Improving Real-Time Drilling Optimization Applying Engineering Performance From Offset Wells

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“SPWLA 53 Annual Logging Symposium, June 16-20, 2012”.

IMPROVING REAL-TIME DRILLING OPTIMIZATION APPLYING ENGINEERING PERFORMANCE FROM OFFSET WELLS. Autor(s): Rafael Bermúdez Martínez, Petrolink Services Inc. Concepción Isidro Olán, Petrolink Services Inc. Copyright 2012, held jointly by the Society of Petrophysicists and Well Log Analysts (SPWLA) and the submitting authors. This paper was prepared for presentation at the SPWLA 53rd Annual Logging Symposium held in Cartagena, Colombia, June 16-20, 2012. Ref.: Ms. No. SPWLA-D-11-00175

Abstract In the Oil and Gas industry, real-time mud logging measurements have been used since the early 70's with a wide range of applications. The advancement in mud logging measurements is focused on optimizing drilling operations. To reach this goal the historical data of the correlation wells represents a valuable source of information, allowing decrease the uncertainty associated to well planning and execution that can be maximized under technical and managerial circumstances. This paper reports the experiences of real-time advanced logging information integration from the well in progress with the historical data of the correlation wells and how this allowed taking preventive decisions to optimize the density window range more accurately, to evaluate operational parameters and to use the best technologies according to the mode`led best practices, to evaluate trends. All this is in order to issue alerts, recommendations, proposal, and mitigations procedures before and during the drilling operations to allow the decision-makers to reduce the NPT and the possible negative HSE impact. The process involves emerging technologies enabling to collect and interoperate data collected by different operators in a transparent way into a knowledge repository that integrates real-time information and offset correlation wells, to analyze and compare the data to the models, to issue alerts and to provide standardized visualization modules in a collaborative environment allowing the decision-makers to reach their goals.

1.-Introduction Surface and down hole data logged from offset wells have always proven vital to optimize the efficiency and success of the current well being drilled. New technological advancements in well logging have permitted better logging correlations and solutions for drilling issues such as casing points, partial and totally lost circulation, wellbore stability and stratigraphic correlations to mention a few. The operative risk of drilling operations becomes significantly higher if there is a retard in well analysis due to infrequent correlation processes. To solve this problem, which was first observed in a Real Time Operation Center (RTOC), the need arose to make a streamlined and better integrated well analysis that would allow preventive measure to be taken in real time by considering the events from the offset wells, Pore Pressure and Fracture Gradient. 1

“SPWLA 53rd Annual Logging Symposium, June 16-20, 2012”.

2.- Real Time Operation Center (Definition) The Real Time Operations Center is site where specialists and experts from various facets of drilling interact to monitor drilling operations in real time round the clock throughout the year. The primary objective of the monitoring services is to take prevention actions for potential problems that can arise which if left ignored could not only be hazardous to drilling operations but also be very expensive.

Figure # 1: Real Time Operation Services Data Work Flow.

Real Time Operation Center Objectives:  The principal objective of the real time operation center is to avoid the operational drilling

problems with the detection of variations into the drilling parameters supported with deliverables and preventive technical analysis to allow decision making to avoid nonproductive time (NPT) on the rig.  Provide high quality service in the process of receiving, handling and data transmission d for consistent alerts to enable timely decisions.

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 Provide operational reliability to our customers applying the Methodology for the Real

Time Operation Centers.  Take timely decision analyzed and supported with real time information between design and operation.  Visualize and reduce operator’s risk. The technologies used for data process in under the WITSML protocol generating the following advantages: •

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Data collection well is available in office in any format: WITS0, WITSML, LAS, XML, XLS, ASCII, and conversion to standard WITSML. Data collection from any source such as: sensors, acquisition units and servers are available. Display all surface and bottom parameters in real time such as: (LWD/MWD/PWD), geophysical log, records of oil, cement and production. Centralized and standard data storage with back up scheme. Real-time data integration and stored in the repository with others engineering applications to analyze pore pressure, petrophysical evaluation and directional paths.

3.- VCDSE Methodology. VCDSE Methodology is an integration process in several stages: Visualization - Concept Definition - Monitoring - Evaluation which analyze the technical requirements, alternatives, risks and uncertainties that allow selecting the best option for the well including technical details and cost effectiveness to prevent future changes in the later stages. In the plan and design of the phases prior to drilling the well, the following stages apply: Visualization, Conceptualization and Definition to generate the Drilling Program which will consider the attributes of the field, reservoir and drilling issues, in addition it will consider the risk of the offset wells during different phases of the Drilling and Completion process, to reach the mechanical and geological objectives established in the plan. The drilling starts the active Monitoring and Evaluation phases to control and adjust the changes when they occur with the Drilling Engineering planned vs. actual on the well. The most common variations found are: uncertainty in the operating windows (pore pressure gradients and fracture), peaks of high pressure zones ZAP, saline intrusions, domes clays (lithology column changes), demonstrations in gas zones among others. It is necessary to perform a " Real-Time Reengineering Drilling Process" to adjust the design with new geological, mechanical and operating conditions on the well. The Real-Time Reengineering Drilling Methodology allows integrate, review and analyze the: Well correlation Problems in the offset well. Densities range analysis Drilling Mechanic Analysis Oil logging evaluation ROP (rate of penetration) 3


D x C Exponent Geopressure analysis Casing design evaluation Hydraulic & Torque and Drag Directional analysis (2D & 3D) These analyses in real time have as an objective generate technical proposals to avoid unplanned events during the drilling process.

Figure # 2: Work Flow applying VCDSE Methodology. 4.- Well Preventive Analysis. A preventive reengineering design is established for each phase which will be drilling in the future, the analysis of the events occurred on the offset well such as: resistances and torque, frictions, partial and total lost circulation, drilling gas kicks, bha perform, casing analysis, operational windows among others. All these analyses allow a drilling specialist to get a speedy and full view of the drilling events occurred on the offset wells to start the analysis with the proper criteria from the lesson learned on the offset wells.

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5.- Traffic Light Methodology Applied on the Well: The traffic light methodology was established as a mechanism to determine the well condition during the phases of drilling and rehabilitation process. It is considered as a fundamental basis for the Drilling Program. However, there are several conditions that are considered potential hazards in stages of the drilling process when the event occurs. During a critical moment, if a well goes into a phase of Alert, it receives preferential treatment by taking the necessary steps required to restore the original condition. The language of colors to denote the state established a well in normal condition is Green; to alert condition is yellow; and a critical condition is red. The following graph shows the definitions of each state.

The well is classified as Normal when the operative conditions and time are inside the range and according to the plan.

The well is classified as Alert condition when the operative conditions and time aren’t inside the range and according to the plan. For example: Lost circulation, High Torque and Drag, ROP kick.

The well is classified as Critical when happen operative conditions which change the Original Drilling Program of the well and it is necessary

Figure # 3: Well Status Classification.

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5.1.- Advantages of apply the Traffic light process in Real-Time. This process begins with the evaluation and analysis of the Drilling Program for each phase of the well being drilled to identify the most important variables to be consider during the drilling monitoring stages such as: Surface drilling parameters (GPM, PSB, Torque, RPM, Density, fluid properties, Vp, Yp, L3, L6) and down hole parameters such as: (MWD, PWD, LWD) among others. As soon as the well is operational, the drilling performance analysis in real time will evaluate if they are fulfilling the drilling operational conditions established in the Drilling Program for this stage. In they are, it is necessary to verify if these new conditions affect the Drilling Performance on the Well or not while disregarding: * High Torque & Drag. * Abnormal Drill String Vibration.(Axial, Torsional, Lateral o Eccentered) * Inefficient hole cleaning. * Partial lost circulation. In the case that even full compliance with the drilling program produces erratic behavior, there is a procedure to place the well in Alert Condition and take all possible actions to bring back the well into the normal condition. To do this it is necessary evaluate all these technical variables such as: • • • • •

Drilling Operation Condition (Surface and Down hole) Hydraulic & Torque and Drag Analysis Directional Evaluation Bit record analysis, BHA and Drill String Wellbore Stability

If the well continues to be in the alerted condition and an improvement with the actions taken are appropriate to evaluate the condition of the well bore stability in order to verify whether these irregular conditions can severely affect the well performance. For example: partial loss circulation, fluctuating torque, kicks among others. If the answer is yes, they must stop drilling and pull out the BHA at the first shoe above of the current depth to ensure the well and then make the technical analysis of the actual problem of the well. In many cases the problem may also depend on the formation pressures condition, real stratigraphic and/or unknown events from the offset wells, in that sense is necessary log the well to make an integral analysis involving correlations, matrix risk analysis with the purpose to make a proposal which include all options to continue drilling the well overcoming the problem. In this stage is where the Drilling Specialist who works into the Real Time Operation Center (RTOC) plays an important role, making the best and integrate analysis (Technical & Operational), geological and correlation as possible to determine the most important reason that could cause the problem on the well in order to propose the best technical option to achieve more benefit for the well at this time. 6


In the case that an irregular condition puts the well in high risk, is necessary place the well to Critical condition because, it will required severe actions to get back the well to normal condition to reach the mechanical and geological objective on the well. Some actions taken in these cases are: • • •

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Side track, Windows. Optimize casing point Adjust density window range according Pore pressure (Pp) and Fracture gradient (Gf) in Real-Time. Technical review and analysis regarding operatives options including time and risk. Geopressure analysis, evaluating changes in the normal compaction trend changes (NCT) in comparison with the offset well (NCT)

Figure # 4: Well Status using Traffic lights Conditions.

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5.2.- Values of Integrated Geopressure (Pp) & (Fg) in the Real Time Process. The success of geopressures integration in real time using data from the downhole tools was based on the strategy of standardization and accesibility of the drilling data generated and stored in real time, applying the WITSML standard (Wellsite Information Transfer Standard Markup Language). This standardization of data in WITSML allow companies get more advantage with this information sharing with Drilling Softwares and automatic calculations in Real Time to obtain Engineering result in preventive manner. Based on the data value, we implemented a procedure with low cost, efficiency and stabilitye to feed the geopressures analysis using data collected in the well. This method allows estimating geopressures in real time along the interest zones to evaluate the wellbore stability condition. Evaluate trends to make the best decision in relation to settlements casing, evaluating loss circulation zones, determine the increase or decrease the mud density and update geopressures cub of the area are few of the most important benefits of this method.

5.3.- Smart System Alarm. The integrated warning system allows evaluating the current condition of the well 500 feet prior with respect to the correlation wells. This provides for measures to avoid the risk status alerted by the system. The drilling events occurred in the offset wells will generate an alert of well correlation as a warning message to conduct a comprehensive analysis and evaluation regarding: • •

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Offset well density “in the well where the event happened” vs. actual density Comportamiento de la Resistividad, Pp y FG del pozo de correlación vs el pozo actual. Behavior of the resistivity, Pore pressure (Pp), Fracture Gradient (Fg) from the correlation well vs. current well condition. Logging trend analysis (GR-Resistivity) Normal compaction trend analysis (NCT)

This preliminary review can detect the condition of the well compared to the event in the correlation well to evaluate the potential risk of occurrence and take preventive measures.

6. - Real Time Drilling Optimization Method. New drilling technologies worldwide have been made it possible to take logging information during the drilling using down hole tools as LWD (Logging While Drilling), making easier to acquire data such as: resistivity, porosity, permeability, density while drilling. This technology allows take re-engineering analysis in real-time based on the actual conditions of the well. The consequence of omitting the calculation of geopressures in real-time will impact the drilling performance of the well generating high probability of the following events: • • • •

Wellbore Stability Lost circulation Stuck Pipe. Kicks Gas. 8

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6.1. - Real Time Drilling Optimization System. The log correlation and prediction plot calculates Pore Pressure (Pp) and Fracture gradient (Fg) in Real-Time using Normal Compaction Trend (NCT) from the offset wells and the down hole parameters such as Gamma Ray and Resistivity. It is also capable of plotting the shale line when Gamma Ray and Resistivity are being received. Additionally, the system can generate alarms to indicate previous drilling events such as: lost circulation, stuck pipe, kicks, high torque and resistances up to 500 ft (tvd) above of depth in the actual well in comparison where these events occurred on the offset well. This methodology uses the WITSML language to generate and compare in Real Time the Pore Pressure (Pp), Fracture gradient (Fg) from the current well taking Normal Compaction Trend tendency from the Offset Wells best matching with the actual well and the system use some official equations to calculate (Pp) and (Fg) written by Eaton, Matthew and Kelly. Although a mechanism was created to draw the shale line when the GR and Resistivity are coming in Real Time, the system need compare the current (Pp) and (Fg) tendency from the actual well with the Offset Wells to determine if exist difference in the compaction process between actual and Offset Wells and evaluate the actual density in from of the current (Pp) and (Fg). This information has allowed to calculate (Pp) and (Fg) in Real-time; however, the most important feature of this method is based on the events from the Offset wells in TVD (True Vertical Depth). This functionality prevents drilling problems from Offset Wells, and at the same time aides in making better decisions making regarding technical matters such as: mud density (increasing or decreasing), casing Point predictions, stop drilling, and others important decisions to prevent drilling events.

6.2. – System Functionalities.  (Pp) and (Fg) calculation using the NCT (Normal compaction trend) from Offset

Wells.  Calculates and plots the Shale line when receiving Gamma Ray and Resistivity in

Real Time.  Features with a Smart System Alarms (SSA) which can generate an alarm to indicate previous Drilling Events from the offset Wells.

6.3.- Advantages of the System.  Optimizes the density window range according the (Pp) and (Fg) in real-time. 

Issues alerts, recommendations and proposals to reduce the Non-Productive Time (NPT).  Compares (Pp) and (Fg) trends in Real Time for multiple wells.  Facilitates informed decision making because of the smart system alarm (SSA)  All data is processing in WITSML.

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Figure # 5: Real-time Drilling Optimization Plot.

6.4.- Calculation Engine Method. The Calculation Engine is an application that uses C # programming language to create algorithms to perform calculations. All functions, methods, whole language cycles are available for the user, with the exception of all the functionality of the GUI (Graphical User Interface). To use this tool you must have development skills. This system receives all data from the WITSML repository to apply the algorithm created, then selected the curve value and as result of the calculation process get the WITSML object. By default this system uses as an input all WITSML information from the repository for each update WITSML object in real time, then the system will be connect to the WITSML server and get back to the last data (value), for each request the system will make a review from the last data to be processed and updated the object before produce the new data. During this process the system will sift through all files of data and will update each data inside the WITSML object. 10

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6.5.- Advantages of the C# Language to apply the calculation method.

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It doesn’t work with raw data such as WITS. It doesn’t work with static data as (.las) files. Allows connecting with any WITSML repository and working with this data. This language can work with Data in time and depth. The algorithms used for data in time and depth always are not equal. Allows creation of many types of WITSML object such as: Log Object – Trajectory Object – Mud log Object. Allows interpolation to make reference with the information available and it is in use with other specific algorithm. Provide two different interfaces for development codes, one interface for user who doesn’t know how the system works and another advance interface for expert users. The data is generating in the well during drilling operations and then the process start with the LWD data is coming in Real Time. The data is taken from WITSO from the server of LWD record then this information travel through the collect server and the conversion process start from WITSO to WITSML. The information from the conversion travel to the network via satellite. All these information are received and saved into the WITSML repository.

In this point start the process of take the data from the Offset Wells to make correlations and further technical analysis. To do this the System takes the information from the offset wells such as: Resistivity Gamma Ray Offset well over burden Normal compaction trend (NCT) Then, with all this information displayed, the Drilling Specialist begins the analysis of the data tendency and many other technical relates thing regarding drilling engineering. The results of these analyses ensure the data from the offset well is taken at the beginning of the Visualization process in real-time with LWD information following this procedure: a. The system displays the well data correlation and the values of (Pp, Gf, NCT, Events etc...) also within the same display shows the data received in real-time from the actual well such as: LWD (GR – Resistivity). b. The system takes the data from the offset well such as: NCT and GR. c. Once you have gamma ray (GR) data and based on the technical analysis of drilling Specialist determines the points of shale along the GR in Real 11


d.

e. f. g. h.

time, likewise determining trends and resistivity values used during the calculation process of geo-pressure (Pp) and (Fg). The data selected by the system for this analysis is taken and processed with a method called "Shrink Boxcar ", the result to apply this method in real-time data is processed Pore pressure (Pp) and fracture gradient (Fg) using two different methods developed by Eaton, Matthews and Kelly. The results are generated immediately after the calculations applications and then the system placed these values inside the WITSML repository. The Real-time visualization shows the analysis result and allows update the trends according drilling advance. The decision making process start in preventive manner according (Pp) and (Fg) in Real-Time. Successful results have been obtained with the implementation of drilling engineering knowledge and technical analysis in real time.

6.6.- Information work flow for the (Pp) and (Fg) calculation in real time

Figure # 6: Technical Workflow to generate (Pp) and (Fg).

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Figure # 7: Work flow inside WITSML platform.

7.- Conclusions The result of the engineering process is to generate values of pore pressure (Pp) and fracture gradient (Fg) in real time is supported by the information from correlation wells allow us creates many new opportunities to achieve the Real Optimization along the Drilling and turn considerable economic savings. This methodology permits successfully and preventively manner such as: fluid density analysis, analyze the tendency of GR / RES and Normal Compaction Trend (NCT) to optimize casing set points along the well path beside other things. Finally, the inclusion of the smart system alarm (SSA) in conjunction with the real time information allows optimizes geopressure preventive actions to achieve more success into the well operations.

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8. – Acknowledgements. I would like to thank my family and all of the Petrolink Services Staff for making this effort possible, especially to Concepción Isidro, Pablo Pérez, Samuel Perez and Lee Geiser, because I received full support from them in this project from the beginning. 9. – References Section:  Pérez-Téllez Carlos, Rodríguez Reginaldo, Ramírez Ignacio, Bermúdez-Martínez

Rafael Angel, Palavicini-Cham Carlos 2012. “Applying a Real-Time Engineering Methodology to Drill Ahead of Potential Undesirable Events”. OTC-23180-PP.  Pérez Téllez Carlos, Ríos J.A., Hinojosa Javier, 2010. “Methodology applied in the

tracing and decision-making during real-time drilling operations and well maintenance”. Reference number: RE-PP-TC-0001-2010.  M.M. Khudiri, M A Shehr, Saudi Aramco, J D Curtis, Petrolink, 2008. “Data

Architecture of Real-Time Drilling and Completions Information at Saudi Aramco”. Paper SPE 116848 presented at the 2008 SPE Russian Oil & Gas Technical Conference and Exhibition, Moscow, Russia, October 28-30, 2008.

10.- About the Authors: Rafael Bermudez Martinez. Eleven years (11) experience working in Oil & Gas industry along various positions such as Drilling Project Engineer, Drilling Design Engineer working on Vertical, Deviated and Horizontal wells with High Pressure and High Temperature (HP-HT), taking part into the Drilling Programs, Drilling Tools selection, Drilling Fluids, Logging Open and Case hole, Cementing and Completion operations. The most relevant experience has been 8 years as a Leader of the Drilling Projects in Venezuela with PDVSA, and then in SAUDI ARAMCO Onshore Drilling Deparment as a Senior Drilling Engineer for onshore fields. In 2010 started working with Petrolink Services Inc as a Drilling Specialist working with PEMEX South Region and recently in 2012 I started working in United States as a Drilling Performance Manager to optimize all technical Issues in Real Time worldwide.

Concepción Isidro Olan. Technical Petrovault Specialist / console and WITSML, main role is the evaluation and analysis systems for the oil industry, Facilities and server configurations for real time, real-time support for México operations team, including main achievements are: work in Jakarta Indonesia with the computer interface as a systems analyst, specialist engineer for connectivity and data.

11.- Vocabulary. 

VCDSE: Visualization, Conceptualization, Definition, Monitoring (during execution) and Evaluation Methodology applied in the design, construction and project evaluation well. 14

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WITS: Specification of Wireless Information Transfer in the Well. Standard protocol of the oil industry (API) used to send and exchange information on the operations performed in the wells.

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WITSML: Standard language for information transfer in the Well (Wellsite Information Transfer from English Standard Mark-up Language) is a standard for the transmission of technical data between organizations in the oil industry. It is based on XML standards for exchange of technical data. WITSML is targeted at the oil companies, service companies, drilling contractor s, application vendors and regulatory agencies.

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LWD: is a technique of conveying well logging tools into the well borehole down hole as part of the bottom hole assembly (BHA). LWD tools work with its Measurement While Drilling (MWD) system to transmit partial or complete measurement results to the surface via typically a drilling mud pulser or other improved techniques, while LWD tools are still in the borehole, which is called "Real Time Data". Complete measurement results can be downloaded from LWD tools after they are pulled out of hole, which is called "Memory Data". LWD technology was developed originally as an enhancement to the earlier MWD technology to completely or partially replace wire line logging operation. With the improvement of the technology in the past decades, LWD is now widely used for drilling (including geosteering), formation evaluation (especially for real time and high angle wells).

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PWD: Pressure while drilling (PWD) data, for instance, is used in a subjective manner and interpretation depends a lot on the operator philosophy. The correct interpretation of PWD data is a powerful tool to identify and avoid problems, reducing operational risks, time and costs, especially in deep and ultra-deep waters.

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MWD: refers to a technique of making down hole measurements of borehole position, tool face orientation, formation parameters and drilling information using sensors located in the bottom hole assembly adjacent to the drill bit. These measurements are made during drilling and can be recorded down hole and/or transmitted to surface.

List of Figures:  Figure # 1: Real Time Operation Services Data Work Flow…………….. Page (2)  Figure # 2: Work Flow applying VCDSE Methodology.………………...Page (4)  Figure # 3: Well Status Classification…………………………………….Page (5)  Figure # 4: Well Status using the Traffic lights Conditions………………Page (7)  Figure # 5: Real-time Drilling Optimization Plot…………………………Page (10)  Figure # 6: Technical Workflow to generate (Pp) and (Fg)…….…………Page (12) 

Figure # 7: Work flow inside WITSML platform…………………………Page (13)

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Improving Real-Time Drilling Optimization Applying Engineering Performance From Offset Wells

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