The Evaluations About Dynamic Characteristics Of Jurassic System Oil Reservoir Of H307-X46 Well Field In Hujianshan Oilfield

The paper is guided on the theory of reservoir engineering. Based on the knowledge of the reservoirs, this study combined the reservoir characteristics and the dynamic feature. The research deepened the understanding of the dynamic characteristics of Yan9 and Yan10 oil reservoir of Jurassic system in H307-X46 well field in Hujianshan oilfield for the low permeability heterogeneous oil reservoir. The detailed study of production parameters and the regular pattern about the movement of oil and water was two important sides of dynamic evaluation. In the research, the thorough analysis of the problems developed from production process could help finding the factors which controlled them. Then, the adjustment countermeasures were proposed. Finally, the adjustment countermeasures could help the oil reservoir keeping produce in a high efficiency and control the water ratio in the production.The main results and proposals from this research are as follow:(1) Entirely, there was a big monocline which plunged west. There were some small uplift developed in the well field partly. Yan9 oil reservoir developed braided delta plain sub-facies. Yan10 oil reservoir developed braided river sub-facies. The type of this oil accumulation was structure- lithology controlled. The oil was drived by the elastic energy from dissolved gas. Although the bottom water developed in this well field, the water-oil volume ratio was 6.62. The energy of bottom water wasn’t active. So the exploitation of this oil reservoir need water injection to supplement the producing energy.(2) The well spacing density and fluid viscosity of each well field were known, the oil production rate were calculated by petroleum reservoir engineering method with effective thickness of reservoir, effective permeability and so on. The liquid production per unit thickness was calculated in the light of reasonable oil recovery rate. The numeric values of H307, A62 and X46 well fields were 1.13m3/ (m·d),1.14m3/(m·d) and 0.83m3/(m·d). Compared the rating values and actual values, the liquid production per unit thickness should be decreased in H307 and A62 well fields.(3) Correspond with the applicable liquid production per unit thickness, the water intake per unit thickness of each well field was 3.43m3/(m·d) for A62,3.39 m3/(m·d) for H307 and 2.5 m3/ (m·d) for X46. Combined with the current pressure level, the water injection rate of A62 well field should be decreased and rate of water injection of H307 well field should be increased a little.(4) There were two main important factors which effected the individual well producing rate. They were reservoir physical properties and structural feature. The better reservoir physical properties the individual well producing rate was more. The regions which individual well producing rate was high were located in the uplifts. There were some unimportant factors such as the development of bottom water and nonhomogeneity feature and so on.(5) The response characteristics in this research area could be divided into four categories. The first was production rate moving upward. The second was production rate maintaining stability. The third was water breakthrough and the last one was production rate moving upward by stimulation. The third was the main type which accouting for 87.4%. The main factors which effected the response from water injection included sedimentary facies, the distribution of oil sand and its connectedness, the reservoir physical properties and nonhomogeneity. Compared with A62 well field, the oil sand was thinner but better connectivity in H307 and X46 well fields. The permeability was higher by 3～4×10-3μm2. H307 and X46 well fields had more homogeneity. So the proportion of wells which were response in H307 and X46 well fields were more than A62 well field by 10 percents.(6) The cycle of water injection response was affected by well spacing or reservoir physical properties and so on. The main production reservoirs of H307 and X46 well fields were Yan92 and Yan93. Their permeability were 13.38×10-3μm2 and 14.58×10-3μm2. The cycle of H307 and X46 well fields were three months. However, the main production reservoirs of A62 well fields was Yan101. Its permeability was 10.57×10-3μm2. The cycle was more than six months. Moreover, the well spacing of H307 and X46 well fields was 433m and the spacing of A62 well field was 520m. So the longer of the well spacing the cycle was larger.(7) After the analysis, the remaining oil could be divided into three categories. The first was controlled by sedimentary facies. The second was controlled by nonuniformity. The third was out of controlled by pattern of well.In order to solve the contradictory between water wells and oil wells and maintain a stable production, this research put forward three proposals:adding perforations for the water wells or oil wells which were not correspondent each other; decreaseing the liquid production per unit thickness of high water cut wells which water type was bottom and plugging bottom water; regulating the injection profiles and production profiles for the wells which couldn’t response after injection long time and the wells which became water breakthrough after responsing will soon.