Petroleum Engineering Research Institute of Dagang Oilfield

Tianjin, China

Petroleum Engineering Research Institute of Dagang Oilfield

Tianjin, China
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Ma C.,China University of Petroleum - East China | Ma C.,Pennsylvania State University | Elsworth D.,Pennsylvania State University | Dong C.,China University of Petroleum - East China | And 10 more authors.
Marine and Petroleum Geology | Year: 2017

The development of expulsion fractures in organic-rich shale is closely related to hydrocarbon generation and expulsion from kerogen. Organic-rich shales from the upper part of the fourth member and the lower part of the third member of the Paleogene Shahejie Formation in the Jiyang Depression, Bohai Bay Basin, East China, are used as an example. Based on thin sections, SEM and thermal simulation experiments, the characteristics of hydrocarbon generation and the conditions supporting the development of expulsion fractures were explored. The key factors influencing these fractures include the presence of kerogens, their distribution along laminae and around particle boundaries, their exposure to heat and the build-up in pressure due to confinement by low permeability. The development of excess pore fluid pressures and intrinsic low rock fracture strength are the main influencing factors. Pressurization by rapid generation of hydrocarbon provides impetus for fracture initiation and cause bitumen to migrate quickly. The shale laminae results in distinctly lower fracture strength laminae-parallel than laminae-normal and this directs the formation of new fractures in the direction of weakness. When pore fluid pressure increases, maximum and minimum principal effective stresses decrease by different proportions with a larger reduction in the maximum principal effective stress. This increases the deviatoric stress and reduces the mean stress, thus driving the rock towards failure. Moreover, the tabular shape of the kerogen aids the generation of hydrocarbon and the initiation of expulsion fractures from the tip and edge. The resulting fractures extend along the laminae when the tensile strength is lower in the vertical direction than in the horizontal direction. Particle contact boundaries are weak and allow fractures to expand around particles and to curve as the stress/strength regime changes. When pore fluid pressure fields at different fracture tips overlap, fractures will propagate and interconnect, forming a network. This paper could provide us more detailed understanding of the forming processes of expulsion fractures and better comprehension about hydrocarbon expulsion (primary migration) in source rocks. © 2017


Yi G.,Henan Polytechnic University | Xing B.,Henan Polytechnic University | Jia J.,Henan Polytechnic University | Zhao L.,Petroleum Engineering Research Institute of Dagang Oilfield | And 3 more authors.
International Journal of Photoenergy | Year: 2014

Macroporous TiO2 photocatalyst was synthesized by a facile nanocasting method using polystyrene (PS) spherical particles as the hard template. The synthesized photocatalyst was characterized by transmission electron microscope (TEM), scanning electron microscopy (SEM), thermogravimetry-differential thermogravimetry (TG-DTG), X-ray diffraction (XRD), and N2-sorption. TEM, SEM, and XRD characterizations confirmed that the macroporous TiO2 photocatalyst is composed of anatase phase. The high specific surface area of 87.85 m2/g can be achieved according to the N2-sorption analysis. Rhodamine B (RhB) was chosen as probe molecule to evaluate the photocatalytic activity of the TiO2 catalysts. Compared with the TiO2 materials synthesized in the absence of PS spherical template, the macroporous TiO2 photocatalyst sintered at 500°C exhibits much higher activity on the degradation of RhB under the UV irradiation, which can be assigned to the well-structured macroporosity. The macroporous TiO2 material presents great potential in the fields of environmental remediation and energy conversion and storage. © 2014 Guiyun Yi et al.


Dong J.,Petroleum Engineering Research Institute of Dagang Oilfield
Drilling Fluid and Completion Fluid | Year: 2015

Two sets of solids-free workover fluids were formulated with natural mineral sulfide scavenger. The adsorption rates of sulfide hydrogen of the workover fluids were as high as 237.33 mg/L. They also had low alkalinity, low corrosivity, did not form scale and were compatible with calcium and magnesium ions, and formation waters. Being solids-free, they posed no damage to reservoirs. Pilot application of the workover fluids in five wells in Dagang Oilfield was successful, average restoration period of these wells was 2 days, and the reservoir formation was proved not damaged by the workover fluids. ©, 2015, North China Petroleum Administration Drilling Technology Research Institute. All right reserved.


Dong J.,Petroleum Engineering Research Institute of Dagang Oilfield | Fan S.,Petroleum Engineering Research Institute of Dagang Oilfield | Guo Y.,Petroleum Engineering Research Institute of Dagang Oilfield | Yang X.,Petroleum Engineering Research Institute of Dagang Oilfield | Zhou X.,Petroleum Engineering Research Institute of Dagang Oilfield
Drilling Fluid and Completion Fluid | Year: 2013

A kind of novel low-density micro-foam workover fluid is developed for low pressure reservoirs, which is composed of foaming agent, active agent and compound foam stabilizing agent, and the micro-foam is formed by one core two films and three layers that is very stable. The experimental evaluation results show that this kind of workover fluid can work in conditions of 130°C and 10 MPa, and has good performances of API filtrate loss 10.3 mL, HTHP filtrate loss 15.6 mL, salt tolerance 10%, calcium tolerance 3%, oil tolerance over 15% and core permeability recovery rate over 89%, as well as the micro-foam can match the leakage ways automatically to prevent lost circulation. The applications of 5 wells are succeeded in 100%, the average recovery rate is 133.8%, and the average recovery time is shorten by 1.6 d, which can protect reservoirs effectively.

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