Acid Stimulation Used in In-Situ Leaching Uranium

2010 ◽  
Author(s):  
Wen-sheng Liao ◽  
Li-min Wang ◽  
Yi-xuan Yao ◽  
Guo-ping Jiang ◽  
Hai-jun Zhao ◽  
...  
Keyword(s):  
Formic Acid ◽  
Injection Rate ◽  
Low Permeability ◽  
Reaction Products ◽  
Treatment Results ◽  
The Core ◽  
Fluid Systems ◽  
Core Permeability ◽  
Significant Production

Acidization was studied on a uranium sandstone deposit in Inner Mongolia with low–permeability and heavy calcium cementation. Acid dissolving test indicates that hydrochloric acid, formic acid and mud acid can easily dissolve formation minerals. With proper volumes and concentrations of acids used, the risk of precipitation of reaction products could be minimized. Core flow acidizing trial shows that the acidic fluid systems of hydrochloride acid, formic acid or acetic acid can significantly improve the core permeability. The average permeability has increased by 763 percent for the above three systems. But mud acid didn’t increase the core permeability; on the contrary, it caused formation damage, and led to lowering permeability. In the pilot test, the injection rate has improved by 118 percent for 6 wells. The acid treatment results indicate that a significant production enhancement of wellfields can be achieved by acid stimulation.

Modeling of Wormhole Propagation in Carbonate Rocks by Use of In-Situ-Gelled Acids

SPE Journal ◽  
2017 ◽  
Vol 22 (06) ◽  
pp. 2032-2048 ◽  
Author(s):  
Behzad Hosseinzadeh ◽  
Mohammad Bazargan ◽  
Behzad Rostami ◽  
Shahab Ayatollahi
Keyword(s):  
Shear Rate ◽  
Mechanistic Model ◽  
Injection Rate ◽  
Two Dimensions ◽  
Low Permeability ◽  
Clear Understanding ◽  
High Permeability ◽  
Influential Parameters ◽  
Dual Core

Summary Diversion in heterogeneous carbonate reservoirs plays the most important role to the success of acidizing. Without the use of diversion, more acid preferentially flows into the high-permeability region and leaves the low-permeability region underreacted. But a clear understanding of diverting agents, such as polymer-based in-situ-gelled acids, can help uniformly stimulate the near-wellbore region. In this paper, we correct the rheological model that was developed by Ratnakar et al. (2013) according to experimental data from Gomaa and Nasr-El-Din (2010b) by considering shear-rate effect in a two-scale continuum model. It is found that the rheology parameters and shear rate are influential parameters in diversion. In addition, the amount of acid required for the breakthrough is found to be strongly dependent on rheology parameters and permeability in single-coreflood simulation. In our study, the viscosity of the spent acid is found to be the key parameter for diversion efficiency. We have constructed a mechanistic model similar to that in Panga et al. (2005) that simulates the acid injection in two dimensions. Then, we extended our simulation to dual-core systems with different permeability contrasts. The results show that there exists an intermediate injection rate that develops a wormhole in low-permeability core. This intermediate injection rate increases with increasing the permeability contrast. The results suggest that the dissolution pattern in the high-permeability core is dependent on the permeability contrast. It changes from wormhole to uniform shape when the permeability contrast increases.

Experimental Analysis of CO2 Injection on Permeability of Vuggy Carbonate Aquifers

2012 ◽  
Vol 135 (1) ◽  
Author(s):  
Ibrahim M. Mohamed ◽  
Jia He ◽  
Hisham A. Nasr-El-Din
Keyword(s):  
Flow Rate ◽  
Initial Permeability ◽  
Co2 Injection ◽  
Reaction Products ◽  
The Core ◽  
Injection Flow Rate ◽  
Injection Flow ◽  
Injection Scheme ◽  
Core Permeability ◽  
Permeability Alteration

Reactions of CO2 with formation rock may lead to an enhancement in the permeability due to rock dissolution, or damage (reduction in the core permeability) because of the precipitation of reaction products. The reaction is affected by aquifer conditions (pressure, temperature, initial porosity, and permeability), and the injection scheme (injection flow rate, CO2:brine volumetric ratio, and the injection time). The effects of temperature, injection flow rate, and injection scheme on the permeability alteration due to CO2 injection into heterogeneous dolomite rock is addressed experimentally in this paper. Twenty coreflood tests were conducted using Silurian dolomite cores. Thirty pore volumes of CO2 and brine were injected in water alternating gas (WAG) scheme under supercritical conditions at temperatures ranging from 21 to 121 °C, and injection rates of 2.0–5.0 cm3/min. Concentrations of Ca++, Mg++, and Na+ were measured in the core effluent samples. Permeability alteration was evaluated by measuring the permeability of the cores before and after the experiment. Two sources of damage in permeability were noted in this study: (1) due to precipitation of calcium carbonate, and (2) due to migration of clay minerals present in the core. Temperature and injection scheme don't have a clear impact on the core permeability. A good correlation between the initial and final core permeability was noted, and the ratio of final permeability to the initial permeability is lower for low permeability cores.

Propagation of Regular HCl Acids in Carbonate Rocks: The Impact of an In Situ Gelled Acid Stage

2011 ◽  
Vol 133 (2) ◽  
Author(s):  
Ahmed M. Gomaa ◽  
Hisham A. Nasr-El-Din
Keyword(s):  
Material Balance ◽  
Chemical Species ◽  
Field Studies ◽  
Injection Rate ◽  
The Core ◽  
The Impact ◽  
First Time ◽  
Recent Laboratory ◽  
Injection Rates

Recent laboratory and field studies indicated that polymer-based in situ gelled acids can cause formation damage. Coreflood experiments using single-stage and multistage acids were conducted at 250 °F. 15 wt. % regular HCl and 5 wt. % in situ gelled acid-based on Fe(III) as a crosslinker were the acids that were used in this study. Propagation of acids and crosslinker inside 20 in. long cores was examined for the first time in detail. Stage volume and injection rate, which were the parameters that affect the propagating of various chemical species, were examined. Samples of the core effluent were collected and the concentrations of calcium, crosslinker, and acid were measured. Material balance was conducted to determine the amount of cross-liker that retained in the core. The results show that in situ gelled acid should be pumped at low injection rates. In situ gelled acid at low injection rate instantaneously plugged the tip of the wormhole and did not create additional wormholes inside the core. Therefore, when the final regular acid stage bypassed the gel, it started to propagate from nearly the last point that the first stage ended. In site gelled acid stage volume should not exceed 0.5 PV. No benefits were gained by increasing the volume of in situ gelled acids. Retention of total iron in the core increased in multistage acid treatments, especially at low acid injection rates.

Novel Spherical Polymer Sealing Agent for Oil-Based Drilling Fluids to Overcome Borehole Instability Problem in Low Permeability Reservoirs

2020 ◽  
Vol 842 ◽  
pp. 290-296 ◽  
Author(s):  
Long Li ◽  
Rong Chao Cheng ◽  
Cha Ma ◽  
Jie Zhang
Keyword(s):  
Suspension Polymerization ◽  
Great Promise ◽  
Low Permeability ◽  
Drilling Fluids ◽  
The Core ◽  
Instability Problem ◽  
Powerful Approach ◽  
Displacement Experiments ◽  
New Type ◽  
Core Permeability

Due to borehole instability problem in low permeability formations, a new type of spherical polymer sealing agent (OLBS) for oil-based drilling fluids was prepared via suspension polymerization, and the sealing effect of polymer sealing agent on low permeability cores was evaluated. The results indicated that OLBS had no influence on the rheological properties of oil-based drilling fluids. The core displacement experiments indicated that OLBS could reduce the core permeability by a significant amount, and thus stop fluid invasion into the formations, so OLBS could provide an excellent sealing effect and improve wellbore strength. Using this polymer sealing agent to plug the low permeability formations is a very powerful approach to address borehole instability problem in troublesome low permeability formations. This sealing agent is suitable for the drilling of long sections of horizontal laterals. In the future, the oil-based drilling fluids containing OLBS might hold great promise to resolve borehole instability problem in low permeability formations.

Determination of Gas Trapping With Foam Using X-Ray Computed Tomography and Effluent Analysis

SPE Journal ◽  
2009 ◽  
Vol 14 (02) ◽  
pp. 222-236 ◽  
Author(s):  
Quoc P. Nguyen ◽  
William R. Rossen ◽  
Pacelli L.J. Zitha ◽  
Peter K. Currie
Keyword(s):  
Ct Images ◽  
Injection Rate ◽  
X Ray ◽  
The Core ◽  
Gas Trapping ◽  
1D Model ◽  
Tracer Distribution ◽  
X Ray Computed ◽  
Trapped Gas

Summary Foam is used worldwide to improve acid placement in matrix acid treatments and to redirect gas flow in improved oil recovery. Gas trapping is a major factor in foam processes; it affects foam mobility and controls diversion of liquids such as acid injected after foam. Most previous studies of gas trapping have relied on fitting effluent-gas tracer profiles to a 1D model for transport of tracer in the presence of trapped gas, including mass transfer between flowing and trapped gas. We present new experiments where X-ray computed tomography (CT) directly determines the gas-tracer distribution in situ. The key is using a gas-phase tracer [xenon (Xe)] visible in CT. The CT images show clearly that the standard 1D model used to interpret tracer effluent profiles is incorrect in its assumptions. For the first time, here we compare the in-situ tracer distribution from CT images to the trapped-gas saturation estimated from fitting the effluent tracer profile to the 1D model, augmented here for the effect of pressure variation along the core. The effluent profile is determined indirectly from the CT images in two ways:by imaging the tracer concentration in the flowline downstream of the core andby using a mass balance on the tracer in the core. Estimates of trapped-gas fraction using the 1D model vary by as much as a factor of 0.2 among reasonable fits to the effluent data, and flowing-gas fraction varies by as much as a factor of 1.5 or 2. The experiments span a range of foam qualities and injection rates in Bentheim sandstone. Estimates of trapped-gas fraction derived from the 1D model decrease with increasing gas-injection rate and increase weakly with increasing liquid-injection rate in our experiments. The CT images show a shift to a wider variety of fluctuating flow paths as liquid- or gas-injection rate increases.

Biodegradation of Free Phytol by Bacterial Communities Isolated from Marine Sediments under Aerobic and Denitrifying Conditions

1999 ◽  
Vol 65 (12) ◽  
pp. 5484-5492 ◽  
Author(s):  
Jean-François Rontani ◽  
Patricia C. Bonin ◽  
John K. Volkman
Keyword(s):  
Marine Sediments ◽  
Bacterial Communities ◽  
Bacterial Degradation ◽  
The Core ◽  
Abiotic Degradation ◽  
Phytenic Acid ◽  
Aerobic And Anaerobic ◽  
Significant Production

ABSTRACT Biodegradation of (E)-phytol [3,7,11,15-tetramethylhexadec-2(E)-en-1-ol] by two bacterial communities isolated from recent marine sediments under aerobic and denitrifying conditions was studied at 20°C. This isoprenoid alcohol is metabolized efficiently by these two bacterial communities via 6,10,14-trimethylpentadecan-2-one and (E)-phytenic acid. The first step in both aerobic and anaerobic bacterial degradation of (E)-phytol involves the transient production of (E)-phytenal, which in turn can be abiotically converted to 6,10,14-trimethylpentadecan-2-one. Most of the isoprenoid metabolites identified in vitro could be detected in a fresh sediment core collected at the same site as the sediments used for the incubations. Since (E)-phytenal is less sensitive to abiotic degradation at the temperature of the sediments (15°C), the major part of (E)-phytol appeared to be biodegraded in situ via (E)-phytenic acid. (Z)- and (E)-phytenic acids are present in particularly large quantities in the upper section of the core, and their concentrations quickly decrease with depth in the core. This degradation (which takes place without significant production of phytanic acid) is attributed to the involvement of alternating β-decarboxymethylation and β-oxidation reaction sequences induced by denitrifiers. Despite the low nitrate concentration of marine sediments, denitrifying bacteria seem to play a significant role in the mineralization of (E)-phytol.

Polymeric Shell with Low Permeability

2012 ◽  
Vol 441 ◽  
pp. 484-488
Author(s):  
Jian Wei Xing ◽  
Cheng Shu Xu ◽  
Yan Ren ◽  
Wen Zhao Shi ◽  
Jin Shu Liu
Keyword(s):  
Interfacial Polymerization ◽  
Outer Wall ◽  
Raw Material ◽  
Low Permeability ◽  
Polypropylene Glycol ◽  
Melamine Formaldehyde ◽  
Combined Process ◽  
Reactive Monomer ◽  
The Core

A polymeric shell with low permeability was manufactured via a combined process including both an interfacial polymerization and an in-situ condensation. A polyisocyanate, tolylene diisocyanate (TDI) or 1,6-hexamethylenediisocyanate (HDI), was added in the core compositions as a reactive monomer for the formation of both polyurethane wall and polyurea wall. PPG-2,000, a polypropylene glycol, was employed as another reactive monomer to form the polyurethane wall. Melamine-formaldehyde precondensate was prepared and used as the raw material for the aminoplast wall formation. The polymeric shell thus consists of three walls, which includes a polyurethane inner wall, a polyurea middle wall and an aminoplast outer wall. The triple-walled shell has proven to possess low permeability and then wrap the paraffin compounds tightly.

Estudio del proceso de lavado de contenedores para eliminar tiempos y movimientos innecesarios, caso: Wash Containers S.A de C.V.

2020 ◽  
pp. 25-36
Author(s):  
Juan Alfredo Lino-Gamiño ◽  
Carlos Méndez-González ◽  
Eduardo José Salazar-Araujo ◽  
Pablo Adrián Magaña-Sánchez
Keyword(s):  
Business Process ◽  
Value Chain ◽  
Process Management ◽  
Core Business ◽  
The Core ◽  
Washing Process ◽  
Overall Performance ◽  
The Times

In the value chain it is important to keep in mind the core business of the company, since it depends largely on the competitiveness of the company and its overall performance, bearing in mind that all business indicators depend on it. In this work we will study the washing process within the company WASH CONTAINERS SA DE CV, to improve the washing processes and in this way reduce times and movements in the process leading the company to reduce costs considerably within the operations company daily, having a more competitive operation and with greater profit margin in its business process. Goals: It Improve the logistics of the movement of containers for washing and with it the core business of the company. Methodology: The action research will be applied applying Business Process Management for the improvement of processes in situ, it will be developed in a certain period of time and with that it will establish an improvement projection. Contribution: The improvement of the times for the disposal of the containers and their subsequent use, allows a better competitiveness and with it the income of the company, on the other hand, the transport companies improve in performance in quantity, quality of disposition and with it their income.

scholarly journals North Atlantic warming over six decades drives decreases in krill abundance with no associated range shift

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Martin Edwards ◽  
Pierre Hélaouët ◽  
Eric Goberville ◽  
Alistair Lindley ◽  
Geraint A. Tarling ◽  
...  
Keyword(s):  
North Atlantic ◽  
Range Shift ◽  
The Core ◽  
Krill Abundance ◽  
The North ◽  
Living Space ◽  
Warming Climate ◽  
Two Temperatures ◽  
The North Atlantic

AbstractIn the North Atlantic, euphausiids (krill) form a major link between primary production and predators including commercially exploited fish. This basin is warming very rapidly, with species expected to shift northwards following their thermal tolerances. Here we show, however, that there has been a 50% decline in surface krill abundance over the last 60 years that occurred in situ, with no associated range shift. While we relate these changes to the warming climate, our study is the first to document an in situ squeeze on living space within this system. The warmer isotherms are shifting measurably northwards but cooler isotherms have remained relatively static, stalled by the subpolar fronts in the NW Atlantic. Consequently the two temperatures defining the core of krill distribution (7–13 °C) were 8° of latitude apart 60 years ago but are presently only 4° apart. Over the 60 year period the core latitudinal distribution of euphausiids has remained relatively stable so a ‘habitat squeeze’, with loss of 4° of latitude in living space, could explain the decline in krill. This highlights that, as the temperature warms, not all species can track isotherms and shift northward at the same rate with both losers and winners emerging under the ‘Atlantification’ of the sub-Arctic.

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