scholarly journals Effect of Shale Properties on Wellbore Instability during Drilling Operations: A Case Study of Selected Fields in Niger Delta-Nigeria

2017 ◽  
Vol 3 (1) ◽  
Keyword(s):  
Niger Delta ◽  
Wellbore Instability ◽  
Drilling Operations

Surviving the Low Oil Price Cycle While Increasing Production Through Best Practices in Workover and Drilling Operations; Case Study of a Marginal Field in Niger Delta, Nigeria

2018 ◽  
Author(s):  
Longfellow Oghale Atakele ◽  
Osahon Noruwa Airhis ◽  
Ntietemi Ekpo Etim ◽  
Fisayo Jordan Ipoola ◽  
John Osadebe Anim ◽  
...  
Keyword(s):  
Best Practices ◽  
Niger Delta ◽  
Oil Price ◽  
Drilling Operations ◽  
Marginal Field

scholarly journals An Assessment of the Causes of Wellbore Instability and Stuck Pipe Occurrences in an Offshore Field, Niger Delta, Nigeria

2020 ◽  
Vol 1 (1) ◽  
Keyword(s):  
Cation Exchange ◽  
Niger Delta ◽  
Drilling Fluid ◽  
Wellbore Stability ◽  
Swelling Potential ◽  
Offshore Drilling ◽  
Wellbore Instability ◽  
Clay Swelling ◽  
Drilling Operations ◽  
Cationic Exchange

Wellbore instability and consequential stuck pipe issues are a common challenge associated with offshore drilling. Usually, the effect of wellbore instability is an increase in nonproductive time, possible loss of tools and costly drilling operations. Hence, there is a need for wellbore stability analyses before and during drilling operations. In “Agaza Field”, offshore Niger Delta, wellbore instability problems were encountered at various depths between 3,696-4,270 ft.; 5,000-5,425 ft. and 7,600-8000 ft. intervals. Sixty-five ditch-cutting samples and composite log plots obtained from both wells were and analyzed to determine the clay swelling potential and the cationic exchange between the formation and the drilling fluid as well as causes of formation instability. Agaza-1 well showed evidence of tight hole at intervals between 4,200 and 7,600 ft. In Agaza-2, there were indications of wellbore stresses from 1,908 ft. to 2,030 ft. However, deeper than 4,225ft depth, high fluctuation of pore pressure coincided with wellbore instability between 4,810 ft. and 5,200 ft. The principal clay minerals present within the formations are Illite, Smectite and Smectite/Illite interlayered types. Result of the cation exchange analysis showed that high concentration of calcium and sodium in the shale is responsible for high dissociation of the constituent minerals hence making the shales unstable. Analysis has shown that samples at some intervals from both wells are associated with high swelling potential while average cation exchange value is 40 meq/100g. Therefore, the primary cause of wellbore instability and stuck pipe within the studied intervals are attributed to high swelling and reactivity over time due to fluidformation interaction. Keywords: Clay cationic exchange, Clay swelling potential, Offshore drilling challenges, Reactive shales. African

scholarly journals Rotary steerable systems: mathematical modeling and their case study

2021 ◽  
Vol 11 (6) ◽  
pp. 2743-2761
Author(s):  
Caetano P. S. Andrade ◽  
J. Luis Saavedra ◽  
Andrzej Tunkiel ◽  
Dan Sui
Keyword(s):  
Directional Drilling ◽  
Steering Control ◽  
Fundamental Physics ◽  
Drilling Tools ◽  
Drilling Operations ◽  
Beam Bending ◽  
Extended Reach Drilling ◽  
And Control ◽  
2D And 3D

AbstractDirectional drilling is a common and essential procedure of major extended reach drilling operations. With the development of directional drilling technologies, the percentage of recoverable oil production has increased. However, its challenges, like real-time bit steering, directional drilling tools selection and control, are main barriers leading to low drilling efficiency and high nonproductive time. The fact inspires this study. Our work aims to contribute to the better understanding of directional drilling, more specifically regarding rotary steerable system (RSS) technology. For instance, finding the solutions of the technological challenges involved in RSSs, such as bit steering control, bit position calculation and bit speed estimation, is the main considerations of our study. Classical definitions from fundamental physics including Newton’s third law, beam bending analysis, bit force analysis, rate of penetration (ROP) modeling are employed to estimate bit position and then conduct RSS control to steer the bit accordingly. The results are illustrated in case study with the consideration of the 2D and 3D wellbore scenarios.

scholarly journals Assessing the Relation between Mud Components and Rheology for Loss Circulation Prevention Using Polymeric Gels: A Machine Learning Approach

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1377
Author(s):  
Musaab I. Magzoub ◽  
Raj Kiran ◽  
Saeed Salehi ◽  
Ibnelwaleed A. Hussein ◽  
Mustafa S. Nasser
Keyword(s):  
Machine Learning ◽  
Rheological Properties ◽  
Nearest Neighbor ◽  
Drilling Fluid ◽  
Gradient Boosting ◽  
K Nearest Neighbor ◽  
Wide Range ◽  
Machine Learning Approach ◽  
Drilling Operations

The traditional way to mitigate loss circulation in drilling operations is to use preventative and curative materials. However, it is difficult to quantify the amount of materials from every possible combination to produce customized rheological properties. In this study, machine learning (ML) is used to develop a framework to identify material composition for loss circulation applications based on the desired rheological characteristics. The relation between the rheological properties and the mud components for polyacrylamide/polyethyleneimine (PAM/PEI)-based mud is assessed experimentally. Four different ML algorithms were implemented to model the rheological data for various mud components at different concentrations and testing conditions. These four algorithms include (a) k-Nearest Neighbor, (b) Random Forest, (c) Gradient Boosting, and (d) AdaBoosting. The Gradient Boosting model showed the highest accuracy (91 and 74% for plastic and apparent viscosity, respectively), which can be further used for hydraulic calculations. Overall, the experimental study presented in this paper, together with the proposed ML-based framework, adds valuable information to the design of PAM/PEI-based mud. The ML models allowed a wide range of rheology assessments for various drilling fluid formulations with a mean accuracy of up to 91%. The case study has shown that with the appropriate combination of materials, reasonable rheological properties could be achieved to prevent loss circulation by managing the equivalent circulating density (ECD).

Managing Wellbore Stability Window and Well Integrity by Adjusting the Tight Margin to Successfully Drill through Naturally Fractured Zone Onshore Niger Delta

2021 ◽  
Author(s):  
Bassey Akong ◽  
Samuel Orimoloye ◽  
Friday Otutu ◽  
Akinwale Ojo ◽  
Goodluck Mfonnom ◽  
...  
Keyword(s):  
Niger Delta ◽  
Wellbore Stability ◽  
Rock Properties ◽  
Failure Behavior ◽  
Natural Fractures ◽  
Gas Well ◽  
Well Integrity ◽  
Trajectory Formation ◽  
Naturally Fractured ◽  
Drilling Operations

Abstract The analysis of wellbore stability in gas wells is vital for effective drilling operations, especially in Brown fields and for modern drilling technologies. Tensile failure mode of Wellbore stability problems usually occur when drilling through hydrocarbon formations such as shale, unconsolidated sandstone, sand units, natural fractured formations and HPHT formations with narrow safety mud window. These problems can significantly affect drilling time, costs and the whole drilling operations. In the case of the candidate onshore gas well Niger Delta, there was severe lost circulation events and gas cut mud while drilling. However, there was need for a consistent adjustment of the tight drilling margin, flow, and mud rheology to allow for effective filter-cake formation around the penetrated natural fractures and traversed depleted intervals without jeopardizing the well integrity. Several assumptions were validly made for formations with voids or natural fractures, because the presence of these geological features influenced rock anisotropic properties, wellbore stress concentration and failure behavior with end point of partial – to-total loss circulation events. This was a complicated phenomenon, because the pre-drilled stress distribution simulation around the candidate wellbore was investigated to be affected by factors such as rock properties, far-field principal stresses, wellbore trajectory, formation pore pressure, reservoir and drilling fluids properties and time without much interest on traversing through voids or naturally fractured layers. This study reviews the major causes of the severe losses encountered, the adopted fractured permeability mid-line mudweight window mitigation process, stress caging strategies and other operational decisions adopted to further salvage and drill through the naturally fractured and depleted intervals, hence regaining the well integrity by reducing NPT and promoting well-early-time-production for the onshore gas well Niger Delta.

Coring Unconsolidated Formations under Challenging Drilling Conditions – A Case Study, Swamp- Niger Delta.

2018 ◽  
Author(s):  
J. A Onyeji ◽  
N. U Abdullahi ◽  
B Owoyemi ◽  
O. A Ekun ◽  
E Akhigbemen ◽  
...  
Keyword(s):  
Niger Delta ◽  
Drilling Conditions
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