Development and Improvement of Organic Salt Solutions of Potassium Citrate As An Environmentally Friendly Completion Fluids for Oil and Gas Wells

2021 ◽  
Keyword(s):  
Corrosion Rate ◽  
Oil And Gas ◽  
Fluid Pressure ◽  
Environmentally Friendly ◽  
Potassium Citrate ◽  
Organic Salt ◽  
Salt Solutions ◽  
Gas Wells ◽  
Oil And Gas Wells ◽  
Swelling Rate

This article provides information on the utilization and development of colloidal formulations based on organic potassium citrate, an alternative, environmentally friendly composite fluid that can support the drilling and production of oil and gas wells. The activity started with a laboratory-scale literature study, the formulation and modification of organic potassium citrate, testing the characteristics and performance of liquids, and improving advanced formulations. This completion fluid based on organic potassium citrate has high solubility and good stability to other pollutant particles. The colloidal organic salt system based on potassium citrate is an alternative function of the replenishment fluid (pressure holding fluid) for cleaning/deepening oil and gas wells. Currently, widely used composite fluids are chloride (Cl-), bromide (Br-), nitrate (NO3-), phosphate (PO4-), and cesium formate. However, these salt solutions are highly corrosive and are not environmentally friendly. The swelling test and the corrosion rate test are carried out using different fluids (i.e., KCl slurry, NaCl polymer, and colloidal organic citrate). The test results show that when the test is performed at room temperature for 16 hours, the organic citrate fluid's swelling rate is lower than 10%, and the KCl and NaCl sludge is higher than 20%. The result of a seven days corrosion test at 350oF is that the citric acid organic liquid is lower than 10 mpy, while KCl and NaCl are higher than 50 mpy. This completion fluid formulation based on organic citrate salts is a new type of completion fluid that has the following specifications: density up to (1.80), corrosion rate (3.19 mpy) @ 248-350oF, pH (6-8), resistance to extreme temperature, turbidity (7 NTU), a swelling rate below 10%, and has good compatibility with formation water. Also, potassium citrate organic salts can be degraded efficiently, making them safe for the environment.

scholarly journals Oil and Gas Wells: Enhanced Wellbore Casing Integrity Management through Corrosion Rate Prediction Using an Augmented Intelligent Approach

2019 ◽  
Vol 11 (3) ◽  
pp. 818 ◽  
Author(s):  
Dhafer A. Al-Shehri
Keyword(s):  
Corrosion Rate ◽  
Fresh Water ◽  
Oil And Gas ◽  
Carbonate Reservoir ◽  
Validation Dataset ◽  
Gas Wells ◽  
Wide Range ◽  
Oil And Gas Wells ◽  
Integrity Management ◽  
Metal Casing

Wellbore integrity management for oil and gas wells plays a vital role throughout the typical lifespan of a well. Downhole casing leaks in oil- and gas-producing wells significantly affect their shallow water horizon, the environment, and fresh water resources. Additionally, downhole casing leaks may cause seepage of toxic gases to fresh water zones and the surface, through the casing annuli. Forecasting of such leaks and proactive measures of prevention will help eliminate their consequences and, in turn, better protect the environment. The objective of this study is to formulate an effective, robust, and accurate model for predicting the corrosion rate of metal casing string using artificial intelligence (AI) techniques. The input parameters used to train AI models include casing leaks, the percentage of metal loss, casing age, and average remaining barrier ratio (ARBR). The target parameter is the corrosion rate of the metal casing string. The dataset from which the AI models were trained was comprised of 250 data points collected from 218 wells in a giant carbonate reservoir that covered a wide range of practically reasonable values. Two AI tools were used: artificial neural networks (ANNs) and adaptive network-based fuzzy inference systems (ANFISs). A prediction comparison was made between these two tools. Based on the minimum average absolute percentage error (AAPE) and the highest coefficient of determination (R2) between the measured and predicted corrosion rate values, the ANN model proposed here was determined to be best for predicting the corrosion rate. An ANN-based empirical model is also presented in this study. The proposed model is based on the associated weights and biases. After evaluating the new ANN equation using an unseen validation dataset, it was concluded that the ANN equation was able to make predictions with a significantly lower AAPE and higher R2. Use of the proposed new equation is very cost-effective in terms of reducing the number of sequential surveys and experiments conducted. The proposed equation can be utilized without an AI engine. The developed model and empirical correlation are very promising and can serve as a handy tool for corrosion engineers seeking to determine the corrosion rate without training an AI model.

Evaluation of High Dissolving-Power Retarded Acid Recipes for Carbonate Acidizing

2021 ◽  
Author(s):  
Norah Aljuryyed ◽  
Abdullah Al Moajil ◽  
Saeed Alghamdi ◽  
Sajjad AlDarweesh
Keyword(s):  
Hydrochloric Acid ◽  
Corrosion Rate ◽  
Carbonate Rock ◽  
Reaction Rate ◽  
Oil And Gas ◽  
Gas Wells ◽  
Low Viscosity ◽  
Oil And Gas Wells ◽  
Carbonate Acidizing ◽  
Acid Retardation

Abstract Development of retarded acid recipes that can have both adequate dissolving power and controllable reaction rate is desired to maximize the effectiveness of matrix stimulation treatments for oil and gas wells. Hydrochloric acid (HCl) has high dissolving power, however, the reaction rate with carbonate rock is uncontrollable and can cause face dissolution. Organic acids have low dissolving power and controllable reaction rate. The objective of this paper was to compare the effectiveness of three low viscosity retarded acid recipes with dissolving powers of 15 wt% and >20 wt% HCl equivalent. The examined acid recipes were 15/28 wt% emulsified acids, retarded acid recipes #1, #2 and #3, and 15/26 wt% HCl. The emulsified acids were at 30:70 ratio of diesel to acid. The retarded acid recipes were prepared at different dissolving power. Retarded acid recipe #3 was equivalent to 15 wt% HCl while retarded acid recipes #1 and #2 were equivalent to >20 wt% HCl. The calcite disc dissolution rate with retarded acids #1 and #2 was significantly lower than 26 wt% HCl and comparable to 15 wt% HCl at 75°F. The solubility of calcite discs in the retarded acid recipe #3 showed acid retardation higher than retarded acid recipes #1 and #2. The corrosion rate of retarded acid recipes #1 and #2 were 0.003-0.015 lb/ft2 at 250°F and 6 hrs, lower than both examined 26-28 wt% HCl and emulsified acids. The pitting indices of retarded acid recipes #1, #2, and #3 were 4, 2, and 1 respectively at 300°F. The pore volumes to breakthrough (PVBT) of retarded acid recipes #1 and #2 were slightly higher than retarded acid recipes #3 at 200°F. The PVBT values for 15 wt% and 28 wt% emulsified acid was comparable to retarded acid recipes #1, #2, and #3, confirming their retardation was effective.

Sealing Analysis of Cement Plug in Offshore Abandoned Wells

2020 ◽  
Vol 993 ◽  
pp. 1333-1340
Author(s):  
Geng Tang ◽  
Hui Yan ◽  
Jun Li ◽  
Xue Feng Song ◽  
Xin Zhang ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Fluid Pressure ◽  
Three Dimensional ◽  
Element Model ◽  
Gas Wells ◽  
Oil And Gas Wells ◽  
Dimensional Finite Element ◽  
Abandoned Wells ◽  
Three Dimensional Finite Element ◽  
Cement Plug

A three-dimensional finite element model of stratum-cement ring-casing-cement plug was established for the failure analysis of the cement plug seal in the abandoned oil and gas wells. The mechanical parameters, length, bottom fluid pressure and casing swaging length of the cement plug under non-uniform ground stress conditions were analyzed. The results showed that when the bottom of the cement plug was subjected to fluid pressure, the stress at the interface between the cement plug and the casing increased, and thereby the cement plug at the bottom and the cementation of the casing failed, resulting in a the decrease in the sealing performance of the cement plug, which may be sealed under fluid corrosion. As the modulus of elasticity and the radius of the cement plug increased, the cement plug stress and the cement failure length increased. As the cement plug length increased, the cement plug stress and the cement failure length decreased, while Poisson's ratio for the cement plug stress and the cement failure length increased. The increase of the bottom fluid pressure could increase the cement plug stress and the cementation failure length. In the abandoned well, where the casing was forged and then grinded after the casing was forged, the length of the casing milling increased, the plug stress of cement reduced. These findings can provide insightful potentials for the parameters of cement plugs when the cement plugs are closed in the offshore oil and gas wells.

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