IWCF Level 1 | Module 2 | Life Cycle of a Well — Transcript

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1. 0:03welcome to module 2
2. 0:04life cycle of a well
3. 0:08by the end of this module you should be
4. 0:10able to
5. 0:11describe the basic life cycle of a well
6. 0:15the main components used in the drilling
7. 0:17process
8. 0:19describe the casing and cementing
9. 0:20process
10. 0:22define the different methods of well
11. 0:24intervention
12. 0:25and describe how a well is plugged and
13. 0:27abandoned
14. 0:32this module consists of five chapters
15. 0:34they are
16. 0:36drilling
17. 0:37casing and cementing
18. 0:40completions
19. 0:41well intervention and work over and
20. 0:44plugging and abandonment
21. 0:47each chapter will end with a short
22. 0:48knowledge check to confirm your learning
23. 0:53chapter one
24. 0:54drilling
25. 0:57once we have identified an appropriate
26. 0:58location we then make plans to drill a
27. 1:01well
28. 1:02this is the only sure way to find out if
29. 1:04there are hydrocarbons present
30. 1:13construction of any well will follow a
31. 1:15series of defined steps
32. 1:17although the steps may vary slightly
33. 1:19depending on the type of well being
34. 1:21drilled
35. 1:22exploration wells or wildcats as they
36. 1:25are sometimes known are drilled to
37. 1:27confirm the presence of hydrocarbons
38. 1:30appraisal wells are drilled to discover
39. 1:32the extent of the oil or gas field
40. 1:35development wells are drilled to produce
41. 1:37the oil or gas that has been discovered
42. 1:39after the exploration and appraisal
43. 1:40wells have been drilled
44. 1:43in this module we will go through the
45. 1:45complete life cycle of a development
46. 1:47well from initial drilling to
47. 1:49abandonment
48. 1:57searching for oil or gas is not so very
49. 2:00different from digging a hole in the
50. 2:01ground
51. 2:03imagine you begin to dig
52. 2:06and keep on digging and digging
53. 2:09and digging
54. 2:11when you reach a certain depth there is
55. 2:12a risk that the walls will cave in this
56. 2:15could pose a danger to life or the
57. 2:17environment and the hull will also be
58. 2:19lost
59. 2:20naturally we must prevent this from
60. 2:21happening and we can do this by
61. 2:23supporting the wall of the hole
62. 2:25in this case we have placed a piece of
63. 2:27pipe in the hole but in the oil field
64. 2:29this is called casing this first casing
65. 2:32will typically be up to 30 inches in
66. 2:34diameter as it will need to be big
67. 2:36enough to allow all the other different
68. 2:38sized casings which may need to be used
69. 2:40as the hole gets deeper to pass through
70. 2:42it
71. 2:44this piece of casing will often pass
72. 2:46through natural groundwater courses or
73. 2:48aquifers that can run close to ground
74. 2:50level
75. 2:51on its own the casing is unable to
76. 2:53isolate the well from these ground water
77. 2:55supplies so we usually have to cement it
78. 2:58in place we will take a closer look at
79. 3:00this process later on
80. 3:02now that the casing is in the ground and
81. 3:04firmly cemented in place
82. 3:06we can continue digging for hydrocarbons
83. 3:08safely
84. 3:12before we start digging or drilling in
85. 3:15oil field terms we need a drilling rig
86. 3:18this is a collection of complex
87. 3:19machinery that is used to drill through
88. 3:21the earth to reach the hydrocarbons
89. 3:24although drilling rigs come in many
90. 3:26different forms they all have to do the
91. 3:27same job to support heavy weights and
92. 3:31rotate the drill bit
93. 3:32we will study drilling rigs and the
94. 3:34people that work on them in later
95. 3:36modules but for now let's focus on the
96. 3:38drill bit
97. 3:41when using an electric drill at home you
98. 3:44must select the drill bit you need for
99. 3:46the job you're doing for instance if you
100. 3:47try to drill brick with a wood bit you
101. 3:50would just blunt the bit and hardly make
102. 3:52any impression on the brick
103. 3:54the same principle applies when drilling
104. 3:56a well
105. 3:59the drill bit is attached at the extreme
106. 4:01end or bottom of the drill string
107. 4:04the drill string is another name for the
108. 4:06many short lengths or joints of drill
109. 4:09pipe that are joined together as the
110. 4:11hole gets deeper
111. 4:12each section of drill pipe is typically
112. 4:1430 feet long and joined together by
113. 4:16threaded connections at each end which
114. 4:18allow the sections to screw into each
115. 4:20other there is a range of other
116. 4:22equipment that is also added to the
117. 4:23drill string we will look at these in
118. 4:25later modules
119. 4:28so how does the drill bit work
120. 4:31quite simply it crushes and grinds up
121. 4:33the rocks as it goes deeper and deeper
122. 4:35into the earth these crushed up pieces
123. 4:37of rock are called cuttings
124. 4:40the type of drill that used is dependent
125. 4:42on the type of rock that is being
126. 4:43drilled through
127. 4:47a tricone bit has a set of three
128. 4:49rotating cones with teeth or inserts
129. 4:52which crush the formation allowing the
130. 4:54mud to remove the cuttings they can be
131. 4:56used in soft or hard formations
132. 4:58depending on the teeth or inserts used
133. 5:02poly crystalline diamond compact or pdc
134. 5:06bits have cutters which shear the rock
135. 5:08with a continuous scraping motion
136. 5:10they're designed primarily for formation
137. 5:12such as shale
138. 5:14a diamond bit uses industrial grade
139. 5:17diamonds to simply grind away the
140. 5:19formation they are designed for very
141. 5:21hard formations
142. 5:23if the cuttings were to remain in the
143. 5:25hole they would jam up the drill bit and
144. 5:27make the drill string drag on the well
145. 5:29bore but which is what we call the hole
146. 5:31that has been drilled
147. 5:32this means that the cuttings have to be
148. 5:34brought to the surface
149. 5:36the cuttings are carried to the surface
150. 5:38using a blend of liquids and additives
151. 5:40called drilling fluid or mud
152. 5:43the mud is mixed and taken from mud
153. 5:45tanks or pits before being pumped down
154. 5:48the drill string
155. 5:50it exits the drill string through holes
156. 5:52or jets situated in the drill bit
157. 5:55the mud then returns to the surface via
158. 5:57the space between the outside of the
159. 5:59drill string and the open hole or casing
160. 6:02this space is called the annulus
161. 6:05the mud is returned to the mud pits
162. 6:06through a return pipe attached to the
163. 6:08top of the 30 inch casing once all the
164. 6:11cuttings have been filtered and
165. 6:12separated out
166. 6:16the mud performs several other important
167. 6:18jobs besides carrying the cuttings up
168. 6:20the well
169. 6:21mud cools the drill bit as it drills
170. 6:24through the earth and most importantly
171. 6:26the weight of the entire column of mud
172. 6:28is used to hold back the pressure
173. 6:29contained in the different layers of
174. 6:31rock and in the reservoir
175. 6:33the pressure created by the weight of
176. 6:35all the mud in the hole is designed to
177. 6:37stop formation fluids flowing into the
178. 6:39well
179. 6:40if this is not contained it could result
180. 6:42in a blowout
181. 8:07chapter 2 casing and cementing
182. 8:13a well is drilled in stages
183. 8:15this means that we start drilling with a
184. 8:17large diameter bit before stopping at a
185. 8:20predetermined depth and putting in new
186. 8:22casing
187. 8:23this casing must then be cemented in
188. 8:25place to support the newly drilled
189. 8:27section of the hole
190. 8:29to drill the next section of the well a
191. 8:31smaller drill bit must be used so that
192. 8:33it can pass through the casing which has
193. 8:35just been put in place
194. 8:37the diameter of each whole section and
195. 8:39the depth to which it is drilled can
196. 8:41vary quite a lot depending on location
197. 8:44geology and of course the final depth
198. 8:47that the well will be drilled to
199. 8:51as you have already seen a well is
200. 8:53usually drilled in four or five stages
201. 8:55each being drilled at a diameter smaller
202. 8:57than the one before it
203. 8:59a typical casing scheme for a well with
204. 9:01four casings could look like this
205. 9:04first a 36 inch diameter hole is drilled
206. 9:07and the 30 inch casing is placed in the
207. 9:09well
208. 9:10next a 26 inch hole is drilled and 20
209. 9:13inch casing is run
210. 9:15then a 17 and a half inch hole is
211. 9:17drilled and 13 and 3 8 inch casing run
212. 9:21finally a twelve and a quarter inch hole
213. 9:23is drilled and nine and five eighths
214. 9:25inch casing run
215. 9:27all of these are cemented in place
216. 9:30the next hole section usually across the
217. 9:33reservoir is typically eight and a half
218. 9:36inch
219. 9:37a seven inch casing is run in the eight
220. 9:39and a half inch hole section
221. 9:42it may be run back to surface and
222. 9:43cemented in the same way as the other
223. 9:45casing strings or suspended from the
224. 9:48bottom of the nine and five eighths inch
225. 9:50casing in which case it is known as a
226. 9:52liner
227. 9:54the liner may or may not be cemented in
228. 9:56place
229. 9:58the use of a liner saves time and money
230. 10:00as much less casing and cement is
231. 10:02required
232. 10:59we will now demonstrate how a section of
233. 11:01casing is cemented in place
234. 11:04having already set the 30 inch conductor
235. 11:06casing in position
236. 11:09drilling recommences and the bit is
237. 11:12rotated and
238. 11:21pushed down by the weight of the drill
239. 11:23string and its components
240. 11:26at the required depth drilling stops and
241. 11:28drilling fluid is pumped through to
242. 11:30clean the cuttings from the hole the
243. 11:32drill string is withdrawn and casing is
244. 11:34lowered
245. 12:15we will now demonstrate how a section of
246. 12:17casing is cemented in place
247. 12:19having already set the 30 inch conductor
248. 12:22casing in position
249. 12:25drilling recommences and the bit is
250. 12:28rotated and pushed down by the weight of
251. 12:30the drill string and its components
252. 12:33at the required depth drilling stops and
253. 12:35drilling fluid is pumped through to
254. 12:37clean the cuttings from the hole the
255. 12:39drill string is withdrawn and casing is
256. 12:41lowered to the bottom of the hole
257. 12:58a special rubber plug is inserted via a
258. 13:00cement head into the top of the casing
259. 13:03cement is pumped after it and down the
260. 13:05casing until the correct volume of
261. 13:07cement has been pumped
262. 13:08then a second plug is inserted
263. 13:11this is then pumped until the first or
264. 13:13bottom plug bumps against the bottom of
265. 13:16the casing
266. 13:17pressure builds up until a diaphragm
267. 13:20fitted in the first plug bursts allowing
268. 13:22cement to flow into and up the annular
269. 13:25space outside the casing
270. 13:27cement flows until the second or top
271. 13:30plug hits the body of the bottom plug
272. 13:33as this plug is solid and doesn't
273. 13:35contain a diaphragm pressure builds
274. 13:38this pressure rise is used as an
275. 13:40indication to stop the cementing pump
276. 13:43when drilling restarts a smaller bit is
277. 13:46used the plugs are drilled through
278. 13:48creating the next whole section
279. 13:51once the drilling of this section is
280. 13:52finished smaller casing will be run into
281. 13:54it and the whole cementing process
282. 13:56repeated
283. 14:00casing is made up in sections or joints
284. 14:02to form longer lengths called casing
285. 14:04strings
286. 14:06joints are usually about 40 feet long
287. 14:08connected together and lowered into the
288. 14:10hole until the designated depth for the
289. 14:11casing has been reached
290. 14:13each connecting joint has to be
291. 14:15tightened up to a specified torque or
292. 14:18force with thread lubricating compound
293. 14:20being used on the two ends to help
294. 14:22ensure a tight seal
295. 14:25every so often centralizers are attached
296. 14:27to the casing as it is being run into
297. 14:29the well
298. 14:30centralizers are bow shaped strips of
299. 14:33spring steel that help keep the casing
300. 14:35centralized within the well ball
301. 14:37the well is conditioned prior to
302. 14:39cementing by circulating clean drilling
303. 14:41fluid down the casing and up the annulus
304. 14:44this is designed to prevent cement being
305. 14:46contaminated when it is placed in the
306. 14:48hole
307. 14:51when the 20 inch casing has been set and
308. 14:53cemented in place the blowout preventers
309. 14:56or bops will be put in place
310. 14:59as the name implies bops protect the
311. 15:01well by preventing blowouts and
312. 15:03controlling unexpected conditions that
313. 15:05may affect the stability of the well
314. 15:07prior to the installation of bops any
315. 15:10formation fluids released would be
316. 15:11diverted away from the rig
317. 15:14we will learn more about bops in modules
318. 15:16three and four
319. 15:24as drilling continues the mud weight is
320. 15:26altered to allow the changes in the
321. 15:28formation and pressures that may be
322. 15:30encountered
323. 15:32if formation fluids enter the wellbore
324. 15:34the bop would be closed to stop the flow
325. 15:37and prevent the fluids from reaching the
326. 15:39surface and allow us to regain control
327. 15:45cementing is a key feature in the life
328. 15:48cycle of a well from cementing the
329. 15:50casing through to remedial cementing and
330. 15:52finally when the well is to be plugged
331. 15:54and abandoned
332. 15:56the cement that has been placed between
333. 15:58the casing and the wellbore has to last
334. 16:00the life of the well and the integrity
335. 16:02of the well is dependent on the quality
336. 16:04of the cement jobs
337. 16:06each section of the well that is
338. 16:08cemented will have its own special
339. 16:09recipe
340. 16:11this is referred to as the cement slurry
341. 16:14the recipe for a cement slurry has to
342. 16:16ensure the ideal bond between casing and
343. 16:18wellbore
344. 16:19various additives go into the slurry to
345. 16:21keep it compatible with the formation
346. 16:24stop it setting too quickly or too
347. 16:26slowly in some cases
348. 16:28and ensure it is easily pumped
349. 16:30before the cement slurry is mixed and
350. 16:32pumped it is tested in a laboratory to
351. 16:35be certain that it is exactly right
352. 16:41as the integrity of the cement job is so
353. 16:43important an electronic tool is lowered
354. 16:46into the casing to verify the cement is
355. 16:48where it should be and is completely
356. 16:50bonded to the casing and wellbore
357. 16:53when approximately 30 feet of new whole
358. 16:55section has been drilled the first job
359. 16:57to be carried out is a formation
360. 16:59integrity test or leak-off test
361. 17:02this involves gradually pumping a small
362. 17:04amount of drilling fluid into the well
363. 17:06until it reaches a designated pressure
364. 17:08many factors affecting well control rely
365. 17:11on this test but it is also used to
366. 17:13evaluate the strength of the cement bond
367. 17:15to ensure there are no possible leak
368. 17:17paths to formations higher up in the
369. 17:19well and to confirm the new whole
370. 17:21section is strong enough for the maximum
371. 17:23mud weight required to drill the next
372. 17:25section
373. 18:24chapter 3
374. 18:26completions
375. 18:30once the targeted well depth is reached
376. 18:33the formation must be tested and
377. 18:35evaluated
378. 18:36core samples may be taken and analyzed
379. 18:39to determine whether the well will be
380. 18:40completed for production or plugged and
381. 18:42abandoned
382. 18:44to determine the potential of a
383. 18:45producing formation the operator may
384. 18:47order a drill stem test or dst
385. 18:51the well is perforated and then flowed
386. 18:53through a temporary test drill string
387. 18:56and flared at various pressures and flow
388. 18:58rates which involves burning off small
389. 19:00amounts of the hydrocarbons produced by
390. 19:02the well
391. 19:03in some instances this can also be done
392. 19:05without the production casing being run
393. 19:11in the case of a production well where
394. 19:13the seven inch liner is already in place
395. 19:16the well will be completed by inserting
396. 19:18a string of production tubing which is
397. 19:20similar to casing but smaller in
398. 19:21diameter
399. 19:23production tubing is anchored and sealed
400. 19:25in the production casing just a short
401. 19:27distance above the liner hanger
402. 19:30the packer is a special tool that is
403. 19:32designed to grip and seal off the
404. 19:33annulus outside the production tubing
405. 19:36and is set in place by applying pressure
406. 19:38or by a sequence of tubing movements
407. 19:41other components are inserted in the
408. 19:43production tubing at strategic points
409. 19:45these will be chosen depending on
410. 19:46anticipated well production
411. 19:48characteristics
412. 19:50closer to the surface a sub surface
413. 19:52safety valve will be included in the
414. 19:54string this is a valve that can be used
415. 19:56to shut the well in from the surface
416. 19:58it is normally held open by pressure and
417. 20:01loss of pressure will automatically
418. 20:03close the valve and shut the well in
419. 20:08before the packer is run a bit and
420. 20:10scraper run is carried out
421. 20:13the bit guides the scraper through the
422. 20:15casing and the scraper cleans the inner
423. 20:17wall of the casing around the area where
424. 20:19the packer is to be set
425. 20:20this helps to make a good seal
426. 20:23the drilling fluid is displaced with
427. 20:25filtered completion fluid which is a
428. 20:27brine based fluid with additives that
429. 20:29inhibit corrosion
430. 20:31the completion fluid must provide
431. 20:32sufficient hydrostatic pressure to kill
432. 20:35the well in the event of the hardware in
433. 20:37the well failing and it must be
434. 20:39compatible with the formation that it
435. 20:40will come into contact with
436. 20:44once the correct amount of production
437. 20:45tubing has been placed in the well the
438. 20:48christmas tree is finally installed
439. 20:50a christmas tree is essentially an
440. 20:52assembly of valves which sits on top of
441. 20:54the well and it connects directly onto
442. 20:57the casing and tubing hangers which hold
443. 20:59the top of the various strings in place
444. 21:02it is designed to ensure that it can
445. 21:03withstand any amount of pressure and
446. 21:05flow that the reservoir can deliver
447. 21:09the valves on the christmas tree provide
448. 21:10a path to allow the well to flow to
449. 21:12production and process equipment they
450. 21:15also provide access to the wellbore for
451. 21:17work over and well interventions to be
452. 21:19able to take place
453. 21:21a further connection and valve on the
454. 21:23side of the christmas tree give access
455. 21:25to the tubing in the event the well
456. 21:27needs to be killed
457. 21:28this would be done by the pumping of
458. 21:30suitably weighted fluid into the
459. 21:32wellbore
460. 21:39the well is now ready to be brought into
461. 21:41operation
462. 21:42to do this the production casing must be
463. 21:45perforated
464. 21:46shaped explosive charges are sent down
465. 21:49the well and placed across the reservoir
466. 21:52the perforating guns can be carried into
467. 21:54the well either by wire line or they can
468. 21:56be attached to the bottom of the drill
469. 21:58pipe or tubing as it is deployed when
470. 22:01they are in place the charges are
471. 22:03detonated
472. 22:04the force of the explosion punches holes
473. 22:06through the casing through the cement
474. 22:08and out into the reservoir rock
475. 23:16chapter 4 well intervention and work
476. 23:19over
477. 23:24work overs will often involve killing
478. 23:25the well then pulling the old completion
479. 23:28or production tubing out before running
480. 23:31in a new completion to reflect the
481. 23:32changing conditions as the well matures
482. 23:36on the other hand one intervention
483. 23:38refers to operations carried out to
484. 23:39alter manage or diagnose well
485. 23:42performance
486. 23:43at any stage in the wells productive
487. 23:45life well intervention can be used to
488. 23:47help maintain optimal operating
489. 23:49conditions
490. 23:52well interventions are often referred to
491. 23:54as rigorous
492. 23:55this means the work is carried out
493. 23:57without a service rig or drilling rig in
494. 23:59attendance as opposed to work over which
495. 24:02generally needs to be rig based
496. 24:05if well entry is not required the
497. 24:07majority of well interventions are
498. 24:08carried out using pumps
499. 24:11wire line and coiled tubing will be used
500. 24:13if there is a need to enter the well
501. 24:15this is called invasive intervention
502. 24:20some well interventions involve running
503. 24:21special electric wire line tools that
504. 24:24log or measure flow rates sensed by the
505. 24:27tools
506. 24:28this may help us to identify where
507. 24:30excess water is being produced or how
508. 24:32and where sand is getting into the well
509. 24:34ball
510. 24:42we may also run slick line which is bare
511. 24:45metal wire with no electrical connection
512. 24:47into the well
513. 24:48on the bottom is a tool which will open
514. 24:50a valve in the side of the tubing
515. 24:52allowing us to inject gas to start or
516. 24:55increase production a technique known as
517. 24:58gas lifting
518. 25:02another operation might involve running
519. 25:04coiled tubing which can be driven deep
520. 25:07into the well in order to inject
521. 25:08chemicals or run specialized tools
522. 25:11it can be used to perform work that
523. 25:13could also be done using slick line or
524. 25:15electric line however coil tubing is
525. 25:18particularly useful as it can more
526. 25:20readily access not only vertical wells
527. 25:22but also deviated and even horizontal
528. 25:25wells which change direction as they are
529. 25:27drilled
530. 25:36to enhance production we might also want
531. 25:39to fracture the well
532. 25:41to do this we pump fluids under high
533. 25:43pressure to fracture the formation
534. 25:45propens such as sand or specifically
535. 25:48sized particles may be used to keep or
536. 25:51prop the fractures open
537. 26:59chapter 5 plugging and abandonment
538. 27:06the final stage in a well's life is
539. 27:08plugging and abandonment
540. 27:11there are three main ways in which this
541. 27:13can be done
542. 27:14they all have one thing in common
543. 27:15however and that is they must comply
544. 27:18strictly with regulatory standards and
545. 27:20specifications
546. 27:23if an exploration well has not
547. 27:25discovered a significant commercial
548. 27:27hydrocarbon show
549. 27:29then it is considered a dry hole and
550. 27:32will be permanently plugged and
551. 27:33abandoned
552. 27:36some wells are temporarily plugged and
553. 27:38abandoned if the well control equipment
554. 27:40such as bops need to be removed but the
555. 27:43intention is to resume well operations
556. 27:46at a later date
557. 27:49finally there are wells that have been
558. 27:51producing for a significant amount of
559. 27:53time but are no longer economically
560. 27:55viable
561. 27:56in this case the well is permanently
562. 27:58plugged and abandoned
563. 27:59but this is only a small yet essential
564. 28:02part of the overall decommissioning
565. 28:04process
566. 28:06at the end of the well's life it will be
567. 28:09decommissioned
568. 28:10in some cases part of the
569. 28:11decommissioning process will involve
570. 28:13running a cement bond log to provide
571. 28:16evidence that the cement is still in
572. 28:17good condition around the casing because
573. 28:20there must be no accidental discharge of
574. 28:22hydrocarbons to surface or into the
575. 28:24water table
576. 28:26the first cement plug is set across the
577. 28:28reservoir or pay zone and left to set
578. 28:31when the cement has gone off the depth
579. 28:33of the top of the fully set cement is
580. 28:36confirmed to ensure that the plug is set
581. 28:38at the correct height
582. 28:41here we see a cement plug being pumped
583. 28:44through the drill pipe and the displaced
584. 28:46liquids going to the surface
585. 28:52typically at least three cement plugs
586. 28:55are set in the well at strategic depths
587. 28:58all of these must be confirmed to be in
588. 29:00the right place and pressure tested to
589. 29:02prove integrity
590. 29:04the christmas tree is removed and the
591. 29:06top of the casing is cut away
592. 29:09for an offshore well the conductor will
593. 29:11be remotely severed at the seabed and
594. 29:13retrieved for disposal
595. 30:16well done you've reached the end of this
596. 30:18module
597. 30:19you should now be able to describe the
598. 30:22basic life cycle of the well
599. 30:25identify the main components used in the
600. 30:28drilling process
601. 30:30describe the casing and cementing
602. 30:32process
603. 30:33define the different methods of well
604. 30:35intervention
605. 30:37and describe how a well is plugged and
606. 30:39abandoned
607. 30:51it's now time to take the final exam
608. 30:54where a pass mark of 70 needs to be
609. 30:56achieved
610. 30:57take if you fail you will be able to
611. 30:59resit the exam you're advised to review
612. 31:01the module before doing so
613. 33:24thank you for completing this training
614. 33:26module we hope this will help you in
615. 33:28your workplace
616. 33:30remember you can revisit this module at
617. 33:32any time to refresh your knowledge