Theoretical and Experimental Study on Optimal Injection Rates in Carbonate Acidizing

2016 ◽  
Author(s):  
K. Dong ◽  
D. Zhu ◽  
A. D. Hill
Keyword(s):  
Experimental Study ◽  
Optimal Injection ◽  
Carbonate Acidizing ◽  
Injection Rates

CALCULATION OF OPTIMAL INJECTION RATE FOR DISPERSED WATERFLOODING SYSTEM

2017 ◽  
pp. 63-67
Author(s):  
L. A. Vaganov ◽  
A. Yu. Sencov ◽  
A. A. Ankudinov ◽  
N. S. Polyakova
Keyword(s):  
Injection Rate ◽  
Oil Field ◽  
Injection Well ◽  
Water Migration ◽  
Mutual Location ◽  
Optimal Injection ◽  
Technical Measures ◽  
Injection Rates

The article presents a description of the settlement method of necessary injection rates calculation, which is depended on the injected water migration into the surrounding wells and their mutual location. On the basis of the settlement method the targeted program of geological and technical measures for regulating the work of the injection well stock was created and implemented by the example of the BV7 formation of the Uzhno-Vyintoiskoe oil field.

scholarly journals Optimal injection rate of water in the Guide Basin hot dry rock mining project

2018 ◽  
Vol 37 (2) ◽  
pp. 721-735 ◽  
Author(s):  
Xiaoxue Yan ◽  
Yanguang Liu ◽  
Guiling Wang ◽  
Yaoru Lu
Keyword(s):  
Injection Rate ◽  
Heat Extraction ◽  
Qinghai Province ◽  
Hot Dry Rock ◽  
Rock Mining ◽  
Optimal Injection ◽  
Production Stages ◽  
Reservoir Simulator ◽  
Guide Basin ◽  
Injection Rates

The energy reserves of hot dry rock resources are huge, thus a model to predict engineering production for efficient and stable development and utilization is sought. Based on the geological characteristics of dry rock resources in Guide Basin, Qinghai Province, China, the fully coupled wellbore–reservoir simulator—T2Well—is used to model a production system using water as a heat transfer medium and simulate the system’s operation to analyze the influence of different injection rates on heat extraction. In later production stages, output temperature and reservoir pressure decrease by 10–30°C and 0.5–30 MPa, depending on injection rate; this occurs earlier and to a greater extent at higher injection rates; thermal breakthrough also occurs earlier (7–10 years). The heat extraction rate is 1–20 MW and the cumulative heat extracted is 2.1–24.2 × 105 J. Lower injection rates result in relatively low heat extraction rates. For maximum economic benefit, an injection rate of 50–75 kg/s is ideal.

Theoretical and Experimental Study on Optimal Injection Rates in Carbonate Acidizing

SPE Journal ◽  
2016 ◽  
Vol 22 (03) ◽  
pp. 892-901 ◽  
Author(s):  
Kai Dong ◽  
Ding Zhu ◽  
A. Daniel Hill
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Injection Rate ◽  
Experimental Results ◽  
Acid Injection ◽  
Optimal Injection ◽  
Mode Size ◽  
Interstitial Velocity ◽  
Injection Rates

Summary Optimal acid-injection rate is critical information for carbonate-matrix-acidizing design. This rate is currently obtained through fitting acidizing-coreflood experimental results. A model is needed to predict optimal acid-injection rates for various reservoir conditions. A wormhole forms when larger pores grow in the cross-sectional area at a rate that greatly exceeds the growth rate of smaller pores caused by surface reaction. This happens when the pore growth follows a particular mechanism, which is discussed in this paper. We have developed a model to predict wormhole-growth behavior. The model uses the mode size in a pore-size distribution—the pore size that appears most frequently in the distribution—to predict the growth of the pore. By controlling the acid velocity inside of it, we can make this particular pore grow much faster than other smaller pores, thus reaching the most-favorable condition for wormholing. This also results in a balance between overall acid/rock reaction and acid flow. With the introduction of a porous-medium model, the acid velocity in the mode-size pore is scaled up to the interstitial velocity at the wormhole tip. This interstitial velocity at the wormhole tip controls the wormhole propagation. The optimal acid-injection rates are then calculated by use of semiempirical flow correlations for different flow geometries. The optimal injection rate depends on the rock lithology, acid concentration, temperature, and rock-pore-size distribution. All these factors are accounted for in this model. The model can predict the optimal rates of acidizing-coreflood experiments correctly, compared with our acidizing-coreflood experimental results. In addition, on the basis of our model, it is also found that at optimal conditions, the wormhole-propagation velocity is linearly proportional to the acid-diffusion coefficient for a diffusion-limited reaction. This is proved both experimentally and theoretically in this study. Because there is no flow-geometry constraint while developing this model, it can be applied to field scales. Applications are presented in this paper.

New Insights on the Effect of Oil Saturation on the Optimal Acid-Injection Rate in Carbonate Acidizing

SPE Journal ◽  
2017 ◽  
Vol 23 (03) ◽  
pp. 969-984 ◽  
Author(s):  
Rahul Kumar ◽  
Jia He ◽  
Mohammed Bataweel ◽  
Hisham Nasr-El-Din
Keyword(s):  
Inductively Coupled Plasma ◽  
Optical Emission ◽  
Injection Rate ◽  
Residual Oil ◽  
Oil Saturation ◽  
Acid Injection ◽  
Reservoir Conditions ◽  
Carbonate Acidizing ◽  
The Impact ◽  
Injection Rates

Summary The optimal injection rate for wormhole propagation and face dissolution at low injection rates during carbonate matrix acidizing is well-established. However, little research is documented on the subject of how the presence of oil affects this process. This study demonstrates the impact of oil saturation on wormhole characteristics while acidizing reservoir and outcrop cores under reservoir conditions (200°F). Coreflood experiments at flow rates ranging from 0.5 to 20 cm3/min were performed to determine the optimal acid-injection rate for wormhole propagation when acidizing homogeneous limestone reservoir cores, low-permeability Indiana limestone cores, and homogeneous dolomite cores with dimensions of a 3- and 6-in. length and a 1.5-in. diameter. The experimental work involved acidizing cores saturated with water, oil, and waterflood residual oil by use of 15-wt% regular hydrochloric acid (HCl). The viscosity of the crude oil used was 3.8 cp at 200°F. Computed-chromatography (CT) scans enabled the characterization of wormholes through the cores. The concentrations of the calcium and magnesium ions in core effluent samples were measured with inductively coupled plasma optical emission spectroscopy (ICP-OES), and the effluent samples were titrated to determine the concentration of the acid. At injection rates of 0.5 to 20 cm3/min, 15-wt% HCl was effective in creating wormholes with minimal branches for cores with residual oil saturation (ROS). Compared with brine- and oil-saturated cores, those at ROS took less acid volume to breakthrough. In addition, the efficiency of regular acid improved with increased acid-injection rates in the presence of residual oil. A decrease in the acid pore volume (PV) to breakthrough for oil-saturated cores was observed at high acid-injection rates, which could be attributed to viscous fingering of acid through oil. Unlike brine-saturated and oil-saturated cores, cores at ROS showed no face dissolution at low acid-injection rates. The conclusions of this work highlight the impact of oil saturation on matrix characteristics while acidizing carbonate rocks.

scholarly journals Investigations of Structural and Residual Trapping Phenomena during CO2 Sequestration in Deccan Volcanic Province of the Saurashtra Region, Gujarat

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Pradeep Reddy Punnam ◽  
Balaji Krishnamurthy ◽  
Vikranth Kumar Surasani
Keyword(s):  
Co2 Sequestration ◽  
Injection Rate ◽  
Deccan Traps ◽  
Deccan Volcanic Province ◽  
Residual Trapping ◽  
Optimal Injection ◽  
Simulation Results ◽  
Insight Into ◽  
Selection Of ◽  
Injection Rates

This work aims to study the structural and residual trapping mechanisms on the Deccan traps topography to elucidate the possible implementation of CO2 geological sequestration. This study provides an insight into a selection of stairsteps landscape from Deccan traps in the Saurashtra region, Gujarat, India. Various parameters affect the efficiency of the structural and residual trapping mechanisms. Thus, the parametric study is conducted on the modeled synthetic geological domain by considering the suitable injection points for varying injection rates and petrophysical properties. The outcomes of this study will provide insights into the dependencies of structural and residual trapping on the Deccan traps surface topography and injection rates. It can also establish a protocol for selecting the optimal injection points with the desired injection rate for the safe and efficient implementation of CO2 sequestration. The simulation results of this study have shown the dependencies of structural and residual trapping on the geological domain parameters.

Experimental study on the restoration from a tilt-azimuth series for improvement in resolution

1995 ◽  
Vol 53 ◽  
pp. 636-637
Author(s):  
Norio Baba ◽  
Norihiko Ichise ◽  
Syunya Watanabe
Keyword(s):  
Experimental Study ◽  
Spherical Aberration ◽  
Incident Beam ◽  
Optical Parameters ◽  
Beam Tilting ◽  
Illumination Method ◽  
Restoration Method ◽  
Illumination Mode

The tilted beam illumination method is used to improve the resolution comparing with the axial illumination mode. Using this advantage, a restoration method of several tilted beam images covering the full azimuthal range was proposed by Saxton, and experimentally examined. To make this technique more reliable it seems that some practical problems still remain. In this report the restoration was attempted and the problems were considered. In our study, four problems were pointed out for the experiment of the restoration. (1) Accurate beam tilt adjustment to fit the incident beam to the coma-free axis for the symmetrical beam tilting over the full azimuthal range. (2) Accurate measurements of the optical parameters which are necessary to design the restoration filter. Even if the spherical aberration coefficient Cs is known with accuracy and the axial astigmatism is sufficiently compensated, at least the defocus value must be measured. (3) Accurate alignment of the tilt-azimuth series images.

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