Research On Reservoir Geological Characteristics And Protection Technology Of Zhujiang Formation In HZ3-13 Oilfield

In recent years,the development of marine oil and gas resources in China has been paid more and more attention.Many offshore oil fields are sought to maximize economic value and improved oil recovery by changing the design of the wellbore and improving the drilling process.The exploration wells in the Pearl River Group of HZ3-13 oilfield have good shows,but the early exploration wells are straight wells with long drilling time.The damage severity exposure rate is low and during drilling there is high risk.In order to ensure the successful operation of the oil field and reduce the operating cost,it is necessary to deepen the reservoir characteristics,clear the reservoir damage type and mechanism,and optimize the drilling fluid system and performance.The reservoir protection technology research was implemented,so as to determine the smooth operation of the oil field group.The offshore oil production and storage is of great significance.In this paper,the geological features such as reservoir lithology,physical properties,sediments and pore structure of reservoirs are studied in deep.This paper combines the problems existing in well exploration,well drilling,well completion and the technical problems that need to be solved.Through a lot of indoor experiments,the following achievements and awareness was made.(1)The main reservoir(L20/L25)of the HZ3-13 oilfield is mainly composed of feldspar quartz sandstone and lithic feldspar quartz sandstone,and the clay mineral content is 8.8%.It is mainly composed of kaolinite and filamentous illite.It is predominantly rich in argillaceous cement and locally rich in calcareous cements.The main oil group belongs to the meso-hypertonic reservoir,mainly dominated by native intergranular pores.The necking and dotted throat is the main throat type.(2)The reservoir has weak,medium,weaker kinds of rate sensitivity damage.The water damage degree is weak,and acidity sensitivity damage is weak.The alkali sensitive damage degree is weak.(3)In-house experimental study combined with the well type and wellbore structure of oilfield development,the UltraFLO drilling fluid system is suitable for the horizontal well part of long displacement well in oilfield.The damage form is based on the external solid phase intrusion of the high permeability reservoir.The experimental results show that the optimized permeability of the UltraFLO drilling fluid system is 90%for the high permeability reservoir and the depth of the liquid intrusion is reduced.The core permeability recovery rate of high permeability reservoir is>90%.Liquid intrusion depth is reduced by 24%.The reservoir protection effect of HZ3-13 oilfield Pearl River is good.(4)The damage of the middle and high porosity and permeability sandstone reservoirs in the Pearl River Formation of HZ3-13 oilfield is mainly analyzed by water sensitivity and solid intrusion caused by particulates migration and the working fluid filtrate intrusion.According to the field development scheme and well type,the UltraFLO drilling fluid system and the stealth acid completion fluid system is matched.The superfine calcium carbonate blocking particles are added,which match the pore throat of the osmotic reservoir and it can achieve the purpose of protecting the reservoir.