Berlian Field Block 1

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Berlian Field Database – Block 1 1 E & P CORE BUSINESS PROCESS & ENVIRONMENT CASE STUDY BERLIAN FIELD DATABASE (Block 1)

description

A case study of the Berlian Field, Malaysia.

Transcript of Berlian Field Block 1

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E & P CORE BUSINESS PROCESS

& ENVIRONMENT

CASE STUDY

BERLIAN FIELD DATABASE (Block 1)

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CONTENTS Page No Block 1 1. INTRODUCTION 2. SUMMARY 3. BACKGROUND INFORMATION 4. FIELD DISCOVERY AND EARLY APPRAISAL 5. PRODUCTION GEOLOGY 6. PETROPHYSICAL DATA

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1. INTRODUCTION This data set will provide you with the background information on an existing hydrocarbon accumulation which is typical of an oil field development opportunity in Malaysia. By using actual field data you will be able to experience the realities of project development and to apply and test the knowledge gained during lectures. A case study provides the opportunity to see the interactions and relationships of all of the disciplines involved and to understand the sequence of events throughout a field life cycle. In particular, you will see how the contributions of the technical disciplines are linked to the business objectives. At this juncture you are to note well that every single costs expended (known as investments) will impact your project economics, namely, the UDC. Therefore prudent spending should be exercised. Sound technical justifications as well as the Value Creations expected from your field appraisal/development activities must be demonstrated prior to executions. Practices described in this brief reflect methods and technology recently applied in PETRONAS operation. However, we encourage you to challenge the existing practice, to develop alternative options if appropriate, and to investigate how new technologies could improve the economics of your project. Just as in reality, you would be working with limited data. Such limitations would give rise to uncertainties; and the most profound in this case is in the hydrocarbon volumes and their distributions. These uncertainties in turn, would eventually translate into risks to your project economics. You would have the opportunity to strike a balance between remaining acceptable risk levels versus expenditures Additional information may be required before the available data can be meaningfully applied to your project. Therefore, this data base will be supplemented during the course by additional data and you will generate extra information as you progress through the exercises. It is essential that you have a thorough knowledge of the data contained in this document and we recommend that you spend some time familiarizing yourself with the material. General information can be obtained from the participants manual. Additional specific information may be available from the instructors in the form of short lectures, consultancy, videos or written reports. Please make sure that you have discussed within your team the specific information you require and its relevance to your project. Wherever possible, certain critical points relevant to your exercise will be highlighted. In addition to raising the level of your technical and business skills, this course will allow you to test and improve your skills related to planning, communication, presentation and team working. We wish you an enjoyable course and every success in your new business venture.

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2. SUMMARY The Berlian East structure, offshore the east coast of Peninsular Malaysia is being considered for development. A total of four wells (exploration and appraisal wells included) have been drilled to date. Based on seismic and well information for the Miocene reservoir sequence, options for field appraisal, development and subsequent production management need to be evaluated. The present knowledge of the field indicates that the economics for development are marginal. However, it is considered that the economics can be improved by including the existing regional infrastructure into a development scenario. Field development will have to take into account of the prevailing fiscal framework and Production Sharing Contract (PSC) agreement.

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3. BACKGROUND INFORMATION 3.1 Location and Infrastructure The Berlian East Field is located some 25km offshore Peninsular Malaysia (Figure 3.1) in a water depth of 76m. Several other nearby fields are being produced under separate production sharing contracts (PSCs) with PETRONAS. The nearest developed field is Berlian, approximately 20 km northwest of Berlian East. This producing field, which has just come on stream, has the following infrastructure: - three 24 slot drilling platforms - one CPP (Central Processing Platform) comprising :

- production module (60 Mstb/d) - water injection module (120 Mstb/d) - gas compression module (50 MMscf/d) - accommodation module (80-men)

Table 3.1 shows the forecast production profile for Berlian.

Year Oil Production (Mstb/d)

Gas Production (MMscf/d)

1 3.5 1.5 2 (current) 48.8 21.4

3 58.6 26.5 4 58.6 27.3 5 48.1 23.3 6 32.3 16.2 7 25.4 13.1 8 20.7 10.9 9 16.6 9.0

10 13.6 7.6 11 11.9 6.7 12 9.9 4.7 13 8.5 3.8 14 7.6 3.4 15 6.9 3.0 16 6.0 2.6 17 5.0 2.2 18 4.1 1.8 19 3.1 1.4 20 1.6 0.1

Table 3.1: Berlian Field Production Forecast

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A terminal is located onshore near Pekan, approximately 29 km from the Berlian East field. The function of the terminal is to act primarily as a tank farm. There are pipelines from the Berlian development to the terminal. Additional crude storage is available at the terminal but an increase in crude throughput would require the upgrading of the existing process facilities. Gas market is available onshore. Crude is exported from the Pekan terminal in the following ways: - through an onshore pipeline to a refinery - By tanker loading from an SBM system. 3.2 Company History Your project team is part of the technical function in your company which was given the contract to operate the field under the PSC. Your company is as a contractor to PETRONAS. PETRONAS (Petroliam Nasional Berhad) was formed in 1974 to act as the government instrument to take charge of petroleum matters. PETRONAS is guided by the following main objectives: • to safeguard the sovereign rights of Malaysia and the legitimate rights and interests

of Malaysians in the ownership and development of petroleum resources • to undertake proper planning for the orderly exploitation and utilization of Malaysia

petroleum resources so as to satisfy both the present and future needs of the country

• to participate actively in the exploitation of petroleum and in the marketing and

distribution of petroleum and petroleum products. • to ensure that the local market is supplied with petroleum and petrochemical

products at reasonable prices. • to encourage local participation in the manufacturing, assembling and fabricating of

plant and equipment used in the oil industry and in the provision of ancillary and supporting services.

• to contribute to the development of the agro based sector of the economy by

making available nitrogenous fertilizers and • to ensure that the people of Malaysia as a whole enjoy the fullest benefits from the

development of the country’s petroleum industry As contractor to PETRONAS, your company is required to observe all these values and ensures that steps are taken to incorporate these objectives in your development plan.

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Rihau

C

Berlian

Berlian East A B

Terminal

0 1 2 30

Location

N

Malaysia

Kuala Trengganu

KualaLumpur

KuantaPeka

Singapore

Berlian

Figure 3.1

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Before 1976, the concession system gave oil companies the right to explore, produce and market petroleum independently, in return for royalty and tax payments to the government. During 1976 PETRONAS started to replace the original concession system with Production Sharing Contracts (PSCs). Under the new system a fundamental change occurred, such that management and control of petroleum resources rests with PETRONAS, while the oil companies operate as contractors. PSCs stipulate the terms under which to operate, the contract periods, the relinquishment terms, the obligation to utilize Malaysian goods and services wherever possible, and the requirements for training Malaysian personnel. The specific terms of PSC agreement which apply to the licence block containing Berlian East are given in Section 14.

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4. FIELD DISCOVERY AND EARLY APPRAISAL The field was discovered by well Berlian East-1 drilled in late 1999 in a crestal position in Block 1 (Figure 4.1). The location was based on an anticlinal feature interpreted from a 1 km by 1.5 km 2D seismic grid shot in 1999. The purpose of the well was to evaluate the reservoir quality and hydrocarbon potentials of Block 1. The quality of the seismic available was considered adequate to delineate the overall structure. However, complex crestal faultings, and shallow gas effects over the area have so far hindered a more detailed interpretation.

Berlian East-1 (BE-1) encountered 29 metres of oil and 7 meters of gas in the M reservoir unit, and 14.2 metres of gas in the L reservoir unit. Berlian East-2 (BE-2) was drilled early in 2000 to test the hydrocarbon potential of Fault Block 3. The well encountered the objective sequence fully water bearing.

Berlian East Field Outline

BE-1

BE-3

Block I

Block II Block III

Block IV

BE-4

BE-2

1 km

Figure 4.1

N

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Berlian East-3 (BE-3) tested the southern flank of Fault Block 1 in March 2001 and confirmed the M and L reservoir to be hydrocarbon bearing. Berlian East-4 (BE-4) was drilled some 3 km due east of Berlian East-1 in February 2002, with the objective of appraising reservoir continuity in the eastern part of Fault Block 1. The well encountered 6.4 metres of net oil sand within the M reservoir. The L reservoir unit was found to be poorly developed. All of the wells described above have been plugged and abandoned. The well results, lithological description and interpretation are available. (Additional learning points : All the above wells were drilled vertically therefore you would have a straightforward sand/HC thicknesses. What would happened to the “lengths” of the above sand (hence hydrocarbon) columns encountered by the wells if they were drilled non-vertical ie deviated wells?)

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5. PRODUCTION GEOLOGY 5.1 Introduction The Berlian East Field is an east-west trending faulted anticline, about 11 km long and some 5 km wide. Predominantly northeast-southwest striking normal faults compartmentalise the field into several fault blocks. The area comprises Pliocene to Recent sequences which unconformably overlie the Late Miocene reservoir units. Sediments of the objective sequence were deposited in a coastal plain to holomarine environment. A summary of the stratigraphy is provided in Figure 5.1. The structural style and the depositional environment are similar to those observed in the Berlian Field. No overpressures have been encountered to date above the N sands in the Berlian East Field. 5.2 Structural Definition The Berlian East anticline is dissected by several predominantly northeast – southwest trending normal faults. The vertical displacement ranges from a few metres to 100 metres. The disappointing result of Berlian East-2 confirms that intra-field faults are sealing, predominantly as a result of low N/G ratio (clay smearing). The maximum structural dip encountered is found on the flanks of the structure. 5.3 Depositional Environment From wireline logs and limited core data in well Berlian East-1 and Berlian East-4, a model of the depositional environment has been derived. The objective sequence has been subdivided into an upper zone (L unit) and a lower zone (M unit). L unit: The top of this unit is marked by the Late Miocene - Pliocene unconformity which is clearly reflected in the sonic and resistivity logs of the Berlian East wells but not recognised on seismic. The unit is thinned at the crest compared to the flank areas. The sediments were deposited in a coastal to holomarine environment. In general the sand to shale ratio is low (0.1 to 0.4) and the net sandstone thickness rarely exceeds 20 metres. The main lower L sand shows some thinning towards the west of the field. The lower L contains several prominent, continuous and laterally correlatable coal beds. M unit: Lithologically this unit can be differentiated based on several prominent coal beds which are also clearly visible on seismic. A reservoir subdivision into discrete drainage units has been proposed.

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[Additional learning points : Coal, although thin, may be quite visible on seismic compared to sand of similar thickness. Why is this so ?]

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LITHOLOGYAGE

LOG DESCRIPTION

PER

IOD

EPO

CH

GR

OU

P O

R

FOR

MA

TIO

N

SEA FLOOR@94 m

SCA

LE

(m

etre

) R

T

TE

RT

IAR

Y

TO

Q

UA

RT

ER

NA

RY

no samples

mainly claystones, poorly consolidated with minor siltstones and sands

claystone, mudstone, siltstone and sandstone interbeds

claystone/mudstone,sandstonewith minor siltstone and coal seams at base

Plei

stoc

ene

to r

ecen

t L

ate

Plio

cene

Ea

rly

Plio

cene

L

ate

Mio

cene

? M

iddl

e M

ioce

ne?

GR

OU

P I

G

RO

UP

L

GR

OU

P J

G

RO

UP

M

sandstone, siltstone, mudstoneinterbeds with frequent coal

mainly siltstone, mudstone with minor shale and sandstone

scarce to absence of coal beds

Figure 5.1 General Stratigraphy of Berlian East

100

200

300

400

500

600

700

800

900

1000

1100

1200

1300

1400

1500

1600

1700

1800

1900

GR

OU

P N

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Sandstones are of varying thicknesses up to 20 metres and comprise widespread almagamated channels which form laterally thick sands which may not necessarily be continuous. Bar deposits and crevasse splays are evident from core data and this interfinger with the channel sandstones. It is possible that some of the channel deposits are more linear in distribution. The environment of deposition is interpreted as Lower Coastal Plain, with some marine influence in evidence, particularly in the lower section. Well logs and cores show some fining upward cycles with flaser bedded sandstones grading into fine sandstones and shales. Cycles are frequently capped by coalbeds. Flaser bedding and wave ripples observed in the BE-4 core corroborate some tidal influence during deposition. The overall thickness of the M unit is some 200 metres at the crest, increasing towards the flanks where thicknesses of up 320 metres have been interpreted. Reservoir quality seems to deteriorate towards the east. 5.4 Diagenesis Streaks of cemented, tight limestone, sometimes dolomitised occur throughout the reservoir sequence. These layers, of up to 1m thickness may be laterally continuous over wide areas of the structure. 6. PETROPHYSICAL DATA The following table contains a summary of the wireline logging and core measurements.

Sand Well Top m.ss

Bottomm.ss

Hm

Net sandm

Net oil sand m

Net gas m

L BE-1 BE-2 BE-3 BE-4

1205.1 1322.5 1232.2 1272.4

1220.4 1331.4 1245.3 1274.2

15.38.9 13.11.8

15.2 0.6

11.7 1.5

14.2

11.3 1.1

M 2/3 BE-1 BE-2 BE-3 BE-4

1242.7 1387.4 1270.9

Shale out

1262.1 1393.2 1293.7

Shale out

19.45.8 22.8

14.9 1.1 8.4

5.8

4.3

7.0

M 7/8 BE-1 BE-2 BE-3 BE-4

Shale out 1406.3 1295.6 1321.1

Shale out1424.0 1321.5 1344.6

17.725.923.5

0.3 6.6

15.4

6.0 12.5

M 9/14 BE-1 BE-2 BE-3 BE-4

1300.0 1433.8 1330.9 1366.0

1333.5 1466.6 1367.2 1386.7

33.534.136.320.7

17.7 10.8 18.6 14.0

17.1

18.2 2.1

M 15 BE-1 BE-2 BE-3 BE-4

1338.5 1474.6 1373.3 1393.4

1348.0 1485.2 1383.9 1399.8

9.5 10.610.66.4

6.1 4.9 8.7 5.5

6.1

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Sand Well Top m.ss

Bottomm.ss

Net HCm

Ø Av.fraction

Sw Av.fraction

Remarks

L BE-1 BE-2 BE-3 BE-4

1205.1 1322.5 1232.2 1272.4

1220.4 1331.4 1245.3 1274.2

14.2

11.3 1.1

0.28 0.23 0.27 0.31

0.31

0.47 0.64

WET

M 2/3 BE-1 BE-2 BE-3 BE-4

1242.7 1387.4 1270.9

Shale out

1262.1 1393.2 1293.7

Shale out

12.8

4.3

0.28 0.24 0.26

0.40

0.56

WET

M 7/8 BE-1 BE-2 BE-3 BE-4

Shale out 1406.3 1295.6 1321.1

Shale out1424.0 1321.5 1344.6

6.0 12.5

0.23 0.27 0.26

0.49 0.55

WET

M 9/14 BE-1 BE-2 BE-3 BE-4

1300.0 1433.8 1330.9 1366.0

1333.5 1466.6 1367.2 1386.7

17.1

18.2 2.1

0.27 0.25 0.25 0.25

0.52

0.43 0.57

WET

LPO 1376.6

M 15 BE-1 BE-2 BE-3 BE-4

1338.5 1474.6 1373.3 1393.4

1348.0 1485.2 1383.9 1399.8

6.1

0.30 0.25 0.28 0.29

0.30 WET WET WET

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Routine core analysis was used to establish porosity / permeability relationships and to calibrate the calculated log porosities. Special core analysis established the saturation exponent (m) and the cementation exponent (n):

m=2 n=2

For a first estimation of net reservoir a GR cut-off of 80 API can be applied. For detailed evaluations the Waxman Smits equation is used. Identifier for the line curves: BS Nominal Borehole Size (inches) CAL Calliper (inches) GR Gamma Ray (API counts) SP Spontaneous Potential (mV) MSFL Microspherically Focused Lateralog (shallow resistivity, Ohmm) lLD Induction Log Deep (deep resistivity, Ohm.m) SFL Spherically Focused Lateralog (Ohm.m) DT Sonic travel time (ms)

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EXERCISE BLOCK 1

(SEPARATE SHEET)

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Exercise 1.1 Life of Field Prepare a five minute presentation outlining the technical, business and non-technical issues you consider important during the various stages of the field life cycle. Exercise 1.2 Exploration Techniques and Identifying Prospects Your company has been offered to buy into acreage offshore East Malaysia where several exploration wells have encountered hydrocarbons. A visit to the partner company is in preparation. The objective is to view the data that are available and to request specific additional information required to quantitatively evaluate the field. The company has indicated that it is prepared to provide all information requested, however, you are expected to contribute towards the original costs of data acquisition and processing. Your shareholders expect a short memo (one page) outlining which outstanding questions (issues) need to be answered (addressed) and what data can provide the answer(s) and which techniques will be most useful to acquire such data.

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Exercise 1.3 Drilling Operations Your team has been assigned the task to plan the drilling of an outstep well in the BERLIAN EAST area. As the Petroleum Engineering and Exploration Department you should provide the drilling department with all necessary data for the project. Please note that you will have to justify the proposed activities to the shareholders. (Group B & D) [Additional Learning Point : In data gathering we would not want to acquire data that would give us the same information as that we have obtained before. We therefore have to “step out” from the known zones into the new unknown zones.] Exercise 1.3 Drilling Operations As the Berlian East Drilling Operations team you to plan the drilling of an outstep well in the area. As a first step you should provide the Petroleum Engineering and Exploration Departments with a detailed list of data you require for the efficient planning of the drilling operation. Please note that you will have to justify your request to the Operations and Exploration Managers. (Group A & C)

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Exercise 1.4 Reservoir Description: Geology Using the data contained in the newly purchased package, summarise your present knowledge of the reservoir geology of the Berlian East Field. Of particular interest is the prediction of lateral and vertical variation in reservoir quality as well as the structural configuration of the area. Which activities would you propose to improve the definition of specific geological reservoir parameters? What are the implications of the present reservoir knowledge for the development and the production planning of the L and M reservoir? [Additional Learning Point : The seismic has inherent limitations in defining a field’s exact structural configuration especially the flanks. This comes about mainly because of seismic imaging difficulty as well as difficulty in velocity field determination for time-depth conversion. The vertical error in the flank positions affect the lateral distributions of the hydrocarbons hence field development. It is therefore prudent to determine as accurately as possible the structural configuration before FDP is formulated. Seismic DHIs sometimes could help to resolve this matter. Where there is no such luxury, calculations on the tolerance of the flank positions is next best.]

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Exercise 1.5 Reservoir Description: Fluids Given the RFT data of Berlian East 3 construct a pressure vs depth plot and advise on fluid types and contacts. Depth mss PSIA -1322.8 1895.7 -1335.6 1910.6 -1340.8 1916.6 -1352.1 1929.3 -1364.1 1945.8 -1383.4 1974.7 [Additional Learning Point : RFT could provide a good indication as to fluid contacts but it could not beat the accuracy of contacts seen directly from the wireline logs!.] Exercise 1.6 Data Interpretation: Log Evaluation The well BE-1 (1300m AHBDF to 1375m AHBDF) has been logged with GR, FDC, CNL and resistivity logs. Perform a “quick look” qualitative and quantitative estimate of lithology, net reservoir sand, net-to-gross ratio, porosity and saturation. Do you observe any fluid contacts on the logs and how do they fit the pressure depth plot derived fluid distribution? Assumption: Archie equation applicable. Core analysis has established ρma: 2.65 g/cm3. ρfl in the oil zone: 0.9 g/cm3

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Exercise 1.7 Data Interpretation: Log Evaluation Results GR and density readings confirm the section as a sand – shale sequence. Net Reservoir: Determined by applying a GR cut off, in this case 80 API. The inspected interval covers 90 m of which 40 m is net sand. For this section, if no other reservoir subdivision is used the N/G is 0.44. Fluid Distribution: The resistivity log indicates hydrocarbons down to 1347 m AHBDF and WUT 1364 m AHBDF. No contact can be established without additional data such as the RFT pressures. The density – neutron combination shows no gas effect and all sands are therefore interpreted as oil bearing with an ODT 1347 m AHBDF.

flma

bma

ρρρρ

φ−−

=

ρb can be read from the log by averaging the reading over a sand interval. It is now possible to calculate porosities but an easier method is to rescale the density log grid: if ρb = 1.85 g/cm3, Ø = 0.46 if ρb = 2.20 g/cm3, Ø = 0.26 if ρb = 2.60 g/cm3, Ø = 0.03 Hydrocarbon saturation: The Deep Resistivity log will provide Rt and using the Archie equation:

RwSwRt mn ** −−= φ Rw can be calculated by reading the value for Ro from the resistivity log in the water zone: Ro = 2.5 Ωm @ Ø = 24%

moR

Rw −=φ

= 0.14 Ωm In the oil zone: Rt = 25 Ωm @ Ø = 28% (values in the lowest and well developed clean oil sand). This leads to Sw = 0.31 and thus So = 0.69 [Additional Learning Point : The industry also uses HKW (Highest Known Water) for Water Up To (WUT) . For “ oil on the rock” case LKO (Lowest Known Oil) may also be used instead of ODT (Oil Down To). Other terms to know is GDT (Gas Down To) for Lowest Known Gas (LKG) situation and Oil Up To (OUT) for Highest Known Oil (HKO)].

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Exercise 1.8 Data Interpretation: Correlation Using the logs of all Berlian East wells establish a field wide datum plane correlation. Advise on a meaningful reservoir subdivision and the implications of your correlation on reservoir continuity. Exercise 1.9 Data Interpretation: Mapping and Cross Sections From the top reservoir depths of the four well logs used in the correlation the information contained in your data package and the interpreted fluid contacts you construct a top M2/3 map. As a step towards quantification of the range of hydrocarbons in place, you should create a high case and low case map (two teams each!). An east west cross section should visualise the main structural elements and sand distribution trends across the field. In view of time constraints, you are advised to plan your resources assigned to the different tasks carefully.

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Top M2/3 Reservoir Map1: 35,000

0 1 km

BE-2

1387BE-4

S/OBE-3

1271

BE-1

1242

BERLIAN FIELD FDP

1300

1360

1400

14001400

1300

1300

1400

65,5000 N

65,2500 N

65,0000 N

45,7

500

E

45,5

000

E

46,2

500

E

46,0

000

E

N

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