Reservoir monitoring with controlled source electromagnetics - a case study from a producing oil field in NW Germany

Author(s):  
Oliver Ritter ◽  
Cedric Patzer ◽  
Kristina Tietze

<p>Injection of fluids (e.g. brines, CO<sub>2</sub>, steam) is commonly used in enhanced oil recovery (EOR) techniques to push crude oil in place towards the production wells. To optimize EOR procedures, it is essential to know the spatial propagation of injected fluids in the subsurface. Electromagnetic monitoring methods are particularly useful to decipher the spatio-temporal distribution of typically resistive oil versus typically conductive fluids.</p><p>We present an overview of soft- and hardware developments, modelling results, and time-lapse field data obtained over five years in an oilfield in NW Germany. CSEM modelling studies showed that conventional surface-based measurements alone do not provide sufficient resolution to changes within a thin (<15 m) reservoir structure located at ~1200 m depth. Combination with sources and/or receivers with vertical components increase sensitivity to such reservoirs very significantly. Based on these findings, a novel horizontal-vertical dipole source using the steel casing of a 1.3 km deep abandoned oil-well was successfully used for current injection in three time-lapse CSEM surveys (2014-2016) across the oilfield. We developed a novel numerical framework to compute the effect of metal casings on CSEM data and included it into our existing modelling and inversion (imaging) software. We also developed a receiver chain to measure the vertical electric field in a shallow observation borehole. Repeatability of the measured data – an essential prerequisite for any monitoring application – was excellent between the repeat surveys despite of high noise levels in an active oil field.</p><p>We also show results of a new numerical framework for 4D (time-lapse) CSEM inversion which allows direct imaging of changes within the 3D electrical conductivity structure of a reservoir. A cascaded inversion scheme in combination with a-priori information (conductivity constraints) and weighting of subdomains of the modelling space shows promising results in solving this mathematically ill-posed problem.</p><p> </p>

Author(s):  
Zonghan Bai ◽  
Qi Kang ◽  
Haihao Wu ◽  
Jing Gong ◽  
Haiyuan Yao

Abstract In the production management of offshore oil field, the production of single well is very important for reservoir understanding and production allocation. Because of the high cost and short life of the conventional underwater flowmeter, the virtual metering technology has gradually become a trend. ESP (electric submersible pump) is a kind of mechanical equipment commonly used in artificial lift oil recovery method, and used in offshore oil field development and production. Based on the characteristics of ESP and real-time production data, this paper establishes the oil well flow inversion model and proposes a fast calculation method to meet the application requirements, which provides a new method for the acquisition of production information of offshore oil fields.


Author(s):  
L.S. Kuleshova ◽  
◽  
I.G. Fattakhov ◽  
Sh.Kh. Sultanov ◽  
R.U. Rabaev ◽  
...  

The paper presents the possibilities of expanding production opportunities in the oil company PJSC Tatneft. For this purpose, the well No.xxx7g with an inclined pilot borehole was drilled at the Bavlinskoye oil field and oriented core samples were taken to study the lithological cross-section and the geological structure of the subsurface horizons. The horizontal wellbore itself is located in the dankovo-lebedyansky horizon, where multi-zone hydraulic fracturing was carried out through ports with packers there. The following methods will increase the share of recoverable oil reserves in the oldest oil-producing Volga region by starting the development of new productive horizons and increase the oil recovery factors for these reservoirs. The methods used in this work will reduce the unit costs of increasing oil production and achieve a cost-effective level of work on wells of this type. The work had its own peculiarities. One of the reasons for the difficulty in interpreting the hydraulic fracturing Minifrac (Meyer software package) was the rather long time of closing fractures in domanic deposits during the registration of pressure drop. In turn, during the minifrac analysis of the Nolte G Time Test graph showed that the fracture did not close, and therefore it is impossible to determine the closing pressure (the pressure gradient of the gap) with reliable accuracy. Note that when interpreting the flow test results, the best match of the experimental and calculated curves is achieved when using the model of a horizontal well operating a homogeneous reservoir. Also, the deterioration of the bottom-hole zone may be associated with a weak opening of the created fractures. Keywords: oil; well; hydraulic fracturing; unconventionals; fracture; core.


2011 ◽  
Vol 347-353 ◽  
pp. 651-658
Author(s):  
Wei Dong Liu ◽  
Su Nan Cong ◽  
Hong Jun Gu ◽  
Zhen Rong Nie

In China, most of undeveloped oil reserves are low and ultra low permeability reservoirs. The total remaining petroleum reserves of CNPC is about 4.07×107m3, and the low and ultra low permeability reserves is 3.16×107m3, So it is important to reasonable develop the oil reserves to keep the petroleum output stable. Under the low permeability layer condition, it is difficult to inject water to the formation, and the output of oil well is very low. The chemical agent can solve the difficulty of injection water and enhance the oil recovery. The relative permeability experiments shows irreducible oil was reduced by the wettability alteration agents, and the mobile oil saturation increased, which enlarging the range of the two phases co-flowing and enhancing oil recovery. As a result with alteration agents, the cross-point relative permeability moves to right, and the core converts to water-wet. In daqing oil field test, the water injection pressure is reduced by 15%, and the term of validity is more than 10 months.


2017 ◽  
pp. 30-36
Author(s):  
R. V. Urvantsev ◽  
S. E. Cheban

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.


Hydrology ◽  
2021 ◽  
Vol 8 (2) ◽  
pp. 57
Author(s):  
Konstantinos Vantas ◽  
Epaminondas Sidiropoulos

The identification and recognition of temporal rainfall patterns is important and useful not only for climatological studies, but mainly for supporting rainfall–runoff modeling and water resources management. Clustering techniques applied to rainfall data provide meaningful ways for producing concise and inclusive pattern classifications. In this paper, a timeseries of rainfall data coming from the Greek National Bank of Hydrological and Meteorological Information are delineated to independent rainstorms and subjected to cluster analysis, in order to identify and extract representative patterns. The computational process is a custom-developed, domain-specific algorithm that produces temporal rainfall patterns using common characteristics from the data via fuzzy clustering in which (a) every storm may belong to more than one cluster, allowing for some equivocation in the data, (b) the number of the clusters is not assumed known a priori but is determined solely from the data and, finally, (c) intra-storm and seasonal temporal distribution patterns are produced. Traditional classification methods include prior empirical knowledge, while the proposed method is fully unsupervised, not presupposing any external elements and giving results superior to the former.


2011 ◽  
Vol 77 (23) ◽  
pp. 8310-8317 ◽  
Author(s):  
Joshua D. Morris ◽  
Jessica L. Hewitt ◽  
Lawrence G. Wolfe ◽  
Nachiket G. Kamatkar ◽  
Sarah M. Chapman ◽  
...  

ABSTRACTMany bacteria spread over surfaces by “swarming” in groups. A problem for scientists who study swarming is the acquisition of statistically significant data that distinguish two observations or detail the temporal patterns and two-dimensional heterogeneities that occur. It is currently difficult to quantify differences between observed swarm phenotypes. Here, we present a method for acquisition of temporal surface motility data using time-lapse fluorescence and bioluminescence imaging. We specifically demonstrate three applications of our technique with the bacteriumPseudomonas aeruginosa. First, we quantify the temporal distribution ofP. aeruginosacells tagged with green fluorescent protein (GFP) and the surfactant rhamnolipid stained with the lipid dye Nile red. Second, we distinguish swarming ofP. aeruginosaandSalmonella entericaserovar Typhimurium in a coswarming experiment. Lastly, we quantify differences in swarming and rhamnolipid production of severalP. aeruginosastrains. While the best swarming strains produced the most rhamnolipid on surfaces, planktonic culture rhamnolipid production did not correlate with surface growth rhamnolipid production.


2016 ◽  
Vol 63 (5) ◽  
pp. 414-420 ◽  
Author(s):  
Wei Yan ◽  
Yong Xiang ◽  
Wenliang Li ◽  
Jingen Deng

Purpose This paper aims to establish the downhole CO2 partial pressure profile calculating method and then to make an economical oil country tubular goods (OCTG) anti-corrosion design. CO2 partial pressure is the most important parameter to the oil and gas corrosion research for these wells which contain sweet gas of CO2. However, till now, there has not been a recognized method for calculating this important value. Especially in oil well, CO2 partial pressure calculation seems more complicated. Based on Dolton partial pressure law and oil gas separation process, CO2 partial pressure profile calculating method in oil well is proposed. A case study was presented according to the new method, and two kinds of corrosion environment were determined. An experimental research was conducted on N80, 3Cr-L80 and 13Cr-L80 material. Based on the test results, 3Cr-L80 was recommended for downhole tubing. Combined with the field application practice, 3Cr-L80 was proved as a safety and economy anti-corrosion tubing material in this oil field. A proper corrosion parameter (mainly refers to CO2 partial pressure and temperature) can ensure a safety and economy downhole tubing anti-corrosion design. Design/methodology/approach Based on Dolton partial pressure law and oil gas separation process, CO2 partial pressure profile calculating method in oil well is proposed. An experimental research was conducted on N80, 3Cr-L80 and 13Cr-L80 material. A field application practice was used. Findings It is necessary to calculate the CO2 partial pressure properly to ensure a safety and economy downhole tubing (or casing) anti-corrosion design. Originality/value The gas and oil separation theory and corrosion theory are combined together to give a useful method in downhole tubing anti-corrosion design method.


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