Prediction of Optimum Injection Rate for Carbonate Acidizing Using Machine Learning

2018 ◽  
Author(s):  
Ziad Sidaoui ◽  
Abdulazeez Abdulraheem ◽  
Mustapha Abbad
Keyword(s):  
Machine Learning ◽  
Injection Rate ◽  
Carbonate Acidizing ◽  
Optimum Injection Rate

A Matrix Acidizing System for Controlled Carbonate Well Stimulation using a Carboxylic Acid Salt with a Chelating Agent

2021 ◽  
Author(s):  
Albert Bokkers ◽  
Piter Brandenburg ◽  
Coert Van Lare ◽  
Cees Kooijman ◽  
Arjan Schutte
Keyword(s):  
Chelating Agent ◽  
Life Time ◽  
Nitrogen Atmosphere ◽  
Injection Rate ◽  
Sodium Gluconate ◽  
Matrix Acidizing ◽  
Well Stimulation ◽  
Stirred Reactor ◽  
Core Flood ◽  
Optimum Injection Rate

Abstract This work presents a matrix acidizing formulation which comprises a salt of monochloroacetic acid giving a delayed acidification and a chelating agent to prevent precipitation of a calcium salt. Results of dissolution capacity, core flood test and corrosion inhibition are presented and are compared to performance of 15 wt% emulsified HCl. Dissolution capacity tests were performed in a stirred reactor at atmospheric pressure using equimolar amounts of the crushed limestone and dolomites. Four different chelating agents were added to test the calcium ion sequestering power. Corrosion tests were executed using an autoclave reactor under nitrogen atmosphere at 10 barg. Core flood tests were performed to simulate carbonate matrix stimulation using limestone cores. It was found that the half-life time of the hydrolysis reaction is 77 min at a temperature of 100 °C. Sodium gluconate and the sodium salt of D-glucoheptonic acid were identified to successfully prevent the precipitation of the reaction product calcium glycolate at a temperature of 40 °C. Computed Tomography (CT) scans of the treated cores at optimum injection rate showed a single wormhole formed. At 150 °C an optimum injection rate of 1 ml/min was found which corresponds to a minimum PVBT of 6. In addition, no face dissolution was observed after coreflooding. Furthermore, the corrosion rates of different metallurgies (L80 and J55) were measured which are significantly less than data reported in literature for 15wt% emulsified HCl. The novelty of this formulation is that it slowly releases an organic acid in the well allowing deeper penetration in the formation and sodium gluconate prevents precipitation of the reaction product. The corrosivity of this formulation is relatively low saving maintenance costs to installations and pipe work. The active ingredient in the formulation is a solid, allowing onsite preparation of the acidizing fluid.

Comparison of Wormhole Profiles on Carbonate Rocks Using Emulsified and Single-Phase Retarded Acids

2022 ◽  
Author(s):  
Norah Aljuryyed ◽  
Abdullah Al Moajil ◽  
Sinan Caliskan ◽  
Saeed Alghamdi
Keyword(s):  
Organic Acids ◽  
Single Phase ◽  
Injection Rate ◽  
Flow Rates ◽  
Low Viscosity ◽  
Propagation Behavior ◽  
Additional Equipment ◽  
Acid Reaction ◽  
Optimum Injection Rate ◽  
Indiana Limestone

Abstract Acid retardation through emulsification is commonly used in reservoir stimulation operations, however, emulsified acid are viscous fluids, thus require additional equipment at field for preparation and pumping requirements. Mixture of HCl with organic acids and/or chemical retarders have been used developed to retard acid reaction with carbonate, however, lower dissolving power. Development of low viscosity and high dissolving retarded acid recipes (e.g., equivalent to 15-26 wt.% HCl) addresses the drawbacks of emulsified acids and HCl acid mixtures with weaker organic acids. The objective of this study is to compare wormhole profile generated as a result of injecting acids in Indian limestone cores using 28 wt.% emulsified acid and single-phase retarded acids at comparable dissolving power at 200 and 300°F. Coreflood analysis testing was conducted using Indiana limestone core plugs to assess the pore volume profile of retarded acid at temperatures of 200 and 300° F. This test is supported by Computed Tomography to evaluate the propagation behavior as a result of the fluid/rock reaction. Wider wormholes were observed with 28 wt.% emulsified acid at 200°F when compared to test results conducted at 300°F. The optimum injection rate was 1 cm3/min at 200 and 300°F based on wormhole profile and examined flow rates. Generally, face-dissolution and wider wormholes were observed with emulsified acids, especially at 200°F. Narrower wormholes were formed as a result of injecting retarded acids into Indiana limestone cores compared to 28 wt.% emulsified acid. Breakthrough was not achieved with retarded acid recipe at 300°F and flow rates of 1 and 3 cm3/min, suggesting higher flow rates (e.g., > 3 cm3/min) are required for the retarded acid to be more effective at 300°F.

Boosting Algorithm Choice in Predictive Machine Learning Models for Fracturing Applications

2021 ◽  
Author(s):  
Abdul Muqtadir Khan
Keyword(s):  
Machine Learning ◽  
Data Science ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Injection Rate ◽  
Model Construction ◽  
Gradient Boosting ◽  
Light Gradient ◽  
Fracture Damage ◽  
Boosting Technique

Abstract With the advancement in machine learning (ML) applications, some recent research has been conducted to optimize fracturing treatments. There are a variety of models available using various objective functions for optimization and different mathematical techniques. There is a need to extend the ML techniques to optimize the choice of algorithm. For fracturing treatment design, the literature for comparative algorithm performance is sparse. The research predominantly shows that compared to the most commonly used regressors and classifiers, some sort of boosting technique consistently outperforms on model testing and prediction accuracy. A database was constructed for a heterogeneous reservoir. Four widely used boosting algorithms were used on the database to predict the design only from the output of a short injection/falloff test. Feature importance analysis was done on eight output parameters from the falloff analysis, and six were finalized for the model construction. The outputs selected for prediction were fracturing fluid efficiency, proppant mass, maximum proppant concentration, and injection rate. Extreme gradient boost (XGBoost), categorical boost (CatBoost), adaptive boost (AdaBoost), and light gradient boosting machine (LGBM) were the algorithms finalized for the comparative study. The sensitivity was done for a different number of classes (four, five, and six) to establish a balance between accuracy and prediction granularity. The results showed that the best algorithm choice was between XGBoost and CatBoost for the predicted parameters under certain model construction conditions. The accuracy for all outputs for the holdout sets varied between 80 and 92%, showing robust significance for a wider utilization of these models. Data science has contributed to various oil and gas industry domains and has tremendous applications in the stimulation domain. The research and review conducted in this paper add a valuable resource for the user to build digital databases and use the appropriate algorithm without much trial and error. Implementing this model reduced the complexity of the proppant fracturing treatment redesign process, enhanced operational efficiency, and reduced fracture damage by eliminating minifrac steps with crosslinked gel.

Machine-learning based prediction of injection rate and solenoid voltage characteristics in GDI injectors

Fuel ◽  
2021 ◽  
pp. 122569
Author(s):  
Heechang Oh ◽  
Joonsik Hwang ◽  
Lyle M. Pickett ◽  
Donghee Han
Keyword(s):  
Machine Learning ◽  
Injection Rate

Optimum Injection Rate of A New Chelate That Can Be Used To Stimulate Carbonate Reservoirs

SPE Journal ◽  
2011 ◽  
Vol 16 (04) ◽  
pp. 968-980 ◽  
Author(s):  
M.A.. A. Mahmoud ◽  
H.A.. A. Nasr-El-Din ◽  
C.A.. A. De Wolf ◽  
J.N.. N. LePage
Keyword(s):  
Acetic Acid ◽  
Ethylenediaminetetraacetic Acid ◽  
Injection Rate ◽  
Carbonate Reservoirs ◽  
Damkohler Number ◽  
Optimum Conditions ◽  
The Core ◽  
Damköhler Number ◽  
Optimum Injection Rate ◽  
Injection Rates

Summary Different chelating agents were used as alternatives for hydrochloric acid (HCl) in matrix acidizing to create wormholes in carbonate formations. Previous studies demonstrated the use of ethylenediaminetetraacetic acid (EDTA), hydroxy ethylenediaminetriacetic (HEDTA), and glutamic acid-N,N-diacetic acid (GLDA) as standalone stimulation fluids to stimulate carbonate reservoirs. The main problem of using EDTA and HEDTA is their low bio-degradability. GLDA was introduced as a standalone stimulation fluid for deep carbonate reservoirs where HCl can cause corrosion and face dissolution problems. In this study, calcite cores 1.5 in. in diameter and 6 or 20 in. in length were used to determine the optimum conditions where the GLDA can break through the core and form wormholes. GLDA solutions with pH values of 1.7, 3, and 3.8 were used. The optimum conditions of injection rate and pH were determined using coreflood experiments. Damköhler number was determined using the wormhole length and diameter from the CT scan 3D and 2D images. GLDA was compared with chelates that are used in the oil industry such as EDTA and HEDTA. GLDA also was used to stimulate parallel cores with different permeability ratios (up to 6.25). GLDA was found to be very effective in creating wormholes at pH = 1.7, 3, and 3.8; at different injection rates; and at temperatures up to 300°F. Increasing the temperature increased the reaction rate and less volume of GLDA was required to break through the core and form wormholes. Unlike HCl, in GLDA there was no face dissolution or washout in the cores even at low injection rates (0.5 cm3/min). An optimum injection rate and Damköhler number were found at which the pore volume (PV) required to create wormholes was the minimum. GLDA at pH 1.7 and 3 created wormholes with a small number of PV (at 1 cm3/min, GLDA at pH 1.7 required 1.5 PV at 300°F, and at pH 3 it required 1.8 PV). Compared with acetic acid, the volume of GLDA at pH 3 required to create wormholes was less than that required with acetic acid at the same conditions. GLDA was found to be effective in stimulating parallel cores up to 6.25 permeability contrast (final permeability/initial permeability).

Selecting and Modifying Multiphase Correlations for Gas-Lift Wells Using Machine Learning Algorithms

2021 ◽  
Author(s):  
Roman Gorbachev ◽  
Andrey Gubaev ◽  
Alexander Lubnin ◽  
Alexey Chorny ◽  
Vasif Kurbanov
Keyword(s):  
Machine Learning ◽  
Multiphase Flow ◽  
Injection Rate ◽  
Machine Learning Algorithms ◽  
Operating Modes ◽  
Bottom Hole ◽  
Urgent Task ◽  
The Republic ◽  
Gas Lift ◽  
Bottomhole Pressure

Abstract In the conditions of the development of the oil fields of the Cuu Long Basin in the continental shelf of the Republic of Vietnam, in the absence of downhole gauge systems, the urgent task is improving the accuracy of the calculation of bottomhole pressure in the producing wells based on the operation modes and construction. The aim of the paper is to create tools for selecting and modifying the correlation of multiphase flow most suitable for the development of a particular group of fields, as well as to develop a tool to implement effective management of the modes of operation of gas-lift wells by choosing the optimal gaslift injection rate. Based on data from 814 instrumental measurements in wells with different construction, liquid flow rate, watercut, GOR and gaslift injection, the calculation of bottom hole pressures was made. The calculated and actual bottomhole pressures were compared with five correlations of multiphase flow, the most suitable correlations were determined and modified, including using machine learning methods, which helped to significantly improve the convergence of calculated and actual bottomhole pressures. On the basis of the newly modified correlation, a calculation of bottom hole pressure (BHP) in each production well was made, the calculation of the change in bottomhole pressure when changing the operating modes of wells has been implemented. For the field group of the Cuu Long Basin, it was revealed that with the increase in watercut in the producing wells significantly reduces the efficiency of the gas-lift method of operation. This effect is not reflected in the widespread correlations of multiphase flow, which does not allow to use the results of calculations without making additional edits. A way to adapt the calculation values to instrumental measurements has been implemented, one of the known correlations has been modified and used in the forecast of changes in bottomhole pressure after changes in operating modes of wells throughout the well stock.

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.

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