1access the spreadsheet and gather the relevant

Question

1. Access the spreadsheet and gather the relevant data.

2. Use the appropriate equation (Oddo and Tomson) to compute the scale saturation index, in a spreadsheet.

3. Run a sensitivity on pH.

4. Prepare charts showing the sensitivities.

5. Write a short report, as for Phase 1, with the same sections. You can join the two reports together.

6. Give a conclusion on the scaling risk for calcite scaling and recommend a suitable course of action

Calcite Scale Model from Oddo & Tomson (1994) modified.

SI = log (Ca)(HCO₃)
+ pH - 2. 76

+ (9.88*10-3)T + (0.61*10-6)T2

- (3.03 *10-5)P

- (2.348 *(IS0.5) ) + (0.77*IS)

Where: SI is the Saturation Index of calcite (Ca) and (HCO₃) are the molar concentrations of Ca and HCO₃ ions in mol/L.
The molecular weight of Ca is 40, HCO₃ is 61.
T = temperature in degrees F

P = pressure in psi

IS = ionic strength of the produced water. This should be converted to mol/L by dividing by an average molecular weight (53.4) and converting to litre (outcome is to divide IS by 53400)

Sensitivity Analysis: use the range of temperature and pressure shown on the Well Data worksheet to calculate the SI for a range of T, P and pH. Produce charts of these relationships.

Your report could include one or two pages of text and one page of tables and figures. The text should include the following:

Discussion : You may want to address the following in your discussion:

(a) Explain the mechanism for production of calcite scale?

(b) Describe the relevance of the Saturation Index and the meaning of a negative or positive value?

(c) What are major limitations of your evaluation and what can be measured?

(d) The well is scheduled as part of a large field development, what would you recommend to the Project Manager?

(e) When the well is in operation and producing, how would you monitor the process to ensure the scale risk was minimised.

 

Step 1: Select the well you are to work with:
Well ID	GLR	CO2	Well		Water Composition
	mcf/bbl	mol%	Depth m		Ionic str	Ca mg/L	HCO3 mg/L			Sensitivity
					mg/L
2407540	200	0.35	3500		20100	610	680			T	P	pH
2475553	200	0.35	3400		20200	620	690			degC	Bar
2478369	200	0.35	3300		20300	630	700
2500985	200	0.35	3200		20400	640	710			120	200	3.5
2523204	200	0.35	3100		20500	650	720			110	180	3.8
2606999	200	0.35	3000		20600	660	730			100	160	4.2
2608875	200	0.30	3500		20700	670	740			90	140	4.6
2622438	200	0.30	3400		20800	680	750			80	120	5.0
2622497	200	0.30	3300		20900	690	760			70	110	5.4
2622990	200	0.30	3200		21000	610	680			60	100	5.8
2623413	200	0.30	3100		21100	620	690			50	80	6.2
2702007	200	0.30	3000		21200	630	700			40	60	6.6
2708503	200	0.27	3500		21300	640	710			30	40	7.0
2709049	200	0.27	3400		21400	650	720			20	20	7.4
2709050	200	0.27	3300		21500	660	730			10	10	7.8
2715499	200	0.27	3200		21600	670	740
2715553	200	0.27	3100		21700	680	750
2717253	200	0.27	3000		21800	690	760
2717468	150	0.35	3000		21900	610	680
2717661	150	0.35	2900		22000	620	690
2723702	150	0.35	2800		22100	630	700
2725030	150	0.35	2700		22200	640	710
2726384	150	0.35	2600		22300	650	720
2728859	150	0.35	2500		22400	660	730
2728865	150	0.30	3000		22500	670	740
2729385	150	0.30	2900		22600	680	750
2729467	150	0.30	2800		22700	690	760
2801427	150	0.30	2700		22800	700	770
2811966	150	0.30	2600		22900	610	680
2812885	150	0.30	2500		23000	620	690
2814610	150	0.27	3000		23100	630	700
2815570	150	0.27	2900		23200	640	710
2817623	150	0.27	2800		23300	650	720
2818077	150	0.27	2700		23400	660	730
2822507	150	0.27	2600		23500	670	740
2824786	150	0.27	2500		23600	680	750
2827847	100	0.35	2700		23700	690	760
2830193	100	0.35	2600		23800	700	770
2830225	100	0.35	2500		23900	610	680
2830693	100	0.35	2400		24000	620	690
2831637	100	0.35	2300		24100	630	700
2831703	100	0.35	2200		24200	640	710
2831886	100	0.30	2700		24300	650	720
2832056	100	0.30	2600		24400	660	730
2832267	100	0.30	2500		24500	670	740
2832584	100	0.30	2400		24600	680	750
2833124	100	0.30	2300		24700	690	760
2902649	100	0.30	2200		24800	700	770
2911475	100	0.27	2700		24900	710	780
2920106	100	0.27	2600		25000	720	790
2932624	100	0.27	2500		25100	730	800
3000473	100	0.27	2400		25200	740	810
3001582	100	0.27	2300		25300	750	820
3001919	100	0.27	2200		25400	760	830