scholarly journals Experimental Investigation of Seepage Mechanism on Oil-Water Two-Phase Displacement in Fractured Tight Reservoir

Geofluids ◽  
2022 ◽  
Vol 2022 ◽  
pp. 1-13
Author(s):  
Xuyang Zhang ◽  
Jianming Zhang ◽  
Cong Xiao
Keyword(s):  
Hydraulic Fracturing ◽  
Water Content ◽  
Production Rate ◽  
Oil Recovery ◽  
Hydraulic Fractures ◽  
Fracture System ◽  
Two Phase ◽  
Phase Displacement ◽  
Before And After ◽  
Oil Water

As a type of unconventional oil and gas resources, tight sandstone reservoir has low permeability and porosity properties and thus is commonly necessary to develop through hydraulic fracturing treatment. Due to the coexistence of natural fractures and induced hydraulic fractures, the heterogeneity of reservoir permeability becomes severe and therefore results in complicated fluid seepage mechanism. It is of significance to investigate the oil-water two-phase seepage mechanics before and after the hydraulic fracturing stimulation with the aim of supporting the actual production and development of oilfield. This paper experimentally investigated the influences of fracture system on seepage characteristics of two-phase displacement in sample cores of fractured tight sandstones. In details, the changes of injection rate, cumulative production rate, recovery ratio, and water content were analyzed before and after the hydraulic fracturing treatments. To further analyze the displacement characteristics of the sample core, the displacement indices of four rock samples in different displacement stages were investigated. The sensitivity of sample core displacement indices to many key factors, including injection time, oil production rate, oil recovery factor and injection multiple factor, and moisture (i.e., water content was 95%, 98%, and 99.5%, respectively), before and after the hydraulic fracturing treatments were obtained synthetically. Besides, the relationship between recovery difference and contribution of fracture to permeability was explored at different water contents. The experimental results reveal that the fracture system shortens the water-free production period and hence reduces the recovery rate. The greater the contribution of fractures to permeability, the lower the recovery of water during this period.

Oil, Water, Slag Three Phases Separation Technology of Heavy Aging Oil

2014 ◽  
Vol 936 ◽  
pp. 1553-1555
Author(s):  
Meng Zheng
Keyword(s):  
Water Content ◽  
Field Test ◽  
Oil Recovery ◽  
Recovery Rate ◽  
Storage Capacity ◽  
Quality Requirements ◽  
Separation Technology ◽  
Oil Water ◽  
Export Quality ◽  
Three Phases

The technology was used for handling heavy aging oil by demulsifier and three phases horizontal scrow centrifuge. Through laboratory and field test, it showed that the water content of the processed aging oil dropped from 50% to 5% below, purity oil recovery rate reached more than 95%, meeting export quality requirements. The technology improved the effective storage capacity of flow station, is of great significance to the safe and steady operation of flow station.

scholarly journals Soft Measurement of Water Content in Oil-Water Two-Phase Flow Based on RS-SVM Classifier and GA-NN Predictor

2014 ◽  
Vol 14 (4) ◽  
pp. 219-226 ◽  
Author(s):  
Dongzhi Zhang ◽  
Bokai Xia
Keyword(s):  
Water Content ◽  
Measurement Model ◽  
Support Vector ◽  
Svm Classifier ◽  
Model Parameters ◽  
Water Mixture ◽  
Measuring Range ◽  
Two Phase ◽  
Soft Measurement ◽  
Oil Water

Abstract Measurement of water content in oil-water mixing flow was restricted by special problems such as narrow measuring range and low accuracy. A simulated multi-sensor measurement system in the laboratory was established, and the influence of multi-factor such as temperature, and salinity content on the measurement was investigated by numerical simulation combined with experimental test. A soft measurement model based on rough set-support vector machine (RS-SVM) classifier and genetic algorithm-neural network (GA-NN) predictors was reported in this paper. Investigation results indicate that RS-SVM classifier effectively realized the pattern identification for water holdup states via fuzzy reasoning and self-learning, and GA-NN predictors are capable of subsection forecasting water content in the different water holdup patterns, as well as adjusting the model parameters adaptively in terms of online measuring range. Compared with the actual laboratory analyzed results, the soft model proposed can be effectively used for estimating the water content in oil-water mixture in all-round measuring range

Application of Increment-Dimension Precise Integration Method in Numerical Simulation of Two-Phase Oil-Water Flows in a Low Permeability Reservoir

2011 ◽  
Vol 243-249 ◽  
pp. 5985-5988
Author(s):  
Fu Liang Mei ◽  
Xiang Song Wu ◽  
Guang Ping Lin
Keyword(s):  
Numerical Simulation ◽  
Production Rate ◽  
Integration Method ◽  
Pore Fluid ◽  
Low Permeability ◽  
Pressure Gradients ◽  
Two Phase ◽  
Precise Integration ◽  
Water Flows ◽  
Oil Water

The numerical simulation of two-phase oil-water flows in a low permeability reservoir was carried out by means of an increment-dimension precise integration method (IDPIM). First of all, state equations denoted with pore fluid pressures at mesh nodes were built up according to finite difference method (FDM). Secondly, the recurrence formulae of the pore fluid pressures at mesh nodes were set up based on IDPIM. Finally, the numerical simulations of two-phase oil water seepages for a typical five point injection-production reservoir as an example were conducted by means of IDPIM and IMPES respectively. Calculation results by IDPIM are in good accordance with those by IMPES, and then IDPIM is quite reliable. At the same time, the effect rule of the startup pressure gradients on recovery degree, liquid production rate and oil production rate has been investigated. The start-up pressure gradients have an outstanding effect on recovery degree, liquid production rate and oil production rate, and the existence of the startup pressure gradients will enhance development difficulty and cost.

Gravity effects on oil–water two-phase displacement in homogeneous porous media

2021 ◽  
Vol 33 (10) ◽  
pp. 102003
Author(s):  
Wenzhe Yang ◽  
Yunsheng Chang ◽  
Jindian Cheng ◽  
Zhiguo Wang ◽  
Xingbo Li ◽  
...  
Keyword(s):  
Porous Media ◽  
Two Phase ◽  
Phase Displacement ◽  
Homogeneous Porous Media ◽  
Gravity Effects ◽  
Oil Water

Evaluation of Fracture Asymmetry of Finite-Conductivity Fractured Wells

2010 ◽  
Vol 132 (1) ◽  
Author(s):  
Djebbar Tiab ◽  
Jing Lu ◽  
Hung Nguyen ◽  
Jalal Owayed
Keyword(s):  
Hydraulic Fracturing ◽  
Production Rate ◽  
Radial Flow ◽  
Asymmetry Factor ◽  
Hydraulic Fractures ◽  
Finite Conductivity ◽  
Asymmetry Ratio ◽  
Pressure Derivative ◽  
Fracture Conductivity ◽  
The Asymmetry

Nearly all commercial hydraulic fracture design models are based on the assumption that a single fracture is initiated and propagated identically and symmetrically about the wellbore, i.e., the fracture growth and proppant transport occurs symmetrically with respect to the well. However, asymmetrical fractures have been observed in hundreds of hydraulic fracturing treatments and reported to be a more realistic outcome of hydraulic fracturing. The asymmetry ratio (length of short fracture wing divided by length of long wing) influenced the production rate adversely. In the worst case, the production rate could be reduced to that of an unfractured well. Several authors observed asymmetrically propagated hydraulic fractures in which one wing could be ten times longer than the other. Most pressure transient analysis techniques of hydraulically fractured wells assume the fracture is symmetric about the well axis for the sake of simplicity in developing mathematical solution. This study extends the work by Rodriguez to evaluate fracture asymmetry of finite-conductivity fracture wells producing at a constant-rate. The analysis presented by Rodriguez only involves the slopes of the straight lines that characterize the bilinear, linear and radial flow from the conventional Cartesian and semilog plots of pressure drop versus time. This study also uses the Tiab’s direct synthesis (TDS) technique to analyze the linear and bilinear flow regimes in order to find the asymmetry factor of the fractured well. With the fracture conductivity estimated from the bilinear flow region, dimensionless fracture conductivity and the asymmetry ratio are calculated. A technique for estimating the fracture asymmetry ratio from a graph is presented. An equation relating the asymmetry ratio and dimensionless fracture conductivity is also presented. This equation assumes that the linear and/or bilinear flow regime is observed. However, using the TDS technique, the asymmetry ratio can be estimated even in the absence of bilinear or linear flow period. It is concluded that the relative position of the well in the fracture, i.e., the asymmetry condition, is an important consideration for the fracture characterization. A log-log plot of pressure derivative can be used to estimate the fracture asymmetry in a well intersected with a finite-conductivity asymmetric fracture. The analysis using pressure derivative plot does not necessarily require the radial flow period data to calculate the asymmetric factor.

scholarly journals Pattern transitions of oil-water two-phase flow with low water content in rectangular horizontal pipes probed by terahertz spectrum

2015 ◽  
Vol 23 (24) ◽  
pp. A1693 ◽  
Author(s):  
Xin Feng ◽  
Shi-Xiang Wu ◽  
Kun Zhao ◽  
Wei Wang ◽  
Hong-Lei Zhan ◽  
...  
Keyword(s):  
Water Content ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Horizontal Pipes ◽  
Terahertz Spectrum ◽  
Oil Water

Efficiency Analysis of the Geological-Technical Activities in Severo-Ostrovnoe Field

2019 ◽  
Vol 16 (11) ◽  
pp. 4584-4588
Author(s):  
I. A. Pogrebnaya ◽  
S. V. Mikhailova
Keyword(s):  
Hydraulic Fracturing ◽  
Production Rate ◽  
Oil Recovery ◽  
Oil Production ◽  
Horizontal Wells ◽  
Oil Field ◽  
Field Development ◽  
Multi Stage ◽  
Field Works ◽  
Technical Measures

The work is devoted to identifying the most relevant geological and technical measures carried out in Severo-Ostrovnoe field from the period of its development to the present. Every year dozens of geotechnical jobs (GJ) are carried out at each oil field-works carried out at wells to regulate the development of fields and maintain target levels of oil production. Today, there are two production facilities in the development of the Severo-Ostrovnoe field: UV1a1 and BV5. With the help of geotechnical jobs, oil-producing enterprises ensure the fulfillment of project indicators of field development (Mikhailov, N.N., 1992. Residual Oil Saturation of Reservoirs Under Development. Moscow, Nedra. p.270; Good, N.S., 1970. Study of the Physical Properties of Porous Media. Moscow, Nedra. p.208). In total, during the development of the Severo-Ostrovnoe field, 76 measures were taken to intensify oil production and enhance oil recovery. 12 horizontal wells were drilled (HW with multistage fracking (MSF)), 46 hydraulic fracturing operations were performed, 12 hydraulic fracturing operations were performed at the time of withdrawal from drilling (HW with MSF), five sidetracks were cut; eight physic-chemical BHT at production wells; five optimization of well operation modes. The paper analyzes the performed geological and technical measures at the facilities: UV1a1∦BV5 of the Severo-Ostrovnoe field. Four types of geological and technical measures were investigated: hydraulic fracturing, drilling of sidetracks with hydraulic fracturing, drilling of horizontal wells with multi-stage hydraulic fracturing, and physic-chemical optimization of the bottom-hole formation zone. It was revealed that two geotechnical jobs, namely, formation hydraulic fracturing (FHF) and drilling of lateral shafts in the Severo-Ostrovnoe field are the most highly effective methods for intensifying reservoir development and increasing oil recovery. SXL was conducted at 5 wells. The average oil production rate is 26.6 tons per day, which is the best indicator. Before this event, the production rate of the well was 2.1 tons per day. Currently, the effect of ongoing activities continues.

Integrated Hydraulic Fracture Geometry Evaluation Based on Pre-Cambrian Tight Silicylate Reservoir in South Oman Salt Basin

2022 ◽  
Author(s):  
Dmitrii Smirnov ◽  
Omar AL Isaee ◽  
Alexey Moiseenkov ◽  
Abdullah Al Hadhrami ◽  
Hilal Shabibi ◽  
...  
Keyword(s):  
Best Practices ◽  
Hydraulic Fracturing ◽  
Hydraulic Fracture ◽  
Hydraulic Fractures ◽  
Bond Quality ◽  
Fracture Geometry ◽  
Acoustic Anisotropy ◽  
Sonic Log ◽  
Before And After ◽  
Fracture Height

Abstract Pre-Cambrian South Oman tight silicilyte reservoirs are very challenging for the development due to poor permeability less than 0.1 mD and laminated texture. Successful hydraulic fracturing is a key for the long commercial production. One of the main parameter for frac planning and optimization is fracture geometry. The objective of this study was summarizing results comparison from different logging methods and recommended best practices for logging program targeting fracture geometry evaluation. The novel method in the region for hydraulic fracture height and orientation evaluation is cross-dipole cased hole acoustic logging. The method allows to evaluate fracture geometry based on the acoustic anisotropy changes after frac operations in the near wellbore area. The memory sonic log combined with the Gyro was acquired before and after frac operations in the cased hole. The acoustic data was compared with Spectral Noise log, Chemical and Radioactive tracers, Production Logging and pre-frac model. Extensive logging program allow to complete integrated evaluation, define methods limitations and advantages, summarize best practices and optimum logging program for the future wells. The challenges in combining memory cross-dipole sonic log and gyro in cased hole were effectively resolved. The acoustic anisotropy analysis successfully confirms stresses and predominant hydraulic fractures orientation. Fracture height was confirmed based on results from different logging methods. Tracers are well known method for the fracture height evaluation after hydraulic frac operations. The Spectral Noise log is perfect tool to evaluate hydraulically active fracture height in the near wellbore area. The combination of cased hole acoustic and noise logging methods is a powerful complex for hydraulic fracture geometry evaluation. The main limitations and challenges for sonic log are cement bond quality and hole conditions after frac operations. Noise log has limited depth of investigation. However, in combination with production and temperature logging provides reliable fit for purpose capabilities. The abilities of sonic anisotropy analysis for fracture height and hydraulic fracture orientation were confirmed. The optimum logging program for fracture geometry evaluation was defined and recommended for replication in projects were fracture geometry evaluation is required for hydraulic fracturing optimization.

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