OR/17/037 Appendix 3 - Stratigraphic interpretations

Hannis, S, and Gent, C. 2017. Petrophysical interpretation of selected wells near Liverpool for the UK Geoenergy Observatories project. British Geological Survey Internal Report, OR/17/037.

Table 12    Two stratigraphic interpretations for the 2 wells studied and some nearby wells. All depths in metres

					Borehole	Kemira 1		Ince Marshes		Morley Bridge		Collinge		Hale		Lovel's Hall
					Easting (m)	347586		346211		346181		341429		347077		347964
					Northing (m)	376421		376439		371455		371112		383134		384935
Well top short name and explanation					Interpreter	NS	CW	NS	CW	NS	CW	NS	CW	NS	CW	NS	CW
OD level	Ordnance datum					8.99	8.99	14.33		17.22		14.8		9.79		12.8
Bromsgrove	Bromsgrove Sandstone Formation					39	39
Sherwood	Sherwood Sandstone Group					281	281
TSZ/?KDM	Kidderminster Formation, conglomerate, pebble beds.					523	523					60		30		36
MM/Bold	Manchester Marls Formation, Bold Formation					618	618			22		165		91		100
CS	Collyhurst Sandstone Formation					738	738	200		56		233		268		165
UVAR	Variscan unconformity					1042	1042	272		526		848		557		344
Salop	Salop Formation								200	526		848	870		30		344
Halesowen	Halesowen Formation					1042	1042	272	398a	700	786b	930	1012c	557	NP	400
Etruria	Etruria Formation (ETM)													668	Npe	599	NP
West C	Westphalian C. CW lists Pennine Upper Coal Measures Formation (PUCM)					1221	NP	331	NP							675	700g
West B	Westphalian B. CW lists Pennine Middle Coal Measures Formation (PMCM)					1248	NP	548	NP	969		1172	1169d	708	NP	741	795h
West A	Westphalian A. CW lists Pennine Lower Coal Measures Formation (PLCM)					1401	1079	700	582	1078		1256		745	700f	933.1
MG	Millstone Grit Group (MG)						1432	944.9						1124
CRAVEN GP	Craven Group								1276
TD	Total depth: deepest well penetration depth					1438	1438	1577	1577
WAWK	Warwickshire Group (Calculated from depths West B-UVAR)					205.6		276		443		324		151		397
PT	Permian-Triassic (Calculated from depths UVAR-top of log depth)					1003.4		272		504		788		527		308

Table notes: NS = Nigel Smith (partly chronostratigraphic), CW = Colin Waters (lithostratigraphic). Blue shading indicates the top of the log, yellow indicates a fault. Table notes by CW: a Base of red beds; b At marked change in GR log & appearance of red beds; c At big change in GR & LD logs & near transition to red beds; d Similar to NS interpretation; e Salop above reddened PMCM; f In part reddened; g Top PUCM at fault at 700 m- big change in GR log; h Top PMCM taken at 795 m at Cambriense MB. Base West B would be lower.

In addition to the two stratigraphic interpretations shown in Table 12, interpretations were also available from the company composite log plots or end of well reports. These data were considered during the reinterpretation presented in Table 12. They are listed below in Table 13 and shown, together with those from Table 12, in the output plots for this study (Figure 2 and Figure 9) for ease of comparison between the alternate interpretations.

Nigel Smith’s (NS) partly chronostratigraphic interpretations were selected for use during this study. Statistical summaries of the petrophysical results were output over these formation intervals. Note that the petrophysical interpretation software (IP) requires a formation top and base to be defined, within the available data range. This means the actual tops and bases reported in the tables throughout this report may show these slightly amended formation tops and bases from the NS version reported in Table 12. The values are summarised below in Table 14.

Table 13    Stratigraphy taken from the company composite logs or end of well reports. In addition, Coal seam depths were taken from the End of Well Report, these are shown in Table 10. For explanation of the formation codes, see Table 12

		Kemira 1		Ince Marshes 1
		Top	Base	Top	Base
Company-reported stratigraphy	SSG	24.4	1042.4	4.3	277.4
	Halesowen			277.4	397.8
	UCM	1042.4	1152.1	397.8	710.2
	MCM	1152.1	1274.1	710.2	944.9
	LCM	1274.1	1438.0
	MG			944.9	1280.2
	CRAVEN GROUP			1280.2	1577.0

Table 14    Stratigraphy loaded into interpretation software for this study and depth ranges of outputs. For explanation of the formation codes, see Table 12

		Kemira 1		Ince Marshes 1
		Top	Base	Top	Base
Software outputs	Plot format output:	25	1448	350	1460
	Las data output:	30	1445	327	1458
	Actual interp data interval:	32	1433	368	1452
Formation interval in software (modified from NS, Table 12)	Bromsgrove	39	281
	Sherwood	281	523
	TSZ_or_KDM	523	618
	MM_Bold	618	738
	CS	738	1042
	Halesowen	1042	1221
	West C	1221	1248	368	548
	West B	1248	1401	548	700
	West A	1401	1433	700	945
	MG			945	1452