WanFu, Zhou (Daqing Oilfield Co. Ltd) | ZhongLian, Han (Daqing Oilfield Co. Ltd) | Gang, Cao (Daqing Oilfield Co. Ltd) | Xin, Wang (Daqing Oilfield Co. Ltd) | QingGuo, Wang (Daqing Oilfield Co. Ltd) | WenJiang, Chen (Daqing Oilfield Co. Ltd) | QingSong, Li (Daqing Oilfield Co. Ltd) | JingMei, Wang (Daqing Oilfield Co. Ltd) | Yang, Han (Daqing Oilfield Co. Ltd) | HaiRong, Fu (Daqing Oilfield Co. Ltd)
In the later stage of development, most oilfields faced high water cut issue after treatments. Meanwhile, how to effectively control oil wells water breakthrough after fracturing so as to increase oil production has become a big challenge for production engineers. This paper introduced a novel selective proppant which can effectively block water from entering well bore after fracturing.
Based on "eggshell principle" and interfacial tension theory, this novel proppant was developed with a new monolayer strong hydrophobic interface treatment technique. This special processing technique could not only reduce the proppant's flow resistance of oil, but also increase its flow resistance of water. As the result, this novel proppant showed the characteristics of excellent lipophilicity and hydrophobicity as well. Experiments indicated that oil water diversion ratio of selective proppant was greater than 1.2, while the ordinary proppant was less than 0.7. The oil wettability index of selective proppant was greater than 0.8, while the ordinary proppant was less than 0.3. The main characteristics of this supporting agent was small apparent density, low broken rate, and high flow capacity. The proppant surface is oil wet, which has the characteristics of oil increasing precipitation. Experiments showed that the seepage velocity of water in selective proppant was obviously lower than in quartz sand, selective proppant with water resistance.
Field test was carried out in 11 wells with selective proppant fracturing. A group of conventional fracturing wells were selected as contrasted wells with similar reservoir and operating conditions. After fracturing with novel proppant, the average water cut of producers was decreased by 7.2% per well, the average oil production was increased by 6.3 tons per well, and the average valid fracturing a period was 14.1 months. As for contrasted wells with conventional fracturing proppant, the average single well water cut decline was only 0.4%, the average single well daily oil 3.1 tons, an average period of only 5.8 months.
The novel proppant showed remarkable advantages in improving oil production and decreasing water cut. This technique has a great future for mature oilfield development.
Li, Hongfu (Research Inst. Petr. Expl/Dev) | Xu, DianPing (No. 4 Oil Production Co.) | Jiang, Jiang (Daqing Research Institute) | Du, Xiongwen (Daqing Research Institute) | Hong, Jichun (Daqing Research Institute) | Jiang, Yang (Daqing Oilfield Co. Ltd) | Xu, Yanshu (Daqing Oilfield Co. Ltd)
The results of five alkaline-surfactant-polymer (ASP) flood pilot tests carried out in single oil-layer and small scale showed that the incremental oil recoveries by ASP over that of the water flooding are over 20% OOIP. In order to realize the industrializing of ASP flooding, an ASP flood field test started in Central Xing2 Area of Daqing oilfield, using the surfactant produced by Daqing oilfield. Based on the great experimental achievements, the chemicals in ASP system were decreased greatly by optimizing the formulation and the injection method. Compared with the small scale site test area, the surfactant, polymer and alkaline were decreased by 1/3, 2/5 and 1/6, respectively, the chemicals can save 147 million RMB. Although the chemicals were decreased, the pilot test results show that the oil recovery was increased by 18% OOIP using the ASP flooding over that of water flooding.
Zhang, Y.G. (Daqing Oilfield Co. Ltd) | Han, H.X. (University of Waterloo) | Dusseault, M.B. (University of Waterloo) | Wang, X.J. (Daqing Oilfield Co. Ltd.) | Zhang, Z.X. (Daqing Oilfield Co. Ltd) | Fan, K.M. (Daqing Oilfield Co. Ltd) | Yu, Y.M. (Daqing Oilfield Co. Ltd)
We introduce an inter-well rock mechanics parameters prediction method using a combination of geophysical well logging data and 3-D seismic data. The method has been used to estimate Poisson¡¯s ratio (¦Í), Young''s modulus (E), fracture closure pressure (PCL), and fracture breakdown pressure (PBD) during fracture treatments, for any reservoir location in the rock volume analyzed. The statistical approach is based first on explicit correlations between static core analysis of rock mechanics parameters and dynamic multi-pole-array sonic logging. By further multiple linear regression analysis, these parameters can in turn be correlated to common well logging curves. Then, inter-well rock mechanics parameters are estimated through the use of the 3-D seismic database, constrained statistically using the logging data from individual wells. As a result, a 3-D rock mechanics properties model is developed for the volume covered. Relevant rock mechanics parameters at any point in the volume can be estimated from the model, allowing hydraulic fracture engineering design to be undertaken before an infill well is drilled.
There has been growing interest in determining in situ dynamic rock mechanical (lithomecanical) parameters in the oil and natural gas E&P industries. Various methods are available for measuring rock mechanics parameters. Mechanical and petrophysical properties are usually obtained from core sample tests using standardized laboratory procedures. This method is limited by the availability of core and by the cost of testing. Although interactive multi- pole-array sonic logging is an important tool for analyzing lithomechanical parameters, logging cost is too high for such tools to be used extensively. A mechanical earth model is one of the key tools for rock mechanical properties characterization as well as for provision of data to implement fully coupled reservoir geomechanics simulation.
Guo, Wankui (Daqing Oilfield Co. Ltd) | Shi, Chengfang (Daqing Oilfield Co. Ltd.) | Yang, Zhenyu (Daqing Oilfield Co. Ltd.) | Hou, Zhaowei (Daqing Oilfield Co. Ltd.) | Jin, Rui (Daqing Oilfield Co. Ltd.) | Wang, Ying (Daqing Oilfield Co. Ltd.) | Zhang, Jiyuan (Daqing Oilfield Company Limited) | Shan, Guanghao (Daqing Oilfield Co. Ltd.) | Wang, Zhi Yao (Daqing Oilfield Co. Ltd.) | Cao, Tie (Daqing Oilfield Co. Ltd.) | Liu, Chun Gang (Daqing Oilfield Co. Ltd.)
Based on the MEOR mechanism study of Brevibacillus brevis and Bacillus cereus, From 2002 to 2004, the two strain and other microbes were applied in the microbial huff and puff as well as the Microbial enhanced waterflood test in Daqing excessively low permeability (1.0md-25md) reservoir. After bacteria injection, 44 among the 60 huff and puff wells shows a significant oil production response—the accumulative oil increment reaches 9175.5 tons and the input-output ratio amounts to 1: 8. The Microbial enhanced waterflood test carried out in June 2004 also provides a satisfying result. After the injection of bacteria, the pressure in the two water injectors decreased more than 2MPa, which results in an injection capacity increase. The Analyse result of production fluid indicate that the selected bacteria can adapt the stratum conditions better and can grow and reproduce . They degrade heavy hydrocarbon ,improve character of crude oil and metabolize active substances. The fluid production of trial field increase and water cut decline . in late 2005 , 7 production wells among 10 production wells get good effect .Fluid production increased from 50.7 tons per day (before bacteria injection) to 68.3 tons per day, and the corresponding water cut declined from 46.8% to 40.3%.oil production is increased from 24.7 tons per day (before bacteria injection) to 40.8 tons per day.The accumulative oil increment more than 5800tons and the input/output ratio is 1:5. These make MEOR a very promising and effective oil recovery method in Daqing low permeabilityreservoirs.