Wellsite Geologist Training Report 3

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OIL EXPLORATION

WELL SITE GEOLOGIST TRAINING REPORT #3

DATE: FROM 15-7-2009 TO 23-7-2009

BY TRAINEE: ANTHONY L.BASSAN PETRODAR OPEARTING COMPANY LTD. EXPLORATION DEPARTMENT

WIRE LINE LOGGING OPERATION A log is a recording versus depth of physical or chemical properties of the rocks and fluids penetrated by drilling the well. In this wireline logging operation we use the Pex tool which is of Schlumberger and it is of the same principle as that of slam of CNLC we use on the previous well only the name of the tools used are different as stated below are name of the Pex tool, and Pex stand for platform express. LITHOLOGY LOGS GR for Gamma ray Gamma Ray log known as GR log. Its measure the intensity of natural radioactivity of rocks. The intensity of GR is high in the Shale. Why? The answer is very simple. The radioactive particles like Uranium, Potassium, and Thorium are very fine grains. During deposition these particles deposit with shale because Shale is also fine grain rock. That’s why the value of GR is high in Shale. GR is the best log for correlation. SP spontaneous potential The potential difference between formation fluid and hole fluid Through SP log we can determine the permeable zone. Caliper log Caliper log use to measure the hole size. Through this log we can determine the caving size and wash outs. HYDROCARBON LOGS Resistivity log (HRLA) for conductive mud and AIT for non conductive In our case it is conductive mud so we use HRLA. Through this tool we obtain the resistivity of formation. The resistivity of hydrocarbon is higher then the resistivity of formation water. Lateral log RD: resistivity deep RS: resistivity shallow MSFL: microspherically RXOZ: focused log POROSITY LOGS Density log (RHOZ)

Formation density was determined with the HLDS. The tool contains a radioactive cesium (137Cs) gamma ray source (622 keV) and far and near gamma ray detectors mounted on a shielded skid that is pressed against the borehole wall by a hydraulically activated eccentralizing arm. Gamma rays emitted by the source experience both Compton scattering and photoelectric absorption. Compton scattering involves the ricochet of gamma rays off electrons in the formation via elastic collision, transferring energy to the electron in the process. The number of scattered gamma rays that reach the detectors is directly related to the number of electrons in the formation, which is related to bulk density. Porosity may also be derived from this bulk density if the matrix density is known. Density uses: Use in lithology confirmation Neutron log (TNPH) Neutron log is used to measure the porosity of rock. The mechanism of neutron log is very interesting. One thing is common in Water, Oil and Gas. What is this? The answer is “Hydrogen”. The mass of hydrogen atom and Neutron is almost same. When we bombarded the neutron in the formation, they collide with the hydrogen, if in the formation the number of Hydrogen atoms is higher (water) then it slow down the speed of neutron as the result little number of neutron will received at the receiver and opposite result will be obtained in the case of Hydrocarbon (Gas). Sonic log (DT) The Sonic log has a great importance in Petrophysics. Through the Sonic log we calculate the porosity of the rock. The principle of this tool is simple. Through sound wave we calculate the porosity. As much pores present in the rock the travel time will be greater and in less porous rock the travel time will be little. Because the speed of sound wave in different medium is different. Pe (PEFZ) E= elements factor The HLDS also measures the photoelectric effect factor (PEF) caused by absorption of low-energy gamma radiation. Photoelectric absorption occurs when gamma radiation reaches <150 keV after being repeatedly scattered by electrons in the formation. As the PEF depends on the atomic number of the elements in the formation, it is essentially independent of porosity. Thus, the PEF varies according to the chemical composition of the formation. PEF values can be used in combination with HNGS curves to identify different types of clay minerals.

MDT-GR OPERATION MDT stands for Modular Dynamic Formation Tester. Through this log we can obtain the Formation Pressure and Formation Fluid Sample. Through these pressure points we can establish the gas water contact, oil water contact, oil gas contact etc. The tools of the MDT are as follows: LFA: is known as life float analyser which is used to detect the type of fluid in the bore hole during pumping out of the sample from the formation. MRPO is modular formation dynamic tester pump out which is used to pump the fluid from the formation through sucking mechanism to the chambers and also out from the tool to the bore hole for LFA detection. MRHY is modular formation dynamic tester hydraulic power which runs the MRPS modular formation dynamic tester single probe which takes the fluid sample and test pressure. MRSC01 is modular Formation Dynamics Tester Sample Chamber number one and there are MRSC02, MRSC03, and MRSC04 used for sample collections. MRPC is modular Formation Dynamics Tester power cartridge which supplies power to the tools. SGTL-L is the gamma ray of the tester TCC-BF is telemetry which sends data from the tools to the wireline truck (unit). LEH-OT Is the cable head which holds the tools. MDT PROCESS The pressure points and fluid sampling points are indicated then MDT job begins and it is as follows:

07:40 09:30 10:15 11;00 01;10 01:40 7;30PM 07:40

R/U and before Cal. RIH to csg GR CORR @ 1700 start main log GR CORR @ 1700 CONT. PRETESTS MOVE DOWN FOR GR CORR. TOOL HOLD UP @1793

9:45 MOVE UP FOR CORR. PRIOR TO SAMPLE

09:45

Gamma ray correlation is done with the Pex gamma ray for depth offset so that it will be accurate when taking the points. The points for the formation pressure and hydrostatic pressure after and during testing the pressure you have to see that the strain gauge and quartz gauge but you should concentrate on quartz gauge and see that the reading is three times the same so the value of the pressure is recorded. QC check is done by plotting the depth to the hydrostatic pressure after to see it graph as is done below.

2965

2960

2955

Series1 Log. (Series1)

2950

2945

2940 1702

1704

1706

1708

1710

1712

1714

1716

Gradient is calculated as difference of two pressure points and two depth points From the line in the graph as opposite over adjacent. Below are the pressure and hydrostatic pressure points we used to make the graph.

No 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

Depth 1227.5 1229 1229.5 1230 1231 1253.5 1634.5 1635 1635.5 1636 1636.6 1669 1670.2 1671 1672.5 1674 1675.5 1677 1703 1705 1707 1709 1711.5 1713 1714.5

HYD. PSI 2130.48 2132.88 2133.68 2134.1 2135.62 2174.36 2827.9 2828.64 2829.37 2830.1

Fmn Press 1696.8 1698.34

2885.92 2887.59 2888.87 2890.24 2889.77 2896.26 2296.78 2943.53 2946.87 2949.69 2953.06 2957.32 2959.86 2962.35

2289.67 2289.09 2289.3 2290.63 2292.77 2294.81 2296.78 2332.33 2335.39 2337.91 2340.63 2344.07 2346.52 2348.38

1699.64 1701.1 1849.33 2301.89 2301.6 2302.3 2303.27

The fluid recovered from the chamber of the modular formation dynamic tester is tested and result shown as follows: Depth m 1672.5 Chamber (Liter):

12.4

Recovery %

80.6% (10 ltr)

Type of Fluid

Filtrate with Fmn water & tr of Oil (2-3%)

PH

Mud Sample

9

10

CL-(mg/l)

4700

15400

Ca++(mg/l)

250

420

mg++ (mg/l)

20

100

7755

25410

8.5

10.2

1.02

1.22

Mf (ml)

18

N/A

Pf (ml)

13

TDS (mg/l) Density (ppg) Sp. Gravity

N/A o

Resistivity(ohm.m) 0.33 @ 34°C [email protected] C From this properties you will know the type of fluid obtain from the chamber which is obtain from the formation.

REMARKS: We are going to do the FMI-Sonic scanner below the casing shoe, cst-gun is cancel and VSP in the case hole, this will be for the next week operation.

SCHLUMBERGER MDT Modular Formation Dynamics Tester SCHLUMBERGER MLT Microlog SCHLUMBERGER MRPS Modular Formation Dynamics Tester Single-Probe SCHLUMBERGER MRSC Modular Formation Dynamics Tester Sample Chamber