Research On Reservoir Protection Technique During Water Injection Process Of JiDong Oilfield

Reservoir protection technology is a systematic strong technology, which runs from drilling to the development and production and every aspect of the reservoir protection can not be ignored. At present, most of the oil field at home and abroad, especially sandstone reservoir oil fields almost all of the water injection development, has acquired a wealth experience and good development results, but there are many issues to be resolved. Oilfield water injection development is an effective means to compensate for the formation deficit and improve the formation pressure, and enhanced oil recovery. Oilfield waste water re-injection after treatment, both to avoid environmental pollution, but also to achieve the purpose of the injection holding pressure. However, if oilfield waste water contains high suspended solids, suspended oil and bacteria, etc, will cause corrosion of the injection surface facilities and clogging damage of formation, resulting in the decline of the water absorbing capacity of injection wells, increased injection pressure, further exacerbated reservoir heterogeneity, which led to lack of oil layer energy and decline of well yield. Therefore, we must do removal treatment according to the requirements of the oil field injection water quality to meet the needs of the water flooding development.Low-permeability reservoirs are easy to be hurt in the mining process, because of the low permeability reservoir has a low effluent seepage and low permeability, any minor damage will cause the reservoir deliverability substantially reduce. Therefore, the low permeability reservoirs protection throughout the development process are very important. To prevent formation damage the most basic way is to do fluid into the well and reservoir, crude oil, formation water compatibility experiments, to avoid the reservoir occurred parasitical changes.Jidong Gao shangpu Oil Field formation physical property fluctuation, crude oil has high wax, high colloid asphalt. From the current development status, through long-term water injection, although the formation forming many large pores, but part of the injection wells are still clogging occurs, resulting in injection pressure increased and can not complete the injection proration amount, the weakening effect of water injection, affected the speed and effects of oil field development seriously. In view of this Oil Field current production status, the need for injection wells in the reservoir causes of injuries and the degree of injuries to do in depth study, and to develop reasonable and feasible water quality guideline and commensurable control measures. In this paper, through to collect a large number of the geological materials, production materials, collecting the core of production wells of Jidong Gao shangpu Oil Field, indoor experiment and theoretical research of combining technical route, in deep study of the factors that cause formation damage in the water injection process, and solid particles on the permeability affection experiment, suspended waste oil on the permeability affection experiment, bacterial on the permeability affection experiment, combined with site process path and water treatment process conditions to determine the suitable Gao shangpu Oil Field water quality index system, provided a reliable theoretical basis for the Oil Field efficient waterflood development.By analyzing the factors causing formation damage in the water injection process learned that two blocks reservoirs are both strong water sensitive formation, weak speed-sensitive; owing to injected water salinity is lower than the two blocks formation water salinity, in the water injection process, both have clay swelling phenomenon; poor compatibility of the injected water and formation water, indoor saturation index calculated the two blocks saturation index of the injected water mixing formation water during water injection, the data indicate that the injected water with two blocks formation water mixed in different proportions both have no CaSO4, but have a tendency of generateing CaCO3. Proportion of injected water in the water injection process increases, Gaoshennan block CaCO3scaling increasingly serious, Gaoshenbei block CaCO3scaling tends to decrease.This paper analysis of the internal cause injection injury of the Jidong Gao shangpu Oil Field Gaoshennan and Gaoshenbei blocks of reservoir seepage properties, the microscopic pore structure characteristics, sensitivity, compatibility, clearly due to the complexity of the reservoir properties and uncertainty leads to water quality standards inconsistent, can not be generalized to the use of a water quality standards to be developed. At the same time, analysis Gao shangpu Oil Field injected water water quality present situation, clearly the external causes of formation damage, that is:the water quality indicators in some months is seriously superstandard, water quality incompetence. This paper also has carried out the antiscale static screening experiments, the clay inhibitor static and dynamic experiments, seeing Jidong Gao shangpu Oil Field reservoir characteristics selects suitable scale inhibitor and clay inhibitor. On the basis of the above studies, given Gao shangpu Oil Field water quality improvement measures to help to protect the reservoir, greatly improving the oil field development effect. Calculated the two block injection wells in the injection process, the daily water injection rate of per meter allowed do not occur the particle migration and occurrence of particle migration allowed to leave the borehole wall of0.5m and1.0m.The prevention of scaling study indicated that:the scale inhibitor of11#, scale inhibitor of12#, scale inhibitor of13#and scale inhibitor of19#have filtered out throughing indoor experiments, these scale inhibitors have a good anti-scaling effect, and anti-scaling is up to100%.The anti-swelling study indicated that:the1#and7#clay inhibitor have screened out throughing indoor dynamic and static evaluation of experiments, the anti-swelling effect are good, when the plus is2%, the injection of100times of the pore volume of clean water, the rate of permeability retention values of up to80%and more, so we choose the1#and7#clay inhibitors for injected water should be added to the clay inhibitor of Jidong Gao shangpu Oil Field.