scholarly journals Clay Minerals from the Perspective of Oil and Gas Exploration

Author(s):  
Shu Jiang
2021 ◽  
Vol 1-2 (183-184) ◽  
pp. 110-129
Author(s):  
Аnatoliy Galamay ◽  
Andriy Poberezhskyy ◽  
Sofiya Hryniv ◽  
Serhiy Vovnyuk ◽  
Dariya Sydor ◽  
...  

Studies of evaporites provide new data to characterize the seawater chemistry in the Early Paleozoic and Middle Mesozoic. In particular, we studied the fluid inclusions in halite from Ordovician (China) and Cretaceous (Laos) evaporites. The corresponding sections on the plot of Ca/SO4 oscillations curve in the Phanerozoic seawater are updated. The calcium content in seawater concentrated to halite precipitation stage was 45.6 mol %, 485 million years ago and 24.3 mol % 112.2–93.5 million years ago. By analyzing the previously published and new factual material, it is established that in Permian evaporites the sulfur isotopic composition is inversely correlated with the sulfate ion content in evaporite basin brines. Thus, the evolution of seawater chemistry in Permian is confirmed by the evolution of the isotopic composition of dissolved seawater sulfate. According to the generalization of 38 Phanerozoic marine evaporite formations, it was found that the peculiarities of the clay minerals associations correlate with the change of the seawater chemical type. Clay minerals associations precipitated from the SO4-rich seawater are characterized by a larger set of minerals, among which smectite and mixed-layered minerals often occur; Mg-rich clay minerals (corensite, paligorskite, sepiolite, talc) also occur. Instead, in the associations of evaporite clay minerals formed from the Ca-rich seawater are represented by the smaller amount of minerals, and Mg-rich minerals are extremely rare. The increased content of magnesium in seawater of SO4-rich type is the main factor in the formation of Mg-rich silicates in evaporites. The composition of clay minerals associations depends on the evaporate basin brine concentration; with its increase, unstable minerals are transformed, which theoretically leads to a decrease in the number of minerals in the associations. However, it was found that evaporite deposits of higher stages of brine concentration often still contain unstable clay minerals – products of incomplete transformation of a significant amount of pyroclastic material from coeval volcanic activity. The main factor determining the composition of clay minerals associations of Phanerozoic evaporites was the seawater (and basin brines) chemical type. Geochemical studies of scattered organic matter and fluid inclusions with hydrocarbon phase in evaporites of the Upper Pechora Basin (overlying oil and gas deposits) indicate the presence of allochthonous bitumoids and allow to use this method to predict oil and gas potential of other areas. Analysis of the results of oil and gas exploration in a number of areas of the Transcarpathian Trough indicates the presence of fluid-saturated reservoirs and the prospects for the discovery of new accumulations of hydrocarbons. Geochemical studies proved the effectiveness of gas-flow survey method for oil and gas exploration, assessing the prospects for fluid saturation of seismic structures.


2021 ◽  
Author(s):  
Jiang yun ◽  
Sun Guoqiang ◽  
Pan Shile ◽  
Wang yetong ◽  
Zhang shuncong

Abstract The Pingtai area is a relatively new oil and gas exploration area in Qaidam Basin, China. As one of the most important sandstone reservoir in the Qaidam Basin, Eocene Lulehe Formation and Xiaganchaigou Formation. Based on the petrological characteristics and element geochemistry of core samples, the paleosalinity and paleoclimate changes are discussed. The results show that the clay mineral assemblage of the Lulehe Formation consists of smectite, chlorite, and illite; while the clay minerals in the Xiaganchaigou Formation consist of illite/smectite mixed layer, chlorite, and illite. The paleosalinity calculated using the B content and Sr/Ba and Rb/Sr ratios indicates that the Lulehe Formation was formed in a freshwater environment, and the Xiaganchaigou Formation was formed in alternating brackish water and fresh water environments. The chemical weathering index (CIA), La/Th ratio, and Eu anomaly index indicate that the overall chemical weathering in the Pingtai area was weak, the provenance was relatively stable, and the influence of diagenesis on the clay minerals and the trace element contents was negligible. From the Lulehe Formation to the Xiaganchaigou Formation, the paleoclimate gradually changed from warm and humid to cold with humid-dry seasonal changes, which is consistent with the global decrease in temperature in the Eocene. Moreover, because of the uplift of the Altun Mountain and the global cooling, the rainfall decreased, resulting in the Xiaganchaigou Formation being formed in a higher salinity environment.


2012 ◽  
Vol 619 ◽  
pp. 302-305
Author(s):  
Hong Yan Wang ◽  
Wen Sheng Xiao ◽  
Xiu Juan Lin ◽  
Xian Feng Wang

Considering the pollution on the environment using dynamite source in oil and gas exploration, harm and damage to people and building, the vehicle mounted hammer source which can replace dynamite source is presented. This paper describes briefly the basic structure and working principles of the vehicle mounted hammer source. A typical pneumatic circuit is researched and designed. And the pneumatic circuit is designed with the powerful functions of PLC, the hardware and software design are introduced. The system has advantages of strong striking force, high velocity, small gas consumption, simple structure and convenient control.


2018 ◽  
Vol 58 (2) ◽  
pp. 557
Author(s):  
Barry A. Goldstein

Facts are stubborn things; and whatever may be our wishes, our inclinations, or the dictates of our passion, they cannot alter the state of facts and evidence (Adams 1770). Some people unfamiliar with upstream petroleum operations, some enterprises keen to sustain uncontested land use, and some people against the use of fossil fuels have and will voice opposition to land access for oil and gas exploration and production. Social and economic concerns have also arisen with Australian domestic gas prices tending towards parity with netbacks from liquefied natural gas (LNG) exports. No doubt, natural gas, LNG and crude-oil prices will vary with local-to-international supply-side and demand-side competition. Hence, well run Australian oil and gas producers deploy stress-tested exploration, delineation and development budgets. With these challenges in mind, successive governments in South Australia have implemented leading-practice legislation, regulation, policies and programs to simultaneously gain and sustain trust with the public and investors with regard to land access for trustworthy oil and gas operations. South Australia’s most recent initiatives to foster reserve growth through welcomed investment in responsible oil and gas operations include the following: a Roundtable for Oil and Gas; evergreen answers to frequently asked questions, grouped retention licences that accelerate investment in the best of play trends; the Plan for ACcelerating Exploration (PACE) Gas Program; and the Oil and Gas Royalty Return Program. Intended and actual outcomes from these initiatives are addressed in this extended abstract.


2020 ◽  
Vol 58 (7) ◽  
pp. 4529-4546
Author(s):  
Ekaterina Shipilova ◽  
Michel Barret ◽  
Matthieu Bloch ◽  
Jean-Luc Boelle ◽  
Jean-Luc Collette

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