scholarly journals Development Favorable Area and Productivity Potential Evaluation Method of a Tight Oil Reservoir

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Shuping Wang ◽  
Fengpeng Lai ◽  
Kongjie Wang ◽  
Zhiping Li ◽  
Hong Wang

Tight oil resources have become the focus of unconventional oil and gas exploration and development. Well placement is an essential factor determining the development of a field. Oil wells should be located in the area with favorable criteria for development. These areas should be screened based upon oil and gas enrichment of the reservoir. The influencing factors and analysis theory of an enrichment area are summarized in this paper. Two types of methods evaluating areas favorable for tight oil and gas production are explained here as well, including model prediction and the combination of geological modeling and reservoir simulation. The area with favorable geological, engineering, and economic attributes has the best development potential. The productivity potential can be used as one basis for selecting areas favorable for production. Based on the previous concept of productivity potential, combined with the characteristics of a tight oil reservoir, this study modified the evaluation of productivity potential, and the calculated potential area was the priority for well placement. The modified equation of productivity potential comprehensively considers effective pore pressure, mobile oil saturation, porosity, permeability, effective thickness, distance from the boundary, and threshold pressure gradient. A tight reservoir was taken as an example for calculation, and the results of the modified method, original productivity potential method, and reserve abundance calculation method are discussed. Two new wells were arranged in the favorable areas obtained by different productivity potential evaluation methods, and the production was calculated under the same parameters for each method. The recovery of this area was 51.65%, which is 1.73% and 2.84% higher than that of the other two methods.


2014 ◽  
Author(s):  
H.. Wang ◽  
X.. Liao ◽  
H.. Ye ◽  
X.. Zhao ◽  
C.. Liao ◽  
...  

Abstract The technology of Stimulated reservoir volume (SRV) has been the key technology for unconventional reservoir development, it can create fracture network in formation and increase the contact area between fracture surface and matrix, thus realizing the three-dimensional stimulation and enhancing single well productivity and ultimate recovery. In China, the Ordos Basin contains large areas of tight oil reservoir with the porosity of 2~12 % and permeability of 0.01~1 mD. The most used development mode is conventional fracturing and water flooding, which is different from the natural depletion mode in oversea, but the development effect is still unfavorable. The idea of SRV is proposed in nearly two years in Changqing Oilfield. SRV measures are implemented in some old wells in tight oil formation. It is a significant problem that should be solved urgently about how to evaluate the volume fracturing effect. Based on the real cases of old wells with SRV measures, the microseismic monitoring is used to analyze the scale of formation stimulation and the complexity of fracture network after volume fracturing; the numerical well test and production data analysis (PDA) are selected to explain the well test data, to analyze the dynamic data, and to compare the changes of formation parameters, fluid parameters and plane streamlines before and after volume fracturing; then the interpretation results of well test with the dynamic of oil and water wells are combined to evaluate the stimulation results of old wells after SRV. This paper has presented a set of screening criteria and an evaluation method of fracturing effect for old well with SRV in tight oil reservoir. It will be helpful to the selection of candidate well and volume fracturing operation in Ordos Basin tight oil reservoir. It should be noted that the evaluation method mentioned in the paper can be expanded to volume stimulation effect evaluation in other unconventional reservoirs, such as tight gas, shale gas and so on.







2021 ◽  
Author(s):  
Jingfeng Yu ◽  
Diao Zhou ◽  
Bo Zhang ◽  
Haiping Meng ◽  
Tong Li ◽  
...  

Abstract MH oilfield is a fan delta deposited unconventional tight oil reservoir with complex lithology of volcanic rocks, metamorphic rocks, conglomerate, and claystone. The drilling efficiency was optimized by using the first-generation boundary mapping technology with Rotary Steering System (RSS) during the first batch drilling campaign (H2-2016∼H1-2017), which was mentioned in IADC/SPE-190998-MS. But with the development going further, more and more wells drilled into shale interbed causing low pay zone exposure, long drilling duration, and numerous drilling hazards. The overall drilling performance was not optimistic as before, the average Rate Of Penetration (ROP) decreased by 30.7% and the average footage per run decreased by 38.9% during horizontal section operation in some specific blocks of MH oilfield. By reviewing the detailed drilling and geology material of the first batch drilling, the challenges were defined. There is lateral irregular thin shale interbed existing in this conglomeratic reservoir which is rarely observed from the nearby wells in the first batch drilling zone. That unstable shale interbed with 0.5-2m thickness isolated the target into 2 to 3 components. The first-generation boundary mapping technology can only detect the nearest up or down boundary, with this limitation, it is difficult to reveal these laterally unstable shale interbed. It is crucial to precisely delineate the irregular thin interbed to develop this complex reservoir. Meanwhile, the bit selection which didn't catch up with the formation change is another issue that needs to be optimized timely. To solve the above challenges, the new generation boundary mapping while drilling technology was introduced to this project, it has 3 or more boundaries detecting ability at the same time, which can delineate the irregular thin interbed and optimize real-time Well Placement decision making. Meanwhile, the bit design and selection based on the timely geological data interpretation helped to improve drilling efficiency. This innovative integrated method deployed in phase II horizontal well drilling campaign proved to be an effective approach to optimize geosteering and drilling performance. The clear reservoir geometry delineation effectively helps avoid entering the irregular shale interbed in real-time, thus improve the pay zone exposure and trajectory smoothness. Till 2018, more than 50 wells were completed, the overall drilling performance of 2018 has been improved by 47.2% of footage per run and 42.2% of ROP compared with statistical results of H2-2017 of the M131 block and nearly back to the normal level. In this paper, the authors will demonstrate how this integrated approach helps optimize Well Placement, enhance drilling efficiency and save budget with some exemplary case studies. With this success, the authors believe this approach and techniques could effectively address the following horizontal well drilling campaign in this unconventional tight oil reservoir.



Lithosphere ◽  
2021 ◽  
Vol 2021 (Special 4) ◽  
Author(s):  
Binchi Zhang ◽  
Dejiang Kang ◽  
Shizhong Ma ◽  
Wenze Duan ◽  
Yue Zhang

Abstract The exploration of unconventional oil and gas, especially the exploration process of tight oil, is closely related to the evolution of tight reservoirs and the accumulation process. In order to investigate the densification and accumulation process of the Fuyu tight oil reservoir in the Sanzhao depression, Songliao Basin, through the new understanding of reservoir petrological characteristics, diagenesis and diagenetic sequence are combined with a large number of inclusions: temperature measurement, spectral energy measurement, and single-well burial history analysis, and then contrastive analysis with current reservoir conditions. The results prove that diagenesis is dominated by compaction and cementation, and the restoration of paleoporosity shows that its porosity reduction rate reached 67% and the densification process started in the early Nenjiang Formation and was finalized at the end of the Nenjiang Formation. The accumulation of the Fuyu oil layer generally has the characteristics of two stages and multiple episodes, and the main accumulation period is the end of the Mingshui Formation. The end of the Nenjiang Formation, where the main body of the reservoir is densified, is just a prelude to the massive expulsion of hydrocarbons in the Songliao Basin, which makes the Fuyu oil layer have the characteristics of first compacting and then accumulating. Through the above analysis, it can be seen that the accumulation of oil and gas in the Fuyu oil layer, Sanzhao depression, is more dependent on the fault-dominated transport system. In addition, it is believed that tight oil accumulation should have the characteristics of short-distance oil enrichment around the fault, and the development area of fracture deserts near the fault sand body should be the key area for further exploration.



2016 ◽  
Author(s):  
Peng Yi ◽  
Weng Dingwei ◽  
Xu Yun ◽  
Wang Liwei ◽  
Lu Yongjun ◽  
...  




2015 ◽  
Vol 89 (s1) ◽  
pp. 65-66
Author(s):  
Hongru LIANG ◽  
Shuangfang LU ◽  
Mingming TANG ◽  
Bihui YAN ◽  
Shan SHEN


2017 ◽  
Author(s):  
Xin Fang ◽  
Xiangan Yue ◽  
Wei Fang ◽  
Shuyun Lu ◽  
Zhi Geng


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