Putaohua Reservoir Research Articles

Main Factors Controlling Oil-Gas Enrichment Regularities and Accumulation Modes of Putaohua Oil Layer in Chaochang Region

In order to clarify some kinds of geological conditions on the hydrocarbon accumulation process, this paper analyses the main factors controlling oil-gas enrichment regularities of Putaohua oil layer in Chaochang region of Daqing city, which conclude tectonics, sedimentary characteristics, oil source condition and the mutual relationship between of them. The results show that the organic abundance of hydrocarbon source rocks of Qing1 section control oil and gas distribution range. The configuring relationships of oil-source fault and reservoir sand body control oil and gas migration. The configuring relationship of sedimentary micro-facies types and structures controls oil and gas distribution. On the basis of these studies, oil and gas accumulation mode in Putaohua reservoir are summarized in Chaochang region. There are two accumulation models: nearby accumulation mode in northwest and updip accumulation mode in southeast.

Sand Bodies Quantitative Research from the Northern Putaohua Reservoir in Songliao Basin

Based on the data of core, well log, mud log and regional geology, the different type of sandbody was studied quantitatively on the northern Putaohua reservoir in Songliao basin by using the following indicators, they are average thickness, thickness standard deviation, thickness skewness, thickness peakedness, width, width to thickness ratio, length, length to thickness ratio, channel divaricating angle α, channel divaricating normal angle β. And then the sandbody distribution characteristics for different sedimentary face were studied in detail.

Geological Evaluation of Puzzle Reservoirs in Putaohua Reservoir of Weixing Oilfield

Low energy sedimentary environment with weak water power and high salinity of formation water are the main requirements of low-resistance oil layer development. Whereas part of formation penetrated by hydrocarbon migration, which shows larger bend degrees of conductive tunnels in formation and higher resistivity measurement due to the oxidization of the residual crude oil, forms high-resistance water layer. Because of the complexity of accumulation conditions, these two difficult reservoirs exist in Putaohua reservoir of Weixing oilfield widely. Combined with these accumulation regularities, this paper analyzes and summarizes the complex oil and water distribution characteristics, provide recognition means, so as to enhance the logging evaluation precision of these two difficult reservoirs effectively.

Hydrocarbon Origin and Accumulation Model of Putaohua Reservoir in Southern Daqing Placanticline Area

There are great oil and gas exploration prospect in south of Daqing Placanticline, with unclear understanding of source rock and accumulation model, the progress of oil exploration is restricted. To definite the source of oil and gas, according to chromatography data and analysis data, combined with potential of hydrocarbon generation and expulsion, oil-gas migration pathway, the hydrocarbon migration and accumulation model is proposed. It can be concluded that the oil from Putaohua reservoir in the south of Daqing Placanticline area mainly come from K2qn1 source rock locally, while the hydrocarbon sources of K2qn1 in the east and west of the depression makes small contribution to the research area. Migrate in source area is the main hydrocarbon migration and accumulation mode. Re-define the oil source of Putaohua reservoir can help enhance the cognition of the hydrocarbon accumulation condition and accumulation model, in order to direct the research for the accumulation and distribution principle of oil and gas exploration and favorable area prediction in the future.

Analysis on Migration Patterns and the Distribution of Oil-Gas Controlling Factors of Yushulin Area

In order to ascertain the oil and gas migration pattern and its effect on gas/oil distribution of Yushulin area of Sanzhao depression in Northern Songliao Basin, this paper makes a comprehensive analysis of the oil source condition, the source-reservoir-seal assemblage relationship, the oil and gas migration pathway and patterns in Putaohua and Fuyang oil reservoir, summarizes the oil and gas migration patterns of Yushulin area, and analyses different oil and gas migration pattern influence on oil/gas distribution in Yushulin area combined with structural history, hydrocarbon generation and expulsion history, sedimentary microfacies research. The results show that there are mainly four types of oil and gas migration patterns in Yushulin area: indigenous – downward type - vertical migration pattern, indigenous - normal type - vertical migration pattern, proximal - lateral migration pattern and proximal – “U” type - complex migration pattern.

Geological Characteristics of Difficult Reservoirs in Logging Interpretation

Logging measurement is the comprehensive reflection of solid particles and liquids in formation. Low energy sedimentary environment with weak water power and high salinity of formation water are the main requirements of low-resistance oil layer development. Whereas part of formation penetrated by hydrocarbon migration, which shows larger bend degrees of conductive tunnels in formation and higher resistivity measurement due to the oxidization of the residual crude oil, forms high-resistance water layer. Because of the complexity of accumulation conditions, these two difficult reservoirs exist in Putaohua reservoir of Weixing oilfield widely. Using geological characteristic parameters, such as, the distance of wells and scale faults, the formation structural location, resistivity measurement, sedimentary microfacies,thickness and porosity conditions, to evaluate oil and water property of the two difficult reservoirs, good results have been obtained.

Experimental Study on Fluid-Solid Coupling Seepage Flow in Putaohua Reservoir

According to existing fluid-solid coupling models, reasonable range and control technology of pressure depression cone has not be formed in Putaohua reservoir. In this paper, using laboratory experiment, the relationship between rock elastic-plastic deformation, single phase permeability of oil or water and relative permeability curves has been measured and the following important facts has been established: oil well bottom hole pressure which is lower than formation pressure is in a reasonable range during the initial stage of commissioning, and a gently pressure depression cone is formed between the formation and wellbore, that can reduce the permeability loss by compaction settlement and particle migration and return to production in reasonable bottom hole pressure while the water flooding takes effect and thus enhance the oil recovery.

Controlling Factors of Hydrocarbon Accumulation and Optimization of Favorable Blocks for Both Flanks of Putaohua Reservoir in Southern Daqing Placanticline

Putaohua reservoir in south of Daqing Placanticline is rich in oil and gas resources. However, the distribution of oil and gas is so complex and the hydrocarbon accumulation process is still unclear by now. Due to low proven reserves, it is not effective to explore the reserves. By use of the logging interpretation and results of production test and together with analysis of the oil and gas distribution and hydrocarbon accumulation process of Putaohua reservoir in south of Daqing Placanticline, the controlling factors of hydrocarbon accumulation in aspects of oil and gas migration pathway, developmental characteristics of sand, local structure etc are discussed in order to optimize potential blocks. The hydrocarbon of Putaohua reservoir in both flanks in south of Daqing Placanticline is from the local K1qn1 source rock. Hydrocarbon migration mainly depends on vertical movement and is supported by short-distance lateral migration; hydrocarbon accumulation is mainly affected by restrictions of oil source fault and high fault block, so that most of hydrocarbon accumulate in the distributary channel and distal bar of reverse faulting footwall, horst, reverse fault and other high fault blocks where are closely adjacent to the oil source faults.

Comprehensive Evaluation for Putaohua Reservoir in Sanzhao Depression

With complicated geological background, Putaohua reservoir in Sanzhao depression has lots of blocks. Based on its distribution characteristics and evaluation unit division as well as combined with detailed geological characteristics, parameters of developed and undeveloped blocks were optimized and the comprehensive evaluation parameters were determined. In order to make a correct evaluation for oil content, oil distribution, reservoir physical properties and productivity, this paper has adopted comprehensive quantitative evaluation method to do the comprehensive classification and evaluation for developed and undeveloped blocks. It can not only further improve oil recovery of developed blocks but also provide scientific basis for selecting favorable blocks for productivity construction of undeveloped blocks. According to the classification standard, the developed and undeveloped blocks of Putaohua reservoir in Sanzhao depression were separately divided into three types including Class Ⅰ, Ⅱand Ⅲ. In view of the geology and development factors, undeveloped blocks of Class Ⅰ are equivalent to developed blocks of Class Ⅱ; undeveloped blocks of Class Ⅱ are equivalent to developed blocks of Class Ⅲ; undeveloped blocks of Class Ⅲ are the poorest of all.

The Key Geological Factors Influencing on Development of Low-Permeability Sandstone Reservoirs: A Case Study of the Taizhao Area in the Songliao Basin, China

As a typical low-permeability reservoir in the periphery of the Daqing oilfield, the Putaohua reservoir in the Taizhao area has a development characteristic similar to that of the low-permeability sandstone reservoirs in China. Through a synthetic analysis of its geology, logging and dynamic data, sandbody connectivity, small faults, tiny structures, fractures and present-day stress are the geological factors influencing the developmental effects. The connectivity of single sandbody and its anisotropy influence distribution of oil and water and inhomogenous fluid flow. The early water breakthrough in some oil wells was mostly caused by high permeability sandbobies. Sand bodies together with small faults and tiny structures influence the development effect of low-permeability reservoirs throuh impacting on fluid flow. Fractures are the main factor for high-water-cut oil-producing wells. Fractures developed in the paleotectonic stress field. The preservation and permeability of every assemblage of fractures are controlled by the present-day stress field, which also influences cracking and injection. There developed four assemblages of tectonic fractures of high dip angle in the Putaohua reservoir. Affected by the present-day stress field, the E-W fractures that have a good connectivity and permeability and big apertures, are the main seepage orientation. At present, the injection pressure has exceeded the unsealing pressure of E-W fractures. Therefore, water content appears early and goes up quickly, causing a serious water flood in the E-W array of oil wells. However, oil wells of other directions show a poor effect.

Micro-geological causes and macro-geological controlling factors of low-resistivity oil layers in the Puao Oilfield

Low-resistivity oil layers are often missed in logging interpretation because of their resistivity close to or below the resistivity of nearby water layers. Typical low-resistivity oil layers have been found in the past few years in the Putaohua reservoir of the Puao Oilfield in the south of the Daqing placanticline by detailed exploration. Based on a study of micro-geological causes of low-resistivity oil layers, the macro-geological controlling factors were analyzed through comprehensive research of regional depositional background, geological structure, and oil-water relations combined with core, water testing, well logging, and scanning electron microscopy data. The results showed that the formation and distribution of Putaohua low-resistivity oil layers in the Puao Oilfield were controlled by depositional environment, sedimentary facies, diagenesis, motive power of hydrocarbon accumulation, and acidity and alkalinity of reservoir liquid. The low-resistivity oil layers caused by high bound-water saturation were controlled by deposition and diagenesis, those caused by high free-water saturation were controlled by structural amplitude and motive power of hydrocarbon accumulation. Those caused by formation water with high salinity were controlled by the ancient saline water depositional environment and faulted structure and those caused by additional conductivity of shale were controlled by paleoclimate and acidity and alkalinity of reservoir liquid. Consideration of both micro-geological causes and macro-geological controlling factors is important in identifying low-resistivity oil layers.

Field Test of Immiscible CO2 Drive in Daqing Oil Field

Abstract The choice of water alternate carbon dioxide flooding in Sanan was decided based on prefeasibility studies on EOR methods suitable for Putaohua reservoir in Sanan area of Daqing Oil Field. This process was first implemented on one pilot, before any industrial extension. This paper introduces the pilot test, evaluates the effects of CO2 drive and analyzes behavioral characteristics of the test.