scholarly journals Experimental study on stress sensitivity of high‐temperature and high‐pressure sandstone gas reservoirs in Yingqiong Basin

2020 ◽  
Vol 8 (11) ◽  
pp. 4116-4125
Author(s):  
Yi‐Long Li ◽  
Xiao‐Ping Li ◽  
Feng Wu ◽  
Hong‐Lin Lu ◽  
Xiao Lei ◽  
...  
2021 ◽  
Vol 143 (11) ◽  
Author(s):  
Xiaoliang Huang ◽  
Zhilin Qi ◽  
Hao Zhang ◽  
Wende Yan ◽  
Chang Yan ◽  
...  

Abstract Water-soluble gas reservoirs have the characteristics of high temperature and high pressure (HTHP) and experience obvious pressure-sensitive effects during the production process. Therefore, the influences of formation water and dissolved natural gas in formation water on water-soluble gas reservoirs are different from conventional gas reservoirs. In view of this, this work first carried out a stress sensitivity test with irreducible water and variable internal pressure at high temperature for a water-soluble gas reservoir, showing that permeability loss ratio and effective stress have an exponential relationship, a result basically consistent with conventional tests. However, the stress sensitivity test result with irreducible water was greater than the stress sensitivity test result without irreducible water; porosity decreased slightly with increasing confining pressure, and the total decrease ratio was less than 5.2%, with an average of 3.01%. Second, a high-pressure, high-temperature, nuclear magnetic resonance (NMR) online detection system was introduced to detect the pore signal of core samples under different effective stress states, and pore compression and deformation characteristics were evaluated. Results show large pores to have been compressed slightly more than small pores, pores to be significantly compressed in the initial stage, and the greater the increase in effective stress, the more obvious the compression. Third, the occurrence and characteristic changes of irreducible water in the process of rock compression were detected by the NMR online system, indicating irreducible water to be difficult to migrate through compression in water-soluble gas reservoirs under slight compression of rock and pore structure and the occurrence and characteristics of irreducible water to have not changed significantly. Finally, by establishing a theoretical model of water-soluble gas reservoirs to simulate the water breakthrough of gas wells under stress sensitivity conditions, this work shows that when stress sensitivity exists, gas-well water breakthrough time is earlier and production is diminished.


2016 ◽  
Vol 174 (3) ◽  
pp. 1033-1041 ◽  
Author(s):  
KeShi Hui ◽  
LiDong Dai ◽  
HePing Li ◽  
HaiYing Hu ◽  
JianJun Jiang ◽  
...  

2015 ◽  
Vol 42 (1) ◽  
pp. 92-96 ◽  
Author(s):  
Jianlong FANG ◽  
Ping GUO ◽  
Xiangjiao XIAO ◽  
Jianfen DU ◽  
Chao DONG ◽  
...  

2019 ◽  
Author(s):  
Mohd Fakrumie Zaidin ◽  
Budi Priyatna Kantaatmadja ◽  
Antonin Chapoy ◽  
Pehzman Ahmadi ◽  
Rod Burgass

2012 ◽  
Vol 594-597 ◽  
pp. 2073-2076
Author(s):  
Zhong Fei Ma ◽  
Li Chen ◽  
Fu Qin Wang

In order to improve the cooling effect and practical applicability of falling temperature technique on high-temperature workplaces, the aeration and cooling principle of the high pressure water rotational jetting ventilation were analysed, and the experimental study was carried out. The results show that water pressure and cooling rate are an approximation of parabolic growth relationship, different structure of jet tube and temperature difference on water and gas also have an obvious effect on the cooling amplitude and air quantity. the guide vanes installed may improve effect of ventilation and cooling the capacity on high pressure water rotational jetting.


2020 ◽  
Author(s):  
Sarah Incel

<p>Impact rocks often reveal particular structures, e.g. shock-induced amorphization and melting of crystals, that formed due to high stresses during shock metamorphism. This experimental study presents four granulite samples that were deformed in a D-DIA apparatus at 2.5 GPa and 3 GPa and at either 1023 K, 1173 K, or at 995 to 1225 K. During deformation of two samples (2.5 GPa and either 995-1125 K or 1173 K) 82 and 794 acoustic emissions (AEs) were recorded, respectively, whereas less than 10 AEs were recorded while deforming the other two granulite sample (3 GPa and 995-1225 K; 2.5 and 1073 K). Microstructures of the samples that emitted 82 and 794 AEs reveal amorphous patches that are absent in the samples corresponding to the runs in which <10 AEs were recorded, indicating a link between AE-activity and amorphization of plagioclase. The contacts between amorphous patches and host-plagioclase crystals are very sharp and amorphization predominantly occurred along two distinct planes inclined at approx. 45° towards the direction of maximum compression. Surrounding the patches, the hosts show extensive fragmentation. Chemical analyses of the amorphous patches demonstrate an enrichment in potassium and silicon relative to the initial plagioclase chemistry and the growth of euhedral quartz crystals within the patches. Such microstructures were previously found in naturally or experimentally shocked rocks and interpreted as shock melts. The occurrence of structures, revealing striking similarities to shock melts, in experimental samples that underwent embrittlement at high-pressure, high-temperature conditions below the sample’s solidus (~1377 K) suggests melting due to elevated transient stresses, e.g. during rupture processes.</p>


Author(s):  
Facheng Wang ◽  
Ming Gao ◽  
Jun Wang ◽  
Yigong Zhang ◽  
Xu Jia ◽  
...  

Developments of oil and gas reservoirs in Bohai Sea, South China Sea etc., are presently accelerated, to cope with the significant increase in energy demand from the mainland, China. In recent developments in Bohai Sea, fluid temperature and pressure have been found dramatically being increased up to 100 °C and 20 MPa respectively. The fact that High Temperature and High Pressure (HTHP) in Bohai area brings design challenges, especially to jacket risers and spool pieces. Pipe-in-Pipe (PIP) flowline systems have been widely employed in this region and are continuously being considered for further developments. This is due to its significant thermal insulation capacity to deal with the High Temperature and High Pressure (HTHP) issue. To cope with the challenges induced by HPHT and structural complexity of PIP, COTEC Offshore Engineering Solutions, together with its mother company, China Offshore Oil Engineering Company, have developed a approach by using ABAQUS and AutoPIPE. This paper describes the relevant experience obtained during one development in Bohai Sea, BZ34-2/4 project containing dozens of risers and spool pieces. Two main parts are presented. Firstly, a beam-element based expansion calculation model adopting ABAQUS has been developed to achieve accurate HPHT induced expansions. The structural behavior of PIP can be represented in the developed model, meanwhile with minimum increase in modeling complexity. Secondly, practical and extensive parametric studies have been carried on the riser and spool flexibility against HPHT induced expansions. Since Bohai Sea has been developed extensively, many risers are post-installed and the existing of restriction areas practically enlarges the difficulties of anchor clamp and spool arrangements. Key parameters of these arrangements, such as Z/L shape, the length between two bends, the combinations of bend angles, the length of protection pipe on the riser etc. have been comprehensively investigated. “Gold” rules for rigid riser accessories arrangements and spool piece layout have been suggested accordingly.


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