Sichuan Key Laboratory of Natural Gas Geology

Chengdu, China

Sichuan Key Laboratory of Natural Gas Geology

Chengdu, China

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Chen S.-J.,Southwest Petroleum University | Chen S.-J.,Sichuan Key Laboratory of Natural Gas Geology | Huang H.,Southwest Petroleum University | Zou X.-L.,Southwest Petroleum University | And 3 more authors.
Natural Gas Geoscience | Year: 2016

Oil accumulation characteristics in low-permeability reservoir of Permian Pingdiquan Formation, Huoshaoshan area were studied through source rock evaluation, oil characteristics and reservoir physical properties analyses. Source rocks of Huobei and Huoshaoshan anticlines were at low-mature stage, and the diversity of reservoir physical properties influenced by sedimentary environment and diagenesis is the key factor to cause oil property differences. The reservoir porosity and permeability of Huobei are low because rock particles are fine and are affected by a strong compaction, and the oil maturity is low. While the reservoir physical properties of Huoshaoshan anticline are relatively high, and the oil maturity is higher than that of Huobei, which shows a property of mixed sources. Through the research above, reservoir-controlling mechanisms were established for tight oil of this area. Huoshaoshan anticline reservoir has the feature of "two stage accumulation" with good reservoir physical property, which accumulates not only local low-mature products, but higher maturity oil from Huodong syncline by the fracture adjustment. Because reservoir in Huobei is tight, the pore space is almost filled with its own low-mature crude oil, which has the characteristics of "self-generation and self-preservation as well as one-period accumulation". © 2016, Science Press. All right reserved.


Lu J.,Southwest Petroleum University | Lu J.,Sichuan Key Laboratory of Natural Gas Geology | Wang L.,Southwest Petroleum University | Chen S.,Southwest Petroleum University | And 10 more authors.
Shiyou Kantan Yu Kaifa/Petroleum Exploration and Development | Year: 2015

Based on comprehensive analysis of the natural gas composition, carbon isotopes and associated oil carbon isotopes, saturated hydrocarbon chromatography, and gas chromatography-mass spectrography, the features and formation mechanisms of natural gas in Santai area, Junggar Basin are studied. The Jurassic natural gas in Santai area is characterized by light ethane carbon isotopes, and the features of associated oil are light carbon isotopes, low Pr/Ph ratio, high C29 and C28 sterane value and low C27 sterane value, which shows that the hydrocarbons were mainly derived from the sapropelic source rock of the Permian Pingdiquan Formation in Fukang sag. The natural gas composition is dominated by methane. The methane carbon isotope value of the natural gas is higher than that of biogenic gas, but it is lower than that of thermogenic gas. Natural gas reservoirs were buried shallowly and always associated with or close to heavy oil which was subjected to serious biodegradation, with occurrence of 25-norhopane. All above indicate that the natural gas in Santai area is typical oil degraded gas by bacteria. Biodegradation was a process of water-hydrocarbon reaction which was affected by the bacteria and thermodynamics. The methane bacteria made use of CO2 and H2 to reduce light carbon isotopes preferentially to generate methane of light carbon isotopic compositions. Biodegraded heavy oil and oil sand are widely distributed in the petroliferous basin, therefore, reservoir oil degradation gas has good exploration prospects. ©, 2015, Shiyou Kantan Yu Kaifa/Petroleum Exploration and Development. All right reserved.


Chen S.,Southwest Petroleum University | Chen S.,Sichuan Key Laboratory of Natural Gas Geology | Lu J.,Southwest Petroleum University | Lu J.,Sichuan Key Laboratory of Natural Gas Geology | And 6 more authors.
Shiyou Xuebao/Acta Petrolei Sinica | Year: 2012

A great exploration breakthrough has been made in the bedrock, the lower part of Oligocene(E3 1) and the Paleocene and Eocene(E1+2) hanging walls of Kunbei fault-terrace belt, where an integrated oilfield with over billion tons of oils has been discovered. With the coexistence and complex distribution of bitumen and crude oils, degrees of crude oil enrichment in this area are different in different well fields, and the exploration effect of the Well Qie-4 area in the middle was relatively poor. The biomarker correlation of source rocks, crude oils and bitumen shows that oils and bitumen in Kunbei have different origins. The crude oil was derived from the upper part of Oligocene(E3 2) mature-stage source rock in Zhahaquan sag, while the bitumen originated from the E3 1 source rock and it has been destroyed and densified during the low evolutionary stage. Based on analyses of crude oil properties, microscopic fluorescence of reservoirs and reservoir inclusions, and combined with evolutionary features of source rocks and their structures, we confirmed that there are two stages of reservoir-forming in Kunbei area, which are the early Miocene(N1) and the reservoir-forming stage after the late Pliocene(N2), respectively. The current oil in the reservoirs mainly came from the second stage. The oil from the first stage mainly migrated laterally along unconformities between bed rocks and overlying sedimentary layers to form reservoirs. Because the paleo-tectonic location of the Qie-6 and Qie-12 well fields was higher than the Qie-4 well field, the scope of reservoir formation in the former was larger while compared with the latter, and its dimension of bitumen formed by later destruction was also huger. The oil from the second stage migrated firstly along the Kunbei faults to hanging walls, then laterally along unconformities and finally along main secondary faults to accumulate in the present traps. Consequently, the main secondary fault is a key factor to control the crude oil migration and accumulation. And the poor exploration effect of the Well Qie-4 area was primarily attributed to its location far away from the east fault of the Qie-16 well and disconnection of the E1+2 reservoir with the Qie-163 well field.


Zhao X.,Southwest Petroleum University | Zhao X.,Sichuan Key Laboratory of Natural Gas Geology | Zhao X.,China University of Petroleum - Beijing | Wu S.,China University of Petroleum - Beijing | And 2 more authors.
Shiyou Xuebao/Acta Petrolei Sinica | Year: 2012

Deepwater turbidity channel reservoirs are usually located in deep sea areas, where a distant spacing pattern for development wells is often allocated due to the cost constraint of prospecting operation. Consequently, the characterization of such underground reservoir architectures of deepwater turbidity channels with the current overlay method for multi-well models used mainly under dense-well pattern conditions usually achieves a poor precision. Therefore, based on drilling and seismic data of a distant well spacing pattern for deepwater turbidity channel reservoirs of the Akpo oilfield in Niger Delta Basin, West Africa, we introduced a novel method to characterize such turbidity channel reservoir architectures in terms of well-to-seismic integration, and discussed its conception and procedures as well. Reservoir architectures of deepwater turbidity channels can be classified into three orders, channel system, channel complex and single channel. Of which the channel complex can be further subdivided into two suborders, channel complex series and channel complex. Various orders of architecture units differ significantly from each other in scale, thus, a well-to-seismic integration of individual oil measures, sublayers and internal sections within sublayers guided by architecture models should be applied to adapting an architecture model of different orders to downhole data (including dynamic data) and seismic information as well as to fulfilling the characterization of reservoir architectures of deepwater turbidity channels. This study will not only have a significantly economic value in efficiently developing deepwater turbidity channel reservoirs but also be of guiding significance for integrating well data with seismic data to characterize architecture elements.


Chen S.,Southwest Petroleum University | Chen S.,Sichuan Key Laboratory of Natural Gas Geology | Zhang H.,Southwest Petroleum University | Lu J.,Southwest Petroleum University | And 11 more authors.
Petroleum Exploration and Development | Year: 2015

Based on observation of cores and casting thin sections, reservoir fluorescence, hydrocarbon geochemical characteristics and oil production test data, the factors controlling the tight oil accumulation and high production in the Da'anzhai Member in the Jurassic Ziliujing Formation in central Sichuan Basin are studied. The shelly limestone, muddy shell limestone and tight limestone are all oil-bearing in the Da'anzhai Member. The dissolved pores and fractures in shelly limestone and the matrix pores (microfractures, intercrystal pores) in tight limestone are all oil-bearing in large area, which is the reason why oil wells can keep low production for a long period of time. On the basis of the extensive oil-bearing, natural gas from the Upper Triassic Xujiahe Formation provided the major power for oil migration and accumulation in the Da'anzhai low amplitude, water-free tight limestone reservoirs, driving the dispersed oil from the matrix pores into an accumulation, so the oil is more enriched in the western structures of central Sichuan Basin where oil wells are higher in gas-oil ratio. In contrast, in the east of central Sichuan, the Huayingshan major faults generally cut through Da'anzhai Member, allowing gas to migrate to the formations above Da'anzhai Member along fractures to accumulate or dissipate, without gas as driving force, as a result, the oil is less enriched than that in the west part of central Sichuan. © 2015 Research Institute of Petroleum Exploration & Development, PetroChina.


Chen S.,Southwest Petroleum University | Chen S.,Sichuan Key Laboratory of Natural Gas Geology | Gao X.,Southwest Petroleum University | Wang L.,Southwest Petroleum University | And 7 more authors.
Petroleum Exploration and Development | Year: 2014

By comprehensively analyzing oil-bearing and non-oil-bearing tight sandstone reservoir properties, pore structure characteristics and contact between source rock and reservoir, reservoir fluorescent photographs of typical wells of Jurassic Lianggaoshan Formation in central Sichuan Basin, the research tries to find out factors controlling the oiliness of the Jurassic Lianggaoshan tight sandstone reservoir. The oiliness of the Jurassic Lianggaoshan tight sandstone reservoir in central Sichuan Basin is controlled by the following factors: (1) The migration pathway between the source rock and reservoir: when there exist sandstone and mudstone transition zones with high mud content and poor physical property between the source rock and reservoir, without fracture connection, it is difficult for oil and gas to migrate into the overlying reservoir; (2) The reservoir physical property: if the reservoir contacts directly with source rock and has good physical properties, oil and gas can migrate and accumulate directly in the reservoir. (3) Development degree of fractures: when the reservoir physical properties are poor, rich fractures can improve porosity and permeability of the reservoir, oil and gas can still migrate and accumulate in the reservoir; if the reservoir physical property is poor and no fractures developed, oil and gas are difficult to migrate and accumulate in the reservoir. Based on the sedimentary and reservoir characteristics of Jurassic Lianggaoshan Formation in central Sichuan Basin and the distribution of source rocks, Yingshan-Guang'an and Hechuan-Baimiao-Luodu two favorable exploration zones are selected. © 2014 Research Institute of Petroleum Exploration & Development, PetroChina.


Yan J.-P.,Sichuan Key Laboratory of Natural Gas Geology | Yan J.-P.,Southwest Petroleum University | Wen D.-N.,Southwest Petroleum University | Li Z.-Z.,Sinopec | And 3 more authors.
Natural Gas Geoscience | Year: 2015

Low permeability is a salient feature of Es3 reservoirs in the southern slope of Dongying Sag. And the complex pore structure makes it difficult to unify electrical parameters, which brings some difficulties to evaluating reservoir saturation. The pore structures of low permeability sandstone reservoir in Es3 are analyzed, based on core physical properties, casting thin sections and mercury injection data. It is divided into 3 categories and 5 subcategories, combined with rock electricity experiment data to extract rock-electrical parameters “a” and “m” from different pore structure of reservoir in Es3. Along with the wellbore profile, using well logging response characteristics, a comprehensive method is established. It can identify different pore structure types and determine the rock-electrical parameters of different pore structure types. As a basis for further saturation calculation, it effectively improved the accuracy of low permeability sandstone reservoir saturation interpretation. © 2015, Science Press. All right reserved.


Chen S.-J.,Southwest Petroleum University | Chen S.-J.,Sichuan Key Laboratory of Natural Gas Geology | Wang L.,Southwest Petroleum University | Yao Y.-T.,Southwest Petroleum University | And 6 more authors.
Natural Gas Geoscience | Year: 2015

Wells with high gas oil ratio of Jurassic Da'anzhai Formation are widely distributed in the western part of Central Sichuan Basin, where oil wells are also mainly distributed. Study on natural gas origin is helpful to understand the hydrocarbon enrichment regularity in Jurassic Da'anzhai Formation, central Sichuan Basin. Based on the comparison of natural gas compositions and carbon isotopes between Da'anzhai Formation and Upper Triassic Xujiahe Formation, combined with the characteristics of condensate light hydrocarbons of Da'anzhai Formation, it suggests that gas of high oil gas ratio wells is characterized by humic or near-humic origin which is similar to the gas from Xujiahe Formation. The mixture of sapropelic gas from Da'anzhai Formation with humic gas from Xujiahe Formation leads to high gas oil ratio wells in Da'anzhai Formation, western part of Central Sichuan Basin. On one hand, when the faults crossed the Da'anzhai Formation, light hydrocarbons in the primitive reservoir of Da'anzhai dissolved in the gas injection from underlying Xujiahe Formation and migrated to the upper formation. On the other hand the injected gas caused deasphalting to fill the reservoir's pores and fractures, which leads to poor exploration effects near faults. ©, 2015, Science Press. All right reserved.


Yan J.-P.,Sichuan Key Laboratory of Natural Gas Geology | Yan J.-P.,Southwest Petroleum University | Wen D.-N.,Southwest Petroleum University | Li Z.-Z.,Southwest Petroleum University | And 4 more authors.
Chinese Journal of Geophysics (Acta Geophysica Sinica) | Year: 2016

The low permeability sandstone reservoir, which has been an important target of exploration and development for oil and gas increase in reserves and production, is difficult to identify accurately because of the complex pore structure. The pore structure classification of complex low permeability sandstone and the investigation of the petrol-physical diversity of rock samples in different types are helpful to determine the reservoir type and the fluid properties of low permeability sandstone reservoir. After the analysis of the pore structure based on physical properties data, mercury injection, nuclear magnetic resonance data and the considering of the properties division level standard of clastic reservoir (SY/T 6285-2011), the low permeability sandstone of Es4 in the southern slope of the Dongying sag is divided into three types of pore structures. And the diversity of every type in mercury injection, nuclear magnetic resonance (saturated T2 spectrum, centrifuged T2 spectrum and free-fluid T2 spectrum), the pore throat distribution, the porosity and permeability are discussed. Many results indicate that the T2 spectrum and capillary pressure curves could reflect the pore throat distribution in some degree. Meanwhile the T2 spectrum could be used to evaluate the pseudo capillary pressure curve to get the pore throat radius. However, it's large of the deviation between the pore throat distribution from this way and mercury injection because of the membrane bound-water affect. In fact, the free-fluid T2 spectrum and the pore throat distribution of mercury injection correspond much better. Based on this feature, after the comparing of the free-fluid T2 spectrum and the pore throat distribution of mercury injection in different pore structure types, the conversion relationship is established between the relaxation time and the pore throat distribution of mercury injection in different pore structure types and the pore size scale (large scale-linear relationship; small scale-piecewise exponential function). Meanwhile, the electrical standards and identification methods of every pore structure are also established based on the cross-plot analysis of logging response. Therefore, the pore structure could be identified along the well hole, and then the pore throat distribution of different pore structure can be quantitatively calculated by using nuclear magnetic resonance logging data. Not only the segment of pseudo-capillary curve's building is avoided, but also the identification of pore structure could be more effective. Overall, this research provides a direct evidence to recognize the low permeability reservoir and sheds a new light on quantitative reconstruction of microscopic pore structure with well logging. © 2016, Science Press. All right reserved.

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