Aphron-Base Drilling Fluid: Evolving Technologies for Lost Circulation Control

Lost circulation has been one of the major problems that impede efficient and cost-saving drilling operations. The nature of lost circulation and its control is not yet fully understood. A method to characterize the mud loss in fracture and the plugging process of lost circulation materials is highly desired to obtain a thorough understanding of mud losses in fracture and provide reference for lost circulation control. This paper presents an easy-to-use method to identify types of lost circulation in fracture and the corresponding control. Three analytical models are presented based on three loss mechanisms, namely, seepage/filtration in a fracture, pipe flow in a fracture, and gravity displacement in a fracture. A numerical model is developed to simulate the deposition of lost circulation materials in fractures and predict the time and the volume of drilling fluid needed for lost circulation control. Case studies with these analytical models provide a deeper insight of this subject. Sensitivity analyses with the numerical model identify the major factors responsible for lost circulation control. High viscosity of drilling fluid may prevent lost circulation, while low viscosity is desired for a fast control of lost circulation. Lowering the density of drilling fluid is another way to prevent the lost circulation and facilitate the deposition of lost circulation materials. Lost circulation materials with high density could deposit faster close to the wellbore and therefore accelerating the control process. High concentration of lost circulation materials is likely to shorten the plugging time, which should be determined referring to the severity of loss. This work provides drilling engineers a practical method for simulating the lost circulation and selecting lost circulation material.

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Study on the viability of egg shell as a lost circulation material in synthetic based drilling fluid

Journal of Physics Conference Series ◽

10.1088/1742-6596/1349/1/012135 ◽

2019 ◽

Vol 1349 ◽

pp. 012135

Author(s):

N K I Nik Ab Lah ◽

K Ngah ◽

A Sauki

Keyword(s):

Drilling Fluid ◽

Lost Circulation ◽

Egg Shell

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Gelation Performance of PAM/PEI Polymer-Based Mud System for Lost Circulation Control

10.3997/2214-4609.202120024 ◽

2021 ◽

Author(s):

M. Shamlooh ◽

A. Hamza ◽

I. Hussein ◽

M. Nasser ◽

S. Salehi

Keyword(s):

Circulation Control ◽

Lost Circulation

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Machine-Learning for the Prediction of Lost Circulation Events - Time Series Analysis and Model Evaluation

10.2118/204706-ms ◽

2021 ◽

Author(s):

Arturo Magana-Mora ◽

Mohammad AlJubran ◽

Jothibasu Ramasamy ◽

Mohammed AlBassam ◽

Chinthaka Gooneratne ◽

...

Keyword(s):

Machine Learning ◽

Time Series ◽

Real Time ◽

Large Scale ◽

Model Comparison ◽

Drilling Fluid ◽

Sensor Data ◽

False Alarms ◽

Suitable Model ◽

Lost Circulation

Abstract Objective/Scope. Lost circulation events (LCEs) are among the top causes for drilling nonproductive time (NPT). The presence of natural fractures and vugular formations causes loss of drilling fluid circulation. Drilling depleted zones with incorrect mud weights can also lead to drilling induced losses. LCEs can also develop into additional drilling hazards, such as stuck pipe incidents, kicks, and blowouts. An LCE is traditionally diagnosed only when there is a reduction in mud volume in mud pits in the case of moderate losses or reduction of mud column in the annulus in total losses. Using machine learning (ML) for predicting the presence of a loss zone and the estimation of fracture parameters ahead is very beneficial as it can immediately alert the drilling crew in order for them to take the required actions to mitigate or cure LCEs. Methods, Procedures, Process. Although different computational methods have been proposed for the prediction of LCEs, there is a need to further improve the models and reduce the number of false alarms. Robust and generalizable ML models require a sufficiently large amount of data that captures the different parameters and scenarios representing an LCE. For this, we derived a framework that automatically searches through historical data, locates LCEs, and extracts the surface drilling and rheology parameters surrounding such events. Results, Observations, and Conclusions. We derived different ML models utilizing various algorithms and evaluated them using the data-split technique at the level of wells to find the most suitable model for the prediction of an LCE. From the model comparison, random forest classifier achieved the best results and successfully predicted LCEs before they occurred. The developed LCE model is designed to be implemented in the real-time drilling portal as an aid to the drilling engineers and the rig crew to minimize or avoid NPT. Novel/Additive Information. The main contribution of this study is the analysis of real-time surface drilling parameters and sensor data to predict an LCE from a statistically representative number of wells. The large-scale analysis of several wells that appropriately describe the different conditions before an LCE is critical for avoiding model undertraining or lack of model generalization. Finally, we formulated the prediction of LCEs as a time-series problem and considered parameter trends to accurately determine the early signs of LCEs.

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Study of the Cause of Lost Circulation while Drilling Fractured Carbonates

10.2118/205806-ms ◽

2021 ◽

Author(s):

Alexey Ruzhnikov

Keyword(s):

Success Rate ◽

Drilling Fluid ◽

Circulation Zone ◽

Lost Circulation ◽

Carbonate Formation ◽

New Information ◽

Fractured Carbonate ◽

Long Time ◽

The Difference ◽

Fractured Carbonates

Abstract Fractured carbonate formations are prone to lost circulation, which affects the well construction process and has longtime effect on well integrity. Depending on the nature of losses (either induced or related to local dissolutions) the success rate is different when the induced losses can be cured with a high chance, and the one related to dissolutions may take a long time, and despite multiple attempts, the success rate is normally low. To have a better understanding of the complete losses across the fractured carbonates, a series of studies were initiated. First, to understand the strength of the loss zone, the fracture closing pressure was evaluated studying the fluid level in the annulus and back-calculating the effect of drilling fluid density. Second, the formation properties across the loss circulation zones were studied using microresistivity images, dip data, and imaging of fluid-saturated porous media. The results of the studies brought a lot of new information and explained some previous mysteries. The formation strength across the lost circulation zone was measured, and it was confirmed that it remains constant despite other changes of the well construction parameters. Additionally, it was confirmed that the carbonates are naturally highly fractured, having over 900 fractures along the wellbore. The loss circulation zone was characterized, and it was confirmed that the losses are not related to the fractures but rather to the karst, dissolution, and megafractures. The size and dip of the fractures were identified, and it was proven the possibility to treat them with conventional materials. However, the size of identified megafractures and karst zones exceeding the fractures by 10 times in true vertical depth, and in horizontal wells the difference is even higher due to measured depth. This new information helps to explain the previous unsuccessful attempts with the conventional lost circulation materials. The manuscript provides new information on the fractured carbonate formation characterization not available previously in the literature. It allows to align the subsurface and drilling visions regarding the nature of the losses and further develop the curing mechanisms.

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Application of Artificial Intelligence Techniques in Predicting the Lost Circulation Zones Using Drilling Sensors

Journal of Sensors ◽

10.1155/2020/8851065 ◽

2020 ◽

Vol 2020 ◽

pp. 1-18

Author(s):

Abdulmalek Ahmed ◽

Salaheldin Elkatatny ◽

Abdulwahab Ali ◽

Mahmoud Abughaban ◽

Abdulazeez Abdulraheem

Keyword(s):

Artificial Intelligence ◽

Real Time ◽

Drilling Fluid ◽

Confusion Matrix ◽

High Accuracy ◽

Functional Networks ◽

Lost Circulation ◽

Drilling Parameters ◽

High Pressure High Temperature ◽

Drilling Cost

Drilling a high-pressure, high-temperature (HPHT) well involves many difficulties and challenges. One of the greatest difficulties is the loss of circulation. Almost 40% of the drilling cost is attributed to the drilling fluid, so the loss of the fluid considerably increases the total drilling cost. There are several approaches to avoid loss of return; one of these approaches is preventing the occurrence of the losses by identifying the lost circulation zones. Most of these approaches are difficult to apply due to some constraints in the field. The purpose of this work is to apply three artificial intelligence (AI) techniques, namely, functional networks (FN), artificial neural networks (ANN), and fuzzy logic (FL), to identify the lost circulation zones. Real-time surface drilling parameters of three wells were obtained using real-time drilling sensors. Well A was utilized for training and testing the three developed AI models, whereas Well B and Well C were utilized to validate them. High accuracy was achieved by the three AI models based on the root mean square error (RMSE), confusion matrix, and correlation coefficient (R). All the AI models identified the lost circulation zones in Well A with high accuracy where the R is more than 0.98 and RMSE is less than 0.09. ANN is the most accurate model with R=0.99 and RMSE=0.05. An ANN was able to predict the lost circulation zones in the unseen Well B and Well C with R=0.946 and RMSE=0.165 and R=0.952 and RMSE=0.155, respectively.

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Laboratory Study on Core Fracturing Simulations for Wellbore Strengthening

Geofluids ◽

10.1155/2019/7942064 ◽

2019 ◽

Vol 2019 ◽

pp. 1-18 ◽

Cited By ~ 3

Author(s):

Biao Ma ◽

Xiaolin Pu ◽

Zhengguo Zhao ◽

Hao Wang ◽

Wenxin Dong

Keyword(s):

Bearing Capacity ◽

Laboratory Study ◽

Drilling Fluid ◽

Drilling Fluids ◽

Lost Circulation ◽

The Core ◽

Fracture Pressure ◽

Fluid Systems ◽

Fracturing Process ◽

Wellbore Strengthening

The lost circulation in a formation is one of the most complicated problems that have existed in drilling engineering for a long time. The key to solving the loss of drilling fluid circulation is to improve the pressure-bearing capacity of the formation. The tendency is to improve the formation pressure-bearing capacity with drilling fluid technology for strengthening the wellbore, either to the low fracture pressure of the formation or to that of the naturally fractured formation. Therefore, a laboratory study focused on core fracturing simulations for the strengthening of wellbores was conducted with self-developed fracture experiment equipment. Experiments were performed to determine the effect of the gradation of plugging materials, kinds of plugging materials, and drilling fluid systems. The results showed that fracture pressure in the presence of drilling fluid was significantly higher than that in the presence of water. The kinds and gradation of drilling fluids had obvious effects on the core fracturing process. In addition, different drilling fluid systems had different effects on the core fracture process. In the same case, the core fracture pressure in the presence of oil-based drilling fluid was less than that in the presence of water-based drilling fluid.

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Numerical Modeling of Foam Drilling Hydraulics

The Journal of Engineering Research [TJER] ◽

10.24200/tjer.vol4iss1pp103-119 ◽

2007 ◽

Vol 4 (1) ◽

pp. 103 ◽

Cited By ~ 1

Author(s):

Ozcan Baris ◽

Luis Ayala ◽

W. Watson Robert

Keyword(s):

Drilling Fluid ◽

Operating Conditions ◽

Drilling Fluids ◽

Drilling Mud ◽

Lost Circulation ◽

Pressure Profiles ◽

Drilling Operations ◽

Parametric Studies ◽

Bit Life ◽

Foam Drilling

The use of foam as a drilling fluid was developed to meet a special set of conditions under which other common drilling fluids had failed. Foam drilling is defined as the process of making boreholes by utilizing foam as the circulating fluid. When compared with conventional drilling, underbalanced or foam drilling has several advantages. These advantages include: avoidance of lost circulation problems, minimizing damage to pay zones, higher penetration rates and bit life. Foams are usually characterized by the quality, the ratio of the volume of gas, and the total foam volume. Obtaining dependable pressure profiles for aerated (gasified) fluids and foam is more difficult than for single phase fluids, since in the former ones the drilling mud contains a gas phase that is entrained within the fluid system. The primary goal of this study is to expand the knowledge-base of the hydrodynamic phenomena that occur in a foam drilling operation. In order to gain a better understanding of foam drilling operations, a hydrodynamic model is developed and run at different operating conditions. For this purpose, the flow of foam through the drilling system is modeled by invoking the basic principles of continuum mechanics and thermodynamics. The model was designed to allow gas and liquid flow at desired volumetric flow rates through the drillstring and annulus. Parametric studies are conducted in order to identify the most influential variables in the hydrodynamic modeling of foam flow.

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Effect of Drilling Fluid Temperature on Formation Fracture Pressure Gradient

10.2118/202087-ms ◽

2021 ◽

Author(s):

Ahmed Mostafa Samak ◽

Abdelalim Hashem Elsayed

Keyword(s):

High Temperature ◽

Pressure Gradient ◽

Thermal Effect ◽

Drilling Fluid ◽

Wellbore Stability ◽

Cooling Effect ◽

Fluid Temperature ◽

Lost Circulation ◽

Fracture Pressure ◽

Downhole Temperature

Abstract During drilling oil, gas, or geothermal wells, the temperature difference between the formation and the drilling fluid will cause a temperature change around the borehole, which will influence the wellbore stresses. This effect on the stresses tends to cause wellbore instability in high temperature formations, which may lead to some problems such as formation break down, loss of circulation, and untrue kick. In this research, a numerical model is presented to simulate downhole temperature changes during circulation then simulate its effect on fracture pressure gradient based on thermo-poro-elasticity theory. This paper also describes an incident occurred during drilling a well in Gulf of Suez and the observations made during this incident. It also gives an analysis of these observations which led to a reasonable explanation of the cause of this incident. This paper shows that the fracture pressure decreases as the temperature of wellbore decreases, and vice versa. The research results could help in determining the suitable drilling fluid density in high-temperature wells. It also could help in understanding loss and gain phenomena in HT wells which may happen due to thermal effect. The thermal effect should be taken into consideration while preparing wellbore stability studies and choosing mud weight of deep wells, HPHT wells, deep water wells, or wells with depleted zones at high depths because cooling effect reduces the wellbore stresses and effective FG. Understanding and controlling cooling effect could help in controlling the reduction in effective FG and so avoid lost circulation and additional unnecessary casing points.

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