The Formation Intrusive Research Of Plugging Agent

In this paper, we have done the invasion depth research into plugging agent and evaluated four types of plugging agents (GX-1, YH-02, KJ-150and class G oil well cement) under the conditions of different permeability(100×10-3μm2、150×10-3μm3、200×10-3μm2、250×10μm2), temperature(70℃、80℃,90℃), displacement pressure(15MPa、18MPa、21MPa、24MPa、27MPa) and displacement velocity(25.0ml/min、32.0ml/min,40.0ml/min、50.0ml/min、60ml/min), in case of the production status of appearing abandoned layers and repeating reperforation but not passing through after plugging which is caused by the dosage design radius of the plugging agent may be greater than the maximum penetration of repeating reperforation gun on the basis of field water absorption while practical plugged channeling construction in Shuanghe oilfield. It is concluded that the performance of GX-1plugging agent is better than that of YH-02,KJ-150and class G oil well cement by analyzing the experimental data. We have established the prediction model of the invasion depth of plugging agent (KTP and KTV the prediction model of the invasion depth) on basis of GX-1plugging agent and optimized the construction technology parameters reasonably through the prediction model of the invasion depth.A large number of lab evaluation tests and core physical simulation experiments results show that:(1) the invasion depth of plugging agent increases as the permeability rises, this is because the compactness of rock samples decreases with increasing permeability, The slurry flow resistance of plugging agent decreases in the rock sample, and the slurry of plugging agent is easy to invade the rock sample deeply. Take GX-1for example, when the permeability is100×10-3μm2, the vertical invasion depth is80.4cm, the front-end horizontal invasion depth of3.0cm and the back-end horizontal invasion depth of2.2cm.when the permeability goes up to250×0-3μm2, the vertical invasion depth is92.3cm, the front-end horizontal invasion depth of3.7cm and the back-end horizontal invasion depth of sand pack tube of2.8cm.(2) The invasion depth of plugging agent decreases with the increase of temperature, this is because the hydration degree of the plugging agent slurry is greatly improved along with increasing temperature, calcium silicate hydrates is formed by hydration, leading to the flow property of the plugging agent slurry worse, the coagulation time shorter, the thickening time shorter, the increase of flow resistance, the plugging agent is unable to invade the reservoir deeply. Take class G oil well cement for example, when the temperature is70℃, the vertical invasion depth is81.1cm, the front-end horizontal invasion depth of2.8cm and the back-end horizontal invasion depth of 2.0cm, when the temperature goes up to90℃, the vertical invasion depth is80.0cm, the front-end horizontal invasion depth of2.7cm and the back-end horizontal invasion depth of sand pack tube of1.6cm.(3) The invasion depth of plugging agent increases as the displacement pressure rises; this is because the improvement of displacement pressure can make the slurry of plugging agent invading the sand body deeply. Take KJ-150for example, when the displacement pressure is15MPa, the vertical invasion depth is81.5cm, the front-end horizontal invasion depth of3.2cm and the back-end horizontal invasion depth of sand pack tube of2.2cm. When the displacement pressure rises to27MPa, the vertical invasion depth is greater than98.3cm, penetrating the simulated formation, the front-end horizontal invasion depth of3.8cm and the back-end horizontal invasion depth of2.7cm.(4) The invasion depth of plugging agent increases with increasing displacement velocity, this is because the increase of displacement velocity can make the slurry flow rate of plugging agent increases in the sand body, the vertical invasion depth will increase correspondingly, Take YH-02for example, when the displacement velocity is25.0ml/min, the vertical invasion depth is82.0cm, the front-end horizontal invasion depth of3.2cm and the back-end horizontal invasion depth of sand pack tube of2.3cm. When the displacement pressure goes up to60.0ml/min, the vertical invasion depth is greater than98.3cm, penetrating the simulated formation, the front-end horizontal invasion depth of3.9cm and the back-end horizontal invasion depth of2.8cm.(5) When the displacement pressure is27MPa, the invasion depths of YH-02and KJ-150are both greater than98.3cm, when the displacement velocity is60.0ml/min, the invasion depth of YH-02is greater than98.3cm, penetrating the simulated formation, the invasion depths of GX-land class G oil well cement are both less than98.3cm, the simulated formation can’t be penetrated; the plugging strength of GX-1is greater than26MPa, while the plugging strength of class G oil well cement is16MPa, so we can conclude that the plugging performance of GX-1is better than the other three blocking agents.(6) We established the prediction model of the invasion depth of plugging agent (KTP and KTV the prediction model of the invasion depth) on basis of the function equation by matching the reservoir property parameters, construction parameters and lab physical simulation experimental data, fitted the function equation of the invasion depth of plugging agent for GX-1. Making use of the prediction model of the invasion depth, we reasonably optimized the operation pressure, discharge and consumption parameters etc. at the same time, we also predicted the invasion depth of plugging agent during field operation reasonably making sure that the invasion depth of plugging agent is less than lm, and then make the Perforating gun penetrate the formation.