scholarly journals Study on Fracability of Tight Reservoir on the basis of Geophysical Logging: a Case Study of Chang 7 Formation in Longdong Area, Ordos Basin

CONVERTER ◽  
2021 ◽  
pp. 518-527
Author(s):  
Zhenhua Li, Et al.
Keyword(s):  
Fracture Toughness ◽  
Oil And Gas ◽  
Thermal Evolution ◽  
Ordos Basin ◽  
Laboratory Data ◽  
Physical Property ◽  
Field Application ◽  
Analysis Model ◽  
Form Complex ◽  
Tight Reservoir

Fracability is the ability to form complex fracture to Increase production in tight reservoir under the same fracturing condition. The factors influencing fracturing include reservoir brittleness, fracture toughness, crack system,thermal evolution andmineral content etc. The tight reservoir physical property are poor, and the oil and gas produced under natural conditions is too little, so it is necessary to fracture the reservoir.In this paper, the brittleness and fracture toughness of Chang 7 Formationof Ordos Basinare calculated by logging data under the constraint of laboratory data. In combination with production practice, a new analysis model of reservoir hydraulicfracturing is constructed. The new analysis method is used to evaluate the fracability of Chang 7 stratum in the Ordos Basin, which ranges from 38.7% to 51.4%. It is basically consistent with the practical fracturing effect of typical wells in this area, which shows that the new method is accurate in calculation, convenient in field application, and can provide experience for the reservoir hydraulic fracturing .

Fracture Toughness Testing and Validation of Pipeline Girth Weld Flaw Acceptance Criteria for Sour Service Under Large Strain

2011 ◽  
Author(s):  
You You Wu ◽  
Wen Guo Yuan ◽  
Tse Ven Steven Chong ◽  
Jens P. Tronskar
Keyword(s):  
Fracture Toughness ◽  
Oil And Gas ◽  
Large Strain ◽  
Axial Strain ◽  
Laboratory Data ◽  
Local Buckling ◽  
Acceptance Criteria ◽  
Service Environment ◽  
Girth Welds ◽  
Sour Service

Fracture toughness is one of the most important input parameters for assessment of pipeline girth weld failure capacity. For many new subsea pipeline projects there is a need to develop flaw acceptance criteria for pipeline installation considering the operation phase which may involve the transport of sour oil and gas and where the pipeline is exposed to large axial strain due to local buckling. Engineering Critical Assessment (ECA) performed using laboratory data based on conservative KISSC testing gives small acceptable flaw sizes which may be below the workmanship criteria for pipeline laying. DNV has conducted extensive research based on the requirements of DNV-OS-F101 and DNV-RP-F108, aiming to establish a method to develop J-R curves applicable for ECA of pipeline girth welds in sour service environment and a methodology to validate the ECA by segment testing in a laboratory-simulated sour service environment as per DNV-RP-F108.

scholarly journals Analysis of Fracturing Ability Factors of Tight Reservoir

2020 ◽  
Vol 165 ◽  
pp. 01004
Author(s):  
Zhenhua Li ◽  
Ke Gai ◽  
Feng Cao
Keyword(s):  
Fracture Toughness ◽  
Organic Matter ◽  
Organic Carbon ◽  
Oil And Gas ◽  
Sedimentary Environment ◽  
Economic Benefits ◽  
Natural Fracture ◽  
Organic Carbon Content ◽  
Multi Stage ◽  
Tight Reservoir

Fracturing ability is the characteristic used to measure whether the tight reservoir could be effectively fractured and form network in the process of hydraulic fracturing in order to improve the production of oil and gas. Research shows that the more brittle the reservoir is, the weaker the fracture toughness is, the more developed the natural fracture is, the higher the maturity of organic matter is, the lower the organic carbon content is, and the better the fracturing ability is. In addition, factors such as crustal stress, sedimentary environment and internal structure of the reservoir also affect the fracturing ability. The analysis of reservoir fracturing ability plays a key role in the strata selection, multi-stage fracturing design and prediction of oilfield economic benefits.

scholarly journals Characteristics and Genetic Mechanism of Chang Eight Low Permeability and Tight Reservoir of Triassic Yanchang Formation in Central-East Ordos Basin

2022 ◽  
Vol 9 ◽  
Author(s):  
Xingying Wang ◽  
Na Liu ◽  
Junxiang Nan ◽  
Xiaolin Wang ◽  
Dazhong Ren
Keyword(s):  
Ordos Basin ◽  
Physical Property ◽  
Low Permeability ◽  
High Porosity ◽  
X Ray Diffraction ◽  
Yanchang Formation ◽  
Fine Grain ◽  
Tight Reservoir ◽  
Target Layer ◽  
Northern Shaanxi

In this article, the characteristics of Chang 8 reservoir of Triassic Yanchang Formation in northern Shaanxi are studied by using polarizing microscope, field emission scanning electron microscope, image particle size, X-ray diffraction analysis of clay, and constant pressure mercury intrusion. The study shows that the target layer is in a relatively stable and uniform sinking burial period after deposition, and the lithology composition in the area is relatively complex, mainly composed of debris–feldspar sandstone and feldspar sandstone, with the characteristics of fine grain and high content of interstitial material. The porosity of the reservoir is generally between 4% and 12%, with an average of 8.05%. The permeability is generally between 0.03 × 10−3 and 0.5 × 10−3 μm2, with an average of 0.16 × 10−3 μm2. Strong compaction and well-developed cementation of calcareous, siliceous, and authigenic illite are important reasons for the formation of extra-low porosity and extra-low permeability reservoirs. But at the same time, because of the protective effect of chlorite film, some residual intergranular pores are preserved, which makes the some reservoirs with relatively good physical property, forming a local relatively high-porosity and high-permeability section of the “highway.”

Analysis on the heterogeneity of reservoir Chang 6 in D district of Ordos Basin

2021 ◽  
Author(s):  
Guilin Yang ◽  
Zhanli Ren
Keyword(s):  
Oil And Gas ◽  
Ordos Basin ◽  
Great Influence ◽  
Vertical Direction ◽  
Physical Property ◽  
Sedimentary Facies ◽  
Research Area ◽  
Control Factor ◽  
Research Areas ◽  
Sand Body

<p>This study is designed to evaluate the heterogeneity of the Chang 6 reservoirs in Study area, and to analyze the effect of heterogeneity on the distribution of oil. Mainly based on the sedimentary microfacies of the chang 6 reservoir, to calculate the mudstone by using the gamma curve in the logging curve, the separation layer and the interlayer were separated by 2 meters, then analyse the data of intercalation and interlayer by means of sedimentary facies, core and thin etc. We believe that the distribution of the sand in the plane and the heterogeneity of the reservoir is the main control factor of the oil distribution in the area, and it has a good area of oil, which own better properties, and the grain size more coarse; The main control factors of the Chang 6 reservoir in D area is the distribution and physical property of the sand body plane, the better the continuity and physical property of the sand body plane, and the better display of the oil-bearing property of the reservoir; The migration will occur in the vertical direction When the oil and gas meet the thinner interlayer, which will have a great influence on the distribution of oil and gas in the vertical direction; The full extent of oil and gas in the reservoir is controlled by the microscopic heterogeneity of the reservoir. In the study area, the reservoir heterogeneity influence the oil and gas distribution by the physical and lithologic characteristics, the distribution of sand body surface and the distribution of layer interval etc mainly. The study on the relationship between the heterogeneity and reservoir distribution of the Chang 6 reservoirs in the research area can be reasonably evaluated for the favorable areas of oil and gas reservoirs and prediction research areas, so as to guide the development of rational development plans in the next step.</p>

Evidence from the Changing Carbon Isotopic of Kerogen, Oil, and Gas during Hydrous Pyrolysis from Pinghu Formation, the Xihu Sag, East China Sea Basin

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8317
Author(s):  
Qiang Cao ◽  
Jiaren Ye ◽  
Yongchao Lu ◽  
Yang Tian ◽  
Jinshui Liu ◽  
...  
Keyword(s):  
Carbon Isotopes ◽  
Oil And Gas ◽  
Thermal Evolution ◽  
Vitrinite Reflectance ◽  
Heating Time ◽  
Source Rocks ◽  
Evolution Process ◽  
Carbon Isotopic ◽  
Hydrous Pyrolysis ◽  
Increasing Temperature

Semi-open hydrous pyrolysis experiments on coal-measure source rocks in the Xihu Sag were conducted to investigate the carbon isotope evolution of kerogen, bitumen, generated expelled oil, and gases with increasing thermal maturity. Seven corresponding experiments were conducted at 335 °C, 360 °C, 400 °C, 455 °C, 480 °C, 525 °C, and 575 °C, while other experimental factors, such as the heating time and rate, lithostatic and hydrodynamic pressures, and columnar original samples were kept the same. The results show that the simulated temperatures were positive for the measured vitrinite reflectance (Ro), with a correlation coefficient (R2) of 0.9861. With increasing temperatures, lower maturity, maturity, higher maturity, and post-maturity stages occurred at simulated temperatures (Ts) of 335–360 °C, 360–400 °C, 400–480 °C, and 480–575 °C, respectively. The increasing gas hydrocarbons with increasing temperature reflected the higher gas potential. Moreover, the carbon isotopes of kerogen, bitumen, expelled oil, and gases were associated with increased temperatures; among gases, methane was the most sensitive to maturity. Ignoring the intermediate reaction process, the thermal evolution process can be summarized as kerogen0(original) + bitumen0(original)→kerogenr (residual kerogen) + expelled oil (generated) + bitumenn+r (generated + residual) + C2+(generated + residual) + CH4(generated). Among these, bitumen, expelled oil, and C2-5 acted as reactants and products, whereas kerogen and methane were the reactants and products, respectively. Furthermore, the order of the carbon isotopes during the thermal evolution process was identified as: δ13C1 < 13C2-5 < δ13Cexpelled oil < δ13Cbitumen < δ13Ckerogen. Thus, the reaction and production mechanisms of carbon isotopes can be obtained based on their changing degree and yields in kerogen, bitumen, expelled oil, and gases. Furthermore, combining the analysis of the geochemical characteristics of the Pinghu Formation coal–oil-type gas in actual strata with these pyrolysis experiments, it was identified that this area also had substantial development potential. Therefore, this study provides theoretical support and guidance for the formation mechanism and exploration of oil and gas based on changing carbon isotopes.

scholarly journals Geological Characteristics of Unconventional Gas in Coal Measure of Upper Paleozoic Coal Measures in Ordos Basin, China

2016 ◽  
Vol 20 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Jinxian He ◽  
Xiaoli Zhang ◽  
Li Ma ◽  
Hongchen Wu ◽  
Muhammad Ashraf
Keyword(s):  
Shale Gas ◽  
Coalbed Methane ◽  
Oil And Gas ◽  
Ordos Basin ◽  
Tight Sandstone ◽  
Gas Reservoir ◽  
Unconventional Gas ◽  
Geological Characteristics ◽  
Upper Paleozoic ◽  
Coal Measures

<p>There are enormous resources of unconventional gas in coal measures in Ordos Basin. In order to study the geological characteristics of unconventional gas in coal Measures in Ordos Basin, we analyzed and summarized the results of previous studies. Analysis results are found that, the unconventional gas in coal measures is mainly developed in Upper Paleozoic in Eastern Ordos Basin, which including coalbed methane, shale gas and tight sandstone gas. The oil and gas show active in coal, shale and tight sandstone of Upper Paleozoic in Ordos Basin. Coalbed methane reservoir and shale gas reservoir in coal measures belong to “self-generation and self- preservation”, whereas the coal measures tight sandstone gas reservoir belongs to “allogenic and self-preservation”. The forming factors of the three different kinds of gasses reservoir are closely related and uniform. We have the concluded that it will be more scientific and reasonable that the geological reservoir-forming processes of three different kinds of unconventional gas of coal measures are studied as a whole in Ordos Basin, and at a later stage, the research on joint exploration and co-mining for the three types of gasses ought to be carried out.</p>

Tectonic thermal history and its significance on the formation of oil and gas accumulation and mineral deposit in Ordos Basin

2007 ◽  
Vol 50 (S2) ◽  
pp. 27-38 ◽  
Author(s):  
ZhanLi Ren ◽  
Sheng Zhang ◽  
ShengLi Gao ◽  
JunPing Cui ◽  
YuanYuan Xiao ◽  
...  
Keyword(s):  
Thermal History ◽  
Oil And Gas ◽  
Ordos Basin ◽  
Mineral Deposit ◽  
Gas Accumulation

scholarly journals Well Integrity Analysis and Application Based on FTA Method

2016 ◽  
Vol 2 (1) ◽  
pp. 20
Author(s):  
Lili Yan
Keyword(s):  
Risk Factors ◽  
Oil And Gas ◽  
Gas Production ◽  
Control Measures ◽  
Analysis Model ◽  
Oil And Gas Production ◽  
Wellbore Integrity ◽  
Minimum Path ◽  
Failure Risk ◽  
Production Run

<p><em>With the increase of development the well integ</em><em>c</em><em>rity</em><em> </em><em>problem are becoming more and more serious. This article uses the </em><em>F</em><em>ault </em><em>T</em><em>ree </em><em>A</em><em>nalysis (FTA) method for many factors, such as completion, production and operation process, pressure annulus, the cementing quality, the wellhead system and leakage of pipe string.</em><em> </em><em>Many wellbore risk factors to conduct a comprehensive analysis and evaluation. Through the qualitative analysis of wellbore integrity failure risk, determining the level of risk factors and establishing the damage analysis model of the wellbore. According to the selected blocks in Shengli Oilfield example analysis of single wells find out the minimum cut sets, the minimum path sets and structure importance. The results showed that the selected block probability of top event is calculated and it’s 0.9961, and the actual selection conforms to statistics prove that the proposed based on the FTA wellbore damage risk analysis method is feasible, and through quantitative analysis and calculation of basic events of different important degree of parameters.</em></p><p><em>According to these risk factors for prevention of failure risk control measures are put forward, which provides reference for predict wellbore integrity to ensure the safety of oil and gas production run smoothly.</em></p>

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