Chapter 7 Horizontal Drilling

Question 1

In a horizontal well a kick is detected but the influx is still in the horizontal sections of the well. The SIDPP is 0kPa and the SICP is 0kPa. What type of kick is this?

Answer 1

Swab kick as the SIDPP and the SICP are zero.

Question 2

When drilling a horizontal well, what is an extra precautions that should be considered in terms of well control?

Answer 2

The MACP in multilateral wells should be calculated based on the weakest formation of all wellbores.

Question 3

Why does gas migrate faster in deviated wells than in comparable vertical wells?

Answer 3

This occurs due to segregation developing in the bore hole, with the lighter fluid tending to rise on the high side of the hole whereas heavier mud moves down the low side of the hole.

Question 4

Describe one well control prevention mitigations when drilling horizontal wells:

Answer 4

1) During well planning, a casing seat should be set as close as possible to the horizontal section. This will allow adequate mud weight to be used to prevent underbalanced without risking the integrity of the formation at the shoe.

Question 5

Describe kick prevention mitigations when tripping in horizontal wells?

Answer 5

• Use the trip sheet and trip tank to monitor the well during trips.
• Trip speed must be minimized to limit swab pressures. Move the pipe slowly until the bit is above the build section and cuttings beds risk are low.
• Minimize the number of round trips by optimizing the drill string & but design.

Question 6

True or False: Unlike in vertical holes, it is often not possible to immediately detect the presence of an influx in the horizontal section by flow checking or shutting the well in.

Answer 6

True:
When the influx reaches the deviated of vertical section of the well, there will be a negligible hydrostatic change resulting from dilution of the mud in the annuals by low density influx fluid.

Question 7

In a shallow horizontal well the kick is not immediately detected. Why is there no increase on the PVT till the kick is close to surface?

Answer 7

The gas will only expand once it leaves the horizontal section.

Question 8

True or False: Using a kick sheet designed for high angle wells to calculate the drill pipe pressure schedule, will result in higher pressures?

Answer 8

False:
Using a vertical designed kill sheet on high angle wells will result in higher well pressures and possible fractured formations.

Question 9

Drillers Method Step #1 - Bubbles

Answer 9

1) Well shut in Pressures Stablished - SIDPP & SICP
2) Pump started at reduced speed - ICP=RSPP+SIDPP & CP=SIDP
3) Circulation continued with gas to surface - ICP=RSPP+SIDPP & CP=Given
4) Invading Fluid is circulated from the annulus tank gain to zero - ICP=RSPP+SIDPP & CP=SIDPP
5) Pump stopped well shut in - DPP=SIDPP & CP=SIDPP

Question 10

Drillers Method Step #2 - Bubbles

Answer 10

1) Well Shut in after step 1 - SIDPP=SIDPP & SICP=SIDPP
2) Pump started at reduced speed - ICP=SIDPP+RSPP & CP=SIDPP
3) Kill mud density reached the bit - FCP & CP=SIDPP
4) Pump stopped - SIDPP=0 & CP=SIDPP
5) Circulation resumed at reduced speed - FCP & CP=SIDPP
6) Wellbore displaced with kill mud, Pump stopped trapped pressure bled off - SIDPP=0 & SICP=0