Alkinani, Husam H. (Missouri University of Science and Technology) | Al-Hameedi, Abo Taleb T. (Missouri University of Science and Technology) | Dunn-Norman, Shari (Missouri University of Science and Technology) | Al-Alwani, Mustafa A. (Missouri University of Science and Technology) | Lian, David (Missouri University of Science and Technology) | Al-Bazzaz, Waleed H. (Kuwait Institute For Scientific Research)
It is not easy to obtain an optimal hole cleaning for the drilling operation because of the complicated relationship between the drilling parameters influencing hole cleaning. The two viscosity components (e.g. plastic viscosity (PV) and yield point (YP)) and the flow rate (Q) are essential parameters for effective hole cleaning. Thus, understanding the relationship between those parameters will contribute to efficient hole cleaning. The aim of this paper is to explore those relationships to provide optimal hole cleaning.
Descriptive data analytics was conducted for data of more than 2000 wells drilled in Southern Iraq. The data were first cleansed and outliers were removed using visual inspection and box plots. The Pearson correlation (PC), a widely used method to measure the linear relationship between two parameters, was utilized to access the relationships between PV and Q, YP and Q, and YP/PV and Q. Moreover, a 10% sensitivity analysis was escorted to quantify and comprehend those relationships.
The PCs were calculated to be 0.5, 0.076, and 0.22 for the relationships between YP, PV, and YP/PV with Q, respectively. YP had the highest direct relationship with Q, while PV had the lowest. When the YP increases, a sufficient Q has to be provided to initiate the flow and maintain the mud cycle. In addition, to prevent large solid particles from settling due to the slip velocity, sufficient annular and particle velocities have to be achieved. After initiating the flow, an increase in flow rate to overcome resistance due to PV will not be significant. Therefore, YP has more effect on Q than PV. To maximize hole cleaning, thickening ratio (YP/PV) should be increased. This requires an increase in flow rate, which can be quantified by using the sensitivity analysis provided to achieve the required Q for any increase in YP/PV.
Al-Hameedi, Abo Taleb T. (Missouri University of Science and Technology) | Alkinani, Husam H. (Missouri University of Science and Technology) | Dunn-Norman, Shari (Missouri University of Science and Technology) | Al-Alwani, Mustafa A. (Missouri University of Science and Technology) | Lian, David (Missouri University of Science and Technology)
Flow rate (Q) affects many drilling operations and parameters such as equivalent circulation density (ECD), hoisting and lowering the drillstring, and breaking gel strength during circulation. The aim of this work is to understand the relationship between ECD and Q based on flow regimes (e.g. laminar, transitional, and turbulent) to avoid or at least minimize the unwanted consequence during drilling practice.
Field data from over 2000 wells drilled in Iraq were collected and analyzed to identify the physical relationship between flow regimes and ECD to enhance the drilling rates. After visualizing the whole dataset, a decision was made to break down the data into three parts based on flow regimes (e.g. laminar, transitional, and turbulent). Descriptive data mining techniques were utilized to establish the relationship between flow regimes and ECD. By achieving better control of ECD in the well, not only faster and cheaper operations are possible, but also safety will be improved.
Previous studies and literature showed that flow regimes can tremendously affect ECD. Many studies have been conducted to understand the relationship between Q and ECD. Nevertheless, the consideration of flow regimes was not implemented in these studies. Inconsistency in the literature results was identified, some concluded the relationship between Q and ECD to be direct, and others showed it to be inverse. Thus, this paper will eliminate this discrepancy in the literature, and it will show that the flow regimes have a pivotal role in the relationship between Q and ECD.
The results of this paper showed that if the flow regime is laminar, the relationship between ECD and Q is inverse. However, in transitional and turbulent flow regimes, the relationship between ECD and Q is direct. That is because, in the laminar flow regime, the cutting will fall out of suspension due to low Q, which will cause a cutting bed to be built and decreases ECD. As Q increases (entering the transitional and turbulent flows) the cutting bed will be eroded, and most of the cuttings will be suspended in the fluid which will increase ECD.
This study examines and expands the understanding between how the characteristics of flow regimes affect ECD. Additionally, this paper will eliminate the discrepancy in the literature about this relationship between ECD and Q.
With maturing oil fields there is an increasing focus on improving the oil recovery factor and pushing the envelope toward a 70% target. This target is indeed very challenging and depends on a number of factors including enhanced oil recovery (EOR) methods, reservoir heterogeneities, displacement efficiency, and reservoir sweep. Other factors also play a role including vertical sweep due to flow behind the casing, well integrity issues, presence of conductive faults, or fractures. Proper surveillance performed to evaluate the injectant plume front, reservoir conformance, well connectivity, assessment of the integrity of wells, and other factors can be crucial for the success of the project and its future development.
The paper discusses special downhole logging techniques including a set of conventional multiphase sensors alongside high precision temperature (HPT) and high-definition spectral noise logging (SNL-HD). It was run to provide complete assessment of the injection – production distribution and any associated well integrity issues that might impair the lateral sweep of injectants into the target layer. This will be done for an injector and producer pair near the wellbore area. The operation was carried out with a tool string that contained no mechanical parts and was not affected by downhole fluid properties. It was conducted under flowing and shut-in conditions to identify flow zones and check fracture signatures. It also provided multiphase fluid velocity profiles.
The results of the survey allowed for in-depth assessment of borehole and behind casing flow, confirming lateral continuity, and provided an assessment of production-injection outside the pay zone. Results will allow for better well planning and anticipation of possible loss of well integrity that might impair production in the future. Combining the behind casing flow assessment with borehole multiphase flow distribution can be used for production optimization by sealing unwanted water contributing zones.
Qureshi, M Fahed (Texas A&M University at Qatar) | Ali, Moustafa (Texas A&M University) | Rahman, Mohammad Azizur (Texas A&M University at Qatar) | Hassan, Ibrahim (Texas A&M University at Qatar) | Rasul, Golam (Texas A&M University at Qatar) | Hassan, Rashid (Texas A&M University)
The hole cleaning is considered a key element of drilling operation as it impacts the economics of drilling operations, operational time of operations and the safety of operations. Inadequate hole cleaning can lead to blockages resulting in loss of circulation and premature wear out of the drill pipe. The transport of solids cuttings as a multiphase flow offers a solution to the hole cleaning issue, as it can aid to lower operational cost, reduce operation time, and enhance the quality of overall drilling operations.
Electrical resistance tomography (ERT) is a promising technology to visualize the 3D flow conditions involved in the hole cleaning process. ERT system is utilized to study and analyze the multiphase flow behavior and to provide in situ volume fraction distribution quantitatively through the drilling annulus. The motive of this work is to investigate the effect of different eccentricities (0-50 %), inner pipe rotation speed (0-120 RPM) and liquid flow rates (160-190 Kg/min) on the secondary phase (solids + air) transport across the annulus using the ERT system. The three-phase flow conditions (water, air, and solids) experiments were conducted in the horizontal flow loop with annulus at Texas A&M University at Qatar (TAMUQ) using ERT system. The flow loop annulus line consists of 6.16 m horizontal/inclined line. The inner diameter of the outer acrylic pipe and the outer diameter of the inner stainless steel pipe were 114.3 mm (4.5 in) and 63.5 mm (2.5 in), respectively. The glass beads (2-3 mm) were injected at a concentration of 5 wt%. The experimental results indicate that the ERT sensors have the capability of providing real-time quantitative images of annular multiphase flow regimes and it can be utilized effectively to observe the secondary phase (solids + air) transport across the opaque region of the annulus. It was also observed that the concentration of secondary phase (solids + air) tends to increase with an increase in the eccentricity of the inner pipe and the inner pipe rotation does not have a significant effect on the concentration of secondary phase (solids + air) at selected experimental conditions.
Because of the higher cost of scale management for subsea (SS) operations compared with platform or onshore fields, and because of the more limited opportunities for interventions, it is becoming increasingly important to obtain and use real production data from wells rather than estimated zone flow contribution from simple permeability (k) and height (h) models for scale-squeeze-treatment design.
In this paper I discuss how scale-squeeze treatments were designed (coreflood evaluation of inhibitor retention/release) and deployed for three SS heterogeneous production wells. A permeability model and a layer-height model were initially developed for each well using detailed geological log data, estimated water/oil-production rates, and the predicted water-ingress location within the wells. Two wells were each treated three times using bullhead scale-squeeze treatments, with effective scale control being reported over the designed lifetime. A production log was acquired before the fourth squeeze campaign of these two wells. This information was incorporated into the squeeze simulation to allow review of the ongoing third squeeze and enhance design accuracy for the upcoming fourth squeezes. A third well was treated twice before production-logging data became available, and the performance of treatments to this well is also assessed.
The production-logging-tool (PLT) data proved very important in changing the understanding of fluid placement and the water-ingress location during production, resulting in changes to the isotherm values used to achieve effective history match to the inhibitor returns (with PLT data incorporated in all three wells), and most significantly affecting the squeeze lifetimes. It was possible to significantly extend the treatment lifetime of two of the wells (cumulative produced water to minimum inhibitor concentration), while the treatment life of one well was greatly reduced because of the PLT-data-modified model predictions.
In this paper I outline the process of reservoir/near-wellbore modeling that is used for most initial squeeze-treatment service companies deployed in the North Sea. I will highlight in detail the value that PLT data can provide to improve the effectiveness of squeeze treatments in terms of understanding of fluid placement during squeeze deployment and water-ingress location within heterogenous production wells. The intention of this paper is to highlight the value that these types of data can provide to improve scale management (squeeze treatment and water shutoff) such that the value created more than offsets the cost of acquiring such information for SS production wells.
The challenges related to liquid loading have been observed during flow-back after hydraulic fracturing, as well as during the production phase, and are further aggravated with the high inclination angles found in deviated wellbores. An experimental study was carried out to investigate the onset of liquid loading in a 6-inch production casing at various inclination angles. A unified mechanism model for the onset of liquid loading is developed for a large-diameter production casing.
The experimental setup includes a 6-inch acrylic test section which can be inclined from 0° to 90°. The study involves two-phase air-water flow in low liquid loading conditions to simulate a gas well. A dye- injection-system was used to detect the onset of liquid film reversal.
The experimental data demonstrates that the major factor that induces liquid accumulation is the liquid film reversal at pipe bottom. The critical gas velocity associated with the onset of liquid film reversal shows a strong function with the inclination angle and liquid flow rate in the current experimental study. Comparison with previous experimental data reveals that it also depends on the gas density and pipe diameter, i.e. it decreases with increasing gas density and increases when pipe diameter increases. Comprehensive model evaluation was conducted in the current study, showing a large discrepancy for inclination angles higher than 45° and few existing models capture all the effects of deviation angle, liquid flow rate, pressure, and pipe diameter. A new model is developed based on the physics of the onset of liquid film reversal, coupled with a new model for the liquid film thickness distribution around the pipe perimeter. It captures well the effects of deviation angle, liquid flow rate, gas and liquid density, viscosity, and pipe diameter on the critical gas velocity, outperforming all other existing models.
The experiments in this study provide new insights into the onset of liquid accumulation in large- diameter deviated wells. The new mechanics model fills the critical gap to enhance accuracy when predicting the onset of liquid loading especially for deviated and large-diameter wells. It can be easily implemented, which will benefit the industry practically. It is also applicable to gas condensate pipelines where smaller inclination angles exist.
Implementation of a drift-flux (DF) multiphase flow model within a fully-coupled wellbore-reservoir simulator is nontrivial and must adhere to a number of strict requirements in order to ensure numerical robustness and convergence. The existing DF model that can meet these requirements is only fully posed for upward flow from 2 degrees (from the horizontal) to vertical. The work attempts to extend the current DF model to a unified and numerically robust model that is applicable to all well inclinations. In order to achieve this objective, some 5805 experimentally measured data points from 22 sources as well as 13440 data points from the OLGA-S library are utilized to parameterize a new DF model - one that makes use of the accepted upward flow DF model and a new formulation extending this to horizontal and downward flow. The proposed model is compared against 2 existing DF models (also applicable to all inclinations) and is shown to have better, or equivalent, performance. More significantly, the model is also shown to be numerically smooth, continuous and stable for co-current flow when implemented in a fully implicitly coupled wellbore-reservoir simulator.
Banack, Ben (Halliburton) | Burke, Lyle H. (Devon Canada Corporation) | Booy, Daniel (C-FER Technologies 1999 Inc.) | Chineme, Emeka (Cenovus Energy) | Lastiwka, Marty (Suncor Energy) | Gaviria, Fernando (Suncor Energy) | Ortiz, Julian D. (ConocoPhillips Canada) | Sanmiguel, Javier (Devon Canada Corporation) | Dewji, Ayshnoor (Halliburton)
It is becoming common to install inflow control devices (ICDs) along steam-assisted gravity drainage (SAGD) production liners to enhance temperature conformance and accelerate depletion. Additionally, some operators advocate the installation of similar outflow control devices (OCDs) along the injection well of the SAGD well pair. Collectively, these inflow and outflow devices are often referred to as FCDs. Industry adoption of flow control devices (FCDs) has increased, and several devices are commercially available for use in SAGD.
In an effort to optimize FCD design and selection, a joint industry partnership (JIP) was formed (
Fiber-optic-based instrumentation was deployed within FCD-equipped wells using permanently installed coiled tubing. Well architecture design changes to a typical completion were not required because fiber-optic sensors are used for most non-FCD wells to collect distributed temperature sensing (DTS) data. Although DTS is a common tool for optimizing SAGD production, it has certain limitations; specifically, temperature changes along production wells do not typically allow a detailed definition or quantification of the inflow distribution along the wellbore.
In addition to DTS, distributed acoustic sensing (DAS) was periodically performed on the FCD wells. DAS logging of SAGD producers has several potential uses, including flow profiling, steam breakthrough and/or noncondensable gas (NCG) detection, multiphase flow characterization, electric submersible pump (ESP) performance, completion failure analysis, and four-dimensional seismic analysis. Although FCD characterization with DAS appears promising, a knowledge gap exists as to how to move beyond qualitative analysis to more quantitative analysis of FCD performance and the lateral emulsion inflow distribution. Pending satisfactory results, DAS logging on active wells can potentially be completed to accelerate improvements of SAGD FCD performance and design as well as increase the efficiency of SAGD recovery through improved steam/oil ratio (SOR) and an associated reduction in greenhouse gases.
This paper describes piloting the collection and analysis of DTS and DAS data to help improve understanding of SAGD inflow distribution. Logs were performed on multiple wells during stable and transient flowing conditions. Early surveillance demonstrated suitability and limitations of fiber-optic-based logging to validate FCD performance in active wells. In addition to field logging, acoustic recording using JIP flow loop testing was completed with accelerometers, geophones, and fiber-optic cables during FCD characterization. The goal was to cross reference the acquired acoustic signals for quantification of flow at devices and validation of performance. An overview of the JIP flow loop FCD acoustic characterization program is described.
An experimental study of a gravity-driven downhole separator for a pumped horizontal or deviated well is presented in this study. It considers the effects of the upstream flow, gas and liquid flow rates and deviation angles on the global separation efficiency and the free gas at the pump intake. The efficacy of downhole separators is typically tested under steady-state conditions where the fluids are injected above the separator. A new outdoor facility, which allows the injection of a two-phase mixture below the separator was designed, constructed, and used in this study. Gas and liquid flow rates and deviation angle are varied to study the liquid holdup in the liquid-rich outlet and the separator efficiency. The experimental results demonstrate the effects of the operation conditions and deviation angle on the behavior of downhole separators. It is found that the separator has two regions of performance; namely, high efficiency region and a region where the efficiency decreases with the liquid flow rate. Moreover, the effect of the deviation angle affects the results. The findings provide conditions under which and where the separator can be operated efficiently in the field.
Lastiwka, Marty (Suncor Energy) | Burke, Lyle H. (Devon Canada Corporation) | Booy, Daniel (C-FER Technologies 1999 Inc.) | Chineme, Emeka C. (Cenovus Energy) | Gaviria, Fernando (Suncor Energy) | Ortiz, Julian D. (ConocoPhillips Canada)
A review of laboratory and field testing of a new flow control device is presented in this paper. The device is designed specifically to limit steam breakthrough in thermal operations.
For the past few years, four companies operating Steam Assisted Gravity Drainage (SAGD) facilities in Alberta's oil sands have come together to study downhole Flow Control Devices (FCDs) in a laboratory setting and to share field data of the application of such devices. Within this collaboration, a new device was designed to address the challenge specific to thermal operations, namely limiting steam breakthrough into production wells. Laboratory tests were undertaken to define the steam-limiting characteristics of this device under field representative SAGD conditions at full scale rates, temperatures and pressures. Tests were performed with oil to gauge viscosity sensitivity, as well as with water and steam at various inflow rates, temperatures and steam qualities. Testing was also performed with Non-Condensable Gas (NCG) to help assess how methane production may affect performance under both low and high Gas Volume Fraction (GVF) conditions. Finally, three-phase erosion testing was performed using water, quartz and air, allowing a realistic, scalable assessment of the device's long-term reliability.
Highlights from these tests are reported and compared to results from testing of conventional, commercially available devices. The new device has shown superior performance relative to other devices designed for non-thermal applications. Thus, it inhibits the influx of steam while allowing the flow of emulsion into a production well. Based on the results of laboratory testing, the device is currently being tested in field operations. Early indications are that the device is performing as expected. Preliminary field data are presented.
Laboratory testing of thermal flow control devices is especially challenging and unique when compared with similar testing for conventional flow control devices. This becomes more evident when testing devices designed specifically to limit steam breakthrough. Furthermore, in thermal operations, the phase change potential that is inherent when operating near the saturation point of water opens new possibilities in the design of flow control devices. A successful, practical implementation of this phase change characteristic was achieved in a collaborative environment.