Study On Acidification Technology Of High Water Content Horizontal Well In C Oilfield

Horizontal wells in C oilfield have several problems mainly in high water content ratio, severe damage and low oil production. Based on the history data of oilfield C, this paper carried out several researches such as water type and regular pattern, diagnose the cause of damage of horizontal well, acidizing fluid system. Oil-soluble blocking agent and foam slug diversion acid inject method. This paper also proposed a set of technology to reduce the water content ratio in target reservoir and enhance the oil productivity. This technology can effectively reduce horizontal wells damage, stimulate the low permeability layer productivity while keeping the water content ratio in an acceptable level. Specific research works in this paper are as follows:1)The production statistics show that the type of C oilfield is a bottom water reservoir with high water content ratio (because of bottom water coning). This paper uses Eclipse (a reservoir simulation software) to analysis of bottom water coning law of horizontal well, providing the basis for water control measures and reservoir stimulation method selection.2)Through simulate damage in drilling and completion of horizontal well and analysis the potential damage factors while production, this paper calculated the horizontal well damage extent and range while drilling and completion, cleared acidizing goals and proposed suggestion for acid fluid.3)Around requirements including retarder. breaking, anti-swelling, corrosion, low damage, effectively plugging and other performance, this paper carried out laboratory experiments such as acid rock reaction speed test, performance evaluation of acid additives. SEM and EDX analysis before and after acid-rock reaction and core flow experiments for different acid fluids, proposed a set of efficient acid fluid system suitable for target reservoir stimulation.4)Considering pore radius distribution in target water layer, this paper evaluated CJF(an acid-soluble type block agent). This paper also evaluated blocking ability, damage extent for oil layer, selectivity, injectivity and acid resistance of CJF.5)This paper proposed foam slug diversion acidizing technology, selected efficient foaming agent, verify the effectiveness of the foam slug diversion with laboratory experiments. Based on the vapor traps theory and conservation of mass and considered both bottomhole temperature and the influence of bias factor changes for diversion effect, this paper build a foam slug diversion during acidizing process model. Plus, this paper also performed a sensitivity analysis of the parameters.Through these studies, this paper proposed a set of acidizing technologies to WSO&foam slug diversion suitable for target oilfield. These technologies can reduce formation damage while keeping water content ratio in an acceptable level. providing a strong technical support for oilfield development.