water blocking
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ACS Omega ◽  
2021 ◽  
Author(s):  
Fuhua Wang ◽  
Haitao Zhu ◽  
Weidong Zhang ◽  
Xian Shi ◽  
Luyi Wang ◽  
...  

SPE Journal ◽  
2021 ◽  
pp. 1-18
Author(s):  
Hu Jia ◽  
Cheng-Cheng Niu ◽  
Chang-Lou Dai

Summary Despite the increasing contribution of renewables to global energy, fossil fuels such as oil and gas still play an important role in energy supply. The development of deep and ultradeep oil and gas reservoirs has become more urgent. Typically, the ultrahigh-temperature and high-pressure (HTHP) environment is a big challenge. Solid-free brine is often used as a weighting component of high-density well completion fluid in the process of well operation, but the large amount of free water can easily cause water blocking damage to the reservoir. Therefore, there is an urgent need to develop a high-density completion fluid system that can be used in HTHP reservoir environments with little free water. In this paper, based on the theory of dispersion, degradation, viscosity extraction, and viscosity stabilization of polymer flexible colloidal particles in brines, an ultrahigh-temperature (180°C)-resistant, solid-free flexible colloidal completion fluid (SFCCF) with variable density and low corrosion was prepared. It breaks through the classical Flory’s water absorption theory. The phosphate brine was selected as the weighting base fluid of SFCCF, and the flexible colloidal particles were saturated with the phosphate brine to improve the density of SFCCF, as well as to reduce free water to lower the potential of water blocking damage. The results show that the dynamic viscosity of SFCCF is adjustable and ranges from 27 to 690 mPa·s, and the density is adjustable in the range of 1 to 1.8 g/cm3. SFCCF is a typical pseudoplastic fluid with shear dilution property, which is the result of the network destruction and the shear deformation of the flexible colloidal particles. The pump rate vs. dynamic viscosity curve is drawn. Under the pump rate of 50 to 800 L/min, the dynamic viscosity of SFCCF (1.2 to 1.7 g/cm3) is less than 40 mPa·s. In addition, SFCCF is viscosity stable for at least 4 days at 180°C and has excellent clay swelling resistance and reservoir fluid compatibility. Finally, SFCCF provides good reservoir protection and rock carrying capabilities and has the advantage of low cost. The successful application of SFCCF in a high-pressure gas well in the East China Sea is summarized, and some recommendations are proposed. The developed SFCCF can significantly reduce water blocking damage in HTHP well operations, providing a new avenue for HTHP well completions.


Polymer Korea ◽  
2021 ◽  
Vol 45 (6) ◽  
pp. 841-848
Author(s):  
Gwang-Mook Choi ◽  
Jin-Ju Choi ◽  
Woo-Cheol Kim ◽  
Hwanmin Hwang ◽  
Myungwoong Kim ◽  
...  

Author(s):  
Francesco Maurelli ◽  
Szymon Krupiński ◽  
Xianbo Xiang ◽  
Yvan Petillot

AbstractLocalisation, i.e. estimation of one’s position in a given environment is a crucial element of many mobile systems, manned and unmanned. Due to the high demand for autonomous exploration, patrolling and inspection services and a rapid improvement of batteries, sensors and machine learning algorithms, the quality of localisation becomes even more important for smart robotic systems. The underwater domain is a very challenging environment due to the water blocking most of the signals over short distances. Recent results in localisation techniques for underwater vehicles are summarised in two principal categories: passive techniques, which strive to provide the best estimation of the vehicle’s position (global or local) given the past and current information from sensors, and active techniques, which additionally produce guidance output that is expected to minimise the uncertainty of estimated position.


ACS Omega ◽  
2021 ◽  
Author(s):  
Tinku Saikia ◽  
Abdullah S. Sultan ◽  
Syed R. Hussaini ◽  
Assad Barri ◽  
Nur Iman Khamidy ◽  
...  

2021 ◽  
Vol 250 ◽  
pp. 501-511
Author(s):  
Natalia Danileva ◽  
Sergei Danilev ◽  
Natalia Bolshakova

Advancement in the production of potassium fertilizers is an important strategic task of Russian agricultural industry. Given annually growing production rates, the reserves of discovered potassium-magnesium salt deposits are noticeably decreasing, which creates the need to ensure stable replenishment of the resource base through both the discovery of new deposits and the exploitation of deep-lying production horizons of the deposits that are already under development. In most cases, deposits of potassium-magnesium salts are developed by underground mining. The main problem for any salt deposit is water. Dry salt workings do not require any additional reinforcement and can easily withstand rock pressure, but with an inflow of water they begin to collapse intensively – hence, special attention is paid to mine waterproofing. Determination of spatial location, physical and mechanical properties of the aquifer and water-blocking stratum in the geological section represent an important stage in the exploration of a salt deposit. The results of these studies allow to validate an optimal system of deposit development that will minimize environmental and economic risks. On the territory of Russia, there is a deposit of potassium-magnesium salts with a unique geological structure – its production horizon lies at a considerable depth and is capped by a regional aquifer, which imposes significant limitations on the development process. To estimate parameters of the studied object, we analyzed the data from CDP seismic reflection survey and a suite of methods of radioactive and acoustic well logging, supplemented with high-frequency induction logging isoparametric sounding (VIKIZ) data. As a result of performed analysis, we identified location of the water-bearing stratum, estimated average thickness of the aquifers and possible water-blocking strata. Based on research results, we proposed methods for increasing operational reliability of the main shaft in the designed mine that will minimize the risks of water breakthrough into the mine shaft.


SPE Journal ◽  
2021 ◽  
pp. 1-16
Author(s):  
Pål Østebø Andersen

Summary This work studies 1D steady-state flow of gas from compressible shale matrix subject to water blocking toward a neighboring fracture. Water blocking is a capillary end effect causing wetting phase (e.g., water) to accumulate near the transition from matrix to fracture. Hydraulic fracturing is essential for economical shale gas production. Water is frequently used as fracturing fluid, but its accumulation in the matrix can reduce gas mobility and production rate. Gas transport is considered at a defined pressure drop. The model accounts for apparent permeability (slip), compressibility of gas and shale, permeability reduction, saturation tortuosity (reduced relative permeability upon compaction), and multiphase flow parameters like relative permeability and capillary pressure, which depend on wettability. The behavior of gas flow rate and distributions of gas saturation, pressure, and permeability subject to different conditions and the stated mechanisms is explored. Water blockage reduces gas relative permeability over a large zone and reduces the gas flow rate. Despite gas flowing, strong capillary forces sustain mobile water over the entire system. Reducing drawdown gave lower driving force and higher resistance (by water blockage) for gas flow. The results show that 75% reduction of drawdown made the gas flow rate a couple orders of magnitude lower compared to if there was no blockage. The impact was most severe in more water-wetsystems. The blockage caused most of the pressure drop to occur near the outlet. High pressure in the rest of the system reduced effects from gas decompression, matrix compression, and slip-enhanced permeability, whereas rapid gradients in all these effects occurred near the outlet. Gas decompression resulted in an approximately 10 times higher Darcy velocity and pressure gradient near the outlet compared to inlet, which contributed to removing blockage, but the added resistance reduced the gas production rate. Similarly, higher gas Corey exponent associated gas flow with higher pressure drop. The result was less blockage but lower gas production. Slip increased permeability, especially toward the outlet, and contributed to increase in gas production by 16%. Significant matrix compression was associated with permeability reduction and increased Corey exponent in some examples. These effects reduced production and shifted more of the pressure drop toward the outlet. Upstream pressure was more uniform, and less compression and permeability reduction were seen overall compared to a system without water blockage.


2021 ◽  
Vol 73 (07) ◽  
pp. 57-57
Author(s):  
Leonard Kalfayan

As unconventional oil and gas fields mature, operators and service providers are looking toward, and collaborating on, creative and alternative methods for enhancing production from existing wells, especially in the absence of, or at least the reduction of, new well activity. While oil and gas price environments remain uncertain, recent price-improvement trends are supporting greater field testing and implementation of innovative applications, albeit with caution and with cost savings in mind. Not only is cost-effectiveness a requirement, but cost-reducing applications and solutions can be, too. Of particular interest are applications addressing challenging well-production needs such as reducing or eliminating liquid loading in gas wells; restimulating existing, underperforming wells, including as an alternative to new well drilling and completion; and remediating water blocking and condensate buildup, both of which can impair production from gas wells severely. The three papers featured this month represent a variety of applications relevant to these particular well-production needs. The first paper presents a technology and method for liquid removal to improve gas production and reserves recovery in unconventional, liquid-rich reservoirs using subsurface wet-gas compression. Liquid loading, a recurring issue downhole, can severely reduce gas production and be costly to remediate repeatedly, which can be required. This paper discusses the full technology application process and the supportive results of the first field trial conducted in an unconventional shale gas well. The second paper discusses the application of the fishbone stimulation system and technique in a tight carbonate oil-bearing formation. Fishbone stimulation has been around for several years now, but its best applications and potential have not necessarily been fully understood in the well-stimulation community. This paper summarizes a successful pilot application resulting in a multifold increase in oil-production rate and walks the reader through the details of the pilot candidate selection, completion design, operational challenges, and lessons learned. The third paper introduces and proposes a chemical treatment to alleviate phase trapping in tight carbonate gas reservoirs. Phase trapping can be in the form of water blocking or increasing condensate buildup from near the wellbore and extending deeper into the formation over time. Both can reduce relative permeability to gas severely. Water blocks can be a one-time occurrence from drilling, completion, workover, or stimulation operations and can often be treated effectively with solvent plus proper additive solutions. Similar treatments for condensate banking in gas wells, however, can provide only temporary alleviation, if they are even effective. This paper proposes a technique for longer-term remediation of phase trapping in tight carbonate gas reservoirs using a unique, slowly reactive fluid system. Recommended additional reading at OnePetro: www.onepetro.org. SPE 200345 - Insights Into Field Application of Enhanced-Oil-Recovery Techniques From Modeling of Tight Reservoirs With Complex High-Density Fracture Network by Geng Niu, CGG, et al. SPE 201413 - Diagnostic Fracture Injection Test Analysis and Simulation: A Utica Shale Field Study by Jeffery Hildebrand, The University of Texas at Austin, et al.


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