International Journal of Scientific & Engineering Research Volume 10, Issue 3, March-2019 1228 ISSN 2229-5518 The Effect of Temperature on Rheological Properties of Cement Slurry Nmegbu C.G.J1, Dagde Kenneth2, Amua Uchechukwu Roseline3 1 Department of Petroleum Engineering, Rivers State University, Port Harcourt. 2 Department of Chemical/ Petrochemical Engineering, Rivers State Universiy, Port Harcourt. 3 Department of Petroleum Engineering, Rivers State University, Port Harcourt. Abstract—This experimental work reveals the effect of temperature on cement slurry rheological properties. Understanding cement slurry rheology is of critical importance for the design, execution and evaluation of oil or gas well cementing operations. The rheolo- gy depends on many factors which includes temperature. Temperature variations in oil and gas wells cause instability of rheological properties of cement slurries during cementing operations. The properties of the cement slurry investigated were plastic viscosity, yield point, gel strength, fluid loss and thickening time. In this research, 345.21ml of fresh water, 1g of Ensta antifoam, 0.5g of disper- sant, 3g of Hydroxyl-Ethyl Cellulose (HEC), 0.1 gal/sk retarder concentration and 773.69g of cement were used to formulate the ce- ment slurry. The behavior of the rheological properties was investigated at temperature range of 80ºF – 190ºF.Polynomial regression analysis was employed to study the behavior of rheological properties at different temperatures. An application (RP Predictor) was created with Visual Basic.NET and used to carry out theoretical analysis on the rheological properties of the cement. The results ob- tained showed that as the temperature increased from 80ºF – 190ºF, the rheological properties investigated decreased:plastic viscosi- tyfrom 105 – 90 (cp), yield point from 129 – 89 ((Ib/100ft2), gel strength from 70 – 21 ((Ib/100ft2), and fluid loss from 76 – 72 (ml/30min). However, the thickening time of the cement slurry increased from 2:50 – 19:58 (hr:min) with a rise in temperature con- firming that adequate thickening time was required for a good cementing job. Also, the predictive models and application developed showed good prospects in predicting the behaviour of rheological properties at any given temperature. Index Terms—Cementing,Cement Slurry, Neat Cement, Enhanced Cement,Rheological Properties, Temperature, Rheological Properties Predictor (RP Predictor), Graphic User Interface (GUI), Regression Analysis. ———————————————————— 1.0 INTRODUCTION IJSER Cementing is a necessary aspect of the drilling oil powder (shape and size of the grains of cement), process. Cementing in drilling engineering involves chemical makeup of the cement, additives, the rela- mixing cement, cement additives, and water (either tive distribution of the components at the surface of fresh or salt) to obtain cement slurry based on de- the grains, mixing and testing procedures. signs. This is then pumped down-hole through the The Temperature effect on the rheological properties pipe to extremely important points in the space of the rheological properties of cement slurries is not around the pipes or in the open hole below the cas- well understood at very high temperatures because ing string. the standard oilfield equipment allows measure- Rudimentary cementing of oil wells began as far ments to be performed at temperatures below 80˚C. back as the turn of the 19th century when few wells Minimal experimental studies at higher tempera- went deeper than 610 metres. Cementing operations tures insinuate the stability of cement slurry which is were usually done by the rig crew. Today, specialist already a concern below 80˚C, is even more prob- service companies routinely cement wells of 6,098 lematic at higher temperatures (Nelson and Guillot, metres and deeper. Cementing operations are either 1990). primary (done in the course of drilling a well) or Significant numbers of research work have been car- secondary/remedial (intended to correct deficiencies ried out in cement technology to comprehend ce- in primary cementing or alter the well completion ment properties to increase the effectiveness of oil for production) (Michaux et al., 1990). well production. Rheology is concerned with the study of the defor- Shahriar (2011), investigated the rheology of oil well mation of fluids and flow of matter. Understanding cement (OWC). The basic processes of the effects of the rheology of cement slurry is of great importance additives on well cement the rheology were studied for the planning, execution and assessment of oil or at various temperatures in the range of 23 to 60 gas well cementing operations. The rheology de- making use of an advanced shear-stress/shear-strain pends on several factors including temperature, wa- controlled rheometer. From the study was found℃ ter-to-cement ratio, specific surface of the cement that, the well cement rheological properties largely IJSER © 2019 http://www.ijser.org International Journal of Scientific & Engineering Research Volume 10, Issue 3, March-2019 1229 ISSN 2229-5518 rely on temperature, cement/water ratio, and addi- This work covers the investigation on the effect of tives present. Combined effects of additives and temperature on rheological properties (plastic vis- temperature caused a significant effect on the slur- cosity, yield stress, gel strength, fluid loss and thick- ries rheological properties. The results showed that ening time) of cement slurry; development of predic- present data for chemical additives need be authen- tive model showing the relationship between rheo- ticated for cementing oil well; additives that demon- logical properties of cement slurry and temperature; strated effectiveness in at moderate temperature in and creating an application for future prediction of conventional cementing, may prove inefficient at the effect of temperature on rheological properties of large temperature in cementing of oil well. cement slurry. Shahriar and Nehdi (2013), developed an artificial intelligence model for rheological properties of oil well cement slurries. Supplementary cementitious materials (SCM) such as fly ash, rice husk ash, silica 2.0 MATERIALS AND METHODS fume, and metakaolin were incorporated. Experi- The experimental materials and apparatus used for ment was carried out to create the database used for this work consists of the following: Hamilton Beach training the model. The rheological properties of the Mixer, Hamilton Beach Mixer Cup, Rheometer, Rhe- slurries were carried out at of 23 to 60ºC temperature ometer cup, Atmospheric Consistometer, Consis- range using an advanced shear-stress/shear-strain tometer, Electronic Balance, API Filter Press, HPHT controlled rheometer. The data got experimentally Filtter Press, Water, Cement and additives. were used to create a predictive model based on feed-forward back-propagation artificial neural net- 2.1 Cement Slurry Formulation works. The results obtained showed that the devel- 345.21 ml of water was added into an hamilton beach oped model effectively predict the effect of key vari- mixer cup and allowed to stir for a minute. Ensta ables such as temperature and amount of SCM on antifoam (1 gram) was added and allowed to stir for OWC rheological properties with an absolute error 5 mins. At 5 minutes Interval, dispersant and HEC of of less than 7%. 0.5 gram and 3grams was added to the mixture John (2017), investigated the effect of temperature on respectively. After the elapsed of 5 mins, the cement cement slurry using fluid loss additives. The study was added at 2 mins for low, 3 mins for high and was to ascertain the effect of temperature on cement 5mins for higher speeds. slurry using various fluid control additives (Starch, The cement slurry was ready for analysis. XC-Polymer, PAC-R, and CMC). The filtration prop- Mudweight was taken and transferred to a erties (mud weight, filtrate volume, and cake thick- consistometer for different temperatures regulations ness) of the cement slurry were analyzed at 82 to at 120 ºF, 150 ºF and 190 ºF while 80 ºF was taken 176 temperature rangeIJSER with 10g to 30g of various without a consistometer at room temperature. After fluid loss control additives concentration. The study℉ each regulations, the slurry was transferred to the found℉ that cement slurry responded differently to rheometer were rheological readings were taken and various fluid loss control additives at various tem- recorded. peratures, and an increase in temperature caused a decrease in the filtrate volume. The results indicated 2.2 Rheological Properties Determination that neat cement slurry had a higher fluid loss rate as i. About 150ml of the cement slurry was transferred compared with cement mixed with additive slurry. into the rheometer cup and stirred for 10 seconds Also, for all temperatures tested, PAC-R showed the and heated to a working temperature (80 ). most ability to reduce fluid loss when used as an ii. The motor was started by placing the switch in a additive as compared to others. high-speed position. Readings were taken at Umekafor and Joel (2010), presented modeling of 300RPM. The gear of the motor was changed while cement thickening time at high temperatures with the motor was running to try for other speeds ( 200, different retarder concentrations. 36 thickening time 100, 60, 30, 6, and 3 RPM). tests were conducted for a 5 inches high temperature iii. Step 2 was repeated at 120 , 150 , and 190 . liner cementing jobs done at 230 to 284 temper- iv. Readings were taken