Study on a Self-Diverting Acid System for Well Stimulation Based on Novel Visco-Elastic Surfactant

2011 ◽  
Vol 287-290 ◽  
pp. 3120-3126 ◽  
Author(s):  
Fu Jian Zhou ◽  
Chun Ming Xiong ◽  
Yang Shi ◽  
Xian You Yang ◽  
Sheng Jiang Lian ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Carbonate Reservoir ◽  
Scanning System ◽  
Low Permeability ◽  
Acid System ◽  
Core Flooding ◽  
Well Stimulation ◽  
Core Permeability ◽  
Carbonate Formations ◽  
Oil Gas

Carbonate reservoir, widely distributed in china, is an important resource of oil and gas. Most of carbonate reservoir are very tight and need to be stimulated to increase the permeability for the flowing of oil/gas. Acid treatment is a kind of stimulation. However, the ordinary acid system cannot stimulate carbonate reservoir effectively because of the heterogeneity among formations. Based on a novel visco-elastic surfactant, this paper develops a self-diverting acid system (DCA) for carbonate formations. This system had been applied in the treatment of carbonate reservoirs successfully. Experiments studying the diverting mechanism had been conducted with HTHP Rheometer, parallel core flooding system and MRI Scanning system. The results indicate that: the viscosity of reacted acid can reach to 200 times higher than that of fresh acid. The injecting pressure of DCA is 20 times higher than that of ordinary acid (HCl) during the parallel core flooding experiment. MRI scanning images of the cores after acid flooding show that DCA can stimulate the cores with middle and low permeability more effectively. In middle and low permeability cores, the length of wormhole created by DCA is 4-8 times longer than that created by ordinary acid. At the same time, the relationship between flooding pressure and core permeability is also studied. This paper reveals the diverting mechanism of DCA through these experiments.

scholarly journals Application of VES Acid System on Carbonate Rocks with Uninvaded Matrix for Acid Etching and Fracture Propagation

Processes ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 159
Author(s):  
Yahong Wu ◽  
Weiwei Luo ◽  
Xunan Jia ◽  
Haoqing Fang ◽  
Honggang Wang ◽  
...  
Keyword(s):  
Fracture Propagation ◽  
Ct Scanning ◽  
Reaction Rates ◽  
Carbonate Reservoir ◽  
Fluid Viscosity ◽  
Acid System ◽  
Core Flooding ◽  
Structure Variation ◽  
The Core ◽  
The Impact

We investigated the performance of viscoelastic surfactant (VES) solution when applied in treatment on the uninvaded matrix using core flooding tests to analyze the impact of VES/CaCl2 concentration on fluid viscosity. In this paper, core samples from Tahe carbonate reservoir, with an average permeability less than 0.02 × 10−3 μm−2 and a small average porosity in the range of approximately 0.04–5.24% are used in the experiments. Computed tomography (CT) scanning is used to provide a detailed description of inner structure variation of cores after the acid system treatment. The results confirmed that a large pressure difference contributed to fracture propagation and the relative permeability of water increased significantly after the treatment. It was also found that higher concentrations of VES and/or Ca2+ induced higher viscosity and a stronger fracturing effect, while a lower concentration improved the reaction rates and etching effect, generating small worm holes inside the core. Foam in-situ produced during the etching process is the major contributor to the fluid viscosity enhancement. The permeability of fracture formed on the surface of the core is more sensitive to the confining pressure. These findings can help better understand the rheological properties of the acid system and etching and fracturing mechanisms during acid treatment, and which provides instructions for field implementation.

GEOSTEERING OF TWO HORIZONTAL WELLS IN SOUTH UMM GUDAIR FIELD: A SUCCESSFUL CASE HISTORY

2005 ◽  
Vol 45 (1) ◽  
pp. 55
Author(s):  
M. Jha ◽  
T. Tran ◽  
D. Hawkins
Keyword(s):  
Natural Water ◽  
Oil And Gas ◽  
Horizontal Wells ◽  
Oil And Gas Industry ◽  
Carbonate Reservoir ◽  
Oil Field ◽  
Low Permeability ◽  
Well Placement ◽  
Horizontal Drilling ◽  
Lower Permeability

The South Umm Gudair (SUG) oil field located in the Neutral zone between Kuwait and Saudi Arabia has produced since 1968 from an active water drive carbonate reservoir of Lower Cretaceous age. The lower zones are homogenous intervals of higher permeability which appear to be sufficiently swept by natural water drive over a period of time. The upper zones of the reservoir have lower permeability, are relatively thin and are bound by tighter intervals that act as possible barriers to the natural water drive system.Geosteering techniques are now extensively used in oil and gas industry for horizontal wells to produce hydrocarbons from thin reservoirs to maximise recovery, and restricting water-coning problems. Recent advancements in well placement using Geosteering allow successful targetting of low permeability reservoir with great precision which results in exposing more drainage area in the target pay.The geosteering technique was considered for the first time in joint operation’s SUG field targetting two horizontal wells. Improved well productivity is achieved through optimised well placement. This success has led to a development plan and strategy of additional horizontal drilling locations to maximise recovery of un-swept oil from the low permeability reservoirs. This paper reviews the success of Geosteering in SUG’s two horizontal wells, completed in July 2004.

Applications of Nanocomposite Materials in the Oil and Gas Industry

2009 ◽  
Vol 83-86 ◽  
pp. 771-776 ◽  
Author(s):  
Vincenzo Savino ◽  
Gasem M. Fallatah ◽  
Mauyed S. Mehdi
Keyword(s):  
Oil And Gas ◽  
Motor Vehicle ◽  
Protective Coatings ◽  
Oil And Gas Industry ◽  
Nanocomposite Materials ◽  
Low Permeability ◽  
Resistant Material ◽  
Gas Industry ◽  
Research Activities ◽  
Oil Gas

Research activities in nanocomposite materials have been carried out for the last decade. Some of the objectives of these activities have been focused in increasing polymer physical properties. This has resulted in products for many fields of application, including: motor vehicle parts, packing, bottles, furniture, protective coatings and flame resistant material. The higher thermal-mechanical properties, better fire resistance characteristics and the low permeability rates present possibilities for the development of nanocomposite materials for components in oil, gas and chemical facilities as pipes, valves and tanks. This paper shows the vision of the authors in some potential uses of nanocomposite materials for manufacturing nonmetallic components and their possible features to reduce the high cost of corrosion.

GEOLOGICAL AND PHYSICAL CHARACTERISTICS OF PRODUCING FORMATIONS AND THEIR ROLE IN OCCURRENCE OF OIL, GAS AND WATER SHOWINGS

2015 ◽  
pp. 117-120
Author(s):  
D. M. Chudnovskii ◽  
V. A. Dolgushin ◽  
J. S. Popova
Keyword(s):  
Oil And Gas ◽  
Physical Characteristics ◽  
The Subject ◽  
Oil Gas

The subject of this study are geological and physical characteristics of productive strata in oil and gas deposits.

ASSESSMENT OF OIL WELL PRODUCTIVITY IN LOW-PERMEABILITY RESERVOIRS IN THE FIELDS OF EASTERN SIBERIA

2017 ◽  
pp. 30-36
Author(s):  
R. V. Urvantsev ◽  
S. E. Cheban
Keyword(s):  
Oil Recovery ◽  
Large Scale ◽  
Oil And Gas ◽  
Oil Extraction ◽  
Low Permeability ◽  
Oil Well ◽  
Eastern Siberia ◽  
Development Costs ◽  
Traditional Fields ◽  
Low Permeability Reservoirs

The 21st century witnessed the development of the oil extraction industry in Russia due to the intensifica- tion of its production at the existing traditional fields of Western Siberia, the Volga region and other oil-extracting regions, and due discovering new oil and gas provinces. At that time the path to the development of fields in Eastern Siberia was already paved. The large-scale discoveries of a number of fields made here in the 70s-80s of the 20th century are only being developed now. The process of development itself is rather slow in view of a number of reasons. Create a problem of high cost value of oil extraction in the region. One of the major tasks is obtaining the maximum oil recovery factor while reducing the development costs. The carbonate layer lying within the Katangsky suite is low-permeability, and its inventories are categorised as hard to recover. Now, the object is at a stage of trial development,which foregrounds researches on selecting the effective methods of oil extraction.

scholarly journals Impact of Diagenesis on the Low Permeability Sandstone Reservoir: Case Study of the Lower Jurassic Reservoir in the Niudong Area, Northern Margin of Qaidam Basin

Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 453
Author(s):  
Wenhuan Li ◽  
Tailiang Fan ◽  
Zhiqian Gao ◽  
Zhixiong Wu ◽  
Ya’nan Li ◽  
...  
Keyword(s):  
Physical Properties ◽  
Oil And Gas ◽  
Qaidam Basin ◽  
Isotope Analysis ◽  
Lower Jurassic ◽  
Low Permeability ◽  
Hydrocarbon Generation ◽  
Northern Margin ◽  
Pore Evolution ◽  
Sandstone Reservoir

The Lower Jurassic reservoir in the Niudong area of the northern margin of Qaidam Basin is a typical low permeability sandstone reservoir and an important target for oil and gas exploration in the northern margin of the Qaidam Basin. In this paper, casting thin section analysis, scanning electron microscopy, X-ray diffraction, and stable isotope analysis among other methods were used to identify the diagenetic characteristics and evolution as well as the main factors influencing reservoir quality in the study area. The predominant types of sandstone in the study area are mainly feldspathic lithic sandstone and lithic arkose, followed by feldspathic sandstone and lithic sandstone. Reservoir porosity ranges from 0.01% to 19.5% (average of 9.9%), and permeability ranges from 0.01 to 32.4 mD (average of 3.8 mD). The reservoir exhibits robust heterogeneity and its quality is mainly influenced by diagenesis. The Lower Jurassic reservoir in the study area has undergone complex diagenesis and reached the middle diagenesis stage (A–B). The quantitative analysis of pore evolution showed that the porosity loss rate caused by compaction and cementation was 69.0% and 25.7% on average, and the porosity increase via dissolution was 4.8% on average. Compaction was the main cause of the reduction in the physical property of the reservoir in the study area, while cementation and dissolution were the main causes of reservoir heterogeneity. Cementation can reduce reservoir space by filling primary intergranular pores and secondary dissolved pores via cementation such as a calcite and illite/smectite mixed layer, whereas high cement content increased the compaction resistance of particles to preserve certain primary pores. δ13C and δ18O isotopes showed that the carbonate cement in the study area was the product of hydrocarbon generation by organic matter. The study area has conditions that are conductive to strong dissolution and mainly occur in feldspar dissolution, which produces a large number of secondary pores. It is important to improve the physical properties of the reservoir. Structurally, the Niudong area is a large nose uplift structure with developed fractures, which can be used as an effective oil and gas reservoir space and migration channel. In addition, the existence of fractures provides favorable conditions for the uninterrupted entry of acid fluid into the reservoir, promoting the occurrence of dissolution, and ultimately improves the physical properties of reservoirs, which is mainly manifested in improving the reservoir permeability.

The Current Situation and Prospects of Development of Low Permeability Oil Reservoir

2013 ◽  
Vol 734-737 ◽  
pp. 1286-1289 ◽  
Author(s):  
Lin Cong ◽  
Wen Long Li ◽  
Jing Chao Lei ◽  
Ru Bin Li
Keyword(s):  
Research Methods ◽  
Oil And Gas ◽  
Low Permeability ◽  
Oil Reservoir ◽  
Oil Exploration ◽  
Gas Field ◽  
Oil And Gas Field ◽  
Low Permeability Reservoirs ◽  
Technical Measures ◽  
Exploration And Development

Internationally the research of low permeability oil reservoir is a difficult point in the exploration and development of oil and gas field. This thesis, based on the research methods of low permeability reservoirs at home and abroad, summaries several major problems encountered in the process of low permeability oil exploration and development under the current technical conditions as well as the corresponding, but more effective technical measures that need to be constantly improved. And that exploration and development of low permeability of the reservoir will be the main battle field for some time in the future of oil exploration and development.

scholarly journals Formation environments and mechanisms of multistage paleokarst of Ordovician carbonates in Southern North China Basin

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Haitao Zhang ◽  
Guangquan Xu ◽  
Mancai Liu ◽  
Minhua Wang
Keyword(s):  
Carbonate Rocks ◽  
North China ◽  
Oil And Gas ◽  
Carbonate Reservoir ◽  
Carbonate Reservoirs ◽  
Geochemical Data ◽  
Near Surface ◽  
Oil And Gas Exploration ◽  
Pore Types ◽  
North China Basin

AbstractWith the reduction of oil and gas reserves and the increase of mining difficulty in Northern China, the carbonate rocks in Southern North China Basin are becoming a significant exploration target for carbonate reservoirs. However, the development characteristics, formation stages, formation environments and mechanisms of the carbonate reservoirs in Southern North China Basin are still unclear, which caused the failures of many oil and gas exploration wells. This study focused on addressing this unsolved issue from the Ordovician carbonate paleokarst in the Huai-Fu Basin, which is located in the southeast of Southern North China Basin and one of the key areas for oil and gas exploration. Based on petrology, mineralogy and geochemical data, pore types, distribution characteristics, and formation stages of the Ordovician paleokarst were analyzed. Then, in attempt to define the origins of porosity development, the formation environments and mechanisms were illustrated. The results of this study showed that pore types of the Ordovician carbonates in the Huai-Fu Basin are mainly composed of intragranular pores, intercrystalline (intergranular) pores, dissolution pores (vugs), fractures, channels, and caves, which are usually in fault and fold zones and paleoweathering crust. Furthermore, five stages and five formation environments of the Ordovician paleokarst were identified. Syngenetic karst, eogenetic karst, and paleoweathering crust karst were all developed in a relatively open near-surface environment, and their formations are mainly related to meteoric water dissolution. Mesogenetic karst was developed in a closed buried environment, and its formation is mainly related to the diagenesis of organic matters and thermochemical sulfate reduction in the Permian-Carboniferous strata. Hydrothermal (water) karst was developed in a deep-buried and high-temperature environment, where hydrothermal fluids (waters) migrated upward through structures such as faults and fractures to dissolve carbonate rocks and simultaneously deposited hydrothermal minerals and calcites. Lastly, a paleokarst evolution model, combined with the related porosity evolution processes, nicely revealed the Ordovician carbonate reservoir development. This study provides insights and guidance for further oil and gas exploration in the Southern North China Basin, and also advances our understanding of the genesis of carbonate paleokarst around the world.

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