Evaluation and application of blast furnace slag as a mud cake modifier

Figures & data

Figure 1 SWB based on physical properties and compaction law of interlayer.

Figure 2 Experimental sample of curing moulding.

Figure 3 Test of shear force at cement–formation interface. (a) Modified compression tester and (b) schematic diagram of test.

Figure 4 Effects of BFS as a mud cake modifier on drilling fluid rheology.

Figure 5 Relationships of SSCFI with MCM addition and curing time. (a) Mud cake thickness is 0.5 mm; (b) mud cake thickness is 0.7 mm and (c) mud cake thickness is 1.0 mm.

Table 1 Increasing rate of SSCFI based on Figure 5.

		Increasing rate of SSCFI (%)
Mud cake thickness (mm)	Curing time (days)	0.5 wt% MCM	1.0 wt% MCM	1.5 wt% MCM	2.0 wt% MCM	2.5 wt% MCM
0.5	2	910.44	1228.88	1363.11	1252.00	1472.00
	7	847.03	1050.46	1302.03	2218.75	2513.90
	15	373.84	366.55	313.83	781.03	741.10
	30	386.51	385.15	370.67	601.91	803.72
0.7	2	215.25	342.71	406.44	1001.36	1669.49
	7	592.89	1057.40	1353.85	4178.70	4618.34
	15	361.08	875.71	949.06	1860.14	2187.02
	30	216.07	523.42	824.34	1113.43	1368.43
1.0	2	1287.50	1359.38	1359.38	13843.75	14262.50
	7	20.93	170.80	98.71	2346.77	2871.00
	15	150.18	92.14	121.52	1636.03	1912.09
	30	–	496.00	537.41	4071.53	4237.18

Figure 6 XRD diffraction patterns of agglomerated cake (The data are XRD intensity, cps).

Figure 7 TG curves of hardened cement paste, mud cake, agglomerated cake and substance between the hardened cement paste and the agglomerated cake.

Table 2 Application effects of MCM on drilling fluid rheology from five wells.

		Addition (t)		Marsh funnel	Initial/final gel	Water	Mud cake	Plastic	Yield
Well number	Depth (m)	MCM	XY-27	viscosity (s)	strength (Pa)	loss (ml)	thickness (mm)	viscosity (mPa s)	point (Pa)
H11-12	1692	0	0	64	2/4	5.5	0.4	19	13.5
	1694	2.0	0.48	51	2/3	6.7	0.5	17	11
	1696	0	0	51	2/5	6.7	0.5	17	11
	1708	1.0	0.25	57	2/5	6.5	0.5	18	12
	1710	0	0	75	2/5	8	0.5	20	12
	1728	0	1.0	56	2/5	6.8	0.5	19	13
H12-8	1760	0	0	50	1.5/11.5	4.8	0.5	16	12
	1800	1.1	0.45	48	1.5/12	5.0	0.5	15	12
	1833	0	0	51	2.5/8	5.6	0.4	14	11
	1881	0.4	0.13	53	3/11	7.2	0.4	17	14
	1883	0	0	53	3/10	7.2	0.4	16	13
	1894	0.35	0.1	50	3/12	7.0	0.7	17	16
H11-708	1690	0	0	63	2/4	5.5	0.4	19	13.5
	1694	2.0	0.48	50	2/3	6.7	0.5	18	10
	1695	0	0	50	2/5	6.7	0.5	18	10
	1700	1.0	0.25	56	2/5	6.5	0.5	19	12
	1706	0	0	74	2/5	8	0.5	20	11
	1728	0	1.0	57	2/5	6.8	0.5	19	13
H10-508	1775	0	0	57	2/4	4.4	0.4	22	8
	1816	0.75	0.5	48	1.5/3	4.4	0.4	16	12
	1830	0	0	48	1.5/3	4.4	0.4	16	12
	1859	0.75	0.5	55	1/3	4	0.5	23	12
	1870	0	0	55	1/3	4	0.4	23	12
	1893	0.75	0.5	51	3/7	4	0.5	15	8
H9-108	1690	0	0	41	1/6	7.6	0.4	10	5
	1694	2.0	0.5	45	1/6	7.6	0.5	11	9
	1695	0	0	46	1/6	–	–	10	5
	1700	0.5	0	43	1.5/9	–	–	14	10
	1706	0	0	46	2/8	–	–	16	5
	1728	0.5	0.13	43	3/10	–	–	17	13

Table 3 Application effects of five wells.

Well number	Length of isolation interval (m)	High quality length (m)	High quality rate of well cementing (%)
H11-12	466	437.1	93.79
H12-8	518.2	449.2	86.68
H11-708	466	307.9	66.07
H10-508	481.64	409.64	85.05
H9-108	731	624.7	85.45