Nitrogen-Based Back Pressure Unit Modernizes Managed Pressure Drilling Operations

2021 ◽  
Author(s):  
Wamidh Louayd Al-Hashmy
Keyword(s):  
Drilling Fluid ◽  
Pressure Control ◽  
Drill String ◽  
Back Pressure ◽  
Managed Pressure Drilling ◽  
Core Function ◽  
Wellbore Pressure ◽  
Drilling Operations ◽  
Pressure Unit ◽  
Static Conditions

Abstract Managed Pressure Drilling (MPD) solutions are no longer the anomaly to Operator strategies, but rather another tool in their belts. With this continual utilization, MPD is evolving to become compact, more effective and safer. The inventive use of a Nitrogen Backup Unit (NBU) has eliminated the reliance of MPD operations on sizable Auxiliary Pumps. The core function of MPD operations is maintaining the total wellbore pressure by manipulating surface applied back pressure. MPD relies on circulating fluid as back pressure is generated by restricting flow against its choke(s). While drilling, fluid circulation is a given; however, that is not the case during static conditions such as drill string connections. The NBU solves this issue by injecting a small volume of nitrogen into the MPD lines upstream of the choke at a pre-set pressure. This supplements the back pressure control at surface should additional pressure be needed after closing the choke or if pressure diminishes during long static periods. Prior to the NBU design, the only effective solution was an Auxiliary Pump setup. This solution doubles the choke manifold footprint, relies on mechanical maintenance, and requires additional dedicated personnel at times. Most critically, the Auxiliary Pump lags the operation minutes before each use and is therefore functioned before static conditions when possible. However, unplanned and sudden events are commonplace – such as Rig Pump failures. When drilling formations with narrow pressure margins, unsafe gases, or crucial hole instability pressure limits, a few minutes can result in considerable and costly outcomes. Once installed during initial rig-up, the NBU is capable of injecting nitrogen-sourced back pressure instantaneously at the literal click of a button – avoiding costly and sometimes hazardous conditions. The NBU modernizes MPD operations and renders the Auxiliary Pump setup outdated in many applications. This paper details this innovative implementation of maintaining wellbore pressure, highlights several field examples of the NBU maintaining back pressure at critical times and shows how the layout used minimizes the operational footprint.

Developing a Managed Pressure Drilling Strategy for Casing Drilling Operations

2009 ◽  
Vol 62-64 ◽  
pp. 456-465
Author(s):  
Babs Mufutau Oyeneyin ◽  
V.C. Kelessidis ◽  
G. Bandelis ◽  
P. Dalamarinis
Keyword(s):  
Real Time ◽  
Drilling Fluid ◽  
Fluid Flows ◽  
Well Design ◽  
Managed Pressure Drilling ◽  
Wellbore Pressure ◽  
Theoretical Predictions ◽  
Drilling Operations ◽  
Horizontal Annuli ◽  
Casing Drilling

Casing drilling can be an effective method of reducing drilling costs and minimising drilling problems but its uptake around the world has been slow with only a few wells drilled so far with casing. Complex geological features like the high overburden on top of shallow unconsolidated reservoirs characteristic of offshore West Africa can benefit from casing drilling when effectively combined with Managed Pressure Drilling technique. For the industry to develop a managed pressure drilling capability that will allow today’s generation of complex wells to be drilled safely with casing, it is necessary to develop models that include the effect of eccentricity , rotation and fluid rheology at bottom hole conditions on flow and pressure regimes, and to embed these models within an easy to use, intuitive well design package for pre planning and as a real time tool to monitor and provide forward simulations based on real time rig and downhole data. The paper presents new results of the theoretical predictions of the wellbore pressure regimes incurred when different types of drilling fluid flows in concentric and eccentric horizontal annuli. The concentric and eccentric casing drilling results are compared with parallel predictions from conventional drillstring results from developed analytical solutions integrated into the VisWELL(DeskTop Simulator) , which is used in simulating well operations.

Design and Experimental Validation of Nonlinear Infinite-Dimensional Adaptive Observer in Automated Managed Pressure Drilling

2017 ◽  
Vol 139 (11) ◽  
Author(s):  
Agus Hasan ◽  
Lars Imsland ◽  
Espen Hauge
Keyword(s):  
Flow Rate ◽  
Drilling Fluid ◽  
Drill String ◽  
Adaptive Observer ◽  
Well Control ◽  
Infinite Dimensional ◽  
Parameter Estimations ◽  
Managed Pressure Drilling ◽  
Process Measurements ◽  
Available Information

Utilizing flow rate and pressure data in and out of the fluid circulation loop provides a driller with real-time trends for early detection of well-control problems that impact the drilling efficiency. Due to limited number of sensors and time delay in processing and measurements, the flow rate and pressure along the annulus and drill string need to be estimated. This paper presents state and parameter estimations for infinite-dimensional models used in automated managed pressure drilling (MPD). The objective is to monitor the key process variables associated with process safety by designing a nonlinear adaptive observer that use the available information coming from the continuous-time online process measurements at the outlet of the well. The adaptive observer consists of a copy of the infinite-dimensional model plus output injection terms where the gain is computed analytically in terms of the Bessel function of the first kind. The design is tested using field data from a drilling commissioning test by Statoil ASA, Stavanger, Norway. The results show that the nonlinear adaptive observer estimates the flow rate and pressure of the drilling fluid accurately.

Kick detection and well control in a closed wellbore

2011 ◽  
Vol 51 (1) ◽  
pp. 109 ◽  
Author(s):  
Steve Nas
Keyword(s):  
Control Process ◽  
Pressure Control ◽  
Control Device ◽  
Primary Objective ◽  
Pressure Management ◽  
Well Control ◽  
Managed Pressure Drilling ◽  
Drilling Operations ◽  
Control Procedures ◽  
Additional Level

Closing the wellbore at the top with a rotating control device (RCD) for some kinds of managed pressure drilling (MPD) operations raises a number of issues with regards to well control and kick detection. The wellbore is closed and the standard flow check of looking into the well is no longer possible. The use of a RCD provides drillers with an additional level of comfort because it is a pressure management device, but it doesn’t eliminate the need to have well control as a primary objective. In recent MPD operations, it has already been observed that well control procedures are relaxed as a result of managed pressure drilling. Is managed pressure drilling the same as primary well control, and how do we deal with kicks in managed pressure drilling operations? At what point in a well control process do we hand over from MPD to drillers’ well control, and who is responsible? This paper will present some of the issues that need to be considered when planning and conducting MPD operations. Early kick detection and annular pressure control are promoted as an essential part of MPD operations, but there can be confusion as to where the responsibility for well control lies. Does the responsibility remain with the drilling contractor and operator or with the provider of the MPD services. The paper provides some case studies where MPD and well control conflicted, causing a number of issues that in some cases led to the loss of wells.

Pressure Profile in Annulus: Solids Play a Significant Role

2014 ◽  
Author(s):  
Feifei Zhang ◽  
Stefan Miska ◽  
Mengjiao Yu ◽  
Evren Ozbayoglu ◽  
Nicholas Takach
Keyword(s):  
Flow Rate ◽  
Pressure Loss ◽  
Drilling Fluid ◽  
Pressure Profile ◽  
Accurate Estimation ◽  
Circulation System ◽  
Precise Knowledge ◽  
Significant Difference ◽  
Wellbore Pressure ◽  
Drilling Operations

In drilling operations, accurate estimation of pressure profile in the wellbore is essential to achieve better bottom hole pressure control. Adjusting the drilling fluid properties and optimizing flow rate require precise knowledge of the pressure profile in the circulation system. Annular pressure profile calculations must consider solids present in the drilling fluid because the solids drilled from formations may have a significant effect on pressure in the wellbore. In cases of high solids fraction or solid pack off, the pressure loss caused by solids is much higher than the friction pressure loss. This paper looks into the effect of solids on the wellbore pressure profile under different conditions. An extensive number of experiments were conducted on a 90-ft-long, 4.5″x8″ full-scale flow loop to simulate field conditions. The effects of solids on pressure profile in the annulus are investigated. In the experimental results, a significant difference is found between the pressure profile with solids and without solids in the wellbore. A practical approach to calculate the pressure profile by considering the effects of solids in the wellbore is developed. This approach is based on the results of solids behavior in the wellbore. Both solids fraction in the well and solids pack off are considered in the proposed approach. The prediction results are in good agreement with the experimental data. The results of this study show how the pressure profile in the wellbore varies when solids present in the annulus. The pressure gradient with solids can be several times larger than the pure friction loss without solids. A decrease in flow rate may lead to a higher pressure profile and the risk of solids pack off in the wellbore because it increases the solids fraction. Results of this paper may have important applications in drilling operations.

scholarly journals Equivalent Circulation Density Analysis of Geothermal Well by Coupling Temperature

2017 ◽  
Author(s):  
Xiuhua Zheng ◽  
Chenyang Duan ◽  
Zheng Yan ◽  
Hongyu Ye ◽  
Zhiqing Wang ◽  
...  
Keyword(s):  
Flow Rate ◽  
Drilling Fluid ◽  
Model Fitting ◽  
Geothermal Gradient ◽  
Pressure Control ◽  
Geothermal Field ◽  
Drilling Fluids ◽  
Geothermal Well ◽  
Time Flow ◽  
Wellbore Pressure

The accurate wellbore pressure control not only prevents from lost circulation/blowout and fracturing formation by managing density of drilling fluid, but also improves productivity by mitigating reservoir damage. The geothermal pressure calculated by constant parameters for geothermal well would bring big error easily, as the changes of physical, rheological and thermal properties of drilling fluids with temperature were neglected. This paper researches the wellbore pressure coupling by calculating the temperature distribution with existed model, fitting the rule of density of drilling fluid with temperature and establishing mathematical models to stimulate the wellbore pressures, which is expressed as the variation of Equivalent Circulating Density (ECD) under different conditions. With this method, temperature and ECDs in the wellbore of the first medium-deep geothermal well ZK212 Yangyi Geothermal Field in Tibet were determined, and the sensitivity analysis was simulated by assumed parameters, i.e. circulating time, flow rate, geothermal gradient, diameters of wellbore, rheological models and regimes, the results indicated the geothermal gradient and flow rate were the most influence parameters on the temperature and ECD distribution, and additives added in drilling fluid should be careful which would change the properties of drilling fluid and induce the temperature redistribution. To make sure the safe drilling, velocity of pipes tripping into the hole, depth and diameter of wellbore are considered to control the surge pressure.

Performance Evaluation of a Highly Inhibitive Water-Based Drilling Fluid for Ultralow Temperature Wells

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Xin Zhao ◽  
Zhengsong Qiu ◽  
Mingliang Wang ◽  
Weian Huang ◽  
Shifeng Zhang
Keyword(s):  
Drilling Fluid ◽  
Hydrate Formation ◽  
Wellbore Stability ◽  
Drilling Fluids ◽  
Offshore Drilling ◽  
Ultralow Temperature ◽  
Water Based ◽  
Drilling Operations ◽  
Inhibition Performance ◽  
Static Conditions

Drilling fluid with proper rheology, strong shale, and hydrate inhibition performance is essential for drilling ultralow temperature (as low as −5 °C) wells in deepwater and permafrost. In this study, the performance of drilling fluids together with additives for ultralow temperature wells has been evaluated by conducting the hydrate inhibition tests, shale inhibition tests, ultralow temperature rheology, and filtration tests. Thereafter, the formulation for a highly inhibitive water-based drilling fluid has been developed. The results show that 20 wt % NaCl can give at least a 16-h safe period for drilling operations at −5 °C and 15 MPa. Polyalcohol can effectively retard pore pressure transmission and filtrate invasion by sealing the wellbore above the cloud point, while polyetheramine can strongly inhibit shale hydration. Therefore, a combination of polyalcohol and polyetheramine can be used as an excellent shale stabilizer. The drilling fluid can prevent hydrate formation under both stirring and static conditions. Further, it can inhibit the swelling, dispersion, and collapse of shale samples, thereby enhancing wellbore stability. It has better rheological properties than the typical water-based drilling fluids used in onshore and offshore drilling at −5 °C to 75 °C. In addition, it can maintain stable rheology after being contaminated by 10 wt % NaCl, 1 wt % CaCl2, and 5 wt % shale cuttings. The drilling fluid developed in this study is therefore expected to perform well in drilling ultralow temperature wells.

scholarly journals Using of surface back pressure with water based mud in managed pressure drilling technique to solve lost circulation problem in Southern Iraqi Oil Fields

2021 ◽  
Vol 11 (3) ◽  
pp. 28-47
Author(s):  
Batool Abdullah Dhayea ◽  
Faleh. H. M. Almahdawi ◽  
Sinan I. M. Al-Shaibani
Keyword(s):  
Water Injection ◽  
Pressure Profile ◽  
Injection Rate ◽  
Back Pressure ◽  
Oil Fields ◽  
Drilling Process ◽  
Lost Circulation ◽  
Managed Pressure Drilling ◽  
Wellbore Pressure ◽  
Circulation Problem

Many drilling problems are encountered continuously while drilling oil wells in the southern Iraqi oil fields. Many of these problems are ineffectively handled resulting in a longer non-productive time. This study aims to identify the formations such as Dammam, and Hartha formations،diagnose potential problems and provide the solution for lost circulation problem. After conducting a comprehensive study on the subject and based on available data, previous studies and some information, the managed pressure drilling (MPD) method was the best technique to solve this problem. This process may use various techniques including control of back pressures .Thus, reducing the risk and control the costs of drilled wells, which have narrow pressure window by managing the wellbore pressure profile.  The well plan software program provided by Halliburton Company was used, this software is based on a database and data structure common to many of Landmark’s drilling applications. Mud used with  various injection rates  to choose the rate that provides the conditions to achieve the best drilling process, as it using mud weights of (8.8 -8.7 ) ppg  and applied a surface back pressure (50 psi). Depending on specifications of second hole the optimal injection rate was chosen using the (hydraulics) program. As a results, rate of water injection (850) gpm, is the best  which it  provides a good efficient cutting transport ratio (CTR), which means high  stability and preventing formation damage in addition to controlling in  mud losses

Study of the Potential of Sodium Carbonate Extracted from Trona as a Drilling Fluid Additive

2020 ◽  
Vol 49 ◽  
pp. 152-172
Author(s):  
Petrus Nzerem ◽  
Enyo June Adejoh ◽  
Oghenerume Ogolo ◽  
Ikechukwu Okafor ◽  
Abdullahi Suleiman Bah Gimba ◽  
...  
Keyword(s):  
Sodium Carbonate ◽  
Sodium Hydrogen Carbonate ◽  
Drilling Fluid ◽  
Research Work ◽  
Drill String ◽  
Drilling Mud ◽  
Purification Method ◽  
Unique Role ◽  
Hydrogen Carbonate ◽  
Drilling Operations

Drilling additives play a unique role during drilling operations, from aiding in the control of various drilling challenges to successfully enhancing downhole drilling efficiency. pH enhancers are amongst the plethora of additives imported into Nigeria at exorbitant prices to aid in drilling operations. These additives includes NaOH, Na2CO3, Ca (OH)2 etc. These additives are used to improve the mud pH and mitigates drill string corrosion. The high cost of importation of these additives, has warranted the need for product substitution which should take advantage of the locally available resources. This paper evaluated the suitability of locally-sourced Trona, as a mud additive in drilling mud. Trona is known chemically as Sodium Sesquicarbonate or Sodium Hydrogen Carbonate. A distinguishing factor in this research work was the purification of Trona by extracting the compound of interest (Na2CO3) from it using the monohydrate process. The purification method involved crushing and screening of Trona as well as calcination, filtration and evaporation processes. The analysis of the Trona and the extracted product was performed using quantitative analysis and characterization tools such as FTIR and EDX. Further experimentation was carried out to evaluate the effects of the extracted sodium carbonate on the mud pH, rheology, and density of the water-based mud. The results were also compared to the results gotten from the addition of conventional Na2CO to similar mud samples. The extracted Na2CO was observed to increase the pH of the mud samples from 8.73 to 9.52 and the commercial Na2CO increased it from 8.73 to 10 and this value is still in the range of API standard. The pH enhancers from both sources also had effect on the mud rheological properties. This indeed showed that the extracted Na2CO from Trona acted as drilling fluid pH enhancer and hence possess the potential for usage in the industry.

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