particularly in the middle part of the reservoir. This suggests that simple carbonate ramp model currently applied is not appropriate for reservoir characterization purpose in this reservoir.

Chemical Mitigation of Sulfide in Water-Injection Systems

This article is a synopsis of paper SPE 50741, "A New Chemical Approach To Mitigate Sulfide Production in Oilfield Water-Injection Systems," by M.D. Johnson, M.L. Harless, and A.L. Dickinson, Baker Petrolite, and E.D. Burger, SPE, EB Technologies, originally presented at the 1999 SPE International Symposium on Oilfield Chemistry, Houston, 16-19 February.

Prévention et inhibition des dépôts de sulfate dans les installations pétrolières. Une application sur un champ saharien

Among the main problems raised by water injection in oilfields, the physiocochemical opposition prevailing between injected water and field water is certainly still the one which is the worst masterd at explitation level. The deposits and the corrosions produced or encouraged by the various precipitation reactions generate degradations which are often irreversible and particularly noxious for the reservoir rock and for the deep production equipments as for the surface ones. Within the framework of research and development work, carried out at the French Petroleum Institute, related to injection and productivity of wells, this article presents the convincing results of a test carried out in full injection-size with a inhibitor of barium sulfate deposits, specifically adapted to the hard production conditions of a field in South Algeria.

Corrosion products associated with attached bacteria at an oil field water injection plant

Attached populations of corrosion enhancing sulfate-reducing bacteria (SRB) and organic acid-producing bacteria (APB) were measured on steel plugs at an oil field water injection plant near Wainwright, Alberta. The sample plugs were colonized to ca. 106 SRB/cm2. Counts for APB ranged from 102 to 10/cm2. Scanning electron microscopic examination of the sample plugs revealed an uneven distribution of surface corrosion deposits. A thin iron sulfide layer covered most of the exposed areas. Thicker sulfur-enriched deposits occurred randomly. The bulk of the thicker deposits were smooth, whereas peripheral regions exhibited a porous texture. The elemental composition of the different regions was the same; however, bacterial cells were concentrated in the porous areas and were not found in the thinner deposits. In transmission electron microscopic thin sections cut perpendicularly through corrosion deposits, bacterial cells were found mineralized in successive stages by iron sulfides. The corrosion deposit matrix also generated strong Cl peaks in energy dispersive X-ray spectra. This entrainment of bacterial cells within a corrosion deposit matrix is consistent with the concept of bacterial enhancement of corrosion by removal of reducing power from iron sulfides galvanically coupled to the steel surface. Key words: microbial corrosion, iron sulfide, cathodic hydrogen, electron microscopy.

Control of biocorrosion using laboratory and field assessments

Biofouling and biocorrosion can be significant problems in oilfield water injection systems, despite extensive use of chemical biocides. This work set out to establish relevant testing and monitoring procedures to optimise microbiological control in these systems. A combination of laboratory based sessile biocide screening trials and onsite monitoring of biofilm bacteria was developed to ensure that an effective biocontrol programme was set up. It is important to use a mixed population of bacteria freshly isolated from biofilms in the system to ensure that any biocide tolerance of the system bacteria is reflected in the laboratory tests. In general, the results are borne out by the site audits of the control regime against sessile bacteria in the system. In an industrial system, biocide resistant populations develop from time to time. In practice it was found that even a small change to the biocide formulation could improve biocontrol, with concomitant reduction in corrosion rates and maintenance costs.

The effect of pressure and temperature on sulphate-reducing bacteria and the action of biocides in oilfield water injection systems

The effects of elevated pressures and temperatures on the growth, morphology and metabolic activity of sulphate-reducing bacteria, isolated from the North Sea, are described. Pressure/temperature profiles, growth curves and sulphate reduction rates are presented for several isolates. The maximum pressure and temperature that supported growth were 65 000 KPa and 45°C respectively. The results are discussed in connection with water injection into oil-bearing reservoirs where there is a concern that generation of hydrogen sulphide by sulphate-reducing bacteria may lead to increased hydrogen sulphide levels (souring) in oil and gas, and to corrosion problems in production facilities. The bacteriostatic effects of a number of commercial biocides were enhanced at elevated hydrostatic pressures and temperatures.