API Guidelines Research Articles

Characterisation of Shirashulahara Lepa – A Non-Codified Formulation

Background
 The Shirashulahara lepa is used in folklore medicine practised as preventive and curative healthcare need in Kerala. The present study was aimed to validate the traditional medicinal knowledge through pharmacognostical standardization. Aim and objective: The objective is to create a Non-codified formulation called Shirashulahara lepa using two different approaches, and then analyze its properties and composition. Methods:The preparation methods of Shirashulahara lepa differ based on the base ingredient used. The first method involves utilizing Narikela taila (Coconut oil) while the second method involves the use of Beeswax. The Preparation of medicine has been carried out and the Physico-chemical parameters of finished lepa such as pH, Spreadability, Rancidity etc were performed as per API guidelines. Obseravtion: Detailed TLC fingerprint profile of methanolic extracts of the formulation and GC-MS of the selected Method has also been performed. Further in-vivo and clinical studies are also suggested. Result: The results obtained from the first method employing Narikela taila were superior.

English

Weighted and unweighted aqueous mud formulations from a biomaterial, at cold temperature of 5°C, were tested for their rheological characteristics. Based on API guidelines and recommended equipment for drilling fluid tests, the rheological properties of the formulations were determined. The muds exhibited pseudoplastic behaviour. The fluid loss volumes of the weighted and unweighted muds are 14 and 21 ml, respectively, while the filter cake thicknesses are 2.5 and 3 mm, respectively. The yield stresses of the weighted and unweighted muds are 209 and 159 lb/100 ft2, respectively. Plastic viscosity of 42 cP for the weighted mud against 23 cP for the unweighted mud showed that the weighted mud has a better cutting lifting capacity if PV is used as an indicator. Mucuna solannie additive can also perform in cold temperature, and has the potential to be used in cold temperature drilling. Key words: Biomaterial, cold temperature, fluid loss, rheological properties.

Experimental Investigation on the Fatigue Behaviour of Heat-Treated Tubular T-Joints

The stress distribution along the weld toe (SCF test) and the fatigue life of tubular T-joints (Fatigue test) were experimentally investigated in this study. Three specimens with identical geometric properties were tested to failure under fatigue cyclic loading at the brace end. Prior to the loading tests procedure, SCF and Fatigue tests, two specimens went through one cycle of heating and cooling naturally. The SCF test results showed that the maximum Stress Concentration Factor (SCF) occurred at the chord saddle for all the specimens. The fatigue cracks were initiated at the chord saddles of the three tested specimens. The fatigue test results showed that the fatigue life was longer the higher the target maximum temperature was. The development of the crack aspect ratio with the normalised crack length was discussed among the specimens. Finally, the fatigue life results obtained from the experiment compared with those from CIDECT and API guidelines.

Managament of Bhagandara (Fistula-in-Ano) by Palasha Ksharasutra prepared with Arkaksheera - A Case Report

A standard Ksharasutra is practiced in treatment of Bhagandara (fistula-in-ano) with high success rate and minimum recurrence rate. In previous research it was noted that Pittaja Prakruti patients sometime might cause more perianal irritation due to Apamarga Ksharasutra. So in this study Palasha Ksharasutra prepared in Arkaksheera was prepared by Palasha Kshara (Ash of Butea monosperma), Arka Ksheera (Calotropis gigantic) and turmeric powder (Curcuma longa). This Ksharasutra was prepared as per the API guidelines and preserved in air tight tube. A patient of Pittaja predominant Prakruti with fistula-in ano having two external opening at 6 and 7 O’ clock position of anus was treated with application of Ksharasutra. The Palasha Ksharasutra prepared in Arkaksheera was applied in these two opening under spinal anesthesia. Then Ksharasutra was changed by weekly interval under local xylocaine jelly 2%. The length of thread was measured weekly and noted in the case to assess the unit cutting time (UCT). The unit cutting time (UCT) of first thread was 7.5 days/cm and second one had UCT 6.8 days/cm. During the treatment patient was doing his job regularly without hampering the quality of life. After 2 months patient was free from all symptoms of fistula with normal scar and without any complications. This case study demonstrated the utility of Palasha Ksharasutra prepared in Arkaksheera in multiple fistula-in ano.

Importance of accounting for the piping system and boundary conditions in determining the maximum surge pressure following heat-exchanger tube-rupture

Shell-tube type heat exchangers are often used to exchange heat between a high-pressure fluid and a low-pressure fluid, and the pressure difference between the two fluids could be significantly high. If the difference in the design pressure between the low-pressure (LP) and high-pressure sides is greater than that covered by American Petroleum Institute (API 520 and 521) 10/13th rule, dynamic analysis is required to ascertain that the maximum surge pressure that could be reached does not compromise the integrity of the LP side of the exchanger. API guidelines also notes that attention should also be given not only to the shell-side of the heat exchanger under evaluation, but also to the “upstream and downstream systems” This paper offers further insight into the importance of including the surrounding piping systems around the subject heat-exchanger where a tube-rupture scenario is considered, and also directs attention to the importance of correctly specifying the appropriate boundary conditions (B.C.) at the far ends of both the upstream and downstream piping systems. It demonstrates the effects of specifying different B.C. on the maximum pressure surge via a case study of a hot separator vapour condenser in a bitumen hydrotreating unit, where the process fluid on the tube-side is a vapour–liquid mixture at 9660 kPa(g). The vapour mass fraction of the process fluid is approximately 0.5, and is mostly hydrogen. The fluid on the LP side is cooling water connected to the plant supply and return cooling systems as well as another adjacent low pressure condenser. The design pressure for the cooling water piping system and the adjacent condenser is 1380 kPa(g).

Soil Structure Interaction Analysis of a Dry Dock

Pile foundation is one of the most popular forms of deep foundations and is widely used for supporting water front structures in weak soils characterized by low shear strength and high compressibility, and also in structures which are subjected to heavy lateral loadings and moments. The lateral forces are mainly due to berthing forces and lateral earth pressure due to unstable slope as a result of dredging or siltation etc. Conventionally API guidelines and Vesic equation are used to analyze the laterally loaded piles. The study of laterally loaded pile in active soil wedge requires a proper assessment of soil structure interaction phenomenon involving the interaction between pile surface and the surrounding soil. The instability of soil wedge can occur due to self weight, surcharge load, dredging, siltation and earthquake force. Laterally loaded piles are analyzed by methods derived from the classical beam on elastic foundation mode in which the soil support is approximated by a series of independent elastic spring. The soil spring constants estimated from API guidelines and Vesic equations are not suitable for piles located in active soil wedge. Hence a numerical study is carried out for on dry dock in site specific soil and in dense sand, in order to study the behaviour of piles in active soil wedge. Based on the P-Y curves plotted for piles located in active soil wedge, appropriate reduction factor is obtained for API guidelines for dense sand. From reduction factors, it is concluded that the effect of active soil wedge decreases with increase in distance from the crest of the wedge. Profile of the active soil wedge using P-Y curve plots from Plaxis results closely matches with the theoretical soil slip plane. Soil spring constants are estimated from the modified API curves and are used to model the dry dock in Staad pro for dense sand in order to validate the results.

The dynamic response of pressure relief valves in vapor or gas service, part I: Mathematical model

In order to prevent unstable operation, or “chatter”, of a pressure relief the API guidelines recommend limiting the irreversible pressure loss in the inlet line to a pressure relief valve to no more than 3% of the valve set pressure. This criterion is based on steady-state operating conditions and a typical blow-down pressure for the valve of about 7% of the set pressure. However, the stability of the valve is also influenced by other factors such as the dynamic response of the valve disk to the unsteady pressures and forces exerted by the fluid on the disk. A model for the opening lift dynamic response of a pressure relief valve in gas/vapor service is presented here which accounts for all of these effects through a set of five coupled nonlinear algebraic/differential equations. These equations are solved by a numerical method that can be implemented on a spreadsheet to predict the position of the valve disk as a function of time for given valve characteristics, operating conditions, and installation parameters. The model incorporates the influence of the various parameters on the stable/unstable nature of the disk response. An example is presented for a typical valve that illustrates the various modes of stable and unstable dynamic response that can be predicted by the model under various conditions. Two additional papers will be forthcoming: Part II – Experimental Investigation and Part III – Analysis of Data and Comparison with Model Predictions.

Wave-in-Deck Forces on Offshore Platforms

The extreme condition storm wave crest heights for many older platforms indicate that there would be “green water” in the lower decks. The API guidelines to determine wave forces acting on the decks of these platforms indicate that most platforms cannot survive such loadings. The decks must either be removed or the decks raised to clear the specified wave crests. A variety of laboratory tests have been performed to address this problem. Several approaches have been developed to compute the wave crest loadings and the responses of the platforms to the loadings. There have been many instances in which platforms have experienced significant wave loadings in their lower decks during hurricanes. Some of these platforms have survived and some have failed. This paper summarizes results from a study of laboratory test results and the performance of platforms in the Gulf of Mexico that have survived and failed during hurricane wave loadings in their decks. Modifications to the API deck wave force guidelines are discussed and validated with laboratory test data and platform field performance during hurricanes.

Fatigue Testing of Drillpipe

Summary Twenty-nine tests in air and 27 tests in a 3.5% NaCl solution were conducted to test the fatigue strength of Grade E 4.5-in.-OD, 16.6-lbm/ft [114-mm-OD, 24.7-kg/m] drillpipe. The effects of stress range, mean stress, corrosion, and upset geometry were tested on the drillpipe body alone and on specimens that included the tool joint, upset, and drillpipe body. Stress range and mean stress effects were significant in noncorrosive and corrosive environments. The effect of upset geometry was minimal on an external upset compared with that on an internal/external upset. Among the specimens that failed, grinding marks on the drillpipe surface, which occurred during inspection at the mill, caused failure of about 60% of the specimens. Grinding created a notch effect and induced a detrimental residual-stress pattern on the pipe surface, which decreased drillpipe fatigue life. API guidelines for cumulative fatigue of Range 2 drillpipe were evaluated in light of these experimental test results and were found to be unsafe for drilling in noncorrosive conditions and possibly too conservative for corrosive conditions.

Qualifying Drillstring Components for Deep Drilling

Summary Deep, hard, or directional drilling imposes extraordinary stresses on drillstring components. Because of theadditional economic risks of deep drilling, the inspection and acceptance of drillstring components should be based ontheir compliance with API and user standards. Inspection procedures that provide the highest probability of finding procedures that provide the highest probability of finding and eliminating unacceptable components should be used. Often, too much reliance is placed on a "report" or"certification" that the drill string components have been"inspected, "The operator assumes that because the material has been inspected, it is suitable for the intended service. This paper addresses three areas in which the above approach may lead to trouble.Widespread, established practices have resulted insome applicable API guidelines being unintentionally ignored by users and inspection companies.API standards for used drillpipe do not address someitems of concern to operators engaged in deep or critical drilling.Inspection companies frequently do not followsimple quality control steps that can markedly improve theresults of their work. Examples of shortcomings in current industry practicesare given. Corrective actions implemented by several companies in the last 12 to 18 months are also given. A hand-held calculator program that will aid in evaluating the wear limits on rotary shouldered connections isprovided in the Appendix. provided in the Appendix. Drillstring Failures Examples of drillstring failures are well documented inliterature. 1 Unfortunately, they are also all too familiarto most drilling engineers and operations managers fromfirsth and experience. Common in-service failures include the following.Fatigue cracks can be induced by cyclic loading inhigh-stress areas of connections and drillpipe tubes(Fig. 1).Washouts caused by leaking drilling mud can erodemetal and enlarge the leak (Fig. 2). Leaks may occur fora variety of reasons, but the most common causes are fatigue cracks, inadequate makeup torque, shoulder sealdamage, or excessive or improper refacing of the shoulders.Tensile breaks occur when the load-carrying capacityof a member is exceeded. This occurs most frequentlyin the tube body (Fig. 3) or in the pin of a connection.Torsional failures occur when the torque applied indrilling exceeds the capacity of a drillstring componentto resist torque. Fig. 4 is an example of a torsional failurein a drillpipe box. Drillpipe failures occur for a variety of reasons. Broadly speaking, these can be grouped into three categories. If a failure occurs eitherthe drill string was designedincorrectly-e.g., the weight and grade were inadequatefor the application;the drillstring was misused-e.g., connections were over torqued during rig floor makeup;ordefective components were accepted and runbecause of inadequate inspection, poor-quality inspection, or poor definition of the standards of acceptance. It has been our experience that persons responsible for drilling wells are much more familiar with the design and proper use of drill strings than they are with inspection proper use of drill strings than they are with inspection processes and acceptance standards for those strings. In processes and acceptance standards for those strings. In the hope of helping to correct this situation, the remainder of this paper addresses some problems and solutions inthe area of drillstring inspection. Drillstring Inspection There seems to be a pervasive attitude among drillingpeople that inspection is someone else's problem. Few oil people that inspection is someone else's problem. Few oil companies would write the following clause into theirday-rate drilling contract. The drilling contractor shall decide well location, well depth, directional program, mud program, logging program, casing and cementing program, and whether the well will be completed or abandoned. Contractor shall provide a report certifying that allthe above was done correctly. On the other hand, most companies do not hesitate todelegate the inspection and acceptance of their drillstring components to their contractor or inspection company. It is still common practice to accept an inspection "report"as proof that the components have been inspected. Frequently, when failures occur, the corrective measure maybe to change inspection companies and to repeat the cycle, without any technical involvement in the inspection process. Our message is that the operator can often process. Our message is that the operator can often substantially reduce his economic exposure to drillstring failuresby becoming involved in the inspection process. JPT P. 1511

Earthquake and Wave Design Criteria for Offshore Platforms

A method that applies experience, projections of environmental conditions, response analyses, and reliability logic is used to develop earthquake and wave design criteria for one class of offshore platform system. The system consists of a steel, tubular-membered, template-type superstructure supported on piles and firm soils, in 300 ft of water. Three fictitious sites are considered: Eastern Gulf of Alaska, Southern California, and the Santa Barbara Channel. Ranges of design wave heights and ground motion velocities are given. Results are compared with those appropriate for a conventional building structure and with those from API RP 2A guidelines for fixed offshore platforms. Good agreement with API guidelines is indicated.