PRABUMULIH, (SOUTH SUMATRA),
PP - 025 boreholes Blowout Causes Gutter Talang Jimar Sub Prabumulih
Likes South City-owned wells Prabumulih namely Pertamina EP Region
Sumatera (31/03) allegedly due to kick can not be overcome. Kick is the leakage of fluid formation (oil, gas, or water) from the soil into the hole that is being drilled accidental.
During normal drilling takes place, in general use Overbalance Drilling method, meaning that in the wellbore is filled with mud that has a certain density so having the hydrostatic pressure that exceeds the formation pressure (pore fluid pressure on the underground rocks) were penetrated, but in other cases there are also Underbalance Drilling method that was used to penetrate the formation pressure is very low, even lower than the fresh water column even known with subnormal zone.It is said to be the Chairman of the Assembly of Experts Association of Indonesian Petroleum Engineers (IATMI), Dr.-Ing Ir Rudi Rubiandini when confirmed about the causes of accidents in the drilling of exploration wells in Prabumulih.
Kick is the leakage of fluid formation (oil, gas, or water) from the soil into the hole that is being drilled accidental. This can occur when the pressure in the hole is smaller than the penetrated formation pressure, which should actually mud hydrostatic pressure greater than the formation being penetrated drilling chisel.
Blowout is the formation fluid flow (underground) uncontrolled which is a continuation of uncontrolled kick. "Currently, we are familiar Surface Blowout (SBO) which is the flow of control is up above the soil surface through the wellbore, while Underground Blowout (UGBO) occurs below the soil surface and seeps to the surface or to another layer beyond the wellbore, "said independent analyst Porong mudflow disaster of this ITB.
Rudi said, statistically about 65% of the blowout that occurred is UGBO. Where the costs can UGBO control of hundreds of thousands of dollars to tens of millions of dollars. Indonesian history had a cost of 30 million dollars in one company in East Kalimantan, and some are up to 60 million dollars as well as in eastern Kalimantan in the oil and gas fields in the sea.
Cause of the blowout is when the kick can not insurmountable, either because the kick coming too fast, or too slow because the operator knows, or because it is naturally very violent nature, such zones are very high-pressure gas.
"When at last blowout occurs, the first tendency will lead to SBO, then the officer will usually immediately cover with Blow Out Preventer (a tool that serves as an insulator on the surface), then do the Pressure Control to immediately issue a fluid kick with the appropriate way to pump mud and open the valve according to the procedure, " his said
However, sometimes when the pressure control was apparently under pressure from forces far exceeds the power of rock-and casing at the top, then it could happen UGBO.Cause until the UGBO technically, first, due to the pressure in the wellbore beyond the power of formation, at the time of issuing the kick. Good kick caused by abnormal formation or accidental loss and kick.
"How to overcome it is to stop the operation, the corresponding inject heavy mud, cement part, and install additional string of casing," he said.
Cause UGBO, second, the gas flowing in the annulus behind the casing after cementing. The damage is usually very fast and extreme. Blowout control options are very limited. Loss or platform wells are common in these cases.
During normal drilling takes place, in general use Overbalance Drilling method, meaning that in the wellbore is filled with mud that has a certain density so having the hydrostatic pressure that exceeds the formation pressure (pore fluid pressure on the underground rocks) were penetrated, but in other cases there are also Underbalance Drilling method that was used to penetrate the formation pressure is very low, even lower than the fresh water column even known with subnormal zone.It is said to be the Chairman of the Assembly of Experts Association of Indonesian Petroleum Engineers (IATMI), Dr.-Ing Ir Rudi Rubiandini when confirmed about the causes of accidents in the drilling of exploration wells in Prabumulih.
Kick is the leakage of fluid formation (oil, gas, or water) from the soil into the hole that is being drilled accidental. This can occur when the pressure in the hole is smaller than the penetrated formation pressure, which should actually mud hydrostatic pressure greater than the formation being penetrated drilling chisel.
Blowout is the formation fluid flow (underground) uncontrolled which is a continuation of uncontrolled kick. "Currently, we are familiar Surface Blowout (SBO) which is the flow of control is up above the soil surface through the wellbore, while Underground Blowout (UGBO) occurs below the soil surface and seeps to the surface or to another layer beyond the wellbore, "said independent analyst Porong mudflow disaster of this ITB.
Rudi said, statistically about 65% of the blowout that occurred is UGBO. Where the costs can UGBO control of hundreds of thousands of dollars to tens of millions of dollars. Indonesian history had a cost of 30 million dollars in one company in East Kalimantan, and some are up to 60 million dollars as well as in eastern Kalimantan in the oil and gas fields in the sea.
Cause of the blowout is when the kick can not insurmountable, either because the kick coming too fast, or too slow because the operator knows, or because it is naturally very violent nature, such zones are very high-pressure gas.
"When at last blowout occurs, the first tendency will lead to SBO, then the officer will usually immediately cover with Blow Out Preventer (a tool that serves as an insulator on the surface), then do the Pressure Control to immediately issue a fluid kick with the appropriate way to pump mud and open the valve according to the procedure, " his said
However, sometimes when the pressure control was apparently under pressure from forces far exceeds the power of rock-and casing at the top, then it could happen UGBO.Cause until the UGBO technically, first, due to the pressure in the wellbore beyond the power of formation, at the time of issuing the kick. Good kick caused by abnormal formation or accidental loss and kick.
"How to overcome it is to stop the operation, the corresponding inject heavy mud, cement part, and install additional string of casing," he said.
Cause UGBO, second, the gas flowing in the annulus behind the casing after cementing. The damage is usually very fast and extreme. Blowout control options are very limited. Loss or platform wells are common in these cases.
According to him, the mud weight required to handle certain scenarios mud-weight little difference and formation integrity. Certainly require further drilling mud weight gain, which may exceed formation integrity. Mud losses can only occur directly on the top layer. The solution casing or liner must be installed and cemented in order to isolate the zones at deeper intervals and high pressure.
Third, there UGBO sidetracking the well during the previous kick, pipes are often caught (stuck) in most of the openhole section, especially at the top of the casing near the base. Sidetracking begins by putting a solid foundation, like a whipstock, to start bending direction. The oldest and is commonly performed using a cement plug in the openhole section in the drillstring fish. The top of the cement plug was drilled to the solid part cement. This process ultimately leaving only a small portion of cement on top of fish. This can lead to UGBO re-occur. This scenario is very dangerous and difficult to control,
Fourth, due to the failure of the cement seal in the annulus, production problems such as this can also result in UGBO during normal production, namely: pressure drop in production, while the pressure in the other zones, both below and above the production zone, remains the same as before. Along with the increased pressure difference between tersbut formation, would result in a potential outbreak of the cement seal for this. Failure of the cement seal mengakibatakan fluid can flow vertically upwards or downwards. Perforation is an effective solution and squeeze cementing between the flow interval.
Fifth, casing failures can result in UGBO too. The level of damage is a function of depth source of the leak and pressure flow source. The deeper the location of the leak, the less likely it will flow to the surface.He said, from these examples outlines most common cause of kick and blowout, either SBO or UGBO.
"It must be understood carefully and always be reviewed periodically to ensure that the drilling teams to understand and put in planning possibilities that will happen. Even more importantly, the symptoms must always be taken when drilling takes place by each executing drilling to raise awareness of the occurrence of kick and blowout, " Rudi he said. (PP / RED)
Third, there UGBO sidetracking the well during the previous kick, pipes are often caught (stuck) in most of the openhole section, especially at the top of the casing near the base. Sidetracking begins by putting a solid foundation, like a whipstock, to start bending direction. The oldest and is commonly performed using a cement plug in the openhole section in the drillstring fish. The top of the cement plug was drilled to the solid part cement. This process ultimately leaving only a small portion of cement on top of fish. This can lead to UGBO re-occur. This scenario is very dangerous and difficult to control,
Fourth, due to the failure of the cement seal in the annulus, production problems such as this can also result in UGBO during normal production, namely: pressure drop in production, while the pressure in the other zones, both below and above the production zone, remains the same as before. Along with the increased pressure difference between tersbut formation, would result in a potential outbreak of the cement seal for this. Failure of the cement seal mengakibatakan fluid can flow vertically upwards or downwards. Perforation is an effective solution and squeeze cementing between the flow interval.
Fifth, casing failures can result in UGBO too. The level of damage is a function of depth source of the leak and pressure flow source. The deeper the location of the leak, the less likely it will flow to the surface.He said, from these examples outlines most common cause of kick and blowout, either SBO or UGBO.
"It must be understood carefully and always be reviewed periodically to ensure that the drilling teams to understand and put in planning possibilities that will happen. Even more importantly, the symptoms must always be taken when drilling takes place by each executing drilling to raise awareness of the occurrence of kick and blowout, " Rudi he said. (PP / RED)
