Effects of Directional Permeability Anisotropy on Sweep Efficiency of Water Injection Under Fracturing Conditions Process

2007 ◽  
Author(s):  
E.O. Munoz Mazo ◽  
J.M. Montoya Moreno ◽  
D.J. Schiozer
Keyword(s):  
Water Injection ◽  
Sweep Efficiency ◽  
Permeability Anisotropy ◽  
Directional Permeability

Carbonated Water Injection for Recovery of Oil and Wettability Analysis

2014 ◽  
Vol 695 ◽  
pp. 499-502 ◽  
Author(s):  
Mohamad Faizul Mat Ali ◽  
Radzuan Junin ◽  
Nor Hidayah Md Aziz ◽  
Adibah Salleh
Keyword(s):  
Oil Recovery ◽  
Oil And Gas ◽  
Promising Result ◽  
Water Injection ◽  
High Mobility ◽  
Wettability Alteration ◽  
Sweep Efficiency ◽  
Gas Flooding ◽  
Carbonated Water Injection ◽  
Carbonated Water

Malaysia oilfield especially in Malay basin has currently show sign of maturity phase which involving high water-cut and also pressure declining. In recent event, Malaysia through Petroliam Nasional Berhad (PETRONAS) will be first implemented an enhanced oil recovery (EOR) project at the Tapis oilfield and is scheduled to start operations in 2014. In this project, techniques utilizing water-alternating-gas (WAG) injection which is a type of gas flooding method in EOR are expected to improve oil recovery to the field. However, application of gas flooding in EOR process has a few flaws which including poor sweep efficiency due to high mobility ratio of oil and gas that promotes an early breakthrough. Therefore, a concept of carbonated water injection (CWI) in which utilizing CO2, has ability to dissolve in water prior to injection was applied. This study is carried out to assess the suitability of CWI to be implemented in improving oil recovery in simulated sandstone reservoir. A series of displacement test to investigate the range of recovery improvement at different CO2 concentrations was carried out with different recovery mode stages. Wettability alteration properties of CWI also become one of the focuses of the study. The outcome of this study has shown a promising result in recovered residual oil by alternating the wettability characteristic of porous media becomes more water-wet.

An Approximate Method for Determining Areal Sweep Efficiency and Flow Capacity in Formations with Anisotropic Permeability

10.2118/16-pa ◽  
1961 ◽  
Vol 1 (04) ◽  
pp. 277-286 ◽  
Author(s):  
M. Mortada ◽  
G.W. Nabor
Keyword(s):  
Principal Axis ◽  
Bedding Plane ◽  
Sweep Efficiency ◽  
Simple Method ◽  
Anisotropic Permeability ◽  
Preferred Direction ◽  
Flow Capacity ◽  
Principal Axes ◽  
Special Cases ◽  
Directional Permeability

Abstract The effects of anisotropic or directional permeability on the areal sweep efficiency and the flow capacity are examined. The paper points out the importance of taking directional permeability into consideration in planning a flood. It analyzes the two-dimensional flow pattern associated with the skewed line drive for a unit mobility ratio. The direct and staggered line drives are treated as special cases of the skewed line drive. Analytical expressions are developed for the areal sweep efficiency at breakthrough and the flow capacity. They are related to the spacing between like wells, the distance between a row of injectors and the nearest row of producers, and the degree of skewness of the line drive. The latter quantity is defined such that it is equal to zero for the direct line drive and equals one-half for the staggered line drive. The a real sweep efficiency and the flow capacity depend also on the orientation of the flood pattern with respect to the principal axis of anisotropy. The paper provides a simple method for determining the a real sweep efficiency and the flow capacity for a formation in which the permeability in the bedding plane is anisotropic. Introduction Directional or anisotropic permeability is manifested by the ability of the formation to conduct fluids more readily along certain preferred directions. This situation occurs in many producing formations and is usually attributed to depositional features in which the sand grains are oriented in a preferred direction. In some cases it results from the formation of a major and a minor fracture system. Directional permeability should be taken into account in many phases of the production and exploration activities. Recognizing its existence in the formation of interest and planning accordingly can lead to increased recovery and substantial savings. For instance, the areal sweep efficiency in a water flood depends to a great extent on the orientation of the flood pattern with respect to the principal axis of permeability. Anisotropic permeability is specified by the directions of its three principal axes and the permeability along each axis. The principal axes of permeability are mutually perpendicular. This paper deals with the areal sweep efficiency at breakthrough and the flow capacity for formations with anisotropic permeability. The flood pattern considered consists of alternate rows of injecting and producing wells. The rows of wells are parallel and form a developed, skewed line drive which is illustrated in Fig. 1. The staggered and direct line drives are treated as special cases of the skewed line drive.

Improvement of Uniform Oil Displacement Technology on the Example of Kazakhstani Fields

2018 ◽  
Vol 9 (3) ◽  
pp. 542
Author(s):  
Abdeli D. ZHUMADILULI ◽  
Irina V. PANFILOV ◽  
Jamilyam A. ISMAILOVA
Keyword(s):  
Oil Recovery ◽  
Research University ◽  
Water Injection ◽  
Oil Fields ◽  
Simulation Test ◽  
Sweep Efficiency ◽  
Oil Companies ◽  
Industrial Companies ◽  
Energy Current ◽  
Water Cut

Most of oil companies today are focused on increasing the recovery factor from their oil fields. New drilling and well technologies as well as last advances in reservoir management, monitoring and Enhanced Oil Recovery (EOR) methods are thought to play a major role to meet the future demand of energy. Current decline in discovery of new oilfields intensified by a decline in oil prices make industrial companies to work on development of new efficient and economic techniques that will allow better production at lower cost. One such technology developed at Kazakh National Research University is presented in this paper. The latter propose the use of specific perforated holes on tubing liners in order to control the rate of water injection into variably permeable layers and to prevent non-uniform displacement of oil. The study was initially conducted on experimental facility that proved a positive correlation between the perforation density and water flow rates. Then the simulation test was performed using the data from several Kazakhstani oil fields. The results show an increase of sweep efficiency as well as a decrease in water-cut compared to traditional well case.

scholarly journals Analytical Model of Waterflood Sweep Efficiency in Vertical Heterogeneous Reservoirs under Constant Pressure

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Lisha Zhao ◽  
Li Li ◽  
Zhongbao Wu ◽  
Chenshuo Zhang
Keyword(s):  
Analytical Model ◽  
Oil Recovery ◽  
Constant Pressure ◽  
Water Saturation ◽  
Water Injection ◽  
Single Layer ◽  
Sweep Efficiency ◽  
Heterogeneous Reservoirs ◽  
Water Cut ◽  
Swept Volume

An analytical model has been developed for quantitative evaluation of vertical sweep efficiency based on heterogeneous multilayer reservoirs. By applying the Buckley-Leverett displacement mechanism, a theoretical relationship is deduced to describe dynamic changes of the front of water injection, water saturation of producing well, and swept volume during waterflooding under the condition of constant pressure, which substitutes for the condition of constant rate in the traditional way. Then, this method of calculating sweep efficiency is applied from single layer to multilayers, which can be used to accurately calculate the sweep efficiency of heterogeneous reservoirs and evaluate the degree of waterflooding in multilayer reservoirs. In the case study, the water frontal position, water cut, volumetric sweep efficiency, and oil recovery are compared between commingled injection and zonal injection by applying the derived equations. The results are verified by numerical simulators, respectively. It is shown that zonal injection works better than commingled injection in respect of sweep efficiency and oil recovery and has a longer period of water free production.

How Much Polymer Should Be Injected During a Polymer Flood? Review of Previous and Current Practices

SPE Journal ◽  
2016 ◽  
Vol 22 (01) ◽  
pp. 1-18 ◽  
Author(s):  
R. S. Seright
Keyword(s):  
Water Injection ◽  
Design Procedure ◽  
Base Case ◽  
Mechanical Degradation ◽  
Sweep Efficiency ◽  
Resistance Factors ◽  
Economics Of Scale ◽  
Field Activity ◽  
Viscous Polymer ◽  
Case Design

Summary This paper provides an extensive review of the polymer concentrations, viscosities, and bank sizes used during existing and previous polymer floods. On average, these values have been substantially greater during the past 25 years than during the first 30 years of polymer-flooding field activity. Reasons for the changes are discussed. Even with current floods, a broad range of polymer viscosities are injected, with substantial variations from a base-case design procedure. Extensive discussions with operators and designers of current polymer floods revealed substantial differences of opinion for the optimum design of polymer floods. This paper examines the validity of arguments that are commonly given to justify deviations from the base-case design. For applications involving viscous oils (e.g., 1,000 cp), the designed polymer viscosities have sometimes been underestimated because of insufficient water injection while determining relative permeabilities; reliance on mobility ratios at a calculated shock front; and overestimation of polymer resistance factors and residual resistance factors. In homogeneous reservoirs, the ratio of produced-oil value to injected-fluid cost is fairly insensitive to injected-polymer viscosity (up to the viscosity predicted by the base-case method), especially at low oil prices. However, reservoir heterogeneity and economics of scale associated with the polymer-dissolution equipment favor high polymer viscosities over low polymer viscosities, if injectivity is not limiting. Injection above the formation-parting pressure and fracture extension are crucial to achieving acceptable injectivity for many polymer floods, especially those using vertical injectors. Under the proper circumstances, this process can increase fluid injectivity, oil productivity, and reservoir-sweep efficiency, and also reduce the risk of mechanical degradation for polyacrylamide solutions. The key is to understand the degree of fracture extension for a given set of injection conditions so that fractures do not extend out of the target zone or cause severe channeling. Many field cases exist with no evidence that fractures caused severe polymer channeling or breaching of the reservoir seals, in spite of injection above the formation-parting pressure. Although at least one case exists (Daqing, China) where injection of very-viscous polymer solutions (i.e., more viscous than the base-case design) reduced Sor to less than that for waterflooding, our understanding of when and how this occurs is in its infancy. At this point, use of polymers to reduce Sor must be investigated experimentally on a case-by-case basis. A “one-size-fits-all” formula cannot be expected for the optimum bank size. However, experience and technical considerations favor use of the largest practical polymer bank. Although graded banks are commonly used or planned in field applications, more work is needed to demonstrate their utility and to identify the most-appropriate design procedure.

Ensemble-Based Optimization of the Water-Alternating-Gas-Injection Process

SPE Journal ◽  
2016 ◽  
Vol 21 (03) ◽  
pp. 0786-0798 ◽  
Author(s):  
Bailian Chen ◽  
Albert C. Reynolds
Keyword(s):  
Net Present Value ◽  
Optimization Technique ◽  
Water Injection ◽  
Mobility Control ◽  
Co2 Injection ◽  
Optimal Controls ◽  
Co2 Flooding ◽  
Displacement Efficiency ◽  
Sweep Efficiency ◽  
Water Alternating Gas

Summary CO2-water-alternating-gas (CO2-WAG) flooding generally leads to higher recovery than either continuous CO2 flooding or waterflooding. Although CO2 injection increases microscopic displacement efficiency, unless complete miscibility is achieved, suboptimal sweep efficiency may be obtained because of gravity segregation and the channeling of CO2 through high-permeability zones or by viscous fingering. Alternating water injection with CO2 injection results in better mobility control and increases sweep efficiency. Water injection also increases pressure that promotes miscibility. However, poorly designed WAG parameters can result in suboptimal WAG performance. In this work, given the number of WAG cycles and the duration of each WAG cycle, we apply a modification of a standard ensemble-based optimization technique to estimate the optimal well controls that maximize life-cycle net present value (NPV). By optimizing the well controls, we implicitly optimize the WAG ratio (volume of water injected divided by the volume of gas injected). We apply the optimization methodology to a synthetic, channelized reservoir. The performances of optimized WAG flooding, optimized waterflooding, and optimized continuous CO2 flooding are compared. Because of the similarity between WAG and surfactant alternating gas (SAG foam), we also optimize the SAG process and provide a more computationally efficient way to optimize the SAG process with the optimal well controls obtained from WAG as the initial guesses for the optimal controls for SAG.

Sign in / Sign up

Export Citation Format

Share Document