Underbalanced Drilling Analysis of Naturally Fractured Mexican Fields through 2D Multiphase Flow

2000 ◽  
Author(s):  
D. Velazquez Cruz ◽  
H. Rodriguez-Hernandez ◽  
I. Cortes-Monroy ◽  
D. Azpeitia-Hernandez ◽  
J. Blanco-Galan
Keyword(s):  
Multiphase Flow ◽  
Underbalanced Drilling ◽  
Naturally Fractured

New Transfer Functions for Simulation of Naturally Fractured Reservoirs with Dual Porosity Models

SPE Journal ◽  
2006 ◽  
Vol 11 (03) ◽  
pp. 328-340 ◽  
Author(s):  
Pallav Sarma ◽  
Khalid Aziz
Keyword(s):  
Transfer Function ◽  
Multiphase Flow ◽  
Shape Factor ◽  
Fractured Reservoirs ◽  
Naturally Fractured Reservoirs ◽  
Dual Porosity ◽  
Fine Grid ◽  
Pressure Diffusion ◽  
Matrix Fracture ◽  
Naturally Fractured

Summary This paper discusses new techniques for the modeling and simulation of naturally fractured reservoirs with dual-porosity models. Most of the existing dual-porosity models idealize matrix-fracture interaction by assuming orthogonal fracture systems (parallelepiped matrix blocks) and pseudo-steady state flow. More importantly, a direct generalization of single-phase flow equations is used to model multiphase flow, which can lead to significant inaccuracies in multiphase flow-behavior predictions. In this work, many of these existing limitations are removed in order to arrive at a transfer function more representative of real reservoirs. Firstly, combining the differential form of the single-phase transfer function with analytical solutions of the pressure-diffusion equation, an analytical form for a shape factor for transient pressure diffusion is derived to corroborate its time dependence. Further, a pseudosteady shape factor for rhombic fracture systems is also derived and its effect on matrix-fracture mass transfer demonstrated. Finally, a general numerical technique to calculate the shape factor for any arbitrary shape of the matrix block (i.e., nonorthogonal fractures) is proposed. This technique also accounts for both transient and pseudosteady-state pressure behavior. The results were verified against fine-grid single-porosity models and were found to be in excellent agreement. Secondly, it is shown that the current form of the transfer function used in reservoir simulators does not fully account for the main mechanisms governing multiphase flow. A complete definition of the differential form of the transfer function for two-phase flow is derived and combined with the governing equations for pressure and saturation diffusion to arrive at a modified form of the transfer function for two-phase flow. The new transfer function accurately takes into account pressure diffusion (fluid expansion) and saturation diffusion (imbibition), which are the two main mechanisms driving multiphase matrix-fracture mass transfer. New shape factors for saturation diffusion are defined. It is shown that the prediction of wetting-phase imbibition using the current form of the transfer function can be quite inaccurate, which might have significant consequences from the perspective of reservoir management. Fine-grid single-porosity models are used to verify the validity of the new transfer function. The results from single-block dual-porosity models and the corresponding single-porosity fine-grid models were in good agreement. Introduction A naturally fractured reservoir (NFR) can be defined as a reservoir that contains a connected network of fractures (planar discontinuities) created by natural processes such as diastrophism and volume shrinkage (Ordonez et al. 2001). Fractured petroleum reservoirs represent over 20% of the world's oil and gas reserves (Saidi 1983), but are, however, among the most complicated class of reservoirs. A typical example is the Circle Ridge fractured reservoir located on the Wind River Reservation in Wyoming, U.S.. This reservoir has been in production for more than 50 years but the total oil recovery until now has been less than 15% (www.fracturedreservoirs.com 2000). It is undeniable that reservoir characterization, modeling, and simulation of naturally fractured reservoirs present unique challenges that differentiate them from conventional, single-porosity reservoirs. Not only do the intrinsic characteristics of the fractures, as well as the matrix, have to be characterized, but the interaction between matrix blocks and surrounding fractures must also be modeled accurately. Further, most of the major NFRs have active aquifers associated with them, or would eventually be subjected to some kind of secondary recovery process such as waterflooding (German 2002), implying that it is essential to have a good understanding of the physics of multiphase flow for such reservoirs. This complexity of naturally fractured reservoirs necessitates the need for their accurate representation from a modeling and simulation perspective, such that production and recovery from such reservoirs be predicted and optimized.

scholarly journals Characteristics of a non-circulating transient flow during gas invasion in the underbalanced drilling process

2019 ◽  
Vol 23 (4) ◽  
pp. 2257-2264
Author(s):  
Na Wei ◽  
Ying-Feng Meng ◽  
An-Qi Liu ◽  
Hai-Tao Li ◽  
Lin Jiang ◽  
...  
Keyword(s):  
Multiphase Flow ◽  
Transient Flow ◽  
Mathematic Model ◽  
Simulation Method ◽  
Pressure Profile ◽  
Drilling Process ◽  
Transient Pressure ◽  
Underbalanced Drilling ◽  
Wellbore Flow ◽  
Gas Liquid Flow

The wellbore flow in a liquid-based underbalanced drilling process consists of a steady multiphase flow during normal drilling and a transient gas-liquid flow without mud-cycling. The theory of steady multiphase flow has been used to calculate the pressure profile of normal drilling. Therefore, it is vital to figure out how to calculate the transient pressure variation caused by formation fluid flow-ing into wellbore when the mud-cycling is stopped. In this paper, a numerical simulation method and a mathematic model are established to study the wellbore flow and to control pressure during the underbalanced drilling process with liquid-based mud. The results also shed a light on the hidden mechanism of this special flow.

Application of Multiphase Flow Methods to Horizontal Underbalanced Drilling

2000 ◽  
Vol 39 (10) ◽  
Author(s):  
S.P. Smith ◽  
G.A. Gregory ◽  
N. Munro ◽  
M. Muqeem
Keyword(s):  
Multiphase Flow ◽  
Underbalanced Drilling

The Virtual Well Engineer – A Real – Time Surveillance Tool for Managed Pressure Drilling Operations

2007 ◽  
Vol 18-19 ◽  
pp. 277-285
Author(s):  
Babs Mufutau Oyeneyin ◽  
Phil Burge ◽  
Lisa Hogg ◽  
Chris Anderson
Keyword(s):  
Multiphase Flow ◽  
Complex Environments ◽  
Hole Cleaning ◽  
Functional Capabilities ◽  
Drilling Performance ◽  
Underbalanced Drilling ◽  
Pressure Profiles ◽  
Managed Pressure Drilling ◽  
Engineering Team ◽  
Drilling Operations

Well engineers face ever increasing technical challenge of drilling in complex environments and the use of Managed Pressure Drilling(MPD) techniques to control annular pressure for improved drilling performance in the oil industry has growing interest[1-4]. Understanding hole cleaning and controlling annular pressure in this complex environment is becoming increasingly important for a range of applications. The Virtual Well Engineer[VWE] has been identified as the engineering tool to address these issues in order to deliver a successful MPD operation. The VWE is the product name for a suite of well planning , monitoring and simulation packages with focus on Managed Pressure Drilling includng underbalanced drilling that allows the well engineering team to interact with virtual reality. Recent works initiated by the Well Engineering Group at The Robert Gordon University have extended the knowledge of multiphase flow in a drilling annulus through the tracking of the transient multiphase flow pattern prevailing and effects on hole cleaning , the pressure profiles and identification of hot spots in concentric and eccentric annular sections . The mechanistic models developed at RGU form the core algorithms for the VWE. This paper presents the architecture and functional capabilities of the VWE – HydraulicsDTS™ , which is used in simulating well operations.

A Multiple-Continuum Approach For Modeling Multiphase Flow in Naturally Fractured Vuggy Petroleum Reservoirs

2006 ◽  
Author(s):  
Yu-Shu Wu ◽  
Guan Qin ◽  
Richard Edward Ewing ◽  
Yalchin Efendiev ◽  
Zhijiang Kang ◽  
...  
Keyword(s):  
Multiphase Flow ◽  
Petroleum Reservoirs ◽  
Continuum Approach ◽  
Naturally Fractured
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