Sharing Knowledge Class

DETAILED DRILLING

Presented by:

Arif Fajar UtomoL2C008118

INTRODUCTION

What is Drilling?Drilling is the only way to verify that a petroleum reservoir probably exists, also the only way to get the petroleum from the reservoir.

The story of oil well drilling is started in the 1800s, at the dawn of industrial revolution and at the time when people need something better than candle to work and read by. Responding to the demand for reliable lighting, companies and people started to find and produce oil lamps that were brighter than candles, and the best oil lamps went for petroleum (in the 1854).

The first well successfully drilled is the Drake Well on 1850s using a Cable Tool Drilling Method which quite different with the nowadays commonly drilling method: The Rotary Drilling Methods.

So, in almost every part in the world, the drilling method goes for the rotary one, and it can be implemented in drilling oil, gas, water, geothermal, petroleum, and mine.

ROTARY DRILLING

There are several differences between the rotary drilling and the cable one, the differences are in the drill bit, the placement of the bits, the way it move, and the use of the drilling fluids.

Rotary rig uses a bit that isn’t anything like cable-tool’s chisel bit. It has rows of teeth or other types of cutting devices that penetrate the formation and then scrape or gouge out pieces of it as the rig system rotates the bit.

Rotary rig doesn’t use cable to suspend the bit in hole, rotary crew members attach the bit to the end of a long string of hollow pipe and it moves in rotary way driven by the rotary table.

In rotary, we knew about the drilling fluid system (also named for the circulating system), in cable tool, they use a manual system.

Normal Drilling Operation

In normal drilling operation, we simply divide the process into several steps. That are :The attachment of the drilling apparatus into the hole.The drilling process.Casing and CementingThe Final Preset Depth TestWell Completion

In this phase, the drilling crews place the drill bit, the drill collar, and the drill pipe and then attach it with kelly and put it on the turn table, then we begin to drill the hole.

The attachment of the drilling apparatus into the hole

The Drilling Process

The drilling process refers to the drilling itself. In this phase the drill bit will move in a rotary motions and begin to cuts up the rock formation. As the drilling progresses, the drilling crews circulate the mud through the pipe in order to push the rock cuttings out of the hole. This will continue, until the preset depth is being reached.

Casing and Cementing

When the preset depth is being reached, things we need to is to run the casing and do the cementing. The purpose of the casing is to prevent the hole from the collapsing. To stick the casing with the hole, we use cement. The cement we use mostly is a portland cement that mixed with some additives and water.

In the cementing, we know two methods, the primary cementing and the squeeze cementing that goes hand in hand.

The primary cementing is the first cementing process we do in the hole (between the outside diameter of the casing and inner diameter of the hole)

After that, we do testing towards the result of the primary cementing process. The test varies from hardness properties, alignment, and proper sealing. If the result is good enough, then we don’t have to do the squeezing cementing, and if it is bad, then we have to.

The Final Preset Depth Test

Actually in drilling we will do such the same thing repeatedly until we reach the final preset depth. And when the final preset depth is expected to be reached (usually known from the rock cuttings), we do 3 kind of tests (may be more) in order to ensure that that was the final depth. The tests are: well logging, drill stem testing, and core sampling

Well Logging

The purpose of this test is to take a measurement of the rock formation there. And in well logging, we knew several methods such electrical logging, radioactive logging, mud logging, and accoustic logging

Drill Stem Testing

The drill stem testing purpose is to measure the pressure of the recent depth in the hole by using such a device.

Core Sampling

Core sampling, don’t misunderstood this as mud logging, they are DIFFERENT. In core sampling or coring, you take the whole long formation from the top into the reservoir using a pipe then you analyzed it, not analyzing the rock cuttings that is being delivered by the drilling mud.

After the test done and the results was positive that it is the final depth, we start doing as what we call for well completion, and this is the one step we do before starting the production phase.

Well Completion

We begin the well completion by lowering doing the perforation. In perforation, we knew several methods that based on the what we use to do the perforation. We can use the perforating gun, acid, and hydraulic fracturing method. But however, the 3 of them has the same purpose: to do a perforation in our reservoir formation.

If we use the perforating gun, we will use explosive charges to create holes that goes through the casing into the rock formation, so that we can make such a tunnel in the formation in which oil can flow.

We use the acid, when the reservoir formation is mainly limestone. The acid is sent down, same to make a tunnel, by dissolving the limestone. If the limestone formation is hard, we add pressure on the acid flow.

While hydraulic fracturing is being implemented when the reservoir rock is mainly sandstone. In HF, we use a high enough viscosity fluid that contain proppant that pumped into the reservoir in high pressure to make the tunnel. The proppant hold the the crack open.

Well Completion

After the perforation is done, we put the tubing on the hole as a conduit for oil and gas to flow up the well. The tubing is being hold by the packers to form a seal around the outside of the tubing, so it will be steady. Finally we put a multivalve structure (the chrismast tree) at the top of the tubing, the christmas tress allow us to control the flow of the oil and also to make such a great pressure difference between the surface and the reservoir.

Thank you for your attention!