Liaohe Depression Research Articles

Study on the Basic Characteristics of the Geothermal Temperature Field in the Middle and Deep Layers of the Liaohe Depression

Study on the Basic Characteristics of the Geothermal Temperature Field in the Middle and Deep Layers of the Liaohe Depression

Lithological and physical characteristics and their controlling factors of the Archaean metamorphic rocks: A case study of the Damintun Sag, in Liaohe depression of Bohai Bay Basin, China

The metamorphic rock hydrocarbon reservoir, located in Damintun Sag, Liaohe Basin, China, is one of the earlies reservoirs in buried hill exploration and development. An Archean metamorphic rock with deep burial adjacent to the Rongshengpu depression in the south of the sag still has great potential for the oil and gas exploration. Based on cores, logs, seismic data, and laboratory measurements, the lithology types, spatial distribution, physical characteristics, lithology controlling factors， and physical properties of the Archean metamorphic buried hill reservoirs are systematically analyzed. The result shows that the lithology of Archean metamorphic rocks in this area can be divided into three types and 19 species, including migmatitic granite, migmatitic gneiss, migmatite, plagioclase amphibole gneiss, leptite, amphibolite, granulite, inhomogeneous basic dike rock, and cataclasite,etc. The metamorphic rock reservoirs in the study area are composed of multiple lithological sections vertically (from bottom to top), ranging from migmatitic granite to gneiss. granulite. and top weathering crust, different types of lithological assemblages can appear. The characteristics of lithology in vertical are comparable, and the lithology is also partitioned from the horizontal view. Metamorphic rock reservoirs can be divided into two types according to their location and physical properties: weathering crust type and inner-type. The former is dominated by dissolved pores and dissolved fractures, while the latter is controlled mainly by structural fractures. Weathering & leaching, rock and mineral components, and tectonic movement control the Archean metamorphic rock reservoirs. Weathering crust reservoirs are controlled mainly by weathering & leaching and lithology types, while the inner reservoirs are controlled by tectono-genesis, lithological assemblage and petrological evolution. Metamorphic rocks with high content of felsic minerals in inner-type reservoirs are likely to be cracked; the storage properties of rocks depend on the content variety of dark minerals, and the appropriate amount of dark minerals is conducive to the formation of fractures. Clastic migmatitic granite and migmatitic gneiss, leptite, and some dynamic metamorphic rocks could be regarded as high-quality reservoirs.

Difference of hydrocarbon generation between argillaceous dolomite and mudstone and its influence on oil source: A case study of the Es4 in the Leijia area, Liaohe depression

Argillaceous dolomite and mudstone are two terrestrial source rocks that commonly occur together, and the difference in hydrocarbon generation characteristics determines the oil accumulation mode. The fourth member of the Shahejie Formation (Es4) in the Leijia area was used as an example to study the hydrocarbon generation characteristics and the overpressure difference caused by oil generation between argillaceous dolomite and mudstone, using hydrocarbon generation kinetics. Furthermore, the source of oil in the argillaceous dolomite reservoir was analyzed by combining the biomarker characteristics. The results indicated that the hydrocarbon generation characteristics of argillaceous dolomite and mudstone are significantly different. Mudstone starts hydrocarbon generation later and has a shorter hydrocarbon generation cycle, while argillaceous dolomite starts hydrocarbon generation earlier and has a longer hydrocarbon generation period. Due to the difference in hydrocarbon generation characteristics, when the burial depth is below 3000 m (EasyRo <0.85%), the oil-generation overpressure in the mudstone is smaller than that in argillaceous dolomite, and the tight oil in the argillaceous dolomite reservoir is mainly generated by and stored in the argillaceous dolomite itself. However, when the burial depth exceeds 3000 m (EasyRo >0.85%), the oil-generation overpressure in the mudstone surpasses that in argillaceous dolomite, and the tight oil has mixed source characteristics. The biomarker characteristics observed in extracts and crude oil confirm the above view. Whether tight oil exploration in argillaceous dolomite reservoir requires attention to the hydrocarbon supply capacity of adjacent mudstone depends on the maturity of organic matter.

Application of geophysical techniques based on multi-attribute inversion in predicting high-quality source rocks

Total organic carbon (TOC) content is an important indicator for evaluating the quality of source rocks. Conventional laboratory analysis and testing, single well interpretation, and other methods are limited by sample data or the number of well locations, and cannot comprehensively and accurately predict the planar distribution of TOC content in source rocks. Based on this, a method for predicting TOC content using seismic inversion with multiple attributes is proposed. The basis for applying seismic attributes to study TOC of source rocks is the inherent relationship between seismic and logging data. By using logging data to calculate TOC, the correlation between seismic attributes of well side seismic traces and logging is established, and seismic attributes are converted into TOC of source rocks. The results show that the TOC content in the third section of the Shahejie Formation of the Liaohe Depression is relatively high, distributed in the range of 1% to 5%. The trend of planar variation is manifested as a gradual decrease from the centre of the depression to both sides, and the centre is concentrated in the Panshan and Qingshui area. The overall prediction effect is good, proving the strong feasibility of this method.

Deformation mechanism and hydrocarbon significance of Eocene organic-rich fine-grained soft sediments in the Leijia Region, Liaohe Depression

Deformation mechanism and hydrocarbon significance of Eocene organic-rich fine-grained soft sediments in the Leijia Region, Liaohe Depression

Application of Random Forest method in oil and water layer identification of logging data: a case study of the Liaohe depression

Accurate identification of oil and water layers is the basis of qualitative evaluation of reservoir fluid properties or industrial value and selection of testing layers of the well. The traditional oil and water layer identification is mainly based on the extensive use of the well’s logging and logging data, which is inefficient and easy to leak interpretation or misinterpretation for those reservoirs with complex geological conditions. In this paper, the random forest method of machine learning is used to select the lithology, porosity, permeability, movable fluid, oil saturation, S0, S1, S2, Tmax of rock as characteristics; smote oversampling is used to expand the sample, and the packet estimation is used to establish the oil and water layer identification model. This method is simple and easy to use, not prone to severe overfitting, and can find the potential rules in the data. The classification performance is excellent, and the accuracy rate can reach more than 89.9%, which solves the problem of low accuracy in oil-water layer identification in the past.

Geochemical heterogeneity, origin and secondary alteration of natural gas inside and outside buried hills of Xinglongtai area, West Sag, Liaohe Depression, Bohai Bay Basin

This work systematically studied the significant geochemical heterogeneity of natural gases inside and outside the buried hills of the Xinglongtai area, West Sag, Liaohe Depression, Bohai Bay Basin. The gases inside the buried hills are thermogenic, whereas those outside the buried hills are dominated by secondary microbial gases, with a biodegraded thermogenic gas contribution. The humic- and sapropelic-type gases are primarily derived from the Es 3 and Es 4 source rocks, respectively. The gases inside the buried hills are primarily derived from the Es 3 source rocks, and decreasing δ 13 C 1 and C 1 /C 1-5 ratio towards the northeast are a result of the decreasing maturity of the adjacent Es 3 source rocks. The different geochemical characteristics of the gases outside the buried hills results from the relative contribution of secondary microbial and thermogenic gases, the maturity and organic type of the thermogenic gas, and biodegradation. In the Xinglongtai area, secondary microbial gas is an important shallow Paleogene exploration target, and the natural gas inside the buried hills is primarily enriched near the Es 3 source rocks. The findings and methods of this work are significant for studies on the origin and accumulation of natural gas inside and outside the buried hills in other petroliferous sags of the Bohai Bay Basin. Considering the geological and geochemical significance of the spatial geochemical heterogeneity of natural gas is essential for researching the origin and accumulation mechanism of gas and oil in complex exploration areas with multiple source rocks. • Sapropelic- and humic-type gases are from Es 4 and Es 3 source rocks, respectively. • Decreasing δ 13 C 1 and C 1 /C 1-5 inside buried hills results from varied maturities . • iC 4 /C 2 , 13 C 1 and 13 C 2 reveal mixing of secondary microbial and thermogenic gas.

Origin, accumulation and secondary alteration of natural gas around Qingshui Sub-sag, Liaohe Depression, China: Insights from molecular and isotopic composition

Fourteen gases and their associated oils were collected at the surface from production wells in the Shahejie Formation, Dongying Formation, and Archean in six zones around the Qingshui Sub-sag of the Liaohe Depression, Bohai Bay Basin. The molecular compositions and carbon and hydrogen isotopic compositions of natural gas were measured. The origin, migration, accumulation, and secondary alteration of natural gas were studied based on the lateral and vertical comparison of natural gas geochemical characteristics. The natural gases include humic-type (δ13C2 > −29.0‰, δ13C1 > −43.0‰), sapropelic-type (δ13C2 < −29.0‰, δ13C1 > −43.0‰), and secondary microbial (δ13C1 of −48.5‰, C1/(C2+C3) of 46.3, δ13CO2 of −1.5‰) gases. The humic-type and sapropelic-type gases were derived from the source rocks in the third and fourth members of the Shahejie Formation, respectively. The humic-type gases dominate. The biodegradation level of natural gas in the study area varies, and biodegraded gases are characterized by high Δ13C(C3–C2), low C3/C2, and low C3/iC4 and are associated with biodegraded oils. The vertical migration of natural gas in the west and east of the Qingshui Sub-sag is limited. There are good additional exploration prospects for humic-type gas, derived from high-maturity source rocks of the third member of the Shahejie Formation in the deep layers (depth >4.5 km) of the Qingshui Sub-sag. Secondary microbial gas is a potential exploration target in the shallow layers (depth <2.5 km).

Production Logging, Openhole-Log Interpretation Help Discover New Oil Reserves

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper OTC 30644, “Discovery of New Oil Reserves by Combining Production Logging With Openhole-Log Interpretation in Low-Resistivity Pay,” by Xinlei Shi, Peichun Wang, and Jinxiu Xu, CNOOC, et al., prepared for the 2020 Offshore Technology Conference, originally scheduled to be held in Houston, 4–7 May. The paper has not been peer reviewed. Copyright 2020 Offshore Technology Conference. Reproduced by permission. In this paper, the authors examine the evaluation of a low-resistivity-pay siliciclastic reservoir in Bohai Bay, China. A significant amount of irreducible water is bound to the rock surface, dramatically lowering the resistivity of the pay zone. The authors explore a theory that the low resistivity is caused by bound water trapped in clay minerals, using production logging to provide the ground truth of reservoir fluids in the low-resistivity pay and improve the petrophysics model. With the improved model, production predictions were made for offset wells based on their openhole logs. The production histories of these wells are highly consistent with the authors’ predictions. Introduction LD oil field is in the eastern Bohai Sea, China, structurally in the transition zone between the Liaohe depression of the Tanlu fault and the Bozhong depression and at the dip end of the Bodong low uplift extending to the northeast. The main oil reservoirs are developed in the Guantao and Dongying formations. Reservoir depth ranges from approximately 1022.1 to 2585.8 m. Reservoir lithology is mainly sandstone and gravelly sandstone. The porosity distribution range of the Guantao formation is 24 to 30%. Permeability distribution range is 333 to 3333 md belonging to medium-high-porosity and - permeability reservoirs. The porosity distribution range of the Dongying formation is from 6 to 12%, and the permeability distribution range is from 3 to 33 md belonging to medium-low- porosity and -permeability reservoirs.

Quantitative evaluation methods of tight reservoirs based on multi-feature fusion: A case study of the fourth member of Shahejie Formation in Liaohe Depression

The formation and development of tight oil reservoirs in the fourth member of the Shahejie Formation (Es4) in the Leijia region of the western sag of the Liaohe Depression are highly heterogeneous and influenced by several factors. The relationship between these variables is extremely complex. In order to avoid deviations caused by single factors and logging data for less drilling when regional tight oil reservoirs have been assessed, quantitative evaluation methods for tight reservoirs based on multi-feature fusion have been proposed. Hand-drawn maps of brittleness index, carbonate rocks thickness, fracture density, mean permeability, and mean porosity are gridded by the Kriging model accompanied by k-means clustering to determine the types of reservoir and classification interval. After that, two quantitative evaluation methods, the overlapping favourability method (OFM) and the principal component analysis (PCA), were used to analyze the five influence factors of the tight oil reservoirs. Finally, reservoir evaluation maps were generated by dividing the interval values into classes. Results show that the weights of the five variables calculated by the hybrid weight method (HWM) are 0.1100,0.4929, 0.0803, 0.2889, and 0.0279. The reservoirs in the study area are finally divided into four types, with the best reservoir types primarily distributed in well areas, such as A99, A82, A91, A78, and A9. At the same time, the main controlling factors for the creation of the reservoir have been analyzed; however, the thickness of carbonate rock in the study area plays a decisive role in the development of high-quality reservoirs. The brittleness index and fracture density can significantly improve the efficiency of the reservoir. Quantitative approaches can effectively and scientifically evaluate the tight reservoirs, which can be widely used.

Accumulation conditions and key exploration & development technologies of heavy oil in Huanxiling oilfield in Liaohe depression, Bohai Bay Basin

The Huanxiling oilfield is located in the southern part of the western slope of the western sag in Liaohe depression. The west side of this oilfield is connected with two sets of high-quality source rocks of Member 3 and Member 4 of Shahejie Formation in Qingshui sub-sag. The oilfield has fan delta, turbidite fan and other types of reservoirs, it also has cap rock of thick mudstone in Member 3 and Member 4 of Shahejie Formation. Under background of the warped basement, the warped fault-block draped compound trap zone are developed, which includes nine types of trap. From perspective of hydrocarbon accumulation, the slope of this area has always been the target area for hydrocarbon migration and accumulation. Inclusion analysis shows that there are multiple stages of hydrocarbon charging in this area, and the main reservoir forming period is the sedimentary period of Member 3 of Shahejie Formation and the sedimentary period of Dongying Formation. High-quality source-reservoir-cap conditions ensure large-scale hydrocarbon accumulation in this area. Based on the theory of compound hydrocarbon accumulation, many types of oil and gas reservoirs, including light oil reservoir and heavy oil reservoir, have been found in this area, with total reserves of 500 million tons. In view of the oilfield characterized by large reservoir burial span, multiple oil-bearing strata, strong heterogeneity and various types of oils, multi-batch seismic data processing & interpretation technology and thin reservoir inversion technology based on geological model are established in the preliminary exploration period, steam-flooding physical simulation technology of heavy oil, oil-reservoir fine description technology of thermal recovery heavy oil, steam huff and puff technology of ordinary heavy oil and steam-flooding technology of mid-deep buried heavy oil are developed in the development period, and technologies such as separate-layer injection, selective injection, sand control and lifting of heavy oil are matched and improved. These technology series provides technical guarantee for efficient exploration and development of Huanxiling oilfield.

Comprehensive evaluation and exploration practice of Sha 4 lacustrine shale oil in Damintun sag, Liaohe depression

Comprehensive evaluation and exploration practice of Sha 4 lacustrine shale oil in Damintun sag, Liaohe depression

Composition effects on pore structure of transitional shale: A case study of the upper Carboniferous Taiyuan Formation in the eastern uplift of the Liaohe Depression, China

Transitional shale is very different from marine shale with respect to mineral composition and pore structure. Insights into the effects of rock composition on pore structure can aid understanding of the storage and migration mechanisms of shale gas in a reservoir. To investigate the compositional effects on pore structure, a combination of geochemical and petrophysical experiments were conducted on four bulk shale samples and their corresponding extracted organic matter (OM) and clay mineral samples. The experimental results show that the removal of OM using H2O2 during clay mineral extraction oxidizes and removes pyrite and siderite from the samples while other inorganic phases remain unaffected. OM hosted more abundant micropores compared with clay minerals, while mesopores and fine-macropores are dominant in clay minerals. Effects of the OM and clay minerals on pore volume and surface area are quantitatively evaluated on the basis of weight-normalized pore-size distribution (PSD) curves of extracted OM and clay mineral samples. In terms of the CO2 adsorption, contribution from OM and clay minerals to micropore volume (MIV) are 19.43–32.92% and 18.75–39.05% respectively, and to micropore surface area (MIS) are 19.30–32.28% and 16.42–35.72%. Other minerals (other than organic matter and clay minerals) account for 34.29–48.93% of the MIV and 39.75–52.98% of the MIS. N2 adsorption results reveal that the pore volume and surface area are mainly attributable to the clay minerals, providing 54.37–80.75% of the BJH pore volume (BJHV) (average 65.83%) and 70.68–87.04% of the BET surface area (BETS) (average 78.71%). The primary medium for pore development in marine shale is OM, whereas pores in the transitional shale are mostly found in the clay and other inorganic minerals. Therefore, the hydraulic fracturing design and drilling-related operations involved in the exploitation of transitional shale gas should be appropriately adjusted and improved in order to accommodate intrinsic characteristics of the transitional shale gas reservoir.

New understanding of Mesozoic geology and new discovery of oil and gas in Xinglongtai buried hill, Liaohe depression

New understanding of Mesozoic geology and new discovery of oil and gas in Xinglongtai buried hill, Liaohe depression

Application of overlapping probability method in carbonate reservoir evaluation: a case study on 4 th member of Shahejie Formation in Gaosheng area of western sag, Liaohe depression

Application of overlapping probability method in carbonate reservoir evaluation: a case study on 4 th member of Shahejie Formation in Gaosheng area of western sag, Liaohe depression

Geological Evaluation of Preferential Steamflooding Pathways in Heavy Oil Reservoirs in Block Qi40 of Liaohe Depression

Geological Evaluation of Preferential Steamflooding Pathways in Heavy Oil Reservoirs in Block Qi40 of Liaohe Depression

Fine exploration practice and enlightenment of middle and shallow reservoirs in Liaohe depression

Fine exploration practice and enlightenment of middle and shallow reservoirs in Liaohe depression

Shale oil and gas generating characteristics of lacustrine Shahejie formation in eastern sag of Liaohe depression, Northeast China

As a known source of commercial oil and gas in the Liaohe depression, the lacustrine Shahejie Shale formation is a target of unconventional petroleum exploration. Characterising hydrocarbon generating and phase behaviour evolution is considered to be an empirical method or a prerequisite in resource evaluation and economic estimation. However, this is poorly understood on the lacustrine Shahejie Shale formation as a candidate for shale oil/gas play. According to kinetics of hydrocarbon generation, in this study the source rock potential and physical properties of generated fluids are analysed. Furthermore, this research provides a case study relating experimental data obtained on samples with modelling results. Samples from different wells that represent a range of maturation levels and lithofacies are discussed in this paper. [Received: April 7, 2017; Accepted: September 9, 2017]

Large-scale removal of lithosphere underneath the North China Craton in the Early Cretaceous: Geochemical constraints from volcanic lavas in the Bohai Bay Basin

Cratons are generally considered as the most stable tectonic units on the Earth. Rare magmatism, seismic activity, and intracrustal ductile deformation occur in them. However, several cratons experienced entirely different fates, including the North China Craton (NCC), and were subsequently destroyed. Geodynamic mechanisms and timing of the cratonic destruction are strongly debated. In this paper, we investigate a suite of Mesozoic intermediate to felsic volcanic rocks which are collected from boreholes in the Liaohe Depression of the Bohai Bay Basin the eastern NCC. These volcanic rocks have Precambrian basement-like Sr–Nd isotopic characteristics, consistent with derivation from the lower continental crust underneath the NCC. The Late Jurassic (~165Ma) intermediate volcanic rocks don't exhibit markedly negative Eu anomalies, which require a source beyond the plagioclase stability field. And the low heavy rare earth elements (HREEs) contents of these samples indicate that their source has garnet as residue. The Early Cretaceous (~122Ma) felsic volcanic rocks are depleted in HREEs but with remarkable Eu anomalies, suggesting that their source have both garnet and plagioclase. The crust thicknesses, estimated from the geochemistry of the intermediate and felsic rocks, are ≥50km at ~165Ma and 30–50km at ~122Ma, respectively. The crustal thinning is attributed to lithospheric delamination beneath the NCC. Our results combined with previous studies imply that the large-scale lithospheric removal occurred in the Early Cretaceous, between 140 and 120Ma.

Pore Distribution Characteristics of the Igneous Reservoirs in the Eastern Sag of the Liaohe Depression

AbstractIn the Es