UNIVERSITI TEKNOLOGI MARA(FAKULTI KEJURUTERAAN KIMIA)DEGREE IN OIL AND GAS ENGINEERINGRESERVOIR ENGINEERING 1ASSIGNMENT 1CORE ANALYSISPREPARED BY: MOHAMMAD FAIZUAN BIN ISMAIL2013252638EH243 4A

INRODUCTIONSidewall coring systems are develop after the well had been drilled and log. Sidewall coring are the most effective ways to determine the knowledge and characteristic of reservoir formation. However, sidewall cores should not be used in lieu of whole cores since the discontinuous sampling could lead to misinterpretation of the geological sequence.

Coring tools is designed to retrieve rock samples from deep in the earth for geologic and engineering studies. The tools do an excellent job of recovering core material, and specialized equipment has been developed to trap reservoir fluids and even seal in bottom-hole pressure. There are two types of coring tools that is for side wall drilling and full diameter drilling. For sidewall coring systems were developed to obtain core samples from a wellbore after it has been drilled and logged, and before casing is run. Most sidewall cores are obtained by percussion sidewall coring systems. These tools shoot hollow, retrievable, cylindrical bullets into the wall of an uncased hole. The tool (gun) is lowered to the desired depth on a wireline, and then fired by electrical impulses controlled from the surface. The bullets remain connected to the gun by wires, and movement of the gun pulls the bullets, containing the samples, from the hole wall. Up to 66 samples, 1 inch (25.4 millimeters) in diameter by 1-3/4 inches (44.5 millimeters) in length, may be taken during one downhole trip. Different bullet core barrel designs are available for unconsolidated, soft, and medium-to-hard formations. It is wise to have more than one type of core barrel on location until acceptable core recovery can be shown. Sidewall core gun with steel bulletsThe rotary or drilled sidewall coring tool was developed to recover wireline sidewall core samples without the shattering impact of the percussion system. Suitable for hard-to-friable rock, the rotary sidewall coring tool uses a diamond-tipped drill to cut individual samples. Leverage applied to the drill snaps the sample from the sidewall. The drill and sample are retracted into the body of the tool where the sample is deposited. The tool is moved to a new location after depositing each sample. A maximum of 30 samples, 1-5/16 inch (23.9 millimeter) diameter by 1-3/4 inch (44.5-millimeter) length, may be taken during one trip. An advantage of the rotary sidewall coring system is that it produces samples of hard rock suitable for quantitative core analysis. Disadvantages are that it is more expensive than percussion sidewall coring in terms of rig time costs, and sample recovery tends to be low in unconsolidated formations. Rotary core drill on wirelineFor the full diameter core tools is Conventional Core Barrel and Sponge-Lined Coring.Conventional coring tools are available to cut cores with outer diameters from 1.75 to 5.25 inches (44.5 to 133.4 millimeters). Core length can run from 1.5 feet (.46 meter) for short radius horizontal well applications to over 400 feet (121.9 meters) for thick, uniform, consolidated formations. Hole size, hole angle, rock strength, and lithology will control the diameter and length of core that may be cut in one trip. The final selection of a particular system will depend upon the formation, location, and objectives of the coring program. Table 1-1 summarizes the conventional coring options available. The sponge-lined coring system was developed to improve the accuracy of core-based oil saturation data. A sponge coring system does not trap reservoir gases, instead it traps oil expelled as the core is brought to the surface. The saturation information is very useful when evaluating enhanced oil recovery projects. A sponge coring system has the advantage of being less expensive to operate than a pressure-retained coring system, while providing an opportunity to improve the accuracy of the core based oil saturation data. The sponge is stable to a temperature of 350F (176.7C). The sponge coring system is limited to cutting a maximum of 30 feet (9.14 meters) of 3.5-inch (88.9-millimeter) diameter core per trip. CoreVaultSystemURTeC 2014: Halliburton introduces CoreVault system for early, accurate volumetric measurements.The CoreVaultsystem keeps rock samples in a sealed container, so 100% of the fluid in the core sample will be preserved for analysis.David Topping, vice president of Wireline & Perforating, explained that prior to the development of the Core Vault system, when traditional coring tools were used to bring samples to the surface, they allowed 50 to 70% of the hydrocarbons to escape from the rock as the samples depressurized. Building a model of the volume of oil and gas in a reservoir, therefore, required operators to estimate this fluid loss rather than measure the fluids in place, and estimates were often inaccurate. By preserving 100% of the fluids within the core sample, the CoreVault system allows for an improved understanding of potentialproductionwithin the reservoir.Figure 2: Disassembled CoreVault tubes after

The CoreVault system builds on the capabilities and reliability of the Halliburton Hostile Rotary Sidewall Coring Tool (HRSCT) that recovers 1.5-in.-OD cores at temperatures up to 400F and pressures up to 25,000 psi. The CoreVault system, when combined with the HRSCT-B tool, allows up to 10 cores to be sealed at reservoir conditions in a single wireline run, saving time over full-hole coring and allowing more targeted samples to be taken.

REFERENCES

1. http://s3.amazonaws.com/ppt-download/downhole-sampling-1195577967589057-5.ppt?response-content-disposition=attachment&Signature=LkopHfzQSC0Vq2SS8%2FNiaPkdoM0%3D&Expires=1431185282&AWSAccessKeyId=AKIAIA7QTBOH2LDUZRTQ2. http://www.corelab.com/cli/routine-rock/turret-hassler-full-diameter-coreholder3. http://www.slb.com/~/media/Files/resources/oilfield_review/ors13/sum13/02_core_truth.pdf4. http://www.nps.gov/Museum/publications/conserveogram/11-16.pdf5. http://www.slb.com/services/drilling/~/media/Files/smith/catalogs/drilling_tools_catalog.ashx6. http://www.slb.com/~/media/Files/resources/oilfield_review/ors13/win13/03_rotary_side.pdf7. http://www.bakerhughes.com/products-and-services8. http://w3.energistics.org/RP40/rp40.pdf