Lithologic Reservoirs

Da’anzhai member of Lower Jurassic Ziliujing Formation is one of the main oil-bearing reservoirs in Sichuan Basin. However, hydrocarbon exploration and development had little program in half a century because of the lack of knowledge about sedimentary facies and favorable reservoir distribution of Da’anzhai member. Taking Fuling demonstration area in eastern Chongqing as an example, based on the field outcrop measurement, description of drilling cores, thin sections, logging and tectonic-depositional backgrounds, it is considered that Da’anzhai member was deposited by lacustrine carbonates, which could be divided into half-deep to deep lake, lake slope, shallow carbonates, shallow terrigenous clastic lake and shore lake. According to the relationship between sub-micro facies and favorable reservoir development, the facies distribution of three sub-members in Da’anzhai member was compiled respectively. It is believed that the shelly beach edge and lake slope in lower first sub-member and upper second sub-member are the most favorable facies belts for reservoirs. The place above shelly beach edge and lake slope whose buried depth is 1 000～ 3 000 m, and the places where the regional tectonic stress concentrated and fractures developed, are predicted as sweet points for favorable unconventional reservoirs and shale gas reservoirs.

Controlling factors for natural productivity of the second member of Toutunhe Formation in eastern Fukang slope, Junggar Basin

WEN Huaguo，JIA Bin，JIANG Yiqin，JIN Jun，QI Liqi，LI Lulu

2014, Vol.26(2): 9–14 Abstract ( 622 ) PDF (920 KB) ( 431 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2014.02.002

The Toutunhe Formation in eastern Fukang slope is one of the most important exploration layers of lithologic traps for Xinjiang Oilfield Company. Most drilling oil production tests show that the reservoir of the second member of Toutunhe Formation is high yield oil layer. However, if they were reformed by fractures, the oil yield decreased rapidly, even cannot see any oil, which restricts the further exploration in reservoir to some extent. Therefore, it is of importance and urgency to analyze how the fracture can make natural productivity differently. Trough the comprehensive research of drilling, logging, lithology, oil production test and analysis assay data, this paper suggested that: sedimentary microfacies, contents of tuffaceous fragments, relative content of clay minerals, radius of pore throat, reservoir sensitivity and strata pressure are the key factors to control reservoir natural productivity of single well in Fudong slope. High content of illite and smectite mixed layer coating, which weakens the water sensitivity damage, the weak acid and velocity sensitivity, and the average radius of the pore throat, those are the main reasons caused the high productivity in the second member of Toutunhe Formation in eastern Fukang slope. This study will provide important theoretical foundation and production instruction for the further lithologic reservoir exploration of Toutunhe Formation in eastern Fukang slope.

Pore structure characteristics of ultra-low permeability reservoirs of Chang 8 oil reservoir set in Zhenyuan area, Ordos Basin

HU Zuowei， LI Yun， WANG Haihong， HOU Changbing， WANG Changyong， LIU Jiang

2014, Vol.26(2): 15–20 Abstract ( 623 ) PDF (895 KB) ( 559 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2014.02.003

As important basic data for petroleum exploration and development, the characteristics of pore structure increasingly became an indispensable part in the comprehensive evaluation and fine description of the oil and gas reservoirs. Based on the analysis of thin sections, routine physical properties and high-pressure mercury injection, this paper systematically studied the characteristics and comprehensive classification of the pore structure of the ultra-low permeability reservoirs of Chang 8 oil reservoir set in Zhenyuan area, Ordos Basin. The results show that the reservoir sandstones are characterized by feldspar and lithic-rich sandstone types, low-porosity and ultra-low permeability, microfine sizes of pore-throat radius, low capacity of oil production, not high efficiency of oil displacement, poor concentration and uniformity of pore-throat sizes, and strong differentiation between coarse-throats and fine-throats. The pore structure of reservoir sandstones can be divided into five types: good, slightly good, moderate, slightly poor and poor types. The moderate and slightly poor types are the most typical types of the pore structure.

Reservoir characteristics of Xujiahe Formation in Woxinshuang area, Sichuan Basin

WANG Changyong， ZHOU Yi， LI Shilin， LI Shuang， WANG Xiaojuan， ZHENG Rongcai

2014, Vol.26(2): 21–26 Abstract ( 572 ) PDF (1013 KB) ( 347 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2014.02.005

Based on the data of cast slice, SEM, X-ray and normal physical properties, this paper studied the reservoir rock types, diageneses characteristics and reservoir space types of Xujiahe Formation in Woxinshuang area, and analyzed the impact of different diagenese on the reservoir. The result shows that the reservoir lithology is mainly feldspathic litharenite and lithic sandstone with the characteristics of low compositional maturity and medium-high textural maturity, and the provenance is proximal and rapidly accumulated. The sandstone in the study area experienced six diageneses: compaction-pressure solution, cementation, dissolution, replacement, fracturing and authigenic mineral filling. The intensely compaction-pressure solution, calcite cementation and authigenic mineral filling are the main reasons for the degradation of reservoir porosity and permeability and densification. The chlorite rim cementation is the main cause for the preservation of some primary intergranular pores. Dissolution to a certain extent, improves the reservoir performance. Fracturing is more effective for communicating the primary pores and secondary pores, and greatly improves the reservoir permeability. Xujiahe Formation in Woxinshuang area mainly developed fractured-porous type and extra-low porosity and ultra-low permeability reservoir. The reservoir porosity and permeability is poorly correlated in whole, but with the porosity getting higher, the correlation between porosity and permeability is gradually getting better. The Woxinshuang area has favorable conditions for oil and gas accumulation and has a certain exploration and development potential.

Characteristics and preservation mechanism of the Ordovician deep burial karst caves in Tahe area

LEI Chuan， CHEN Honghan， SU Ao， HAN Shumin

2014, Vol.26(2): 27–31 Abstract ( 421 ) PDF (840 KB) ( 623 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2014.02.005

The Ordovician karst caves in Tahe area are characterized deep buried depth, and they are the typical examples to study deep buried caves. The preservation mechanism is not clear. Based on drilling, logging and seismic data, this paper studied the recognition, distribution and fillings of deep burial paleo-karst caves. The result shows that: ①filling degree in highland is higher than that in slope relatively; ②stalactite precipitation associated with collapse is mainly in karst highland; ③clastic rock derived from brine sediment is observed in caves; ④there are several cave systems under the unconformity within 200 m depth. All of these conclusions suggest that the preservation of caves is related to the ground water level. The preservation mechanism of deep buried karst caves may be the hydraulic support of undercurrent.

Reservoir characteristics of Chang 4+5 oil reservoir set in Hujianshan area, Ordos Basin

YANG Yuchuan， LI Fengjie， DAI Tingyong， LI Junwu， YANG Chengjin

2014, Vol.26(2): 32–37 Abstract ( 531 ) PDF (1037 KB) ( 443 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2014.02.006

Based on the analysis of cores, logging, thin sections, scanning electronic microscope, physical properties and mercury injection, this paper discussed the characteristics of sedimentary facies, petrologic features, pore types, physical properties, diagenesis and effects on reservoir. The result shows that the Chang 4+5 oil reservoir set in Hujianshan area is mainly made up of debris-feldspar sandstone and feldspar sandstone, and the main pore types are primary intergranular pore and feldspar dissolved pores. The porosity of the reservoir is 10.86%, and the permeability is 0.56 mD. The reservoir belongs to low porosity, ultra-low permeability reservoir and tight reservoir. The diageneses contain compaction, cementation and dissolution, and the protection from chlorite membrane to primary intergranular pores and dissolution are very constructive to the reservoir. Reservoir of Chang 4+5 oil reservoir set in Hujianshan area can be divided into four types, and typeⅡand type Ⅲ are the main reservoirs.

Sedimentary system of Upper Triassic Xujiahe Formation in Santai-Yanting area, Sichuan Basin

LI Yanan， ZHENG Rongcai， LI Guohui， WANG Xiaojuan， LI Nan， WANG Changyong

2014, Vol.26(2): 38–46 Abstract ( 570 ) PDF (1253 KB) ( 598 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2014.02.007

Based on the core and thin section observation, this paper analyzed the sedimentary system of Xujiahe Formation in Santai-Yanting area from the aspects of petrology, sedimentary structures, paleontology evidence and well logging. It is believed that the sedimentary system includes delta, lake and barrier coast. Among them, delta sedimentary system can be divided into braided river delta and meandering river delta in accordance with the different properties of water runoff into the water basin, furthermore, both of the braided river delta and meandering river delta can be subdivided into three sub-facies, including delta plain, delta front and prodelta. Lake sedimentary system consists of two sub-facies, including lakeshore and shallow lake. Barrier coast sedimentary system mainly consists of tidal flat sub-facies. On this basis, the sedimentary facies models of braided river delta and meandering river delta were established respectively, and the distribution characteristics and space allocating relation of facies and sub-facies in different periods of Xujiahe Formation in the study area were analyzed.

Characteristics and genesis of low permeability reservoir of the first member of Fuyi Formation in Gaoyou Sag

WU Siyi， SIMA Liqiang， YUAN Long， WEN Xinfang

2014, Vol.26(2): 47–53 Abstract ( 511 ) PDF (936 KB) ( 386 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2014.02.008

Based on the data of cores, thin sections and mercury penetration, this paper studied the characteristics of sedimentary facies, petrology, properties and genesis of low permeability reservoir of the first member of Fuyi Formation in Gaoyou Sag by using statistics and correlation method. The results show that the reservoir of the first member of Fuyi Formation formed in subaqueous distributary channel and mouth bar. The reservoir rock is mainly composed of fine grained feldspathic sandstone and feldspathic litharenite, they were poorly sorted, with high content of cements, and both the compositional maturity and textural maturity are low. The reservoir properties are poor, with low porosity and permeability. The pore types are mainly intergranular dissolved pores, followed by intragranular dissolved pores and mold pores. The main reservoir space is secondary pores. Deposition is the fundamental factor for causing the low permeability of the reservoir, and cementation and strong compaction are the main factors for the low permeability. Because of the strong cementation during the early formation of reservoir, relatively weak dissolution in later period and more developmental carbonate cementation during the late diagenetic stage, the characteristics of low permeability reservoir is significant.

Provenance analysis of Middle Jurassic Toutunhe Formation in eastern Fukang slope, Junggar Basin

JIN Jun， WEN Huaguo， XIANG Baoli， QI Liqi， YU Jingwei， LI Lulu

2014, Vol.26(2): 54–58 Abstract ( 530 ) PDF (1189 KB) ( 402 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2014.02.009

Middle Jurassic Toutunhe Formation is the main exploration layer in eastern Fukang slope in Junggar Basin. It is significant to search provenance of reservoir sandbodies for oil and gas exploration and development. This paper systematically analyzed clastic components, type and combination characteristic of heavy minerals, clay minerals partition, sandbody distribution and palaeogeomorphology characteristics, and suggested that middle Jurassic Toutunhe Formation in eastern Fukang slope is a multi-source area deposition. During the sedimentary period of Toutunhe Formation, the north-east and southwest direction provenance both exist. The main sources are volcanic rock area at north-east and the middle to high-grade metamorphic rock area at south, the supply of the provenance from the northeast gradually weakened, and the supply from the south gradually increased, and the Beisantai might provide a small part of provenance.

Sedimentary environment of Fengcheng Formation in Urho area, Junggar Basin

GONG Boshi， WEN Huaguo， LI Conglin， WANG Liang， ZHENG Rongcai， QI Liqi

2014, Vol.26(2): 59–66 Abstract ( 716 ) PDF (1215 KB) ( 766 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2014.02.010

Fengcheng Formation in Urho area of Junggar Basin is an important exploration horizon, and there has been some controversy to its sedimentary environment. This paper explored sedimentary facies mark, facies types and characteristics of Fengcheng Formation by studying rock and mineral sedimentary structures, paleontological and geochemical characteristics. We discovered that the sedimentary environment of Fengcheng Formation is epicontinental offshore lake in deep-water, with blocked anoxic and high salinity. This formation mainly developed the deposition of semi-deep lake facies which can be divided into three sub-facies: hydrothermal pulsatile jet deposition, low-density turbidite sand and ash flow micro-facies. Mineral salts enrichment, high salinity and the horizontal distribution of hydrothermal exhalative sedimentation are obviously controlled by the Permian basement fractures in Wuxia area, and this fractures were presumed as channel for high temperature and high salinity brines hot jet activity. Based on all these studies, we established a hydrothermal exhalative model of the epicontinental offshore lake, mixed with internal and external sedimentary sources of Fengcheng Formation, which could further guide the oil and gas exploration in this area.

Characteristics of shale reservoir of Da’anzhai segment in Fuling area, eastern Chongqing

GU Zhong’an， ZHENG Rongcai， WANG Liang， LIANG Xiwen

2014, Vol.26(2): 67–73 Abstract ( 705 ) PDF (1014 KB) ( 553 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2014.02.011

Based on outcrop observation, drilling core description, physical properties and organic geochemical analysis, this paper studied the shale reservoir characteristics of Da’anzhai segment in Fuling area. The results show that high quality shale reservoirs of Da’anzhai segment are mainly developed in the semi-deep lake-deep lake phase, and the shale rock types include shale, silty shale, （inclusive） bioclastic shale and calcareous shale. Primary pores in shale reservoir disappeared after the diagenesis of compaction, cementation and solution, but the tectonic deformation and fracturing in late Yanshan-Himalayan formed a certain number of cracks. The dissolved pores and holes developed along fractures in the late diagenetic stage constitute important reservoir space and seepage channel space of shale reservoirs, and greatly improved the reservoir properties. The shale reservoir in the study area belongs to typical ultralow porosity and low permeability fractured reservoirs. The reservoir distribution is mainly controlled by sedimentary facies and fracture extent. The thick shale rich in organic matter in semi-deep lake-deep lake phase is favorable reservoir for shale gas resources.

Reservoir characteristics and favorable areas prediction of Jurassic Toutunhe Formation in eastern Fukang slope, Junggar Basin

YAN Xue， ZHENG Rongcai， WEN Huaguo， HUANG Jianliang， JIANG Huan， ZHANG Tao

2014, Vol.26(2): 74–80 Abstract ( 759 ) PDF (1180 KB) ( 313 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2014.03.012

On the basis of slice identification and data statistics, this paper analyzed the lithology characteristics, physical properties and controlling factors of standstone of Toutunhe Formation in eastern Fukang slope, Junggar Basin. The result shows that residual primary intergranular pores developed well and are the effective reservoirs, and the reservoir properties are controlled by sedimentary microfacies and diagenesis. Among them, compaction and cementation are the most important factors. Based on the analysis of relationship between reservoirs and sedimentary faceies, the maps of microfacies and sand body thickness were made by making the three submembers of Toutunhe Formation as the mapping unit, and the distribution of standstone reservoir was predicted and evaluated. The favorable reservoir development area was predicted, and five favorable areas with great potential were identified.

Hydrocarbon accumulation model and main controlling factors of Chang 9 oil reservoir set in Hongjingzi area

WU Yanyan， ZHENG Rongcai， LIANG Xiaowei， LI Fuping， WANG Haihong， HOU Changbing

2014, Vol.26(2): 81–88 Abstract ( 745 ) PDF (1516 KB) ( 490 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2014.02.013

Upper Triassic Yanchang Formation in Ordos Basin is characterized by deep thickness of sedimentation and abundant oil and gas resources, which is one of the most important target zones for oil and gas exploration in the basin. According to the study of geologic background and reservoir characteristics of Chang 9 oil reservoir set in Hongjingzi area, this paper comprehensively analyzed the sedimentary facies, sand body distribution, hydrocarbon migration pathway and paths. The result shows that the Chang 9 oil reservoir set in the study area is typical shallow water delta sedimentary system, with Chang 7 organic material as the main oil sources. The excess fluid pressure is the main driving force for oil and gas generated by Chang 7 hydrocarbon source rocks, which migrated to the top structure of Chang 9 reservoir through the pores and fractures and accumulated. The main controlling factors of hydrocarbon accumulation are oil source, channel and pressure difference.

Short-term base level cycle and reservoir genesis analysis of Chang 8 oil reservoir set in Jiyuan Oilfield

ZHAO Hongbo， TANG Hui， CHENG Gang， WANG Dingfeng， ZHANG Yuqin， ZHANG Xiaodong

2014, Vol.26(2): 89–95 Abstract ( 588 ) PDF (989 KB) ( 365 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2014.02.014

Based on the theory of high resolution sequence stratigraphy, the short-term base level cycle of delta front of Chang 8 oil reservoir set in Jiyuan Oilfield was divided into two types, including non-symmetric short-time cycle and symmetric short-time cycle. The non-symmetric short-time cycle includes upward-deepening and upward-shallowing cycles, and the symmetric short-time cycle includes three kinds of cycle: the ascending half cycle thickness is greater than the descending half cycle thickness, the ascending half cycle thickness is less than the descending half cycle thickness, and the ascending half cycle thickness is approximately equal to the descending half cycle thickness. According to the forming reason, the reservoir sand bodies of Chang 8 oil reservoir set were divided into three categories and six types, and each kind of sand body is obviously controlled by relationship between the accommodate space（A） and sediment supply（S）. In the process of the base level rising, when the A/S<1, mainly formed cutting distributary channel sandbody, while when the A/S>1, mainly formed complete type channel sand body. In the process of base level falling, when the A/S<1, mainly formed isolated type mouth bar sand body, while when A/S>1, mainly formed superposition type mouth bar sand body and far bar sand body. In a complete base level cycle, if there not only kept rising short-term base level of deposition, but also retained the decline phase deposition, so the composite dam sand bodies formed. Chang 8 oil reservoir set in Jiyuan Oilfield belongs to lithologic reservoir. Therefore, further study on shortterm base level change rule and its control effect on sand bodies, forecasting and looking for underwater distributary channel, the superposition type sand dam and mouth bar sand bodies will be the main direction of next exploration.

Application of seismic multi-attribute fusion technique to the reservoir prediction in Beier Depression

WU Haibo， WANG Jiang， LI Junhui

2014, Vol.26(2): 96–101 Abstract ( 639 ) PDF (994 KB) ( 582 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2014.02.015

Seismic attribute analysis is an efficient method for reservoir prediction. However, using only one attribute to predict reservoir leads to multiple-understanding, especially for the fault-depressed basin which has the characteristics of multi-provenances, fast variation of sedimentary facies, multi-period volcanic movements and complicated lithologies. All of these factors result in poor prediction accuracy. Therefore, this paper proposed a seismic multi-attribute fusion technique based on different sedimentary characteristics and separated regions for reservoir prediction. Firstly, according to the sedimentary characteristics, different regions were divided with seismic waveform classification technique. Then, the relation statistics between seismic multi-attribute and reservoir information were carried out and the linear fitting was completed for the further step. At last, the separated fitting results were integrated into the final prediction results for the whole area. For the reservoir prediction of Nantun Formation in Beier Depression, Hailaer Basin, stepwise linear regression was put into use on the basis of sand data from 164 wells and the selected 8 seismic attributes. Its correlation coefficient is only 0.42. With the seismic multi-attribute fusion technique based on sedimentary characteristics and selected regions, the whole area fitting was carried out. Its correlation coefficient reaches 0.89 and the reservoir prediction result fits well with the reservoir development and the sedimentary rules in drilled wells, which indicates that the method can improve the accuracy of reservoir prediction.

Formation mechanism of reservoir cement of Yanchang Formation in Ordos Basin and its geological significance

QI Yalin， YIN Peng， ZHANG Dongyang， LI Jihong， LU Wei， BAI Chang’e

2014, Vol.26(2): 102–107 Abstract ( 552 ) PDF (941 KB) ( 460 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2014.02.016

The reservoir of Triassic Yanchang Formation in Ordos Basin generally is characterized by complex composition, low maturity and roundness of rocks and poor physical properties, and belongs to typical ultra-low porosity and low permeability reservoir. Strong cementation and compaction are the main controlling factors for reservoir densing. X-ray diffraction, scanning electron microscopy and polarizing microscope were applied to analyze the distribution, assemblage types and occurrence of cements. Based on the study of modern lake sedimentology, the relationship between deposition and formation fluid composition and clay, carbonate and siliceous cements was discussed. The results show that the sedimentary fluid controls the distribution of detrital clay minerals in the lake basin, controls the conversion from detrital clay minerals to authigenic clay minerals, and controls the formation and distribution carbonate cements. Formation fluid chemical composition provides material basis and specific diagenetic environment for the cementation. This study provides the basis for the qualitative-semiquantitative prediction of favorable diagenetic facies.

Research and application of wellbore temperature and pressure distribution models for CO₂injection well

ZHANG Yonggang， LUO Yi， LIU Yuelong， LU Yulin， WEI Kaipeng

2014, Vol.26(2): 108–113 Abstract ( 501 ) PDF (873 KB) ( 695 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2014.02.017

In order to explain the gas breakthrough phenomenon in CO2 flooding field test and accurately optimize the injection pressure, a mathematical model to describe the temperature and pressure distribution was established based on the analysis of wellbore heat transmission and the theory of heat transfer. The temperature and pressure distribution for CO2 injection well in Honghe Oilfield was studied, meanwhile the gas breakthrough phenomenon in CO2 flooding field test was explained by the model combined with the actual injection parameter. The results show that the wellbore temperature increases with the increasing of well depth, while keeps lower than the formation temperature, and the wellbore pressure increases linearly approximately with the increasing of well depth. The greater injection pressure leads to that the bottomhole pressure exceeds formation fracture pressure, which is the root cause of gas breakthrough. The theoretical calculation agreed well with the field analysis, which shows that the model had an excellent guiding significance to the field test.

Application of ant colony algorithm to FMI logging segmentation

HE Feng， LIU Ruilin， BAI Yadong， REN Shuangshuang

2014, Vol.26(2): 114–117 Abstract ( 484 ) PDF (776 KB) ( 502 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2014.02.018

This paper described the basic principles of OTSU algorithm, segmented the image that created by simulate function with iterative algorithm, OTSU algorithm, and fuzzy C-means clustering algorithm respectively, and analyzed the reasons. We introduced the basic principles of OTSU algorithm optimized by ant colony, and segmented the FMI logging image of a dissolved cavity reservoir. It is concluded that the OTSU algorithm optimized by ant colony can segment the sub-image of the fracture, emposieu and cave, and the efficiency is improved, which provides a very good foundation for the further quantitative calculation.

Seismic wave reverse-time migration noise analysis within different common imaging point gathers

CHEN Keyang， WU Qingling， FAN Xingcai， CHEN Shumin， LI Lailin， LIU Zhenkuan

2014, Vol.26(2): 118–124 Abstract ( 375 ) PDF (1181 KB) ( 670 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2014.03.019

There are two kinds of common imaging point gathers of the seismic imaging methods, one is the common imaging point offset gather, and the other is common imaging point angle gather. We carried out numerical experiments on the wave field characteristics and difference of two kinds of common imaging point gathers with relation of seismic wave reverse-time migration method. Taking tilted interface model and complex Marmousi model as examples, we composed two kinds of common imaging point gathers, of which the angle gather was made up by using Poynting vector during the reverse-time migration process. The computational results show that both the two kinds of common imaging point gathers are flat with correct velocity model. The noise distribution in the offset gather is not fixed, therefore, so it is not suitable for refining processing afterward, while the migration noise of the angle gather is almost focused on higher angle gather area, and with the branch angle stack processing, the low angle stacking section has the better S/N and the formation information is improved greatly. What’s more, the low frequency noise energy is positive proportional to the reflection coefficient of the interface.

Experiment research on shrink-proof expansion to huff and puff for Kexia heavy oil reservoir in Liudong area

XU Sha， YIN Xiangxiang， LIU Linquan， ZHANG Xin， ZENG Xianyou

2014, Vol.26(2): 125–127 Abstract ( 391 ) PDF (830 KB) ( 551 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2014.02.020

Based on geologic characteristics of Kexia heavy oil reservoir, research on shrink-proof expansion treatment was carried out before huff and puff test. Combined with the results of reservoir sensitivity evaluation, shrink-proof expansion optimization and static performance evaluation, through the research of temperature resistance performance and core flow experiments, this paper determined the anti-swelling cycles, treatment radius and injection program on site. The results show that the favorable anti-swelling agents are 1% HCS-G and 1% EXHCS, they are resistant to high temperature of 230 ℃, and can meet the requirements of steam stimulation; The shrink-proof treatment radius is 3.5 m, the anti-swelling cycle is about 2 years, and shrinkage and expansion cycle is about 1 year. And this paper also designed the injection program on site.

Experimental study on flow properties of air foam in heterogeneous reservoir

HUANG Chunxia， GUO Maolei， YU Huagui， ZHANG Xinchun， ZHANG Guanhua， ZHOU Haicheng

2014, Vol.26(2): 128–132 Abstract ( 394 ) PDF (877 KB) ( 511 )

doi: https://doi.org/10.3969/j.issn.1673-8926.2014.02.021

This paper analyzed the percolation capacity and influencing factors of air foam in single homogeneous cores with different permeabilities and different gas-liquid ratios, and studied the fractional flow rates of parallel cores with different permeability ratios. The experimental results indicate that the larger the gas-liquid ratio is, the larger the flow resistance of foam system is; with the increase of permeability and volume of foam system injected, the resistance factor gets larger, and the blocking ability of foam system increases; the fluid diversion capacity is good while foam flow in heterogeneous reservoir, but with the increase of permeability ratio, the ability of foam system to divert liquid tends to decrease.